Patent Application
20230414583
The present invention relates to both the substance definition and synthesis of lysergic acid derivatives with modified LSD-like action to be used in substance-assisted psychotherapy.
Psychedelics are substances inducing unique subjective effects including dream-like alterations of consciousness, affective changes, enhanced introspective abilities, visual imagery, pseudo-hallucinations, synesthesia, mystical-type experiences, disembodiment, and ego-dissolution (Liechti, 2017; Passie, Halpern, Stichtenoth, Emrich, & Hintzen, 2008).
Psychedelics, mainly lysergic acid diethylamide (LSD) and psilocybin, are currently investigated as potential medications. First clinical trials indicate potential efficacy of LSD and psilocybin in addiction (Bogenschutz, 2013; Bogenschutz et al., 2015; Garcia-Romeu et al., 2019; Garcia-Romeu, Griffiths, & Johnson, 2014; Johnson, Garcia-Romeu, Cosimano, & Griffiths, 2014; Johnson, Garcia-Romeu, & Griffiths, 2016; Krebs & Johansen, 2012), anxiety associated with life-threatening illness (Gasser et al., 2014; Gasser, Kirchner, & Passie, 2015), depression (R. Carhart-Harris et al., 2021; R. L. Carhart-Harris, Bolstridge, et al., 2016; Davis et al., 2021; R. R. Griffiths et al., 2016; Roseman, Nutt, & Carhart-Harris, 2017; Ross et al., 2016), and anxiety (R. R. Griffiths et al., 2016; Grob et al., 2011; Ross et al., 2016). Several trials investigating therapeutic effects of LSD, psilocybin and other psychedelics are also ongoing. There is also evidence that the psychedelic brew Ayahuasca which contains the active psychedelic substance N,N-dimethyltryptamine (DMT) (Dominguez-Clave et al., 2016) may alleviate depression (Dos Santos et al., 2016; Palhano-Fontes et al., 2019; Sanches et al., 2016). In contrast, there are no comparable therapeutic studies or elaborated concepts on the use of psychedelic lysergic acid derivatives other than LSD to treat medical conditions.
Although no psychedelic is currently licensed for medical use, psilocybin and LSD are already used in special therapeutic-use programs (Schmid, Gasser, Oehen, & Liechti, 2021). LSD is a serotonergic psychedelic similar to psilocybin with comparable acute effects, although with significant longer duration of action (8-12 hours for LSD compared with 6 hours for psilocybin) (Becker et al., 2022; Holze et al., 2022; Holze, Vizeli, et al., 2021).
A potentially important disadvantage of LSD is its long duration of acute action resulting in the need for long days of supervising patients and related costs. On the other hand, LSD has advantages over psilocybin and other shorter-acting substances. In particular, there is a long history of use of LSD (Nichols, 2016) and substantial information on its safety pharmacology (Holze, Caluori, Vizeli, & Liechti, 2021; Nichols & Grob, 2018). The pharmacology of LSD is well studied (Holze, Caluori, et al., 2021; Holze et al., 2019; Holze, Vizeli, et al., 2021; Holze et al., 2020; Nichols, 2018b; Vizeli et al., 2021) and LSD is also among the most potent known psychedelic in vivo resulting in the need of only very low doses to produce the desired effect (Luethi & Liechti, 2018). Accordingly, it would be desirable to design an LSD analog with similar pharmacological properties in terms of potency, efficacy, and safety to LSD and with a similar or preferably different and faster metabolism and thus shorter duration of action than classic LSD. Novel lysergic acid derivatives can be equally suitable or superior to treat medical conditions. Specifically, existing psychedelic treatments such as LSD, psilocybin and DMT may not be suitable to be used in every patient considered for psychedelic-assisted therapy. Generally, the availability of several substances with different properties is important and the present lack thereof is a therapeutic problem which will further increase with more patients needing psychedelic-assisted therapy and an increase in demand for such treatment once the efficacy of first treatments is documented in large clinical studies. For example, some patients may react with strong adverse responses to existing therapies such as psilocybin presenting with untoward effects including headaches, nausea/vomiting, anxiety, cardiovascular stimulation, or marked dysphoria (Davis et al., 2021; R. R. Griffiths et al., 2016; Holze et al., 2022; Ross et al., 2016). On the other hand, the long duration of action of LSD may, in some cases, be a limited factor and the increased therapeutic session time may significantly contribute to the medical treatment costs. Further on, such long therapy sessions need tedious planning. Thus, novel compounds with psychedelic-like action are needed.
Structurally, LSD is an ergoline derivative, unlike psilocybin. Although they share some structural features such as the tryptamine core, the main pharmacophore of LSD remains significantly different to psychedelic tryptamines such as psilocybin and DMT, and their binding modes and overall pharmacological profiles are different (Cao et al., 2022; Rickli, Moning, Hoener, & Liechti, 2016; Wacker et al., 2017). Psychedelics from the ergoline, tryptamine and phenethylamine classes are all thought to induce their acute psychedelic effects primarily via their common stimulation of the 5-HT2A receptor. All serotonergic psychedelics including LSD, psilocybin, DMT, and mescaline are agonists at the 5-HT2A receptor (Rickli et al., 2016) and may therefore produce overall largely similar effects. However, there are differences in how the substances interact with the 5-HT2A receptor at the binding site and some compounds even bind to the receptor but do not produce subjective effects (Cao et al., 2022). Additionally, there are differences in the receptor activation profiles and in the subsequent signal transduction pathway activation patterns between the substances that may induce different subjective effects. Furthermore, LSD potently stimulates the 5-HT2A receptor but also 5-HT2B/C, 5-HT1 and D1-3 receptors (Rickli et al., 2016). Psilocin, i.e., the active metabolite present in the human body derived from the prodrug psilocybin, also stimulates the 5-HT2A receptor but additionally inhibits the 5-HT transporter (SERT) (Rickli et al., 2016). Mescaline binds in a similar, rather low concentration range to 5-HT2A, 5-HT2C, 5-HT1A and α2A receptors. In contrast to LSD, psilocybin and mescaline show no affinity for D2 receptors (Rickli et al., 2016). Taken together, LSD can have greater dopaminergic activity than psilocybin and mescaline, psilocybin can have additional action at the SERT. Mescaline and its derivatives do not interact with the SERT in contrast to psilocybin. Taken together, the pharmacological profiles of psychedelics may be different at the 5-HT2A receptor but clearly also regarding additional effects at other receptors which can then translate into different and even unique effect profiles for each substance.
In humans, subjective effects of psychoactive doses of LSD appear within 15-60 minutes, peak at 2-4 hours and dose-dependently last 8-12 hours. The plasma half-life is approximately 4 hours (Holze et al., 2019; Holze et al., 2022; Holze, Vizeli, et al., 2021). The long duration of action of LSD reflects the presence of LSD in plasma and is thus linked to the concentration-time curve in a specific subject and the plasma half-life (Holze et al., 2019). The same is true for psilocybin, where the presence of the active metabolite psilocin in its unconjugated form in plasma defines the duration of action of psilocybin in humans. The plasma half-life of unconjugated psilocin is on average 2 hours (Becker et al., 2022), consistent with the shorter duration of action of psilocybin compared with LSD. It can therefore be expected that a structurally related compound of LSD with a shorter plasma half-life would also have a similarly shorter duration of action.
The acute subjective effects of psychedelics are mostly positive in most humans (R. L. Carhart-Harris, Kaelen, et al., 2016; Dolder, Schmid, Mueller, Borgwardt, & Liechti, 2016; Dolder et al., 2017; Holze et al., 2019; Schmid et al., 2015). However, there are also negative subjective effects such as anxiety in many humans (Davis et al., 2021; R. R. Griffiths et al., 2016; Ross et al., 2016) likely depending on the dose used (Holze et al., 2022), personality traits (set), the setting (physical and social environment) and other factors (Studerus, Gamma, Kometer, & Vollenweider, 2012). The induction of an overall positive acute response to the psychedelic is critical because several studies showed that a more positive experience is predictive of a greater therapeutic long-term effect of the psychedelic (Garcia-Romeu et al., 2014; R. R. Griffiths et al., 2016; Ross et al., 2016). Even in healthy subjects, a more positive acute response to a psychedelic including LSD has been shown to be linked to more positive long-term effects on well-being (R. Griffiths, Richards, Johnson, McCann, & Jesse, 2008; Schmid & Liechti, 2018).
LSD has relevant acute side effects to different degrees depending on the subject treated and including increased blood pressure, nausea and vomiting, elevated body temperature and blood sugar, numbness, tremor, negative body sensations, and dysphoria (Holze, Caluori, et al., 2021). Such side effects of a substance are often linked to its interactions with pharmacological targets. For example, interactions with adrenergic receptors can result untoward clinical cardio-stimulant properties. Additionally, changes in the relative activation profile of serotonin 5-HT receptors and other targets change the quality of the psychoactive effects. Alterations in the binding potency, the binding mode, and the potency in activating the subsequent signaling pathways at 5-HT2A receptors as well as the molecule's lipophilicity can mostly determine the clinical dose to induce psychoactive effects. Alterations changing the metabolic stability of the compounds can also change the duration of action of the substance significantly.
New LSD-based derivatives, namely lysergic acid-based derivatives, are needed to provide substances with an improved effect profile such as, but not limited to, more positive effects, less adverse effects, different qualitative effects, and change of duration of acute effect.
The present invention provides for a composition of a compound represented generically by
As such, class 1 is a lysergic acid amide as represented in
The present invention provides for a composition of a compound represented generically by
The present invention provides for a composition of a compound represented generically by
The present invention provides for a composition of a compound represented generically by
The present invention provides for a composition of a compound represented generically by
The present invention provides for a method of changing neurotransmission, by administering a pharmaceutically effective amount of a compound of
The present invention provides for a method of treating an individual by administering a pharmaceutically effective amount of a compound of
Other advantages of the present invention are readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
The present invention provides for a composition of a compound represented generically by
As such, class 1 is a lysergic acid amide as represented in
The present invention also provides for a composition of a compound represented generically by
The present invention also provides for a composition of a compound represented generically by
The present invention also provides for a composition of a compound represented generically by
The present invention provides for a composition of a compound represented generically by
The compounds represented by
Any of the pharmaceutically acceptable salt can also contain one or more deuteron or fluorine atoms and any stereoisomers are included.
The general chemical terms used for
Those skilled in the art will appreciate that the compounds of the present invention have at least two chiral carbons, and may therefore exist as racemates, as individual enantiomers or diastereomers or epimers, and as mixtures of individual enantiomers or diastereomers or epimers in any ratio. Those skilled in the art will also appreciate that those compounds of the invention where R1, R6, R8 or R8′ in
Those skilled in the art will also appreciate that certain of the compounds of the present invention have at least one double bond leading, depending on the double-bond's substituents, to cis/trans or E/Z configurational isomerism. While it is a preferred embodiment of the invention that the compounds of the invention are used as pure configurational isomers, the present invention also contemplates the compounds of the invention existing in individual cis/trans or E/Z mixtures, respectively.
The individual enantiomers and diastereomers and epimers can be prepared by non-chiral or chiral chromatography of the racemic or enantiomeric or diastereomeric or epimeric mixtures of compounds represented by
The individual cis/trans or E/Z configurational isomers can be accessed by either selective synthesis or by separation techniques addressing the different physicochemical properties of the configurational isomers by applying techniques such as chromatography, crystallization, distillation, or extraction.
In patients that have adverse reactions to other psychedelics, lysergic acid derivatives can be useful as alternative treatments. In some patients, lysergic acid derivatives can also be useful because another experience than made with phenethylamines, psilocybin or LSD is necessary or because a patient is not suited for therapy with these existing approaches a priori. Thus, lysergic acid derivatives of
Based on structural relations, the compounds of
This assumption is further emphasized by the handful of known and psycho-pharmacologically-described lysergic acid derivatives, compounds such as the N6-modified compounds ETH-LAD, PRO-LAD, ALL-LAD, the amide-modified compounds DAM-57, LPD-824 or LSM-775, as well as the N1-derivatized compounds ALD-52, OML-632 and MLD-41 which have shown psychoactive effects in human (Abramson, 1959; A. Shulgin & Shulgin, 1991)
The present invention provides compounds of
Therefore, the present invention provides a method of changing neurotransmission, by administering a pharmaceutically effective amount of a compound of
The present invention also provides generally for a method of treating an individual, by administering a pharmaceutically effective amount of a compound of
The condition or disease being treated can include, but is not limited to, anxiety disorders (including anxiety in advanced stage illness e.g. cancer, as well as generalized anxiety disorder), depression (including postpartum depression, major depressive disorder and treatment-resistant depression), headache disorder (including cluster headaches and migraine headache), obsessive compulsive disorder (OCD), personality disorders (including conduct disorder), stress disorders (including adjustment disorders and post-traumatic stress disorder), drug disorders (including alcohol dependence or withdrawal, nicotine dependence or withdrawal, opioid dependence or withdrawal, cocaine dependence or withdrawal, methamphetamine dependence or withdrawal), other addictions (including gambling disorder, eating disorder, and body dysmorphic disorder), pain, neurodegenerative disorders (such as dementia, Alzheimer's Disease, Parkinson's Disease), autism spectrum disorder, eating disorders, or neurological disorders (such as stroke).
The neuronal interaction of compounds represented in
The intensity and quality of the psychoactive effect including psychedelic or empathogenic (also called entactogenic or MDMA-like) effects (Holze et al., 2020), the quality of perceptual alterations such as imagery, fantasy and closed or open eyes visuals, and body sensation changes, the pharmacologically active doses, the duration of action may be different or similar to that of LSD.
LSD and some of its modified derivatives are known to interact with serotonin 5-HT2A, 5-HT2C, 5-HT1A, as well as with dopamine receptors (Nichols, Frescas, Marona-Lewicka, & Kurrasch-Orbaugh, 2002; Rickli et al., 2016; Watts et al., 1995).
LSD and some of its modified derivatives are also known to substitute for LSD in a two-lever drug discrimination assay (Nichols et al., 2002).
Among the known lysergic acid derivatives with psychoactive properties there have been investigated mainly three structural regions of the original LSD molecule.
One structural feature investigated earlier is substitution of the N1 in the LSD molecule, leading to N-acyl (e.g., N-acetyl, N-propionyl, N-butyryl), N-alkyl (e.g., N-methyl) or N-methoxy substituted LSD derivatives (Abramson, 1959; Halberstadt et al., 2020).
Some of these substituents are prone to fast metabolism and it was found that the compounds behave as prodrugs and only after N1-deprotection the compounds are active at the target receptors and psychoactive.
The second structural feature of the original LSD molecule modified earlier to gain psychoactive compounds is the N6-substituent. As such, the N6-methyl group was replaced by alkyl, allyl, propargyl, phenethyl, branched alkyl, alkylcycloalkyl (Hoffman & Nichols, 1985; Huang, Marona-Lewicka, Pfaff, & Nichols, 1994; Nichols, 2018a; Nichols et al., 2002; Nichols, Monte, Huang, & Marona-Lewicka, 1996; Oberlender, Pfaff, Johnson, Huang, & Nichols, 1992; Pfaff, Huang, Marona-Lewicka, Oberlender, & Nichols, 1994; A. Shulgin & Shulgin, 1991) and WO2021019023A1, WO2021175816A1. A few of the compounds were investigated in human and were just touched upon being psychoactive, and only three such compounds were described, at least in anecdotal reports, to be psychedelic (A. Shulgin & Shulgin, 1991).
The third structural feature of the original LSD molecule modified—or, mentioned only theoretically—to get potentially psychoactive compounds were the substituents of the amide group attached to the C8 atom of LSD. As such, N-monoalkyl, branched N-monoalkyl, symmetrical and unsymmetrical N,N-dialkyl, N-alkyl-N-alkenyl, N,N-dialkenyl, N,N-dialkynyl, N-ethyl-N-(2,2,2-trifluoroethyl), N-ethyl-N-(2-methoxyethyl), N-cycloalkyl, N-alkyl-N-cycloalkyl, N-alkyl-N-cycloalkyl or N-oxacycloalkyl derivatives have been described or mentioned as a theoretical idea. (Brandt et al., 2020; Huang et al., 1994; Nichols, 2018a; Nichols et al., 2002; Nichols et al., 1996; Oberlender et al., 1992; Pfaff et al., 1994; Watts et al., 1995) and WO2021019023A1, WO2021175816A1.
However, some of these compounds have only described in theory and have never been prepared chemically and investigated biologically, or even psycho-pharmacologically. Thus, it remains unclear to what extent some of these compounds show psycho activity in general or, more specifically, psychedelic properties.
When it comes to a combination of the aforementioned structural modification of the original LSD molecule, namely on N1, N6 and amide function attached to C8, hardly any compounds are known, one of the few exceptions being the N1-propionyl version of ETH-LAD (Brandt et al., 2017). Other compounds have only been described theoretically in, e.g., WO2021019023A1, WO2021175816A1 but their preparation and chemical characterization was never described.
One of the main reason for this lies in the unremittingly seek for N,N-diethylamide substituted derivatives of lysergic acid, driven by the findings that as soon as even one of the ethyl groups of the original LSD molecule is structurally altered, e.g., to a methyl, propyl or isopropyl group, the subsequent compound significantly loses its potency of psychoactive doses. Only very few structural modifications of the N,N-diethylamide moiety are allowed to retain at least some of the psychoactive properties, whereby the nature of the retained psycho activity remains elusive and has not been described in detail.
Another reason for the extremely limited number of chemically prepared and biologically investigated samples of lysergic acid derivatives bearing an amide different from N,N-diethylamide combined with a N6-substituent different than N-methyl lies in the laborious access of these compounds. By knowing from existing, previously described structure-activity relationship, that when not using N,N-diethylamide as the amide substituent, there seemed to be little interest in doing synthetic effort for getting additional examples of compounds that bear this extremely rare combinations of pharmacophores.
One reason the N6-substituent consists mostly of a methyl group in the aforementioned compounds lies in the use of lysergic acid as starting material; this acid is found chemically bound, as a chemical substructure, in nature mainly in ergot fungi, from which the compound ergotamine can be isolated. A hydrolysis of ergotamine and subsequent purification delivers pure lysergic acid, a compound otherwise chemically accessible only with extreme efforts.
Another reason that contributes to the broadly retained “original” 6-methyl substituent can be the synthetic conditions that were used in past to remove this methyl group. By this, the classical Von-Braun reaction applies cyanogen bromide in boiling tetrachloromethane, both highly problematic compounds to handle.
Taken together, virtually all lysergic acid derivatives with known psychoactive properties contain either the N,N-diethylamide pharmacophore with the N6-substituent varied, or the N6-substituent is retained as N6-methyl and the amide part is varied.
The nature of the psychoactive properties of the hitherto known psychoactive lysergic acid derivatives is often not described in detail and it remains unclear whether they behave as stimulants, as entactogens or as psychedelics (Holze et al., 2020) or a combination thereof.
In case of psychedelic properties of hitherto known lysergic acid derivatives, the nature of psychopharmacology (e.g., subjective effects profile compared with other substance) has only been described in detail and clinically for LSD (Holze et al., 2022; Holze, Vizeli, et al., 2021; Holze et al., 2020). Thus, it remains unclear whether any formerly described lysergic acid derivative would be suitable in the scope of invention mentioned herein at all.
Some of the invented lysergic acid compounds represented by
Introduction of one fluorine in one of the N-ethyl amide substituents is expected to retain psychedelic properties of the LSD molecule (for example in compound TRALA-04).
Introduction of one fluorine in the N6-substituent of ET-LAD retains psychedelic properties of the LSD molecule (as in compound TRALA-15).
As a conclusion, it is highly likely that a combination of these structural features also leads to a lysergic acid derivative with psychedelic properties.
The few hitherto known psychedelic active lysergic acid derivatives all show a similar duration of action with only little differences, mainly in the range of 8-12 hours. Duration of action is dependent mostly on the elimination half-life (Holze et al., 2019; Holze et al., 2022; Holze, Vizeli, et al., 2021), although also receptor occupation and kinetics may play a role (Wacker et al., 2017).
Metabolism of the original LSD molecule has been investigated in human biological fluids (Canezin et al., 2001). Main metabolic attacks were identified to occur in a) the diethylamide part to either N-monodeethlyation or monohydroxylation on one of the ethyl groups, b) N6-demethylation to form 6-Nor-LSD, c) oxidation/hydroxylation in the indole moiety. Only recently, it was shown by Vizeli et al. that a genetic influence of CYP2D6 on pharmacokinetics and acute subjective effects of LSD occurs in healthy subjects (Vizeli et al., 2021). The main metabolite of LSD in humans is 2-oxo-3-hydroxy-LSD (Luethi, Hoener, Krahenbuhl, Liechti, & Duthaler, 2019), therefore the main metabolic attack occurs at the indole part of LSD.
Due to the rather long and in some cases unfavorably long duration of psychedelic action of the original LSD molecule the inventors chose, as an option and not limiting, an “anti-stability approach” that is opposite to the usual way of optimizing pharmacologically active molecules. In classical medicinal chemistry, one goal is to keep or increase biological activities while/whereby also increasing metabolic stability. For some compounds of invention and represented by
Since it is also within the scope of invention to access psychedelic lysergic acid derivatives with shorter duration of action in comparison to the original LSD molecule, with structures represented by
Substitution on N1 of the original LSD molecule need, if psychedelic properties are key properties, a metabolically liable group attached to this position that releases the parent compound upon metabolism since, according to the existing SAR, nearly no substituents seem to be tolerated in this position to get agonistic serotonin 5-HT2A receptor ligands (Halberstadt et al., 2020), the primary site responsible for psychedelic properties of lysergic acid derivatives. Thus, LSD or similar compounds substituted on N1 mostly serve as prodrugs only and liberate the parent compound. Accordingly, duration of action is either be unchanged or rather be prolonged than shortened. One of the few exceptions where N1-substituents can lead to metabolically unchanged active compounds is the N1-substituted 1-methyl-LSD (Abramson, 1959), but at this point this remains unclear, and the compound showed significantly lower potency in human. Nevertheless, N1-substituents are within the scope of invention since they can contribute to modify duration and nature of action of the lysergic acid derivatives represented by
The aforementioned “anti-stability approach” was applied on the N6 nitrogen of some of the lysergic acid derivatives represented by
Further on, the aforementioned “anti-stability approach” was applied on the amide group of some of the lysergic acid derivatives represented by
A different metabolism provoked by the N1, N6 or amide substituents different to that of the original LSD molecule may also take place on any part of the chemical structure of the invented compounds represented by
In no way is the “anti-stability approach” limiting the scope of invention, and for compounds represented by
The aforementioned modifications can take place on either N6 or on the amide part or in any combination thereof.
Not only receptor interactions, receptor profiles, subsequent signal transduction cascades, receptor heterodimerization, overall psychological and psychedelic effects can change by structural modifications represented in
Any of the aforementioned substituent attached to N1, N6 or to the amide can additionally also be combined with a substituent attached to the amide or to N6 or N1 consisting of an alkyl, alkenyl or alkynyl, cycloalkyl, alkylcycloalkyl, benzyl, heteroarylmethyl, each containing none, one or several fluorine, deuterium atoms or nitrile groups.
In another embodiment, any of the aforementioned structural modifications can be combined with one or several fluorine and/or deuterium atoms in any combination on the whole lysergic acid core, namely the ergoline core structure. As such to mention, but not limiting in any way, is the introduction of a deuteron at C8 of the ergoline structure to stabilize lysergic acid derivatives represented by
The chemical stability of aforementioned functional groups such as enamides, ynamides, alkoxyamides (also known as Weinreb amides), geminal N-amidoethers, enamines, ynamines, alkoxyamines or geminal aminoethers towards acidic, basic or any other chemical conditions is dependent on factors such as pH, solvent medium, temperature, surface, nucleophilicity or electrophilicity of reaction partners or on gas containment of the environment. Metabolic stability in a biological environment such as a human body is additionally driven by factors such absorption rate, exposure to enzymes, enzyme activity, genetic polymorphism, retention time in a body medium such as gastrointestinal tract, rate of body distribution or transportation times. All these aspects can be influenced by the changes introduced to the compounds and result in the desired effects and effect-durations in humans.
The stability of a functional group, a substituent or, generally spoken, a molecule, towards aforementioned factors can significantly be influenced and modified by specific incorporation of stabilizing or destabilizing atoms or atom groups. Furthermore, the overall metabolic stability of a compound is also driven by properties such as the overall lipophilicity, three-dimensional structure, dissociation constants, solubility, steric accessibilities and steric bulkiness and other characteristics.
Fluorine is a strong electron-withdrawing atom and its incorporation to a substituent can significantly reduce the electron richness. Further on, it modifies dipole moment, dissociation constants of acidic and basic groups, the lipophilicity, pH value, and, to a certain extent, also steric properties of a fluorine-containing molecule are influenced. Thus, fluorine can change physicochemical properties and incorporation into a molecule can have a dramatic influence on interaction with biological targets, on chemical/metabolic stabilities and on metabolic pathways. Fluorine atoms incorporated to a molecule further allow so-called multipolar interactions with partially charged functional groups. This makes fluorine as an excellent tool for medicinal chemistry.
Deuteron is a stable isotope of hydrogen. Due to its slightly different metric, incorporated into a molecule it can influence physicochemical properties. With this, kinetic isotope effects, inverse kinetic isotope effects and also steric isotope effects can be observed. Chemical bonds involving deuterium are stronger and of different length compared to protium (hydrogen), which make such compounds significantly different in biological reactions. Thus, incorporation of a deuteron into a molecule can greatly influence its biological stabilities.
Consequently, both fluorine and deuteron can be used to replace or to be added to a substituent in order to modify the overall stability and biological properties of the compounds invented and represented by
In analogy to these medicinal chemistry concepts, the biological properties of the invented compounds (ADME, target selectivity and target interaction, the mode of action, duration of action, the psychodynamic processes, and the qualitative perceptions, e.g., in terms of psychedelic or empathogenic intensity in comparison to the original LSD molecule) can not only be influenced by the aforementioned application of fluorine or deuteron to the functional groups such as enamides, ynamides, alkoxyamides, geminal N-amidoethers, enamines, ynamines, alkoxyamines or geminal aminoethers but also by introducing them to simpler substituents such as alkyl, alkenyl or alkynyl, cycloalkyl, oxacycloalkyl, alkylcycloalkyl, alkyloxacycloalkyl, benzyl or heteroarylmethyl substituents attached to N1, N6 or to the amide function attached to C8 of the ergoline core structure (
From older structure-activity relationships (Brandt et al., 2020; Huang et al., 1994; Nichols, 2018a; Nichols et al., 2002; Nichols et al., 1996; Oberlender et al., 1992; Pfaff et al., 1994; Watts et al., 1995) it is known, that the amide function of lysergic acid amides does not tolerate larger groups than N,N-diethyl substituents without losing biologic activity such as receptor affinities at receptors such as the 5-HT2A receptor relevant for human psychoactive effects. Surpassing its size or using a smaller group such as a methyl group has led to a quite impressive loss of binding properties on the 5-HT2A receptor as well as on human potency. When modifying the N6-substituent, examples found in literature (Hoffman & Nichols, 1985; Huang et al., 1994; Nichols, 2018a; Nichols et al., 2002; Nichols et al., 1996; Oberlender et al., 1992; Pfaff et al., 1994; A. Shulgin & Shulgin, 1991) have shown that expansion of the N6-methyl group up to a certain degree is tolerated for retaining in vivo potency, as shown, e.g., in drug discrimination studies or with anecdotal reports based on administration to humans. However, the inventors are not solely intending to access compounds with in vitro or in vivo potencies similar or higher than the prototypical LSD per se. In fact, a favorable overall profile may become more relevant, and lower potencies do in no way limit the use of such compounds.
LSD is normally used by oral administration. Buccal or nasal resorption as well as intravenous or intramuscular application has also been used. While the compounds represented by
While all the lysergic acid derivatives represented in
The synthetic access to the compounds of invention is shown in
The group presented in the preparation section, namely compounds 2a to 2m, 12a to 12g, 13, 14a to 14c and 16a to 16c, as shown in
A general access to some the lysergic acid derivatives of the class 1 is outlined in
Compounds from the class 1 (
The access to the sulfoxide can also be performed as follows. Phenylvinylsulfoxide or a substituted analog is treated with a primary amine R—NH2 in a suitable organic solvent such as THF, dioxane, ethyl acetate or dichloromethane to form the corresponding N-(2-phenylsulfinylethyl)-R-amine (Hu, Chan, He, Ho, & Wong, 2014). The obtained amine is then coupled with lysergic acid or lysergic acid hydrate as described before to get an amide suitable to undergo thermolysis for enamide formation. As above, the sulfoxide group is chiral and can bear either R or S configuration or be any mixture of stereoisomers.
In another embodiment to access enamides (e.g., subclass 1f), an aldehyde can be coupled with a primary aldehyde to form an imine, which is then coupled (Golding & Wong, 1981; He, Zhao, Wang, & Wang, 2014; Kulyashova & M., 2016; Meuzelaar, van Vliet, Neeleman, Maat, & Sheldon, 1997) with an activated lysergic acid derivative suitable for amide coupling and subsequent elimination. The coupling intermediate is then forced to eliminate to the corresponding enamide.
Another embodiment for accessing such enamides (e.g. subclass 1f), is the formation of oxazolines and subsequent lithiation and alkylation which causes ring opening and formation of an enamide (Xu, Xiao-Yu, Wang, & Tang, 2017).
Further on, enamides (e.g., subclass 1f), can be accessed by direct elimination using, e.g., lithium bis(trimethylsilyl)amide (LiHMDS) (Spiess, Berger, Kaiser, & Maulide, 2021).
Fluorinated enamides (e.g. subclass 1f), as shown in the class 1 (
The formation of ynamides (e.g., subclass 1g), outlined in the class 1 (
Compounds of the class 2 (
Some compounds represented by class 2 as represented in
For some R6 substituents to be introduced bearing strong electron-withdrawing substituents the secondary N6 of 6-Nor-LSD or other lysergic acid derivatives with N—H in 6-position the nucleophilic character of the secondary amine may not be sufficient high for use as a nucleophile. In such cases, the lysergic acid derivative has either to be protected adequately to selectively deprotonate N6 or the electrophile must be activated. In such a way it can be helpful to use transition metals or transition metal oxides or salts such as silver salts to accelerate N-alkylation. Favorably AgNO3 or AgOTf (AgCF3SO3) is added to the reaction mixture of the corresponding secondary N6 amine and alkylating agent in an organic solvent such as tetrahydrofuran (THF), dioxane, an alcohol such as methanol (MeOH), ethanol (EtOH), isopropyl alcohol (iPrOH) or dichloromethane (DCM). The mixture can be held at 0-100° C., more favorably at 20-100° C.
It is well known that due to the extremely deactivated reactivity (i.e., due to the electron-withdrawing properties of fluorine), in certain cases a 2,2,2-trifluoroethyl substituent cannot be simply introduced into an amine by applying one of the above conditions, and even 2,2,2-trifluoroethyl triflate, a compound of much more reactivity than 2,2,2-trifluoroethyl iodide, shows extremely low reactivity in nucleophilic substitutions with certain amines. Such substituents can be introduced onto an amine by using a synthetic equivalent, namely and exemplarily, 2,2,2-trifluoroacetaldehyde ethyl hemiacetal (alternative name: 1-ethoxy-2,2,2-trifluoro-ethanol) (Mimura, Kawada, Yamshita, Sakamato, & Kikugawa, 2010). The intermediate formed is then reduced with a suitable reducing agent such as NaBH4 or Na(OAc)3BH or NaBH3CN.
Enamine compounds represented by class 2 (subclass 2f) as represented in
Furthermore, enamine compounds represented by class 2 (subclass 2f) as represented in
Alkoxyamine compounds, also known as N-hydroxyethers, represented by class 2 (subclass 2h) as represented in
Arylamines or heteroarylamines represented by class 2 (subclass 2i) as represented in
Benzylamines and (heteroarylmethyl)amines represented by class 2 (subclass 2i) as represented in
N6 substituents can also consist of a cycloalkane or oxacycloalkane (subclass 2d and 2g in
Further on, these cycloalkane substituents represented by the subclass 2d and 2g in
Yet another access to compounds represented by the subclass 2d and 2g in
Compounds of the class 3 (
Compounds of the class 4 (
Compounds of the class 5 (
A selection of the synthesized lysergic acid derivatives is being investigated at the key target for psychoactive effects in vitro (Liechti et al. data on file). The main target of psychedelics is the 5-HT2A receptor (Holze, Vizeli, et al., 2021) and typically there is a high affinity binding at this receptor (Rickli et al., 2016). Additionally, the binding potency at the 5-HT2A receptor is typically predictive of the human doses of psychedelics to be psychoactive for many compounds (Luethi & Liechti, 2018). Furthermore, the psychedelic effects of psilocybin in humans have been shown to correlate with 5-HT2A receptor occupancy measures using positron emission tomography (Madsen et al., 2019). Thus, interactions with this target are relevant and predict psychedelic action with high likelihood for most psychedelics. However, this may not be the case for all substances within this class.
Additional receptors such as the serotonergic 5-HT1A and 5-HT2C or dopaminergic D2 receptors are thought to moderate the effects of psychedelics (Rickli et al., 2016). Although some psychedelics like psilocybin do not directly act on dopaminergic receptors, they have nevertheless some dopaminergic properties by releasing dopamine in the striatum (Vollenweider, Vontobel, Hell, & Leenders, 1999) likely via 5-HT1A receptor activation (Ichikawa & Meltzer, 2000). Furthermore, LSD has activity at D2 receptors (Rickli et al., 2016) and some of its behavioral effects in animals may be linked to this target (Marona-Lewicka, Thisted, & Nichols, 2005) although the acute psychoactive effects in humans are mainly if not fully mediated via 5-HT2 receptor (Holze, Vizeli, et al., 2021; Preller et al., 2017).
Activity of compounds at monoamine transporters are thought to mediate MDMA-like empathogenic effects (Hysek et al., 2012). Importantly, LSD is a high affinity 5-HT2A receptor ligand and extremely low doses are needed to induce psychoactive effects in humans. Even doses at 0.1 mg or below can have extraordinarily strong psychedelic effects in humans and the same is likely the case for the substances developed within the present invention although higher or lower potency is also possible in some lysergic acid compounds, to be evaluated in detail clinically. Key results of the preliminary pharmacological profiling of the compounds described herein were:
Some of the lysergic acid derivatives represented in
A microsomal investigation of some of the lysergic acid derivatives represented in
Receptor interaction profiles of the novel substances at the key targets and compared with LSD and psilocin (the active metabolite of the prodrug and psychedelic psilocybin) were determined and are shown in
Together, the in vitro profiles of lysergic acid derivatives represented in
There are several problems when using LSD that can be solved using the compounds described herein. Namely, a long duration of action of psychedelic experience can be limited in some cases. Derivatives represented in
The compounds represented by
The group presented in the preparation section, namely compounds 2a to 2m, 12a to 12g, 13, 14a to 14c and 16a to 16c (see
The compounds according to the invention and represented in
The compounds according to the invention and represented in
The compounds according to the invention and represented in
The compounds according to the invention and represented in
The modified properties can be tailored and applied individually to the patient's need. This is not only targeted by changing the compound's receptor profile but also greatly by the modification of ADME (Absorption, Distribution, Metabolism and Excretion) via the introduction of more, similar, or less liable substituents in positions N1, N6 or in the carboxamide attached to C8 of the ergoline structure, as in compounds represented in
Preparation of the Compounds
A general access to some the lysergic acid derivatives of the class 1 is outlined in
Compounds from the class 1 (
The access to the sulfoxide can also be performed as follows. Phenylvinylsulfoxide or a substituted analog is treated with a primary amine R—NH2 in a suitable organic solvent such as THF, dioxane, ethyl acetate or dichloromethane to form the corresponding N-(2-phenylsulfinylethyl)-R-amine (Hu et al., 2014). The obtained amine is then coupled with lysergic acid or lysergic acid hydrate as described before to get an amide suitable to undergo thermolysis for enamide formation. As above, the sulfoxide group is chiral and can bear either R or S configuration or be any mixture of stereoisomers.
In another embodiment to access enamides (e.g., subclass 1f), an aldehyde can be coupled with a primary aldehyde to form an imine, which is then coupled (Golding & Wong, 1981; He et al., 2014; Kulyashova & M., 2016; Meuzelaar et al., 1997) with an activated lysergic acid derivative suitable for amide coupling and subsequent elimination. The coupling intermediate is then forced to eliminate to the corresponding enamide.
Another embodiment for accessing such enamides (e.g., subclass 1f), is the formation of oxazolines and subsequent lithiation and alkylation which causes ring opening and formation of an enamide (Xu et al., 2017).
Further on, enamides (e.g. subclass 1f), can be accessed by direct elimination using, e.g., LiHMDS (Spiess et al., 2021).
Fluorinated enamides (e.g., subclass 1f), as shown in the class 1 (
The formation of ynamides (e.g., subclass 1g), outlined in the class 1 (
Compounds of the class 2 (
Some compounds represented by class 2 as represented in
For some R6 substituents to be introduced bearing strong electron-withdrawing substituents the secondary N6 of 6-Nor-LSD or other lysergic acid derivatives with N—H in 6-position the nucleophilic character of the secondary amine may not be sufficient high for use as a nucleophile. In such cases, the lysergic acid derivative has either to be protected adequately to selectively deprotonate N6 or the electrophile has to be activated. In such a way it can be helpful to use transition metals or transition metal oxides or salts such as silver salts to accelerate N-alkylation. Favorably AgNO3 or AgOTf (AgCF3SO3) is added to the reaction mixture of the corresponding secondary N6 amine and alkylating agent in an organic solvent such as THF, dioxane, an alcohol such as MeOH, EtOH, iPrOH or DCM. The mixture can be held at 0-100° C., more favorably at 20-100° C.
It is well known that due to the extremely deactivated reactivity, i.e., due to the electron-withdrawing properties of fluorine, in certain cases a 2,2,2-trifluoroethyl substituent cannot be simply introduced into an amine by applying one of the above conditions, and even 2,2,2-trifluoroethyl triflate, a compound of much more reactivity than 2,2,2-trifluoroethyl iodide, shows extremely low reactivity in nucleophilic substitutions with amines. Such substituents can be introduced onto an amine by using a synthetic equivalent, namely and exemplarily, 2,2,2-trifluoroacetaldehyde ethyl hemiacetal (alternative name: 1-ethoxy-2,2,2-trifluoro-ethanol) (Mimura et al., 2010). The intermediate formed is then reduced with a suitable reducing agent such as NaBH4, Na(OAc)3BH, or NaBH3CN.
Enamine compounds represented by class 2 (subclass 2f) as represented in
Furthermore, enamine compounds represented by class 2 (subclass 2f) as represented in
Alkoxyamine compounds, also known as N-hydroxyethers, represented by class 2 (subclass 2h) as represented in
Arylamines or heteroarylamines represented by class 2 (subclass 2i) as represented in
Benzylamines and (heteroarylmethyl)amines represented by class 2 (subclass 2i) as represented in
N6 substituents can also consist of a cycloalkane or oxacycloalkane (subclass 2d and 2g in
Further on, these cycloalkane substituents represented by the subclass 2d and 2g in
Yet another access to compounds represented by the subclass 2d and 2g in
Compounds of the class 3 (
Compounds of the class 4 (
Compounds of the class 5 (
Detailed Description of the Chemical Preparation of the Compounds
General preparation and equipment information: NMR was performed on a Bruker NMR (1H: 300 MHz and 19F: 282 MHz) at ambient temperature. Reaction controls were performed by silica gel TLC (F254; UV detection) and HPLC UV & MS (Agilent 1100, UV at 210 nm and 313 nm, Waters SQD, ESI+ mode) under basic as well as acidic conditions (solvents: A: either 0.02% NH4OH in water or 0.05% TFA in water, B: acetonitrile, gradients from 5% to 95% B, reversed phase C18 HPLC column). All reactions, workups, drying steps, and storing were performed under exclusion of daylight and of electric light such as neon lighting or light bulbs containing wavelengths of the blue and/or UV spectrum. Working was performed in either light-excluding lab ware or under orange to red light (UV free LED). This helps to prevent decompositions of the compounds. Further on, reactions und some purifications can be performed under protecting gas such as Nitrogen or Argon to further protect the compounds from decompositions. Purifications were performed by using silica gel column chromatography and organic solvents such as mixtures of an alcohol (MeOH or EtOH) and dichloromethane, and in some cases, 0.1% to 1% of NH4OH 25% or 0.1% to 1% NEt3 was added. In a similar way, preparative TLC (silica gel) using the aforementioned solvents was applied as well. Working safety: a suitable personal protecting ware common to lab works and fume hoods with a movable glass window were used. Possible contaminations on e.g., gloves or surfaces can quickly be detected by having a long-wave UV lamp (e.g., 366 nm) at hands, preventing further distribution of active materials. Typically, compounds bearing an intact lysergic acid amide substructure, show a strong blueish fluorescence even in trace amounts. Quick deactivation of the potential central effects of these compounds can be performed by using, e.g., a mixture of bleach and diluted alcohol.
An appropriate purity as well as identity check and determination of epimeric identity is crucial to evaluate the compounds of invention for their biological properties. The inventors did not rely on TLC or single HPLC analysis but instead set up a deeper evaluation of analyses, since for some compounds TLC or single HPLC is not sufficient to judge.
Purity check of the final compounds was performed on two different HPLC systems with different columns and different eluents, at 195 nm as well as at 313 nm (reaction controls: 210 nm and 313 nm). The very low absorption wavelength reveals any organic contaminants, and the higher wavelength corresponds approximatively to a characteristic local maximum of these compounds and would reveal whether there would by any structurally related contaminations. Further on, 1H-NMR and, where applicable, by 19F-NMR helped further to judge purities.
Identity check of the final compounds was performed by HPLC-MS as well as by 1H-NMR and, where applicable, by 19F-NMR. For important notes to NMR analysis and interpretations, see the following instructions.
General method for the amide couplings. To a suspension of 286 mg (1 mmol) lysergic acid monohydrate (note: the water-free lysergic acid can be used similarly) in 4 mL DMF anhydr. were added 258 mg (1.59 mmol) 1,1′-carbonyldiimidazole (CDI) in one portion. The suspension became clear after a few minutes, and an HPLC-UV and -MS based activation check after 30 min by dissolving a minimal sample of reaction mixture in MeOH anhydr. (important) indicated clean and complete methyl ester formation (lysergic acid methyl ester appeared as two epimers). Thus, the amine to be coupled (1.05 to 1.5 eq) as either free base or as hydrochloride salt was premixed with diisopropylethylamine (DIPEA; 435 μL, 2.5 eq) in 2 mL DMF anhydr. and the clear amine solution was added all at once to the above activated lysergic acid solution. Note: in some cases, a large excess of the free amine (up to 10 eq, no DIPEA) did force the reaction to give C8-epimeric ratios much more towards the desired and pharmacologically active 8R-carboxamide epimer. This way was used of forcing the epimeric ratio depending on availability of amines to be used and on economic reasons. After the reaction control (by TLC: DCM/MeOH 9/1 and HPLC MS and UV at 210 nm and 313 nm) indicated complete or near complete conversion (note: in any case there was formed a mixture of C8-epimers in ratios ranging from approx. 8R:8S=8:2 to 4:6, based on interpretation of UV absorption at 313 nm. For amines with low nucleophilicity such as di(2,2-difluoroethyl)amine up to four days reaction time was needed), the DMF was either removed in vacuo at 40° C. using a strong vacuum pump before extraction as following was performed, or the reaction mixture was directly partitioned between water (40 mL) and 40 mL heptane/EtOAc 1:1 (40 mL). The layers were separated, and the very dark aq. layer was further extracted with the heptane/EtOAc 1:1 (2×20 mL). The combined, cognac-colored org. layers were further washed with water (3×20 mL) and dried by slowly filtering them through a Na2SO4 pad. After evaporation of the org. volatiles there was obtained a green to brown residue as crude product. This was purified by either column chromatography or prep. TLC as described under the chapter General to get the corresponding lysergic acid amide derivative as free base. As a general observation and in agreement with (Bailey, Verner, & Legault, 1973; Hoehn, Nichols, McCorvy, Neven, & Kais, 2017; Hoffman & Nichols, 1985; Stachulski, Nichols, & Scheinmann, 1996), on normal phase chromatographic conditions, the first compound eluted from silica gel showing blue fluorescence under long-wave UV corresponded to the pharmacologically active compound with an 8R-carboxamide configuration and thus to the desired C8 epimer. The second and invariably more polar compound with blue fluorescence corresponded to the 8S-carboxamide epimer, also known as the iso-compound. This was confirmed by LCMS for masses (where an inverse order of elution was observed on reversed-phase column) and by NMR for structural proof, by comparing the isolated lysergic acid derivatives with the isolated iso-lysergic acid derivatives as well as with thorough existing literature, e.g., (Brandt et al., 2017; Hoehn et al., 2017; Hoffman & Nichols, 1985; Stachulski et al., 1996). Since not all lysergic acid derivatives separate well from their iso-lysergic acid derivatives on HPLC conditions the inventors did not solely rely on TLC analysis (where, in rare cases, not a distinct separation occurred), 1H-NMR analysis was used for the proper epimer separation check as well. Generally, there is a hindered rotation about the amide CN bound which can cause more complex spectra. It is important to note, that, for the H9 proton, 1H-NMR revealed usually only a single signal (usually around 6.3-6.4 ppm, singlet up to multiplet) for symmetrically substituted amides. Most non-symmetrically substituted amides showed two signals (usually around 6.3-6.4 ppm, singlets up to multiplets in some cases) for this H9 proton, in a non 1:1 ratio. To proof the absence of any 8S-configured impurities (iso-compounds) potentially contaminating the desired 8R-configured derivatives—in addition to HPLC UV and MS analysis wherein the 8R/8S epimers were not always baseline separated—the iso-compounds were also measured in 1H-NMR, and a comparison of spectra indicated also two signals between around 6.3 and 6.4 ppm in a non-1:1 ratio for the H9 proton but both signals having different chemical shifts than the two signals of H9 from the 8R-configured compounds. With this, the epimeric purities were ultimately proven for asymmetric amides as well. The desired free base products were dried under high vacuum to get rid of any residual NH3 or NEt3, whereafter a solid or a foam with an aspect of golden, brownish, or beige color was obtained. The obtained iso-compounds (isolated compounds with an 8S-carboxamide configuration) are worth to isolate as well and can easily be epimerized at the C8 center, to get mixtures of 8R- and 8S-carboxamides, by the application of bases in an appropriate solvent by known procedures (GB579484A). The obtained epimeric mixtures are then separated by the above purification steps. By this, yields of lysergic acid derivatives with a desired 8R-carboxamide configuration are easily increased. On larger batches, it is worth to repeat this procedure several times, to maximize yields.
General procedure for hemitartrate or tartrate salt formation. Note: only for the desired 8R-carboxamide epimers conversion to their salts is described, and the C8 epimers (with an 8S configuration, so-called iso-compounds) were either kept as their free bases, or, for 1H-NMR spectra comparison, some were converted to the salts as well. A solution of 10% (+)-tartaric acid in methanol anhydr. was prepared (exact weighing for calculation of the volumes needed). The purified lysergic acid amide derivative as free base was dissolved in a minimal amount of MeOH anhydr. under slight warming, where necessary, and was neutralized with 0.5 (for hemitartrates) to 1 mol. equivalent (for tartrates) of the above (+)-tartaric acid solution. Alternatively, neutralization could be performed by direct addition of the (+)-tartaric acid solution to the free base foam. Next, diethyl ether (Et2O) anhydr. was added until the maximum of precipitation was reached. The suspension formed was allowed to stand for the time needed either at ambient temperature or in the fridge, depending on ease of suspension forming. The liquid layer was cautiously decanted or removed by using a front-clogged Pasteur pipet (cotton wool or alike) and the residue was rinsed with MeOH/Et2O 1:1 and finally with Et2O before it was dried in high vacuo overnight. The aspects of the residual crystalline lysergic acid amide hemitartrates or tartrates was of white to off-white color. Determination of exact tartaric acid content can be performed by 1H-NMR (ratio of lysergic acid derivative to tartaric acid: this can be 1:0.5 up to 1:1, or even 1 to more than 1, when an excess of tartaric acid was used incautious, and the excess was not properly removed). Comment on 1H-NMR spectra of the tartrate salts (see also existing literature, e.g., (Bailey et al., 1973; Hoehn et al., 2017; Hoffman & Nichols, 1985; Stachulski et al., 1996): as observed on the free bases of the lysergic acid derivatives, for the H9 proton 1H-NMR revealed only a single signal (around 6.3-6.4 ppm, singlet up to multiplet in some cases) for symmetrically substituted amides. Non-symmetrically substituted amides showed two signals (around 6.3-6.4 ppm, singlets up to multiplets in some cases) for this H9 proton, in a non 1:1 ratio. To proof the absence of any 8S-configured impurities (iso-compounds)—in addition to HPLC UV and MS analysis wherein the 8R/8S epimers were not always baseline separated—the iso-compounds were also measured in 1H-NMR, and a comparison of spectra indicated also a non 1:1 ratio for the H9 proton but having different chemical shifts than the two signals of H9 from the 8R-configured compounds. With this, the epimeric purities were ultimately proven for asymmetric amides as well.
General procedure for N6 alkylations with alkyl halides, adapted from (Hoffman & Nichols, 1985). To a mixture of 97 μmol (in case of 6-Nor-LSD this corresponds to 30 mg) of free base of the N6 Nor-compound and 26.8 mg (2.0 eq) K2CO3 in 0.5 mL DMF anhydr. was added 116 μmol (1.3 eq) of the corresponding alkyl halide under Nitrogen. After the reaction control (either TLC: DCM/MeOH 9/1 by, in some cases adding 0.1% NEt3, or by HPLC UV and MS) indicated complete conversion (note: N6 alkylation is much faster than C8 epimerization and thus, at ambient temperature and under the chosen reaction conditions virtually no epimerization took place, as has been previously demonstrated (Stachulski et al., 1996) the mixture was worked up. In cases where the N6 alkylation was very slow (e.g., less than some 20% conversion after one day) the reactions could significantly be forced towards completion by adding a second, and, in some cases, a third equivalent of alkylating agent after one, two and three days, respectively. Thus, after stirring for the time needed the reaction mixture was concentrated in high vacuo at 40° C. to remove most of the volatiles including DMF and the residue was dissolved in the eluent used for chromatography and purified by silica gel column chromatography as described in the chapter General. For most compounds, a solvent system of DCM/MeOH/NEt3=98/2/0.1 was suitable. The free base product was dried under high vacuum to get rid of any residual NH3 or NEt3, whereafter a solid or a foam with an aspect of golden, brownish, or beige color was obtained. Where necessary, the products could further be purified by dissolution in a hot solvent such as benzene and, when needed, filtering and then precipitating them from the filtered and cooled solution by adding some heptane (Hoffman & Nichols, 1985). A such precipitate is then collected by filtration and dried under high vacuum. When desired, the free base compounds can be converted to a pharmaceutically acceptable salt. In some cases, the inventors observed a very weak salt character, and it was possible, in the case of some tartrate salts, even to separate the tartaric acid completely from the lysergic acid amide derivative by precipitations of the tartaric acid from a solution.
9,10-Didehydro-N-methyl-N-propyn-3-yl-6-methylergoline-8R-carboxamide (TRALA-01), 2a. According to the general amide coupling method described, from 286 mg lysergic acid monohydrate (A. T. Shulgin & Shulgin, 1997), 258 mg CDI and 276 mg N-methyl-propargylamine (4 eq), no DIPEA used. Yield: 77 mg (24%) TRALA-01 as a beige amorphous solid and 75 mg (18%) iso-TRALA-01 as a gray-greenish solid. Tartrate salt formation according to the general method described; yield: 62 mg 2a tartrate product as an off-white solid. Analytical data of 2a as tartrate: 1H-NMR (DMSO-d6): (relating complexity of interpretation: see chapter General; amide couplings) ˜2.50 (s, N(6)Me, superimposed by DMSO), 2.59 (m, 1H), 2.92 (s, 1H), 3.11 (m, 2H), 3.23 (t, 1H), 3.25-3.44 (m, ˜2H), 3.51 (m, ˜2H), 3.89-4.38 (m, ˜3H), 4.23 (s, tartaric acid), 6.28 (ca. 60%)/6.35 (ca. 40%) (2×s, sum=H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 7.00-7.11 (m, 3 arom. H), 7.17-7.23 (m, 1 arom. H), 10.75 (bs, NH). LCMS (M+H): expected for 2a: M=319.41; found: 320.3.
9,10-Didehydro-N-ethyl-N-propyn-3-yl-6-methylergoline-8R-carboxamide (TRALA-02), 2b. According to the general amide coupling method described, from 286 mg lysergic acid monohydrate, 258 mg CDI, 180 mg N-ethyl-propargylamine hydrochloride (1.5 eq) and 435 μL DIPEA (2.5 eq). Yield: 110 mg (33%) TRALA-02 as a brownish amorphous solid and 116 mg (35%) iso-TRALA-02 as a brown solid. Tartrate salt formation according to the general method described; yield: 104 mg product 2b tartrate as an off-white solid. Analytical data of 2b as tartrate: 1H-NMR (DMSO-d6): (relating complexity of interpretation: see chapter General; amide couplings) 1.11/1.25 (2×t, sum=3H), 2.54 (s, N(6)Me, superimposed by DMSO), 2.69 (t, ˜1H), 3.04-3.21 (m, ˜3H), 3.35-3.65 (m, ˜4H), 3.96 (m, ˜1H), 4.21 (m, ˜1H), 4.24 (s, tartaric acid), 4.35 (m, 1H), 6.25 (ca. 50%)/6.36 (ca. 50%) (2×s, sum=H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 7.00-7.11 (m, 3 arom. H), 7.17-7.23 (m, 1 arom. H), 10.74 (bs, NH). LCMS (M+H): expected for 2b: M=333.43; found: 334.2. Analytical data of iso-2b as tartrate: 1H-NMR (DMSO-d6): 1.10/1.26 (2×t, sum=3H), 2.64 (s, N(6)Me), 2.76 (t, ˜1H), 2.98 (m, ˜1H), 3.13 (m, ˜1H), 3.27-3.67 (m, ˜4H), 3.87 (m, ˜1H), 4.16 (m, ˜1H), 4.20 (s, tartaric acid), 4.39 (m, 1H), 6.32 (ca. 55%)/6.39 (ca. 45%) (2×s, sum=H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 7.07 (bs, 3 arom. H), 7.14-7.23 (m, 1 arom. H), 10.76 (bs, NH). LCMS (M+H): expected for iso-2b: M=333.43; found: 334.2.
9,10-Didehydro-N-(cyanomethyl)-N-ethyl-6-methylergoline-8R-carboxamide (TRALA-03), 2c. According to the general amide coupling method described, from 286 mg lysergic acid monohydrate, 258 mg CDI and 168 mg 2-(ethylamino)acetonitrile (2 eq), no DIPEA used. Yield: 30 mg (9%) TRALA-03 as a beige amorphous solid and 104 mg (31%) iso-TRALA-03 as a brownish mass. Tartrate salt formation according to the general method described; yield: 31 mg product 2c tartrate as an off-white solid. Analytical data of 2c as tartrate: 1H-NMR (DMSO-d6): (relating complexity of interpretation: see chapter General; amide couplings) 1.13/1.26 (2×t, sum=3H), 2.52 (m, ˜1H, superimposed by DMSO), 2.56 (s, N(6)Me, superimposed by DMSO), 2.71 (t, ˜1H), 3.15 (m, ˜2H), 3.59 (m, ˜3H), 3.96 (m, ˜1H), 4.27 (s, tartaric acid), 4.41 (m, ˜2H), 6.28 (s, H9), 7.03-7.10 (m, 3 arom. H), 7.19-7.24 (m, 1 arom. H), 10.74 (bs, NH). LCMS (M+H): expected for 2c: M=334.42; found: 335.2.
9,10-Didehydro-N-ethyl-N-(2-fluoroethyl)-6-methylergoline-8R-carboxamide (TRALA-04), 2d. According to the general amide coupling method described, from 573 mg lysergic acid monohydrate, 517 mg CDI, 255 mg N-ethyl-(2-fluoroethyl)amine hydrochloride (1 eq) and 523 μL DIPEA (1.5 eq). Yield: 153 mg (22%) TRALA-04 as a beige foam and 156 mg (23%) iso-TRALA-04 as a brown foam. Tartrate salt formation according to the general method described; yield: 158 mg 2d tartrate as an off-white solid. Analytical data of 2d as tartrate: 1H-NMR (DMSO-d6): (relating complexity of interpretation: see chapter General; amide couplings) 1.07/1.21 (2×t, sum=3H), 2.52 (m, ˜1H, superimposed by DMSO), 2.54 (s, N(6)Me, superimposed by DMSO), 2.69 (t, 1H), 3.01-3.19 (m, ˜2.5H), 3.41 (m, ˜1H), 3.53 (m, ˜2.5H), 3.62-3.95 (m, ˜2.5H), 4.23 (s, tartaric acid), 4.59 (t×q, 2H), 6.27 (s, H9), 7.00-7.11 (m, 3 arom. H), 7.17-7.23 (m, 1 arom. H), 10.73 (bs, NH). 19F-NMR (DMSO-d6): −221.29, −222.13. LCMS (M+H): expected for 2d: M=341.43; found: 342.3.
9,10-Didehydro-N-(2,2-difluoroethyl)-N-ethyl-6-methylergoline-8R-carboxamide (TRALA-05), 2e. According to the general amide coupling method described, from 492 mg lysergic acid monohydrate, 444 mg CDI, 250 mg N-(2,2-difluoroethyl)ethylamine hydrochloride (1 eq) and 448 μL DIPEA (1.5 eq). Yield: 202 mg (33%) TRALA-05 as a golden foam and 252 mg (41%) iso-TRALA-05 as a brown mass. Tartrate salt formation according to the general method described; yield: 204 mg 2e tartrate as an off-white solid. Analytical data of 2e as tartrate: 1H-NMR (DMSO-d6): (relating complexity of interpretation: see chapter General; amide couplings) 1.08/1.23 (2×t, sum=3H), 2.53 (s, N(6)Me, superimposed by DMSO), 2.62 (m, ˜1.5H, superimposed by DMSO/N(6)Me), 3.02-3.19 (m, ˜2.5H), 3.41 (m, ˜1H), 3.54 (m, ˜2.5H), 3.74 (t×m, 1.5H), 3.93 (m, 1.5H), 4.25 (s, tartaric acid), 6.15 (t×m, 1H), 6.24 (minor)/6.26 (major) (2×s, sum=H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 7.00-7.11 (m, 3 arom. H), 7.17-7.24 (m, 1 arom. H), 10.73 (bs, NH). 19F-NMR (DMSO-d6): −120.46 (major), −122.04 (minor). LCMS (M+H): expected for 2e: M=359.42; found: 360.3. Analytical data of iso-2e as tartrate: 1H-NMR (DMSO-d6): (relating complexity of interpretation: see chapter General; amide couplings) 1.05/1.23 (2×t, sum=3H), 2.64 (m, N(6)Me), 2.77 (m, 1H), 2.97 (m, 1H), 3.13 (m, 1H), 3.32 (m, ˜2H), 3.48-3.78 (m, ˜4H), 3.81-4.10 (m, ˜1.8H), 4.22 (s, tartaric acid), 6.11 (t×m, 1H), 6.30 (s, H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 7.07 (m, 3 arom. H), 7.21 (m, 1 arom. H), 10.76 (bs, NH). 19F-NMR (DMSO-d6): −120.42 (major), −121.87 (minor). LCMS (M+H): expected for iso-2e: M=359.42; found: 360.3.
9,10-Didehydro-N-ethyl-N-(2,2,2-trifluoroethyl)-6-methylergoline-8R-carboxamide (TRALA-06), 2f. According to the general amide coupling method described, from 573 mg lysergic acid monohydrate, 517 mg CDI, 328 mg N-(2,2,2-trifluoroethyl)ethylamine hydrochloride (1 eq) and 522 μL DIPEA (1.5 eq). Yield: 128 mg (17%) TRALA-06 as a yellowish foam and 170 mg (23%) iso-TRALA-06 as a brown mass. Tartrate salt formation according to the general method described; yield: 108 mg 2f tartrate as an off-white solid. Analytical data of 2f as tartrate: 1H-NMR (DMSO-d6): (relating complexity of interpretation: see chapter General; amide couplings) 1.09/1.23 (2×t, sum=3H), 2.54 (s, N(6)Me, superimposed by DMSO), 2.67 (m, ˜1H, superimposed by DMSO/N(6)Me), 2.99-3.20 (m, ˜3H), 3.54 (m, ˜3H), 3.96 (m, 1H), 4.24 (m, ˜1.5H, superimposed by tartaric acid), 4.26 (s, tartaric acid), 4.47 (m, ˜0.5H), 6.21 (minor)/6.24 (major) (2×s, sum=H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 6.99-7.12 (m, 3 arom. H), 7.17-7.23 (m, 1 arom. H), 10.74 (bs, NH). 19F-NMR (DMSO-d6): −68.27 (major), −69.38 (minor). LCMS (M+H): expected for 2f: M=377.41; found: 378.3.
9,10-Didehydro-N-methyl-N-(2,2,2-trifluoroethyl)-6-methylergoline-8R-carboxamide (TRALA-07), 2g. According to the general amide coupling method described, from 573 mg lysergic acid monohydrate, 517 mg CDI, 299 mg N-(2,2,2-trifluoroethyl)methylamine hydrochloride (1 eq) and 522 μL DIPEA (1.5 eq). Yield: 108 mg (15%) TRALA-07 as a yellow foam and 174 mg (24%) iso-TRALA-07 as a brown foam. Tartrate salt formation according to the general method described; yield: 86 mg 2g tartrate as an off-white solid. Analytical data of 2g as tartrate: 1H-NMR (DMSO-d6): (relating complexity of interpretation: see chapter General; amide couplings) 2.54 (s, N(6)Me, superimposed by DMSO), 2.63 (m, ˜1.5H, superimposed by DMSO/N(6)Me), 2.97-3.20 (m, 3H), 3.28 (s, CONMe), 3.52 (d×d, 1H), 4.15 (m, 1H), 4.24 (m, 2H), 4.26 (s, tartaric acid), 4.53 (m, ˜0.5H), 4.69 (d×t, 2H), 6.23 (minor)/6.29 (major) (2×s, sum=H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 7.01-7.12 (m, 3 arom. H), 7.17-7.23 (m, 1 arom. H), 10.73 (bs, NH). 19F-NMR (DMSO-d6): −68.62 (major), −69.36 (minor). LCMS (M+H): expected for 2g: M=363.39; found: 364.3. Analytical data of iso-2g as tartrate: 1H-NMR (DMSO-d6): (relating complexity of interpretation: see chapter General; amide couplings) 2.61 (s, N(6)Me), 2.73 (t, 1H), 2.94 (m, ˜1.6H), 3.08 (d×d, ˜1.3H), 3.29 (s, CONMe), 3.42 (m, ˜1H), 3.94 (m, 1H), 4.21 (m, ˜2H, superimposed from tartaric acid), 4.26 (s, tartaric acid), 6.27 (minor)/6.33 (major) (2×s, sum=H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 7.01-7.12 (m, 3 arom. H), 7.16-7.24 (m, 1 arom. H), 10.75 (bs, NH). 19F-NMR (DMSO-d6): −68.52 (major), −69.13 (minor). LCMS (M+H): expected for iso-2g: M=363.39; found: 364.3.
9,10-Didehydro-N,N-di(2-fluoroethyl)-6-methylergoline-8R-carboxamide (TRALA-08), 2h. According to the general amide coupling method described, from 492 mg lysergic acid monohydrate, 444 mg CDI, 250 mg di(2-fluoroethyl)amine hydrochloride (1 eq) and 448 μL DIPEA (1.5 eq). Yield: 80 mg (13%) TRALA-08 as a beige foam and 161 mg (26%) iso-TRALA-08 as a beige foam. Tartrate salt formation according to the general method described; yield: 76 mg 2h tartrate as an off-white solid. Analytical data of 2h as tartrate: 1H-NMR (DMSO-d6): 2.57 (s, NMe, superimposed by DMSO), 2.68 (t, 1H), 3.03-3.21 (m, 3H), 3.52 (d×d, 1H), 3.70 (d×m, 2H), 3.87 (d×t, 2H), 3.98 (m, 1H), 4.24 (s, tartaric acid), 4.53 (d×t, 2H), 4.69 (d×t, 2H), 6.28 (s, H9), 7.01-7.12 (m, 3 arom. H), 7.18-7.23 (m, 1 arom. H), 10.73 (bs, NH). 19F-NMR (DMSO-d6): −221.98, −222.95. LCMS (M+H): expected for 2h: M=359.42; found: 360.3.
9,10-Didehydro-N,N-bis(2,2-difluoroethyl)-6-methylergoline-8R-carboxamide (TRALA-09), 2i. According to the general amide coupling method described, from 394 mg lysergic acid monohydrate, 356 mg CDI, 250 mg bis(2,2-difluoroethyl)amine hydrochloride (1 eq) and 360 μL DIPEA (1.5 eq). Yield: 33 mg (6%) TRALA-09 as a brown mass and 44 mg (8%) iso-TRALA-09 as a brown mass. Tartrate salt formation according to the general method described; yield: 18 mg 2i tartrate as an off-white solid. Analytical data of 2i as tartrate: 1H-NMR (DMSO-d6): (relating complexity of interpretation: see chapter General; amide couplings) ˜2.50 (NMe, superimposed by DMSO), 2.64 (t, 1H), 3.03-3.28 (m, 3H), 3.52 (d×d, 1H), 3.86 (txt, 2H), 3.97-4.15 (m, 3H), 4.27 (s, tartaric acid), 6.24 (s, H9), 6.25 (5.97-6.53: sharply split t×m; 2×CHF2), 7.02-7.14 (m, 3 arom. H), 7.18-7.25 (m, 1 arom. H), 10.74 (bs, NH). 19F-NMR (DMSO-d6): −121.26, −121.29, −122.87. LCMS (M+H): expected for 2i: M=395.40; found: 396.2.
9,10-Didehydro-N-ethyl-N-(methoxy)-6-methylergoline-8R-carboxamide (TRALA-10), 2j. According to the general amide coupling method described, from 1.14g lysergic acid monohydrate, 1.04g CDI, 0.51 g N-methoxy-ethylamine hydrochloride (1 eq) and 1.04 mL DIPEA (1.5 eq). Yield: 113 mg (17%) TRALA-10 as a yellow foam and 146 mg (22%) iso-TRALA-10 as a brown foam. Tartrate salt formation according to the general method described; yield: 74 mg 2j tartrate as an off-white solid. Analytical data of 2j as tartrate: 1H-NMR (DMSO-d6): (relating complexity of interpretation: see chapter General; amide couplings): 1.13 (t, 3H), 2.56 (s, NMe, superimposed by DMSO), 2.62 (m, ˜1H), 3.06-3.18 (m, 3H), 3.52 (d×d, 2H), 3.66 (q, 2H), 3.76 (s, OMe), 3.93 (m, 1H), 4.25 (s, tartaric acid), 6.30 (s, H9), 7.01-7.12 (m, 3 arom. H), 7.18-7.23 (m, 1 arom. H), 10.73 (bs, NH). LCMS (M+H): expected for 2j: M=325.41; found: 326.3.
9,10-Didehydro-6-methylergoline-8R-((RS)-2-ethynylazetidide) (TRALA-11), 2k. According to the general amide coupling method described, from 243 mg lysergic acid monohydrate, 220 mg CDI, 100 mg (RS)-2-ethynylazetidine hydrochloride (1 eq) and 222 μL DIPEA (1.5 eq). Yield: 52 mg (19%) TRALA-11 as a beige foam and 90 mg (32%) iso-TRALA-11 as a beige foam. Tartrate salt formation according to the general method described; yield: 45 mg 2k tartrate as an off-white solid. Analytical data of 2k as tartrate (relating complexity of interpretation: see chapter General; amide couplings): 1H-NMR (DMSO-d6): 2.24 (m, 1H), 2.48-2.62 (m, ca. 3H, superimposed by DMSO and NMe), 2.52 (s, NMe, superimposed by DMSO), 3.12 (m, 1H), 3.18 (s, CCH), 3.52 (m, 2H), 3.75 (m, 1H), 3.86 (m, ca. 1.5H), 4.25 (s, tartaric acid), 4.27 (m, ca. 0.5H), 4.83 (m, ca. 0.5H), 4.32 (m, ca. 0.5H), 6.26 (minor)/6.35 (major) (2×s, sum=H9; note: the azetidine moiety contains a stereocenter which is assumed to be racemic; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings) 7.01-7.11 (m, 3 arom. H), 7.21 (m, 1 arom. H), 10.73 (bs, NH). LCMS (M+H): expected for 2k: M=331.42; found: 332.2.
9,10-Didehydro-N-(2-fluoroethyl)-N-(methoxy)-6-methylergoline-8R-carboxamide (TRALA-14), 2n. 1.) Preparation of N-methoxy-2-fluoroethylamine hydrochloride (10; adapted from US20100029670A1). To a solution of 1.0g (8.39 mmol) ethyl N-methoxycarbamate (8) in 5 mL DMF anhydr. were added 0.352g (8.81 mmol) NaH 60% dispersed in mineral oil under nitrogen and ice-cooling. After stirring for 5 min the mixture was allowed to stir at ambient temperature for 1h. Next, 1.46g (8.39 mmol) 1-fluoro-2-iodomethane was added and the mixture was heated to 75° C. for 6h. The mixture was cooled to ambient temperature and mixed with water and EtOAc (70 mL, each), and the layer were separated. The org. layer was further washed once with water (1×70 mL), dried over MgSO4, and concentrated in vacuo to get 1.05g (75%) of the intermediate 9 as a yellow oil. 1H-NMR (CDCl3): 1.33 (t, CH2CH3), 3.75 (s, OCH3), 3.81 (d×t, CH2CH2F), 4.24 (q, CH2CH3), 4.59 (d×t, CH2F). 19F-NMR (CDCl3): −224.0. The intermediate 9 (1.03g) was mixed with 1.5 mL EtOH, 1.5 mL water and with 1.25g KOH, and the mixture was heated to 75° C. for 5h, whereby the flask (25 mL) was plugged with a septum attached to a Teflon tube. The second end of the tube was placed into a small gas washing bottle containing 2M aq. HCl. After the reaction time the mixture was heated to 90° C. and any residual product was forced to transfer to the gas washing bottle using a slow Nitrogen stream (balloon, needle, over 1 h). The 2M HCl containing the product was concentrated in vacuo, and the residual semi-solid was co-evaporated with MeOH, quickly dried in high-vacuo and then triturated with Et20/hexane and filtered off. After drying there were obtained 326 mg (40%) N-methoxy-2-fluoroethylamine hydrochloride (10) as a rose-colored solid. 1H-NMR (soluble in CDCl3): 3.66 (d×t, CH2CH2F) 4.12 (s, OCH3), 4.89 (d×t, CH2F). 19F-NMR (CDCl3): −223.2.2.) Amide coupling reaction: According to the general amide coupling method described, from 248 mg lysergic acid monohydrate, 155 mg (1.1 eq) CDI, 123.5 mg N-methoxy-2-fluoroethylamine hydrochloride (10; 1.1 eq) and 377 □L DIPEA (2.5 eq); the solution of amine 10 and DIPEA in DMF was added dropwise under ice-cooling, and the reaction mixture was allowed to warm to ambient temperature over several hours. Yield: 21 mg (7%) TRALA-14 as a golden beige solid. Analytical data of 2n: 1H-NMR (CDCl3): 2.62 (s, NMe), 3.24 (m, 2H), 3.57 (d×d, 1H), 3.81 (s, OMe), 3.95 (d×t, 1H), 4.04 (d×t, 1H), 4.10 (bm, 1H), 4.24 (m, 1H), 4.57 (t, 1H), 4.73 (t, 1H), 6.47 (s, H9) 6.92 (m, 1 arom. H), 7.14-7.26 (m, 3 arom. H), 7.55 (m, 0.5H), 7.73 (m, 0.5H), 7.98 (bs, NH). 19F-NMR (CDCl3): −222.5. LCMS (M+H): expected for 2n: M=343.40; found: 344.2.
1.) Amide Formation
9,10-Didehydro-N-ethyl-N-(2-(phenylthio)ethyl)-6-methylergoline-8R-carboxamide, 4. According to the general amide coupling method described, from 974 mg lysergic acid monohydrate, 880 mg CDI, 885 μL N-ethyl-2-(phenylthiol)ethanamine (3; 1.1 eq) and 885 μL DIPEA (1.5 eq). Yield: 550 mg (38%) title product as a golden foam. Analytical data of 4: 1H-NMR (CDCl3): 1.12-1.32 (m, 3H), 2.59-2.78 (m, 4H), 2.92 (t, 1H), 3.04 (m, 1H), 3.10-3.32 (m, 3H), 3.40-3.68 (m, 5H), 3.89 (bm, 1H), 6.30/6.37 (2×s, H9) 6.93 (t, 1 arom. H), 7.15-7.49 (m, 8 arom. H), 8.00 (bs, NH). LCMS (M+H): expected for 4: M=431.60; found: 432.3.
2.) Sulfoxide Formation
9,10-Didehydro-N-ethyl-N-(2-(phenylsulfinyl)ethyl)-6-methylergoline-8R-carboxamide, 5. To an ice-cooled solution of 405 mg (0.94 mmol) 4 in 20 mL DCM were added 81 μL aq. HCl 37% (1.05 eq). Next, a solution of 211 mg (1.0 eq) meta-chloroperbenzoic acid (mCPBA) in 20 mL DCM was added over the course of 5 min. After 20 min, LCMS analysis indicated formation of sulfoxide (50%; a small second peak having the same mass corresponded to the N-oxide, identities proven by isolation and 1H-NMR), as well as double oxidated product (20%), among starting material (30%), and the reaction was quenched by the addition of 20 mL of aq. 10% Na2S2O3 solution. After stirring vigorously for 5 min, the layers were separated and the aq. layer was further extracted with DCM (2×20 mL), and the combined org. layers were dried over Na2SO4 and concentrated in vacuo. The greenish-black residue (547 mg) was purified by silica gel chromatography (DCM/MeOH/NEt3). Yield: 54 mg (13%) title product as an off-white foam, among 258 mg recovered starting material. Analytical data of 5: 1H-NMR (CDCl3; note: the sulfoxide bears an additional chiral center and adds complexity): 1.15-1.36 (m, 3H), 2.58-2.78 (m, 4H), 2.80-2.95 (bm, 1H), 2.95-3.20 (m, ˜2.5H), 3.25-3.38 (m, ˜2.5H), 3.5-3.8 (m, 5H), 3.93 (bm, 1H), 6.23/6.27 (both minor) and 6.32/6.38 (both major) (each as a s, H9; sum=1H) 6.94 (m, 1 arom. H), 7.15-7.27 (m, 3 arom. H), 7.50-7.61 (m, 3 arom. H), 7.65-7.72 (m, 2 arom. H), 7.95 (bs, NH). LCMS (M+H): expected for 5: M=447.60; found: 448.2.
3.) Thermolysis
9,10-Didehydro-N-ethenyl-N-ethyl-6-methylergoline-8R-carboxamide (TRALA-12), 21. A mixture of 54 mg (0.121 mmol) 9,10-Didehydro-N-ethyl-N-(2-(phenylsulfinyl)ethyl)-6-methylergoline-8R-carboxamide (5) and 51 mg (5 eq.) NaHCO3 in 8 mL m-xylene was heated to 130-140° C. under nitrogen. After a total of 2 days there were observed some 25% conversion (LCMS), among starting material and some decomposition products. The volatiles were removed in high vacuo at 50° C. and the residue was purified by first dissolving it in 1 mL DCM/MeOH/NEt3=90/10/0.2 and filtering it through a silica gel pad (height 1 cm) using 70 mL of the same solvent system. This removed most of the dark color. The eluate was concentrated in vacuo and the residue was further purified by silica gel chromatography using the same solvent system starting at 98% DCM. There were obtained ca. 2 mg of the title product. Analysis on either basic or acidic HPLC MS (see chapter General) indicated the same purity (approx. 85%) revealing the product's stability against these conditions. LCMS (M+H): expected for 21: M=321.43; found: 322.2. 1H-NMR (CDCl3): the signals were in accordance with the spectrum obtained by the alternative route (e.g., 6 to 7 to 5 to 21;
4.) Enamides by Base-Promoted Elimination Reactions (Microscale)
9,10-Didehydro-N-(2,2-difluoroethenyl)-N-ethyl-6-methylergoline-8R-carboxamide (TRALA-13), 2m. This reaction could be performed either with the use of LDA or with BuLi, no epimerization observed. A solution of 7 mg (18.5 μmol) TRALA-06 (2f) in 0.2 mL THF anhydr. under nitrogen was cooled to −100° C. (liquid nitrogen, acetone/THF 4:1 mixture as cooling bath). Next, 2.0 eq of 1.6M BuLi or, in a second experiment, 2.0 eq. of a freshly prepared lithium diisopropylamide solution in THF (from BuLi and diisopropylamine in THF) were added within 30 s. Both basic and acidic HPLC MS from a sample hydrolyzed in a drop water and diluted with MeOH indicated 30% product formation (according to integral of UV absorption at 313 nm, as well as according to integral of e/z=358, versus the starting material) among intact starting material; there was no significant decomposition observed and the product remained intact. To further test chemical stability, a hydrolyzed sample stored at ambient temperature overnight (thus, basic conditions) remained intact. Another hydrolyzed sample was made acidic by addition of excess tartaric acid and, after storing for 24h, reanalysis indicated the same product distribution as after initial hydrolysis of the reaction. LCMS (M+H): expected for 2m: M=357.41; found: 358.3.
1.) Hydroamination
N-ethyl-2-(phenylsulfinyl)ethanamine, 7 The procedure was adapted from (Hu et al., 2014). To ethylamine 2M in THF anh. (6 mL; 12 mmol) was added 1.33 mL (10 mmol) phenylvinyl sulfoxide (6) and the clear solution was allowed to stir for 18h under nitrogen. The volatiles were removed in vacuo at 50° C. and the residual viscous orangish oil was purified by silica gel chromatography (DCM/MeOH/NEt3=100/0/0.5 to 95/5/0.5). Yield: 1.72g (72%) title product as a colorless oil. Analytical data of 7: 1H-NMR (CDCl3; note: the sulfoxide bears a chiral center; enantiomeric ratio not determined): 1.11 (t, CH3), 2.67 (q, NHCH2), 2.96 (m, CH2), 3.13 (m, CH2), 7.48-7.57 (m, 3 arom. H), 7.62-7.67 (m, 2 arom. H). LCMS (M+H): expected for 7: 197.30; found: 198.1.
2.) Amide Formation
9,10-Didehydro-N-ethyl-N-(2-(phenysulfinyl)ethyl)-6-methylergoline-8R-carboxamide, 5. According to the general amide coupling method described, from 394 mg lysergic acid monohydrate, 356 mg CDI, 272 mg N-ethyl-2-(phenylsulfinyl)ethanamine (7; 1.0 eq) and 356 μL DIPEA (1.5 eq). Yield: 191 mg (31%) title product as a beige solid. Analytical data of 5: 1H-NMR (CDCl3; note: the sulfoxide bears an additional chiral center and adds complexity; due to its synthesis path, herein it might rather be racemic): 1.15-1.36 (m, 3H), 2.58-2.78 (m, 4H), 2.80-2.95 (bm, 1H), 2.95-3.20 (m, ˜2.5H), 3.25-3.38 (m, ˜2.5H), 3.5-3.8 (m, 5H), 3.93 (bm, 1H), 6.23/6.27 (both minor; first more dominant) and 6.32/6.38 (both major) (H9; sum=1H) 6.92/6.94 (m, 1 arom. H), 7.15-7.27 (m, 3 arom. H), 7.50-7.61 (m, 3 arom. H), 7.65-7.72 (m, 2 arom. H), 7.95 (bs, NH). LCMS (note: the same retention time obtained as for the sulfoxide 5 obtained via the alternative route, see chapter “2.) Sulfoxide formation;” M+H): expected for 5: 447.60; found: 448.2.
3.) Thermolysis
9,10-Didehydro-N-ethenyl-N-ethyl-6-methylergoline-8R-carboxamide (TRALA-12), 21. A mixture of 180 mg (0.402 mmol) 9,10-Didehydro-N-ethyl-N-(2-(phenylsulfinyl)ethyl)-6-methylergoline-8R-carboxamide (5) and 283 mg (5 eq.) K2CO3 in 26 mL m-xylene was heated to 130-140° C. under nitrogen. After a total of 22 hours there were observed some 40% conversion (LCMS), among starting material and only minor decomposition products. Longer heating provoked progressive decomposition. The volatiles were removed in high vacuo at 50° C. and the residue was purified by first dissolving it in 5 mL DCM/MeOH/NEt3=90/10/0.1 and filtering it through a silica gel pad (height 1 cm) using 150 mL of the same solvent system. This removed most of the dark color. The eluate was concentrated i.v. and the residue was further purified by silica gel chromatography using DCM/MeOH/NEt3=98/2/0.1 to 90/10/0.1 as eluent. The crude product (24 mg) eluted first (and second the starting material; recovered: 89 mg) and was further purified by silica gel prep. TLC using DCM/MeOH/NEt3=98/2/0.1 as eluent. Finally, there were obtained 9 mg (7%) of the title product 21. Analysis on either basic or acidic HPLC MS indicated the same purity (approx. 90%) revealing the product's stability against these conditions. 1H-NMR (CDCl3): (relating complexity of interpretation: see chapter General; amide couplings) 1.3 (m; superimposed by some Et2O and impurities, CH2CH3), 2.63 (s, NMe), 2.74 (t×m, 1H), 2.87 (m, 1H), 3.16 (d×d, 1H), 3.28 (bm, 1H), 3.56 (d×d, 1H), 3.78 (m, 2H), 4.10 (bm, 1H), 4.43 (d, 1H), 4.62 (d, 1H), 6.34-6.44 (two superimposed s, H9; sum=1H; note: epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings) 6.93 (m, 1 arom. H), 7.03 (d×d, 1H), 7.15-7.27 (m, 3 arom. H), 7.95 (bs, NH). LCMS (M+H): expected for 21: M=321.43; found: 322.2.
1.) Synthesis of LSD
9,10-Didehydro-N,N-diethyl-6-methylergoline-8R-carboxamide (LSD), 2o. According to the general amide coupling method described, from 3.52g lysergic acid monohydrate, 3.18g CDI and 13.4 mL diethylamine (10 eq; no DIPEA used). Yield: 1.64g (41%) LSD as a beige foam and 0.65g (16%) iso-LSD as a brown sticky mass. Analytical data of 20 (LSD) as free base in accordance with lit. ref.: 1H-NMR (CDCl3): 1.19 (t, 1×CH2CH3), 1.26 (t, 1×CH2CH3), 2.63 (s, NMe), 2.72 (t×m, 1H), 2.93 (t, 1H), 3.08 (d×d, 1H), 3.26 (bm, 1H), 3.47 superimposed with 3.57 (m and d×d, total 5H), 3.92 (bm, 1H), 6.37 (s (hint of a triplet), H9. Note: the isolated epimer iso-LSD showed this signal as a tat 6.31), 6.93 (t, 1 arom. H), 7.14-7.27 (m, 3 arom. H), 7.99 (bs, NH). LCMS (M+H): expected for 2o: M=323.41; found: 324.3.
2.) N6-Demethylation of LSD: Preparation of 6-Nor-LSD.
9,10-Didehydro-N,N-diethylergoline-8R-carboxamide (6-Nor-LSD), 11. This has been adapted from (WO2006128658A1). To an ice-cooled solution of 1.35g (4.17 mmol) LSD (20) in 40 mL DCM was added 1.13g (1.2 eq) mCPBA Q77% (wet). After stirring for 10 min (note: LCMS analysis indicated clean and complete formation of the N-oxide intermediate as two chromatographically well separated epimers with e/z=340; reason: the N-oxide group bears an additional chiral center) a freshly prepared solution of 580 mg (0.5 eq) FeSO4 heptahydrate in 3.0 mL MeOH p.A. was added quickly. The cooling bath was removed and stirring at ambient temperature was continued until complete disappearance of the N-oxides (note: the reason for incomplete conversion of the N-oxide towards the desired product is because one of the N-oxide epimers converts more quickly back to the starting material LSD than N-demethylation rate takes place, see e.g., (McCamley, Ripper, Singer, & Scammells, 2003). By varying reaction conditions to form the N-oxides of, e.g., LSD, the epimeric ratio of N-oxides can be influenced which will, therefore, lead to higher N-demethylation rates; on file, unpublished results). After 3.5h the reaction mixture was poured into 50 mL 0.1 M ethylenediaminetetraacetic acid (EDTA) solution with a pH=9 (adjusted with NH4OH 25% aq.). After vigorous shaking, the layers were filtered through a small celite pad and then separated, and the aq. layer was further extracted with DCM (3×50 mL). The combined org. layers were dried over Na2SO4 and concentrated in vacuo. The dark brown residue was purified by silica gel chromatography (DCM/MeOH/NH3=95/5/0.1 to 90/10/0.1). There was obtained 449 mg recovered LSD (20; eluted first) and 587 mg (46%) 6-Nor-LSD (11) as a tan solid. The recovered LSD (20) could easily be reused for the same reaction which yielded each time the desired 6-Nor-LSD (11) in essentially the same yields (reaction repeated twice from recovered LSD). 1H-NMR (CDCl3): 1.20 (t, 1×CH2CH3), 1.30 (t, 1×CH2CH3), 2.81 (t×m, 1H), 3.23-3.58 (m, 8H), 3.69 (m, 1H), 3.96 (m, 1H), 6.38 (t, H9), 6.92 (t, 1 arom. H), 7.15-7.26 (m, 3 arom. H), 7.97 (bs, N1H). LCMS (M+H): expected for 11: M=309.41; found: 310.3.
3.) N6-Alkylation of 6-Nor-LSD: Preparation of Compounds 12a-g.
9,10-Didehydro-N,N-diethyl-6-(2-fluoroethyl)ergoline-8R-carboxamide (TRALA-15), 12a. According to the general procedure for N6 alkylation described, from total 28.5 μL (3×9.5 μL, 2nd addition on day 2, 3rd addition on day 3) 1-fluoro-2-iodoethane iodide 30 mg 6-Nor-LSD (11), reaction time: 3 days. Yield: 9 mg (26%) TRALA-15 as a beige foam. Analytical data of 12a as free base: 1H-NMR (CDCl3): 1.20 (t, 1×CH2CH3), 1.27 (t, 1×CH2CH3), 2.73 (t, 1H), 2.85-3.11 (m, 2H), 3.18-3.63 (m, 8H), 3.87 (bm, 1H), 4.68 (d×m, CH2F, 2H), 6.36 (s, H9), 6.91 (t, 1 arom. H), 7.14-7.25 (m, 3 arom. H), 8.04 (bs, NH). 19F-NMR (CDCl3): −219.0 (s). LCMS (M+H): expected for 12a: M=355.46; found: 356.3.
9,10-Didehydro-N,N-diethyl-6-(3-fluoropropyl)ergoline-8R-carboxamide (TRALA-16), 12b. According to the general procedure for N6 alkylation described, from total 35.4 μL (2×17.7 μL, 2nd addition on day 2) 1-bromo-3-fluoropropane and 50 mg 6-Nor-LSD (11), reaction time: 2 days. Yield: 12 mg (20%) TRALA-16 as a yellow solid. Analytical data of 12b as free base: 1H-NMR (CDCl3): 1.20 (t, 1×CH2CH3), 1.27 (t, 1×CH2CH3), 1.9-2.1 (bm, 2H), 2.60-2.84 (m, 2H), 2.84-2.98 (m, 2H), 3.14 (bm, 2H), 3.4-3.6 (m, 6H), 3.82 (bm, 1H), 4.61 (d×m, CH2F, 2H), 6.35 (s, H9), 6.93 (s, 1 arom. H), 7.15-7.26 (m, 3 arom. H), 7.94 (bs, NH). 19F-NMR (CDCl3): −220.3 (s). LCMS (M+H): expected for 12b: M=369.49; found: 370.4.
9,10-Didehydro-N,N-diethyl-6-(2-fluoro-1-propen-3-yl)ergoline-8R-carboxamide (TRALA-17), 12c. According to the general procedure for N6 alkylations described, from total 33.9 μL (3×11.3 μL, 2nd addition on day 2, 3rd addition on day 3) 3-bromo-2-fluoro-1-propene and 30 mg 6-Nor-LSD (11), reaction time: 3 days. Yield: 20 mg (56%) TRALA-17 as a yellow foam. Analytical data of 12c as free base: 1H-NMR (CDCl3): 1.21 (t, 1×CH2CH3), 1.27 (t, 1×CH2CH3), 2.75 (t, 1H), 2.99 (t, 1H), 3.22-3.62 (m, 8H), 3.72 (d×d, 1H), 3.85 (bm, 1H), 4.58 (d×d, 1H), 4.77 (d×d, 1H), 6.37 (s, H9), 6.91 (t, 1 arom. H), 7.14-7.26 (m, 3 arom. H), 8.09 (bs, NH). 19F-NMR (CDCl3): −97.7 (s). LCMS (M+H): expected for 12c: M=367.47; found: 368.3.
9,10-Didehydro-N,N-diethyl-6-((RS)-(2,2-difluorocyclopropyl)methyl)-ergoline-8R-carboxamide (TRALA-18), 12d. According to the general procedure for N6 alkylation described, from total 60 mg (3×20 mg, 2nd addition on day 2, 3rd addition on day 3) rac. 2-(bromomethyl)-1,1-difluorocyclopropane and 30 mg 6-Nor-LSD (11), reaction time: 3 days. Yield: 11 mg (28%) TRALA-18 as a yellowish solid. Analytical data of 12d as free base: 1H-NMR (CDCl3): 1.11 (m, 1H), 1.21 (t, 1×CH2CH3), 1.28 (t, 1×CH2CH3), 1.53, (m, 1H), 1.84 (m, 1H), 2.62-3.28 (m, 5H), 3.38-3.68 (m, 6H), 3.87 (bm, 1H), 6.37 (s, H9), 6.92 (s, 1 arom. H), 7.14-7.25 (m, 3 arom. H), 8.05 (bs, NH). 19F-NMR (CDCl3): −128.7 (m: −128.15; −128.71; −128.75; −129.31), −142.4 (m: −141.63; −142.18; −142.58; −143.14). LCMS (M+H): expected for 12d: M=399.49; found: 400.3.
9,10-Didehydro-N,N-diethyl-6-(cyanomethyl)ergoline-8R-carboxamide (TRALA-19), 12e. According to the general procedure for N6 alkylation described, from total 24.4 μL (2×12.4 μL, 2nd addition on day 2) chloroacetonitrile and 50 mg 6-Nor-LSD (11), reaction time: 2 days. Yield: 33 mg of a yellow foam which still contained some impurities (approx. 15%) based on NMR analytics. Thus, the product was further purified by prep. TLC (DCM/MeOH/NEt3=98/2/0.2) to get 7 mg (13%) TRALA-19 as a yellow foam. Analytical data of 12e as free base: 1H-NMR (CDCl3): 1.21 (t, 1×CH2CH3), 1.27 (t, 1×CH2CH3), 2.71 (t×m, 1H), 3.08 (d×d, 1H), 3.30 (t, 1H), 3.37-3.57 (m, 5H), 3.72 (bm, 1H), 3.76 (d, 1H), 3.91 (bm, 1H), 4.07 (d, 1H), 6.37 (s, H9), 6.94 (t, 1 arom. H), 7.15-7.26 (m, 3 arom. H), 8.06 (bs, NH). LCMS (M+H): expected for 12e: M=348.45; found: 349.2.
9,10-Didehydro-N,N-diethyl-6-(2-oxopropyl)ergoline-8R-carboxamide (TRALA-20), 12f. According to the general procedure for N6 alkylation described, total 27.9 μL (3×9.3 μL, 2nd addition on day 2, 3rd addition on day 3) chloroacetone and 30 mg 6-Nor-LSD (11), reaction time: 2 days. Yield: 18 mg (51%) TRALA-20 as a yellow-beige foam. Analytical data of 12f as free base: 1H-NMR (CDCl3): 1.19 (t, 1×CH2CH3), 1.27 (t, 1×CH2CH3), 2.26 (s, 3H), 2.78 (t, 1H), 2.95 (t, 1H), 3.09 (d×d, 1H), 3.28-3.60 (m, 7H), 3.81-3.95 (m, 2H), 6.39 (s, H9), 6.90 (t, 1 arom. H), 7.13-7.25 (m, 3 arom. H), 8.12 (bs, NH). LCMS (M+H): expected for 12f: M=365.48; found: 366.3.
9,10-Didehydro-N,N-diethyl-6-benzylergoline-8R-carboxamide (TRALA-21), 12g. According to the general procedure for N6 alkylations described, from 13.8 μL benzyl bromide and 30 mg 6-Nor-LSD (11), reaction time: 2.5h. Yield: 16 mg (41%) TRALA-21 as a beige foam. Analytical data of 12g as free base: 1H-NMR (CDCl3): 1.14 (m, 2×CH2CH3), 2.83 (m, 2H), 3.10 (d×d, 1H), 3.25-3.52 (m, 5H), 3.57 (m, 1H), 3.73 (m, 2H), 4.36 (d, 1H), 6.38 (s, H9), 6.92 (t, 1 arom. H), 7.13-7.23 (m, 3 arom. H), 7.24-7.38 (m, 3 arom. H), 7.44 (m, 2 arom. H), 8.14 (bs, NH). LCMS (M+H): expected for 12g: M=399.54; found: 400.3.
9,10-Didehydro-N,N-diethyl-6-cyclopropylergoline-8R-carboxamide (TRALA-22), 13. The procedure was adapted from WO2009068214. To a solution of 42.2 mg (136.2 μmol) 6-Nor-LSD (11) in 0.45 mL MeOH anhydr. were added subsequently 41.1 μL (1.5 eq) 1-ethoxy-1-trimethylsiloxycyclopropane, 8.7 μL (1.1 eq) glacial acetic acid and 18 mg (2 eq) NaBH3CN (caution from HCN vapors when opening the bottle) and the mixture was heated to 60° C. for 4h under nitrogen. The mixture was cooled to ambient temperature, the volatiles were stripped off and the residue was partitioned between ethyl acetate and saturated aq. NaHCO3. The org. layer was dried over Na2SO4 and concentrated in vacuo. The residual crude product was purified with silica gel chromatography using DCM/MeOH/NEt3=98/2/0.1 as eluent. Yield: 20 mg (42%) TRALA-22 as a beige foam. Analytical data of 13 as free base: 1H-NMR (CDCl3): 0.51 (m, 1H), 0.62 (m, 1H), 0.82 (m, ˜2H), 1.24 (m, 2×CH2CH3), 1.87 (m, 1H), 2.72 (m, 1H), 3.01 (t, 1H), 3.36 (d×d, 1H), 3.42-3.56 (m, 4H), 3.63 (m, 1H), 3.76-3.93 (m, 2H), 6.39 (s, H9), 6.92 (t, 1 arom. H), 7.13-7.25 (m, 3 arom. H), 8.15 (bs, NH). LCMS (M+H): expected for 13: M=349.48; found: 350.3.
9,10-Didehydro-N,N-diethyl-6-cyclobutylergoline-8R-carboxamide (TRALA-23), 14a. To a solution of 42.2 mg (136.2 μmol) 6-Nor-LSD (11) and 15.2 μL (1.5 eq) cyclobutanone in 0.45 mL dichloromethane anhydr. were added 57.6 mg (2 eq) NaBH(OAc)3 and the mixture was stirred under nitrogen at ambient temperature for 2h. The mixture was diluted with water, stirred for 10 min, diluted with DCM and NaOH 1M was added to a final pH of 8-9. The layers were separated, and the aq. layer was further extracted with 2×DCM. The combined org. layers were dried over Na2SO4 and concentrated in vacuo. The residual crude product was purified with silica gel chromatography using DCM/MeOH/NEt3=98/2/0.1 as eluent. Yield: 13 mg (26%) TRALA-23 as a yellow foam. Analytical data of 14a as free base: 1H-NMR (CDCl3): 1.24 (m, 2×CH2CH3), 1.72 (m, 2H), 2.11 (m, 2H), 2.31 (m, 2H), 2.73 (m, 2H), 3.23 (d×d, 1H), 3.36-3.60 (m, 7H), 3.80 (m, 1H), 6.36 (s, H9), 6.90 (t, 1 arom. H), 7.13-7.24 (m, 3 arom. H), 8.06 (bs, NH). LCMS (M+H): expected for 14a: M=363.51; found: 364.4.
9,10-Didehydro-N,N-diethyl-6-(3-oxetanyl)ergoline-8R-carboxamide (TRALA-24), 14b. As described for compound X, from 42.2 mg (136.2 μmol) 6-Nor-LSD (11) and 12 μL (1.5 eq) 3-oxetanone in 0.45 mL dichloromethane anhydr. and 57.6 mg (2 eq) NaBH(OAc)3. Yield: 23 mg (46%) TRALA-24 as a beige-yellow foam. Analytical data of 14b as free base: 1H-NMR (CDCl3): 1.20 (t, CH2CH3), 1.29 (t, CH2CH3), 2.79 (m, 2H), 2.97 (m, 2H), 3.38-3.63 (m, 5H), 3.83 (m, 1H), 4.13 (p, 1H), 4.70 (t, 1H), 4.86 (m, 3H), 6.38 (s, H9), 6.87 (t, 1 arom. H), 7.13-7.23 (m, 3 arom. H), 8.16 (bs, NH). LCMS (M+H): expected for 14b: M=365.48; found: 366.4.
9,10-Didehydro-N,N-diethyl-6-((oxetan-3-yl)methyl)ergoline-8R-carboxamide (TRALA-25), 14c. As described for compound X, from 42.2 mg (136.2 μmol) 6-Nor-LSD (11) and 17.6 mg (1.5 eq) oxetane-3-carbaldehyde in 0.45 mL dichloromethane anhydr. and 57.6 mg (2 eq) NaBH(OAc)3. Yield: 25 mg (48%) TRALA-25 as a beige foam. Analytical data of 14c as free base: 1H-NMR (CDCl3): 1.20 (t, CH2CH3), 1.29 (t, CH2CH3), 2.79 (m, 2H), 2.97 (m, 2H), 3.38-3.63 (m, 5H), 3.83 (m, 1H), 4.13 (p, 1H), 4.70 (t, 1H), 4.86 (m, 3H), 6.38 (s, H9), 6.87 (t, 1 arom. H), 7.13-7.23 (m, 3 arom. H), 8.16 (bs, NH). LCMS (M+H): expected for 14c: M=379.51; found: 380.4.
1.) N6-Demethylation of TRALA-02: Preparation of 6-Nor-TRALA-02.
9,10-Didehydro-N-ethyl-N-propyn-3-ylergoline-8R-carboxamide (6-Nor-TRALA-02), 15. It followed exactly the procedure described for 6-Nor-LSD (11) by using 366 mg (1.1 mmol) TRALA-02 (2b) in 11 mL DCM, 295 mg (1.2 eq) mCPBA and 153 mg (0.5 eq) FeSO4 heptahydrate in 0.8 mL MeOH. The crude product was purified by silica gel chromatography using DCM/MeOH/NEt3=95/5/0.1 as eluent. Recovered starting material (2b; 67 mg; 18%) eluted first, followed by the title compound 15, yield: 172 mg (49%) as a tan solid. Analytical data of 15 as free base: 1H-NMR (CDCl3): 1.21 (2×t, sum=3H), 2.31 (m, 1H), 2.84 (t×m, 1H), 3.28-3.43 (m, ˜3H), 3.55-3.87 (m, ˜4H), 3.99 (m, 1H), 4.28 (m, 2H), 6.38 (ca. 60%)/6.48 (ca. 40%) (2×s, sum=H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 6.93 (s, 1 arom. H), 7.15-7.27 (m, 3 arom. H), 7.96 (bs, N1H). LCMS (M+H): expected for 15: M=319.41; found: 320.3.
2.) N6-Alkylation of 6-Nor-TRALA-02: Preparation of Compounds 16a-c.
9,10-Didehydro-N-ethyl-N-propyn-3-yl-6-(2-fluoroethyl)ergoline-8R-carboxamide (TRALA-26), 16a. According to the general procedure for N6 alkylations described, from total 28.5 μL (3×9.5 μL, 2nd addition on day 2, 3rd addition after 8h on day 2) 1-fluoro-2-iodoethane and 31 mg 6-Nor-TRALA-02 (15), reaction time: 6 days. Yield: 15 mg (42%) TRALA-26 as a yellow-beige foam. Analytical data of 16a as free base: 1H-NMR (CDCl3): 1.32 (m, 3H), 2.31 (m, 1H), 2.73 (t, 1H), 2.99 (m, 2H), 3.28 (m, 2H), 3.45-3.75 (m, 4H), 3.92 (m, 1H), 4.26 (m, 2H), 4.59 (m, 1H), 4.75 (m, 1H), 6.36 (ca. 55%)/6.45 (ca. 45%) (2×s, sum=H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 6.91 (t, 1 arom. H), 7.14-7.26 (m, 3 arom. H), 8.03 (bs, NH). 19F-NMR (CDCl3): −218.99, −219.03. LCMS (M+H): expected for 16a: M=365.45; found: 366.2.
9,10-Didehydro-N-ethyl-N-propyn-3-yl-6-(2-fluoro-1-propen-3-yl)ergoline-8R-carboxamide (TRALA-27), 16b. According to the general procedure for N6 alkylations described, from total 33.9 μL (3×11.3 μL, 2nd addition on day 2, 3rd addition after 8h on day 3) 3-bromo-2-fluoro-1-propene and 31 mg 6-Nor-TRALA-02 (15), reaction time: 6 days. Yield: 12 mg (33%) TRALA-27 as a yellow foam. Analytical data of 16b as free base: 1H-NMR (CDCl3): 1.31 (m, 3H), 2.31 (m, 1H), 2.74 (t×m, 1H), 3.01 (m, 1H), 3.31 (m, 2H), 3.48-3.78 (m, 5H), 3.89 (m, 1H), 4.27 (m, 2H), 4.59 (d×d, 1H), 4.78 (d×d, 1H), 6.37 (ca. 60%)/6.45 (ca. 40%) (2×s, sum=H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 6.92 (t, 1 arom. H), 7.14-7.26 (m, 3 arom. H), 7.99 (bs, NH). 19F-NMR (CDCl3): −97.77, −97.85. LCMS (M+H): expected for 16b: M=377.47; found: 378.3.
9,10-Didehydro-N-ethyl-N-propyn-3-yl-6-((RS)-(2,2-difluorocyclopropyl)-methyl)ergoline-8R-carboxamide (TRALA-28), 16c. According to the general procedure for N6 alkylations described, from total 59.4 μL (3×19.8 μL, 2nd addition on day 2, 3rd addition after 8h on day 3) rac. 2-(bromomethyl)-1,1-difluorocyclopropane and 31 mg 6-Nor-TRALA-02 (15), reaction time: 6 days. Yield: 13 mg (33%) TRALA-28 as a yellow foam. Analytical data of 16c as free base: 1H-NMR (CDCl3): 1.11 (m, 1H), 1.31 (m, 3H), 1.52 (m, 1H), 1.84 (m, 1H), 2.31 (m, 1H), 2.61-3.35 (m, 5H), 3.47-3.78 (m, 4H), 3.91 (m, 1H), 4.29 (m, 2H), 6.37 (ca. 50%)/6.45 (ca. 50%) (2×s, sum=H9; note; epimeric purity proof of C9 of the ergoline structure: see chapter General; amide couplings), 6.92 (s, 1 arom. H), 7.14-7.26 (m, 3 arom. H), 8.00 (bs, NH). 19F-NMR (CDCl3): −141.65, −141.73, −142.20, −142.28, −142.57, −142.60, −143.13, −143.16. LCMS (M+H): expected for 16c: M=409.48; found: 410.3.
Microsomal assays: The objective of this experiment was the investigation of the microsomal stability of 10 novel lysergamides (
Throughout this application, various publications, including United States patents, are referenced by author and year and patents by number. Full citations for the publications are listed herein. The disclosures of these publications and patents in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains.
The invention has been described in an illustrative manner and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention can be practiced otherwise than as specifically described.
| Number | Date | Country | |
|---|---|---|---|
| 63353673 | Jun 2022 | US |
