Claims
- 1. A chemical compound having the formula: ##STR11## in which: A is a single bond or a D or L-isomer of Pro, MeArg, HArg or Arg;
- B is a D or L-isomer of MeArg, HArg, Arg, Lys, Orn or NR.sub.1 (CH.sub.2).sub.n NR.sub.2 R.sub.3 ;
- C is Gly, Gly(NH.sub.2), OH, NH.sub.2, or when B is NR.sub.1 (CH.sub.2).sub.n NR.sub.2 R.sub.3, C is absent;
- R.sub.1 and R.sub.2 are each H or CH.sub.3 ;
- R.sub.3 is H or C(.dbd.NH)NH.sub.2 ;
- W is Phe, 4'-Alk Phe, Ile, Cha, Tyr or O-Alk Tyr; Tyr and O-Alk Tyr being D-isomers
- X is Phe, 4'-Alk Phe, O-Alk Tyr, Ile or Tyr;
- Y is Val, Ile, Abu, Chg, Gln, Lys, Cha, Nle, Leu, Ala or Gly;
- Z is D or L isomer of Cys;
- n is 2 to 6; or a pharmaceutically acceptable salt or ester prodrug thereof; and
- "Alk" represents a lower alkyl of 1 to 4 carbons.
- 2. A compound of claim 1 in which A is Pro and C is NH.sub.2.
- 3. A compound of claim 1 in which A is Pro and C is Gly(NH.sub.2).
- 4. A compound of claim 1 in which A and B are both Arg.
- 5. A compound of claim 1 in which A is MeArg.
- 6. A compound of claim 1 in which the compound is [1-(.beta.,.beta.-diethyl-.beta.-mercaptopropionic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-arginine]vasopressin or a pharmaceutically acceptable salt thereof.
- 7. A compound of claim 1 in which the compound is [1-.beta.,.beta.-diethyl-.beta.-mercaptopropionic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-arginine-9-desglycine]vasopressin or a pharmaceutically acceptable salt thereof.
- 8. A pharmaceutical composition having vasopressin V.sub.2 -antagonist activity comprising a pharmaceutical carrier and, dispersed therein, an effective therefor but nontoxic quantity of a compound of claim 1.
- 9. A pharmaceutical composition having vasopressin V.sub.2 -antagonist activity comprising a pharmaceutical carrier and, dispersed therein, an effective therefor but nontoxic quantity of the compound of claim 6.
- 10. A pharmaceutical composition having vasopressin V.sub.2 -antagonist activity comprising a phramaceutical carrier and, dispersed therein, an effective therefor but nontoxic quantity of the compound of claim 7.
- 11. The method of producing vasopressin V.sub.2 -antagonist activity in a patient in need thereof which comprises administering parenterally or intranasally to said patient an effective therefor, nontoxic quantity of a compound of claim 1.
- 12. The method of producing vasopressin V.sub.2 -antagonist activity in a patient in need thereof which comprises administering parenterally or intranasally to said patient an effective therefor, nontoxic quantity of the compound of claim 6.
- 13. The method of treating congestive heart failure in a patient in need thereof which comprises administering parenterally or intranasally to said patient an effective therefor, nontoxic quantity of a compound of claim 1.
- 14. The method of treating congestive heart failure in a patient in need thereof which comprises administering parenterally or intranasally to said patient an effective therefor, nontoxic quantity of the compound of claim 6.
- 15. The method of treating hypertension in a patient in need thereof which comprises administering parenterally or intranasally to said patient an effective therefor, nontoxic quantity of a compound of claim 1.
- 16. The method of treating hypertension in a patient in need thereof which comprises administering parenterally or intranasally to said patient an effective therefor, nontoxic quantity of the compound of claim 6.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| 86307580.0 |
Oct 1986 |
EPX |
|
BACKGROUND OF THE INVENTION
This application is a continuation-in-part of application Ser. No. 782,671 filed Oct. 2, 1985, which is now abandoned.
This invention relates to [1-(.beta.,.beta.-diethyl-.beta.-mercaptopropionic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-arginine]vasopressin compounds which have unexpected aquaretic activity. Pharmaceutical compositions and methods for inducing water diuresis (aquaretic activity) in patients in need thereof are also part of this invention.
M. Manning et al., J. Med. Chem. 25 406 (1982), discloses certain compounds related in structure to those of the present invention. Note that Manning's series of compounds involve structures which have L-tyrosine at position 2. The compounds, particularly the 1-.beta.-,.beta.-diethyl-.beta.-mercaptopropionic acid congeners, are also described as potent VSP antagonists at V.sub.1 -receptor sites which results in anti-vasopressor activity. The compounds were also determined to have weak agonist or anti-diuretic activity at V.sub.2 -receptor sites. Finally, Manning concludes that predictability in this field was uncertain, even within closely related structural pairs of compounds.
The Manning publication, along with earlier patent applications filed by our assignee such as Ser. No. 673,828 now U.S. Pat. No. 4,599,324, 673,829 now U.S. Pat. No. 4,604,378 and 747,646 now U.S. Pat. No. 4,640,120, indicate that substitution of an acyclic propionic acid unit at position 1 of VSP-like structures increase antagonism at V.sub.1 (pressor) receptors and decrease or reverse antagonism at V.sub.2 (antidiuretic) receptors. Contrary to these teachings, we have now found that VSP-like compounds which have a Tyr(Et) unit at position 2 and a Mpr(Et) unit at position 1 of their structures have very potent V.sub.2 -antagonistic properties. Therefore, they have useful water diuretic properties. The compounds of this invention are the first potent V.sub.2 -antagonists whose structures do not have a spiroalkyl-containing propionic acid at position 1 in the VSP art to the best of our knowledge.
In the description herein and in the claims, the nomenclature common in the art of peptide and, more specifically, vasopressin chemistry is used. When no configuration is noted, the amino acid unit is in the L, or naturally occurring, form. The thio members of the .beta.-mercaptopropionic acid (1) and cysteine (6) units are added for clarity in certain structural formulas.
Exemplary of the peptide art designations used herein are the following: dPen, .beta.-mercapto-.beta.,.beta.-dimethylpropionic acid; Mpr, .beta.-mercaptopropionic acid; Mpr(Et), .beta.-mercapto-.beta.,.beta.-diethylpropionic acid; Pmp, .beta.-mercapto-.beta.,.beta.-cyclopentamethylenepropionic acid; Gly, glycine; Tyr, tyrosine; Tyr(Et), ethyl ether of tyrosine; D-Tyr(Et), O-ethyl-D-tyrosine; L-Tyr(Et), O-ethyl-L-tyrosine; Arg, arginine; MeArg, N-methylarginine; HArg, homoarginine; Phe, phenylalanine; Cad, cadaverine, NH.sub.2 (CH.sub.2)5NH.sub.2 ; Val, valine; Lys, lysine; Orn, Ornithine; Cha, cyclohexyl-alanine; Ile, isoleucine; Gln, glutamic acid amide or glutamine; Lysine, lysine; Nle, norleucine; Leu, leucine; Ala, alanine; Abu, .alpha.-amino-n-butyric acid; O-AlkTyr, O-alkyltyrosine; 4'-AlkPhe; 4'-alkylphenyl-alanine; Chg, cyclohexylglycine; Clz, 2 chlorobenzyloxy carbonyl; VSP, vasopressin; AVP, 8-arginine vasopressin; VAVP, 4-valine-8-arginine vasopressin; Asn, asparagine; Tos, tosylate; BHA, benzhydrylamine; DIEA, diisopropylethylamine; 4-MeBzl, 4-methylbenzyl; TFA, trifluoroacetic acid; DCC, dicyclohexylcarbodiimide; HOBT, 1-hydroxybenzotriazole; ACM, acetamidomethyl.
A is a single bond or a D or L-isomer of Pro, MeArg, HArg or Arg;
B is a D or L-isomer of MeArg, HArg, Arg, Lys, Orn or NR.sub.1 (CH.sub.2)nNR.sub.2 R.sub.3 ; and
C is Gly, Gly(NH.sub.2), OH or NH.sub.2, or when B is NR.sub.1 (CH.sub.2)nNR.sub.2 R.sub.3, C is absent;
R.sub.1 and R.sub.2 are each H or CH.sub.3 ; R.sub.3 is H or C(.dbd.NH)NH.sub.2 ;
W is Phe, 4'-Alk Phe, Ile, Cha, Tyr or O-Alk Tyr;
X is Phe, 4'-Alk Phe, O-Alk Tyr, Ile or Tyr;
Y is Val, Ile, Abu, Chg, Gln, Lys, Cha, Nle, Leu, Ala or Gly;
Z is D or L isomer of Cys; and
n is 2 to 6; or a pharmaceutically acceptable salt or ester prodrug thereof.
A subgeneric group of the compounds of formula I are those in which the Tyr(Et) is the D-isomer; A is Pro or Arg; B is Arg; and C is Gly(NH.sub.2) or NH.sub.2.
"Alk" represents a lower alkyl of 1 to 4 carbons.
Also included in this invention are various derivatives of the compounds of formula I such as addition salts, prodrugs in ester form and complexes. The addition salts may be either salts with pharmaceutically acceptable cations such as NH.sup..sym., Ca.sup..sym..sym., K.sup..sym. or Na.sup..sym. at a terminal acid group, when present, or with a pharmaceutically acceptable salt at a basic center of the peptide (as in Cad or Arg unit). The acetate salt forms are especially useful although hydrochloride, hydrobromide and salts with other strong acids are useful. In the isolation procedures outlined in the Examples, the peptide product is often isolated as the acetate salt. The compounds also form inner salts or zwitter ions as when a free terminal carboxy group is present.
Prodrugs are derivatives of the compounds of formula I which degrade to the parent compound in vivo. The ester prodrug forms are, for example, lower alkyl esters of the acids of formula I which have from 1-8 carbons in the alkyl radical or aralkyl esters which have 6-12 carbons in the aralkyl radical such as various benzyl esters. Such ester derivatives are prepared by methods known to the art. Other latentiated derivatives of the compounds of formula I will be obvious to those skilled in the art. "Complexes" include various solvates, such as hydrates or alcoholates, or those with supporting resins, such as a Merrifield resin.
The compounds of formula I are prepared by cyclizing a linear peptide intermediate of this invention by means of the two mercapto groups located, respectively, in the cysteine unit at position 6 and in the .beta.-mercaptopropionic acid unit at position 1. The cyclization reaction occurs in the presence of a mild oxidizing agent which, at high dilution, is capable of oxidizing intramolecularly the dimercaptan to a disulfide.
Oxidation of the following linear peptide; ##STR2## in which A, B, C, W, X, Y and Z are as defined for formula I, is carried out as described generally above. For example, an excess of an alkali metal ferricyanide, such as potassium or sodium ferricyanide, is used. The linear intermediate is dissolved in a suitable unreactive solvent, preferably in an aqueous solvent, at a neutral pH, about 7-7.5. The reaction is run at ambient temperature, or lower, until substantially complete. Lower alcohols, such as methanol, may be added. Preferably, the concentrations of the linear peptide dimercaptan and the oxidizing agent are low, say 0.01 molar concentration of oxidizing agent in several liters of aqueous solution to cyclize 1-6 grams of dimercaptan.
Other mild oxidation agents having an oxidation potential roughly equivalent to ferricyanide may also be used for the ring closure reaction. Oxygen, iodine, diiodoethane, hydrogen peroxide or cupric catalyzed oxidation are alternatives. Of course, one skilled in the art will recognize that certain cyclization methods are not appropriate if an interfering reaction site is present in the structure of the starting material of formula II. The linear mercaptan starting material may or may not have protecting groups common in the art present at the various amino acid units or at the mercapto positions. In the former case, the protecting groups are removed after cyclization. In the case of the ACM-SH protecting groups, removal of the protective group and cyclization may both be accomplished using iodine in aqueous methanol. Usually, however, the free linear peptide is cyclized.
The peptides of formula I are conveniently isolated by acidifying the aqueous oxidation mixture, such as using glacial acetic acid, and passing the reaction mixture over an ion-exchange chromatographic column, for example, over a weakly acid, acrylic resin column with elution using buffered base, or by gel filtration over a bead-formed gel prepared by cross-linking dextran with epichlorohydrin. Often, the acetate salt is isolated by this method.
The important intermediates of formula II, in free or protected form are conveniently prepared using solid-phase methods of peptide synthesis as discussed in M. Manning et al., J. Med. Chem. 25 46 (1982). A commercial benzhydrylamine support resin (BHR) is used to prepare the amide end products of formula I, i.e. in which C is NH.sub.2 or Gly(NH.sub.2), (the amides), and a chloro-methyl support resin (CMR) is used to prepare the acid compounds of formula I, i.e. in which C is OH or Gly, (the acids). Solution or enzymatic synthetic methods can also be used.
The peptide chain of the linear peptides of formula II is built up, stepwise, proceeding from the C-terminal unit working toward the characterizing unit 1. Each unit is properly protected as known in the peptide art and as described below. The sequence of step reactions is conveniently carried out in a Beckman 990-B peptide synthesizer without isolation of each intermediate peptide. The details of the overall synthetic procedure are in the working examples presented hereinafter.
The various amino acids, which are consecutively added to the resin supported chain are protected as known to the art. For example, the Boc protecting group is used for an amino group especially at the .alpha.-position of the amino acid; ethylcarbamoyl, adamantyl, t-butyl, acetamidomethyl, trityl or an optionally substituted benzyl, for the mercapto groups at the propionic acid and Cys units; nitro; carbobenzoxy, methylene-2-sulfonyl or tosyl for a Arg, MeArg or HArg unit; and ethyloxycarbonyl or an optionally substituted carbobenzoxy (Z) for amino or hydroxyl groups. The protective groups should, most conveniently, be those which are easily removed, such as using acid treatment for the tert.-butyloxycarbonyl (Boc) group, sodium-liquid ammonia or modified catalytic hydrogenation for the benzyl or carbobenzoxy groups.
The protected linear peptide intermediate is split from the carrying resin matrix, for example, by using ammonia in an aqueous miscible solvent, and, then, is treated to remove the protective groups, such as by using sodium-liquid ammonia. This procedure gives the amide derivative of the linear peptide intermediate.
More conveniently, the two steps are combined by treating the resin supported peptide with anhydrous hydrogen fluoride using a suitable carbonium ion scavenger, such as anisole, to give the linear peptide intermediate of formula II in good yield.
An alternative procedure for preparing the compounds of formula I is the attachment of one or more of the side chain units (A, B or C) to the acid form of the next lower cyclized peptide. For example, compounds of formula I in which B is cadaverine are prepared by the method described in U.S. Pat. No. 4,543,349. The condensation comprises the condensation of the polypeptide in the carboxy terminal acid form with the side chain unit whose acid or second basic center is protected, usually in the presence of DCC with HOBT or DMAP.
The compounds of this invention have potent V.sub.2 vasopressin antagonist activity. Vasopressin is known to contribute to the anti-diuretic mechanism of action within the kidney. When the action of the compounds of this invention antagonizes that of the natural anti-diuretic hormone (ADH), the body excretes water due to an increased permeability of the terminal portions of the renal tubule. This mechanism of action is at the vasopressin receptors (V.sub.2 -receptors) located on the plasma membrane of certain renal epithelial cells. It is antagonistic in nature, not agonistic.
Any patient suffering from the syndrome of inappropriate antidiuretic hormone secretion (SIADH) or from an undesirable edematous condition is a target for compounds which have substantial V.sub.2 -antagonist activity. Examples of clinical conditions indicated for such compounds include hypertension, hepatic cirrhosis, congestive heart failure or a component of any traumatic condition resulting from serious injury or disease.
The compounds of the present invention are, therefore, potent antagonists at V.sub.2 -receptor sites as well as lower activity at the V.sub.1 -receptor sites and have a potent aquaretic or water diuretic activity in human or animal patients in need of such activity.
The compounds of this invention, therefore, are used to induce water diuresis via a V.sub.2 -antagonism as noted above in patients in need of such antagonist treatment by administration internally, particularly parenterally or by insufflation, to said patients. A non-toxic but effective quantity of the chosen compound is preferably combined with a pharmaceutical carrier. Dosage units contain a nontoxic, effective quantity of the active ingredient selected from the range 0.05-50 mcg/kg, preferably 1-15 mcg/kg, based on a 70 kg patient. The dosage units are administered from 1 to 5 times daily or by continuous intravenous drip.
The pharmaceutical compositions of this invention, which contain an active ingredient of formula I, comprise a dosage unit quantity as described above dissolved or suspended in a standard liquid carrier. Such a carrier is isotonic saline. The composition is often used in an ampoule or a multiple dose vial suitable for parenteral injection, such as for intravenous, subcutaneous or intramuscular administration. A composition for insufflation may be similar but is often administered in a metered dose applicator or inhaler. Pulverized powder compositions may be used along with oily preparations, gels, buffers for isotonic preparations, emulsions or aerosols.
Antagonistic activity at the V.sub.2 -vasopressin receptors is determined in a protocol which determines in vivo diuretic activity in the hydropenic rat (ED.sub.300 .mu.g/kg). This procedure is described in the literature: F. Stassen et al., 1st International Conference on Diuretics, Miami, FL., March (1984).
These data demonstrate the compounds of this invention, especially Compounds A and B, are very potent V.sub.2 -antagonists compared with a representative dPen.sup.1, congener (Compound D). As such they represent the first potent V.sub.2 -antagonists whose structures do not have a cycloalkyl moiety at position 1.
Non-Patent Literature Citations (2)
| Entry |
| Manning et al., "Design of Potent and Selective Antagonists of the Vasopressor Responses to Arginine-Vasopressin", J. Med. Chem., 1982, 25, 406-414. |
| Manning et al., "Synthesis and Some Pharmacological Properties of 18 Potent O-Alkyltyrosine-Substituted Antagonists of the Vasopressor Responses to Arginine-Vasopressin", J. Med. Chem., 1985, 28, 1485-1491. |
Continuation in Parts (1)
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Number |
Date |
Country |
| Parent |
782671 |
Oct 1985 |
|
Patent Grant
4749782
