Patent Grant
8367812
This application claims priority under 35 U.S.C. §119 of FR 05/05283, filed May 26, 2005, and is a continuation of PCT/FR 2006/001098, filed May 16, 2006 and designating the United States (published in the French language on Nov. 30, 2006 as WO 2006/125884 A3; the title and abstract were also published in English), each hereby expressly incorporated by reference in its entirety and each assigned to the assignee hereof.
The field of the invention is the synthesis of functionalized organosilicon compounds.
The invention relates more particularly to organosilicon compounds comprising at least one activated azo group. Said activation can result, for example, from the presence of carbonyl groups near the nitrogens. The organosilicon moiety of these compounds can comprise for example hydrolyzable or condensable groups of type ≡SiOR or ≡SiOH.
Such organosilicon compounds with available activated azo group(s) (for example those with the group —CO—N═N—CO—) are very useful, notably in the synthesis of organic active molecules (for example nitrogen-containing heterocycles) for use in the areas of agrochemistry and pharmacy, for example as dienophiles in a hetero-Diels-Alder reaction.
However, few of these compounds are available, in particular because they are difficult to prepare. It would therefore be desirable to be able to extend the range of organosilicon compounds that are available.
In the sparse prior art, we find patent application FR-A-2340323, which discloses organosilicon compounds of formula (I*):
Y—X—CO—N═N—CO—X1—Z*
in which X and X1, which may be identical or different, each represent an imino group, an oxygen atom or a substituted or unsubstituted methylene group; Y is a substituted or unsubstituted alkyl, aryl or aralkyl group, or is identical to Z*; Z* is an alkyl, aryl or aralkyl group with, as substituent, at least one silane group of formula Si(OR)3 or OSi(OR)3 in which R is a linear or branched alkyl group, preferably with 1 to 6 carbon atoms.
Organosilicon compounds of formula (II*) and (III*):
R1*—O—CO—N═N—CO—NH—(C6H6)—(CH2)m—Si(OR2)3 (II*)
R1*—O—CO—N═N—CO—NH—(CH2)n—Si(OR2*)3 (III*)
in which R1* and R2*, which may be identical or different, each represent a linear or branched alkyl group preferably containing between 1 and 6 carbon atoms, m is equal to 0, 1, 2 or 3 and n is equal to 1, 2 or 3, are mentioned.
An organosilicon compound with azo groups of formula Ethyl-O—CO—N═N—CO—NH—(CH2)3—Si (OEthyl)3, according to formula (III*), is disclosed in example 3.
The key stage in the synthesis of organosilicon compounds of this type with an activated azo group comprises the oxidation of a function of the hydrazo (NH—NH) type to a corresponding azo (N═N) function.
According to FR-A-2340323, this transformation is carried out by means of an oxidizing system comprising an oxidizing agent formed by a halogenated derivative (chlorine, bromine, N-bromosuccinimide among other examples) and a base of the pyridine type.
Thus, the method described in example 3 of FR-A-2340323 envisages the application of an organic solution of precursor Ethyl-O—CO—HN—NH—CO—NH—(CH2)3—Si(OEthyl)3 and of pyridine, in dichloromethane. N-Bromosuccinimide (NBS) is added to this solution which is stirred for 2 hours after adding NBS. The solvent and the pyridine are removed by evaporation under vacuum, whereas the solid salts formed during the reaction are then removed by filtration. After washing the residue, the organosilicon compound with azo groups of formula (III*) is recovered in the filtrate. According to this document, the oxidizing system NBS-pyridine is used in excess (10 mol. %) relative to the precursor.
Finally, the end product is not pure. It contains residues that are undesirable and disadvantageous, notably in terms of industrial hygiene and of ecotoxicity on the one hand, and, on the other hand, in terms of performance in applications.
This known method has at least four drawbacks.
In view of the prior art, one of the essential aims of the present invention is to propose an improved method of preparation of organosilicon compounds with azo group(s), by oxidation of the hydrazino group of a precursor to an azo group.
Another essential aim of the invention is to provide a method of preparation of organosilicon compounds with azo group(s), which avoids the use of solid reagents such as solid NBS, which make the method somewhat more complicated, notably for incorporation in the reaction mixture.
Another essential aim of the invention is to provide a method of preparation of organosilicon compounds with azo group(s), which offers better performance than those of the prior art, notably in terms of productivity and of yield of target azoalkoxysilane.
Another essential aim of the invention is to provide a method of preparation of organosilicon compounds with azo group(s), which is to be economical.
Another essential aim of the invention is to provide a method of preparation of organosilicon: compounds with azo group(s), which would enable the quality of the final product to be optimized, notably with respect to the purity of organosilicon compounds and in particular by reducing to traces, or even completely eliminating undesirable residues of the base used, and notably pyridine residues when the base comprises pyridine. In doing so, the method is improved in terms of the quality of the final product, industrial hygiene and environmental impact.
Another essential aim of the present invention is to provide novel organosilicon compounds with azo group(s), with reduced content of pyridine residues.
These aims, among others, are achieved by the invention which relates, firstly, to a method of preparation of organosilicon compounds comprising one or more compounds, which may be identical to or different from one another, of formula (I) specified below:
[(G0)3SiO1/2]m[(G0)2SiO2/2]n[G0SiO3/2]o[SiO4/2]p[(G2)a(G1)a′(Z—CO—N═N—CO-A)SiO(3-a-a′)/2]q (I)
in which:
The inventors have found an alternative to the NBS oxidizing reagents known in this type of reaction, without affecting the performance of the method (yield/productivity), nor the quality of the product, while allowing the method to become more economical.
Moreover, said compounds (I) obtained by the method according to the invention are remarkably pure. In particular, these compounds have little or no (undetectable traces) of undesirable residues derived, for example, from base B, such as pyridine residues when B comprises pyridine.
Without wishing to be bound to a theory, it is possible that this purity is at the origin of the excellent stability found for said compounds (I) resulting from the two-phase method according to the invention. By “stability” we mean notably stability in storage, especially in humid conditions, but in particular stability when heated.
According to an alternative or cumulative embodiment, it is envisaged to use a stoichiometric amount of Ox relative to precursor (II), whereas in the known method according to application FR-A-2340323 the oxidizing agent is in excess.
Preferably, Ox is selected from the halogens, the halogen derivatives and mixtures thereof, and even more preferably from the group comprising: bromine, tert-butyl hypochlorite, trichloroisocyanuric acid, chlorine and mixtures thereof.
According to a particular embodiment of the method according to the invention, a base B is used that comprises pyridine in stoichiometric amount relative to precursor (II). Said use of a limited amount of pyridine represents a significant advance relative to the prior art, for, as already explained above, pyridine forms undesirable residues that are very difficult to remove from the final organosilicon compounds (I).
According to an interesting embodiment, permitting optimization of the purity of the final target organosilicon compounds (I), a post-treatment is proposed in one or more stages, offering a significant improvement in quality of the final organosilicon compounds (I), contributing to the complete or almost complete removal of the undesirable residues arising, for example, from base B, in particular pyridine residues, which may be present when base B comprises pyridine. This post-treatment is all the more remarkable as it does not affect the yield and/or productivity with respect to the final organosilicon compounds (I).
The method according to the invention for the preparation of organosilicon compounds with an azo group (I) can be classed as a method of synthesis comprising at least the following stages:
The oxidation in stage (ii) corresponds to the method of preparation according to the present invention.
For the preparation, for example, of organosilicon compounds with an azo group (I), in whose structure the symbol Z then represents the divalent radical —(CH2)3—NH—, the synthesis scheme that is employed can be as follows:
To summarize, stage (i) of obtaining the precursor (II) and stage (ii) of oxidation of (II) to (I) conform to the following general methodology:
Stage (i):
Preferably, purification of the organosilicon compounds (I) is carried out by applying a post-treatment by which the content of impurities is reduced or even eliminated. Said impurities may originate for example from base B. Thus, when base B contains pyridine, pyridine residues may be formed, which are particularly undesirable from the standpoint of industrial hygiene and the performance of compounds (I) in applications.
Thus, according to a preferred embodiment of the invention, the post-treatment essentially comprises bringing the organosilicon compounds (I) in contact with a trap for impurities, said trap being selected:
Even more preferably, the post-treatment essentially comprises:
In fact, stages a) to d) constitute a first treatment and stages e) to h) a second treatment, and these two treatments can be applied simultaneously or successively in any order.
Moreover, it is possible for the post-treatment used in the method according to the invention to comprise only one of these two treatments a) to d), on the one hand, and e) to h), on the other hand.
Apart from the general operating conditions described above, we should dwell a little longer on the organosilicon compounds with activated azo functional group(s) (I), obtained or that can be obtained by this method according to the invention.
As noted above, said compounds (I) are free or almost free (undetectable traces) of impurities, notably of pyridine residues. The invention therefore relates to organosilicon compounds with activated azo functional group(s) (I), as novel products, that can be obtained by the method according to the invention, characterized in that they are free or almost free (undetectable traces) of impurities, notably of pyridine residues.
Preferably, these novel organosilicon compounds (I) can be characterized by a content (wt. %) of pyridine residues less than or equal to 0.3, preferably to 0.2, and even more preferably to 0.1.
These organosilicon compounds with activated azo functional group(s) (I), which can be obtained by the method according to the invention, are also characterized in that they are stable when heated, e.g. at temperatures between 80 and 180°.
The invention also relates to the organosilicon compounds with activated azo functional group(s) (I), as novel products, characterized by a degree of hydrolysis/condensation (mol. %) of the functions G2 less than or equal to 40, preferably to 10, and even more preferably to 1.
Moreover, in the following we shall return again to the meaning of the symbols in formula (I) above.
Firstly, it has to be understood that the group (Z—CO—N═N—CO-A) is joined to the Si atom of the SiO(3-a-a′)/2 unit via the divalent radical —Z—.
Moreover, aliphatic hydrocarbon group means, in the sense of the invention, a linear or branched group, preferably comprising from 1 to 25 carbon atoms, optionally substituted.
Advantageously, said aliphatic hydrocarbon group comprises from 1 to 18 carbon atoms, better still from 1 to 8 carbon atoms and even better still from 1 to 6 carbon atoms.
As saturated aliphatic hydrocarbon group, we may mention the alkyl groups, such as the methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, pentyl, isopentyl, neopentyl, 2-methylbutyl, 1-ethylpropyl, hexyl, isohexyl, neohexyl, 1-methylpentyl, 3-methylpentyl, 1,1-dimethylbutyl, 1,3-dimethylbutyl, 2-ethylbutyl, 1-methyl-1-ethylpropyl, heptyl, 1-dimethylhexyl, 1-propylbutyl, 4,4-dimethylpentyl, octyl, 1-methylheptyl, 2-ethylhexyl, 5,5-dimethylhexyl, nonyl, decyl, 1-methylnonyl, 3,7-dimethyloctyl and 7,7-dimethyloctyl, hexadecyl radicals.
The unsaturated aliphatic hydrocarbon groups comprise one or more unsaturations, preferably one, two or three unsaturations of the ethylenic type (double bond) and/or acetylenic type (triple bond).
Examples of them are the alkenyl or alkynyl groups derived from the alkyl groups defined above by elimination of two or more hydrogen atoms. Preferably, the unsaturated aliphatic hydrocarbon groups comprise a single unsaturation.
Within the scope of the invention, carbocyclic group means a monocyclic or polycyclic radical, optionally substituted, preferably of C3-C50. Advantageously, it is a C3-C18 radical, preferably mono-, bi- or tricyclic. When the carbocyclic group comprises more than one cyclic nucleus (as in the case of polycyclic carbocycles), the cyclic nuclei are condensed two by two. Two condensed nuclei can be orthocondensed or pericondensed.
The carbocyclic group can comprise, unless stated otherwise, a saturated moiety and/or an aromatic moiety and/or an unsaturated moiety.
Examples of saturated carbocyclic groups are the cycloalkyl groups. Preferably, the cycloalkyl groups are of C3-C18, and better still of C5-C10. We may notably mention the cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, adamantyl or norbornyl radicals.
The unsaturated carbocycle or any unsaturated moiety of the carbocyclic type has one or more ethylenic unsaturations, preferably one, two or three. It has advantageously from 6 to 50 carbon atoms, and better still from 6 to 20, for example from 6 to 18. Examples of unsaturated carbocycles are the C6-C10 cycloalkenyl groups.
Examples of aromatic carbocyclic radicals are the (C6-C18)aryl groups, and better still (C6-C12)aryl and notably phenyl, naphthyl, anthryl and phenanthryl.
A group having both an aliphatic hydrocarbon moiety as defined above and a carbocyclic moiety as defined above is, for example, an aralkyl group such as benzyl, or an alkaryl group such as tolyl.
The substituents of the aliphatic hydrocarbon groups or moieties and of the carbocyclic groups or moieties are, for example, alkoxy groups in which the alkyl moiety is preferably as defined above.
By hydrolyzable monovalent group, as was discussed above in connection with the symbols G2, we mean groups such as, for example: halogen atoms, notably chlorine; the groups —O-G7 and —O—CO-G7 where G7 represents: a saturated or unsaturated, aliphatic hydrocarbon group, or a saturated, unsaturated and/or aromatic, monocyclic or polycyclic, carbocyclic group, or a group having a saturated or unsaturated, aliphatic hydrocarbon moiety and a carbocyclic moiety as defined above, and G7 can optionally be halogenated and/or substituted with one or more alkoxy; the groups —O—N═CG8G9 in which G8 and G9 assume, independently, any one of the meanings given above for G7, and G8 and G9 can be halogenated and/or optionally substituted with one or more alkoxy; the groups —O-NG8G9 in which G8 and G9 are as defined above.
Advantageously, said hydrolyzable monovalent group is a radical: C1-C8 alkoxy, linear or branched, optionally halogenated and/or optionally substituted with one or more (C1-C8)alkoxy; C2-C9 acyloxy optionally halogenated or optionally substituted with one or more (C1-C8)alkoxy; C5-C10 cycloalkyloxy; or C6-C18 aryloxy. As an example, the hydrolyzable group is methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, methoxymethoxy, ethoxyethoxy, methoxyethoxy, β-chloropropoxy or β-chloroethoxy or alternatively acetoxy.
As monovalent carbocyclic groups that can be formed together, in formula (I), by two substituents G2 and the silicon atom to which they are attached, we may mention for example the ring systems:
As single rings that can be formed together on the one hand by the substituents G3 and G4 of the nitrogen atom present in symbol A of formula (I) and on the other hand by the substituents R2 and R3 of the nitrogen atom present in symbol J of formula (III), we may mention for example the following rings where the free valence is carried by a nitrogen atom: pyrrole, imidazole, pyrazole, pyrrolidine, Δ2-pyrroline, imidazolidine, Δ2-imidazoline, pyrazolidine, Δ3-pyrazoline, piperidine; preferred examples are: pyrrole, imidazole and pyrazole.
In preferred forms F1 of formula (I):
In more preferred forms F2 of formula (I):
In even more preferred forms F3 of formula (I):
According to an especially preferred embodiment, the functionalized organosilicon compounds of general formula (I) are selected from the group comprising the following species:
The siloxane oligomers (2i) constitute a subgroup of compounds of formula (I). This subgroup is derived from a group of compounds of formula (I) corresponding to condition -(C1)- of the method according to the invention, namely when a=0, then:
To obtain said compounds (I) complying with condition -(C1)-, it is advisable to employ an additional reagent (III) during the corresponding oxidation.
The amount of additional reagent (III) employed is not critical, but it is preferable, according to the invention, for this amount, relative to precursor (II), to be at least 0.1M, preferably from at least 1M up to 100M or more and, even more preferably, should be between 1 and 10M.
An example of additional reagent (III) is trimethylethoxysilane.
Advantageously, species (2i) are subdivided into subspecies:
According to an interesting variant of the especially preferred embodiment, the functionalized organosilicon compounds of general formula (I) are selected from the group of the following (sub)species:
Within this variant, functionalized organosilicon compounds of general formula (I) that are particularly preferred are those formed by a mixture (3i) of at least one species (i) and/or of at least one subspecies (2i.1) and/or of at least one subspecies (2i.2).
In practice, it is possible for the organosilicon compounds according to the invention to comprise at least one mixture (3i) including compounds (i) and/or (2i.1) and/or (2i.2) of formula (I) in which:
The invention also relates to organosilicon compounds of general formula (I), which can be obtained by the method according to the invention, taken in themselves and selected from the group comprising the following species:
If no additional reagent (III) is used, the compounds produced are silanes of the species (i), or in other words those corresponding to the following formula (I′):
(G2)a(G1)a′(Z—CO—N═N—CO-A)SiO(3-a-a′)/2 (I′)
in which
Even more preferably, the silanes of formula (I) in which a represents an integer equal to 3 and the symbols G1, G2, Z and A correspond to the same definitions as those given above for the preferred form F3.
As examples of silanes (i) of formula (I′) that are especially suitable, we may notably mention the species of type (i) where a=3, a′=0, m=n=o=p=0 and q=1, of formulas:
(C2H5O)3Si—(CH2)3—NH—CO—N═N—COOC2H5 (ia)
(C2H5O)3Si—(CH2)3—NH—CO—N═N—COOCH3 (ib)
(CH3O)3Si—(CH2)3—NH—CO—N═N—COOC2H5 (ic)
(n-C4H9O)3Si—(CH2)3—NH—CO—N═N—COOC2H5 (id)
(C2H5O)2(Me3SiO)Si—(CH2)3—NH—CO—N═N—COOC2H5 (ie)
(C2H5O)2(Me3SiO)Si—(CH2)3—NH—CO—N═N—COOCH3 (if)
(CH3O)2(Me3SiO)Si—(CH2)3—NH—CO—N═N—COOC2H5 (ig)
(n-C4H9O)2(Me3SiO)Si—(CH2)3—NH—CO—N═N—COOC2H5 (ih)
The invention will be better understood and its advantages will be seen more clearly from the examples given below, which illustrate the scope and the advantages of the method and of the novel products defined above.
These examples describe:
The above examples therefore show that:
Load Materials:
Load Materials:
The residue, which is in the form of an orange paste, is taken up in 45 mL of a heptane/iPr2O mixture (1/1:vol/vol) then filtered on a glass frit (125 mL) of porosity 4. The filter cake is washed with additional 2×10 mL of the previous solvent mixture.
(i) Mixture of pyridine and pyridinium hydrobromide
From the standpoint of industrial hygiene and ecotoxicity, the presence of pyridine residues is problematic. It is therefore particularly interesting to have samples containing a minimal amount of these compounds.
As the pyridine residues are made up of a mixture of pyridinium hydrobromide and pyridine, a double treatment has been envisaged:
Treatment with Carbon Black 2S is carried out according to the following operating procedure:
The treatment with the resin is carried out according to the following operating procedure:
(i) N.D. = not determined
The above examples show that the treatment with Carbon Black 2S can remove the pyridinium hydrobromide, while the resin can trap the pyridine. Used consecutively, these two treatments therefore make it possible to obtain samples that are free or almost free of pyridine derivatives.
The synthetic route followed in the laboratory is described, though without examples, in many documents. It is shown schematically below.
Load Materials
Procedure
| Number | Date | Country | Kind |
|---|---|---|---|
| 05 05283 | May 2005 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR2006/001098 | 5/16/2006 | WO | 00 | 1/5/2009 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2006/125884 | 11/30/2006 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4118367 | Dawes et al. | Oct 1978 | A |
| 5362794 | Inui et al. | Nov 1994 | A |
| 5380828 | Ravichandran et al. | Jan 1995 | A |
| Entry |
|---|
| Mitchell, H. et al, “Animation of Arenes with Electron-Deficient Azodicarboxylates,” J. Org. Chem., 1994, pp. 682-687, vol. 59. |
| Dawes, K et al., Chemical modification of natural rubber—a new silane coupling agent, Plastics and Rubber: Materials and Applications, Feb. 1978, pp. 24-25, XP0009060017, London, England. |
| Dawes, K et al., Chemical modification of natural rubber—a new silane coupling agent, RUBBERCON '77, 1977, pp. 18.1-18.11. |
| International Search Report, Oct. 13, 2006. |
| Number | Date | Country | |
|---|---|---|---|
| 20090216000 A1 | Aug 2009 | US |
