# Patent

## Title
Preparation of cyanate esters

## Abstract

Particular monomers are: 2-cyano-4,4-dimethoxy-3-hydroxy-1-butene; 2-cyano-4,4-dibutoxy-3-hydroxy-1-butene; 4,4-dibutoxy-2-ethoxycarbonyl-3-hydroxy-1-butene; 2-butoxycarbonyl-4,4-dibutoxy-3-hydroxy-1-butene; 4,4-dimethoxy-2-hydroxythoxycarbonyl-1-butene; 4,4-dimethoxy-2-dimethylaminoethoxycarbonyl -3-hydroxy-1-butene; and 4,4-dimethoxy-2-ethoxycarbonyl-3-hydroxy-1-butene.

## Background
The present invention concerns new polyfunctional ethylenic monomers

These new polyfunctional ethylenic monomers correspond to the general formula (I): ##STR2## wherein:

R represents a cyano group, substituted or unsubstituted acyl group, substituted or unsubstituted alkoxycarbonyl group or substituted or unsubstituted aryloxycarbonyl group,

R.sub.1 and R.sub.2 are identical, each representing a --CHR.sub.3 R.sub.4 group wherein R.sub.3 and R.sub.4 may be identical or different and represent a hydrogen atom or an alkyl, alkenyl or aralkyl radical, or

R.sub.1 and R.sub.2 together form a bivalent radical --CH.sub.2 --(CR.sub.5 R.sub.6)n--CHR.sub.7, wherein n is 0 or 1 and R.sub.5, R.sub.6 and R.sub.7 may be identical or different and represent a hydrogen atom or methyl group.

"Substituted or unsubstituted acyl" can mean, for example, an acetyl, propionyl, benzoyl or phenylacetyl radical.

"Substituted or unsubstituted alkoxycarbonyl" can mean, for example, a methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, dimethylaminoethoxycarbonyl or hydroxyethoxycarbonyl radical.

"Substituted or unsubstituted aryloxycarbonyl" can mean, for example, a phenoxycarbonyl radical.

"Alkyl" may mean, for example, a methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 1-methylpropyl or 1-ethylpropyl radical.

"Alkenyl" may mean, for example, an allyl or methallyl radical.

"Aralkyl" may mean, for example, a benzyl radical substituted if required, on the aromatic ring, or a phenethyl radical substituted if required on the aromatic ring.

A more particular object of the invention is a product as defined above characterised in that in formula (I), R represents a cyano or substituted or unsubstituted alkoxycarbonyl group and R.sub.1 and R.sub.2, when identical, each represent a methyl, ethyl or butyl group. Alternatively, R.sub.1 and R.sub.2 together form a bivalent radical such as ethylene, trimethylene, propylene or 2,2-dimethyl-1,3-propanediyl.

Among these latter products the invention particularly covers:

Products of formula (I) above can be prepared by methods which are known per se, consisting in reacting the monoacetal of the glyoxal of formula (II): ##STR3## (wherein R.sub.1 and R.sub.2 have the signification given above) with an ethylenic derivative having formula (III):

(wherein R has the signification given above) in the presence of an aprotic alkaline catalyst advantageously selected from the tertiary amines. Preferably the alkaline catalyst is [2,2,2]-diazabicyclo-1,4-octane, hereinafter termed DABCO.

Such methods are described in the following patents: U.S. Pat. Nos. 3,499,024; 3,743,669; 4,652,669; FR Nos. 1 506 132; 2 120 686; EP Nos. 185 234; 196 708.

Products of general formula (I) are valuable polyfunctional monomers which can be used, for example, to prepare polymers.

The following examples are given by way of example and are in no way limiting:

A solution constituted by:

The solution was diluted with 150 g diethyloxide then washed with 100 g of 1 N hydrochloric acid and the aqueous phase washed twice with 150 g diethyloxide. The recombined organic phases were washed with water until the washings were neutral then dried over anhydrous magnesium sulphate, filtered and vacuum concentrated. Finally the colourless residual oil was vacuum distilled.

17.58 g of 2-cyano-4,4-dimethoxy-3-hydroxy-1-butene was thus obtained which distilled at 80.+-.3.degree. C. 0.05 mbar. Microanalysis C %   H %    N %     O % ______________________________________ C.sub.7 H.sub.11 NO.sub.3 calculated 53.5    7.05 8.9   30.55 Mol. Wt = 157.17 found      53.8    7.1  8.7 ______________________________________

.sup.1 H NMR in CDCl.sub.3 at 200 MHz:

6.12 ppm (m, 2H, CH.sub.2 .dbd.),

4.33 ppm (d, 1H, J=5.8 Hz, CH(OMe).sub.2),

4.19 ppm (m, 1H, CHOH),

3.48 ppm (s, 3H, OCH.sub.3),

3.47 ppm (s, 3H, OCH.sub.3)

2.86 ppm (m, 1H, OH).

.sup.13 C NMR in CDC.sub.13 at 50 MHz:

132.8 ppm CH.sub.2 .dbd.,

122 ppm.dbd.C ,

116.8 ppm C.tbd.N,

104.9 ppm CH(OMe).sub.2,

71.8 ppm CHOH,

56 ppm OCH.sub.3,

55.2 ppm OCH.sub.3.

0.17 mole acrylonitrile and 30 g (0.15 mole) of 95.5% by weight dibutoxyethanal in butanol were reacted using the method of example 1to form 22 g of 2-cyano-4,4-dibutoxy-3-hydroxy-1-butene which distilled at 108.degree. C. under 0.1 mbar.

118 mmoles ethyl acrylate and 10 g (86.5 mmoles) of 90% by weight dimethoxyethanal in methanol were reacted using the method of example 1 to form 4,4-dimethoxy-2-ethoxycarbonyl-3-hydroxy-1-butene as a liquid which distilled at 108.degree. C. under 0.3 mbar. Microanalysis C %    H %    O % ______________________________________ C.sub.9 H.sub.16 O.sub.5 calculated 52.94    7.89 39.17 Mol. Wt = 204.2 found     52.6     7.9 ______________________________________

0.4 moles butyl acrylate and 70 g (0.355 mole) of 95.5% by weight dibutoxyethanal in butanol were reacted using the method of example 1 to form 2-butoxycarbonyl-4,4-dibutoxy-3-hydroxy-1-butene as a colourless liquid which distilled at 130.degree. C. under 0.2 mbar. Microanalysis C %    H %    O % ______________________________________ C.sub.17 H.sub.32 O.sub.5 calculated 64.5     10.2 25.3 Mol. Wt = 316.44 found     64.6     10.2 ______________________________________

A solution constituted by: 70.degree. C.

The solution was subjected to silica chromatography, eluting with a 9/1 vol/vol dichloromethane/methanol mixture and the eluates distilled under vacuum.

4.4-dimethoxy-3-hydroxy-2-hydroxyethoxycarbonyl-1-butene was obtained which distilled at 185.degree. C..+-.5.degree. C. under 5 mbar. Microanalysis C %    H %    O % ______________________________________ C.sub.9 H.sub.16 O.sub.6 calculated 49.1     7.3  43.6 Mol. Wt = 220.22 found     49.1     7.4 ______________________________________

A solution constituted by: agitation.

The solution obtained was filtered over silica, eluting with a 9/1 vol/vol dichloromethane/methanol mixture. The eluates were recombined then concentrated under vacuum, and the oil distilled under vacuum. 4.5 g of 4,4-dimethoxy-2-dimethylaminoethoxycarbonyl-3-hydroxy-1-butene was obtained which distilled at 160.degree. C..+-.5.degree. C. under 5 mbar. Microanalysis C %   H %    N %     O % ______________________________________ C.sub.11 H.sub.21 NO.sub.5 calculated 53.4    8.6  5.7   32.3 Mol. Wt = 247.29 found      53.4    8.6  5.6 ______________________________________

400 mmoles ethyl acrylate and 70 g (355 mmoles) of 95.5% by weight dibutoxyethanal in butanol were reacted using the method of example 1 to form 4,4-dibutoxy-2-ethoxycarbonyl-3-hydroxy-1-butene as a liquid which distilled at 120.degree. C. under 0.4 mbar.

It goes without saying that the present invention has been described by way of non-limiting illustration only. Any modification, particularly as regards technical equivalents, may be made without departing from the scope of the invention.

## Claims

1. A polyfunctional ethylenic monomer having the general formula (I): ##STR4## wherein: R is an alkoxycarbonyl group group wherein R.sub.3 and R.sub.4 may be identical or different and is selected from the group consisting of hydrogen atom and alkyl, alkenyl phenylalkyl groups, or R.sub.6).sub.n --CHR.sub.7 wherein n is 0 or 1 and R.sub.5, R.sub.6 and R.sub.7 may be identical or different representing a hydrogen atom or methyl group.

2. An ethylenic monomer as defined in claim 1, wherein in formula (I), R.sub.1 and R.sub.2, when they are identical, each represents a methyl, ethyl or butyl group, or R.sub.1 and R.sub.2 together form a bivalent radical selected from the group comprising ethylene, trimethylene, propylene and 2,2-dimethyl-1,3-propanediyl radicals.

3. 4,4-dibutoxy-2-ethoxycarbonyl-3-hydroxy-1-butene.

4. 2-butoxycarbonyl-4,4-dibutoxy-3-hydroxy-1-butene.

5. 4,4-dimethoxy-3-hydroxy-2-hydroxyethoxycarbonyl-1-butene.

6. 4,4-dimethoxy-2-dimethylaminoethoxycarbonyl-b 3-hydroxy-1-butene.

7. 4,4-dimethoxy-2-ethoxycarbonyl-3-hydroxy-1-butene.

8. A monomer according to claim 1 wherein said alkoxycarbonyl group is unsubstituted alkoxycarbonyl, hydroxyalkoxycarbonyl or dialkoxyaminoalkoxycarbonyl.

9. A monomer in accordance with claim 1 wherein said phenylalkyl is unsubstituted.