HU196946B - Process for production of 2e, 4e-stereochemical unsaturated carbonic acid esthers - Google Patents

Abstract

The invention relates to a process for the preparation of 2E, 4E carboxylic acid esters. According to the invention, 2E, 4E-carboxylic acid esters of general formula I (wherein X is hydrogen, hydroxy or C 1-4 alkoxy and R is C 1-4 alkyl) are prepared by dissolving a salt of general formula LIX (wherein X. has the above meaning and M represents a metal ion, ammonium ion or an ammonium ion optionally substituted by one or more alkyl and / or aralkyl group (s)) in a polar solvent with an alkyl halide of the general formula LXIII RY LXIII (wherein R has the above meaning and Y is halogen). Formula I and LIX

Description

The present invention relates to a process for the preparation of an unsaturated carboxylic acid ester of the formula (2E, 4E) in which X is hydrogen or methoxy, R is a (1-4C) alkyl, by reacting a salt of formula (LIX) represents a sodium ion, potassium ion, calcium ion, aluminum ion, ammonium ion, ethylammonium ion, diethylammonium ion or dibenzylammonium ion in a polar solvent, preferably a dipolar aprotic solvent, particularly preferably dimethylformamide, dimethylsulfoxide, hexam The alkyl halide LXIII, wherein Y is halogen and R is as defined above, is reacted at a temperature of 10 to 10 ° C, preferably 20 to 40 ° C, and the resulting product is isolated from the reaction equation in a known manner.

The 2E, 4E unsaturated carboxylic acid esters of formula (I) - ahotX and R are as defined above - are novel, selective and potent insecticides which inhibit the metamorphosis of the columns and can be used as such as non-polluting pesticides.

Several processes for the preparation of compounds of formula I, wherein X 6 R is as described above, are described in the literature.

According to British Patent No. 1368,266, the ester of formula I, wherein X is hydrogen and R is C 1-4 alkyl, is prepared from the dihydrocitrone of formula II and is prepared from a phosphonate of formula III -anion - where R is as defined above, R ^! is an alkyl group condensed to form a mixture of the desired esters of formula (1) and (IV).

A disadvantage of the method is, on the one hand, the inaccessible phosphonate anion of formula (III) - wherein R and R ^! and in the synthesis of the unsaturated 2E, 4E unsaturated carboxylic acid ester of formula (I), wherein X is hydrogen and R 'is as described above, in addition to the unwanted formula (IV). where X is hydrogen and R is the ester of the above-2Z, 4E stereochemistry and can be separated only in a complicated manner or at a loss.

In another process described in the above patent, an unsaturated ketone of formula (V) is reacted with a karaanion of formula (VI), wherein R and R ¹ are as defined above, or an ylide of formula (VII), wherein R and R * is as defined above, is reacted with a mixture of the desired unsaturated ester of formula (I) wherein X is hydrogen and R is as defined above and the unwanted unsaturated ester of formula (IV) where X is hydrogen and R is as defined above come.

The disadvantage of this method is also due to the difficulty of separating the resulting isomeric mixture and the difficulty in accessing the unsaturated ketone of formula (V).

According to a further process described in the above patent, the dihydrocitrone of formula II is reacted with an acetylide of formula VIII wherein R ^{2 is}

It is condensed with lithium, sodium, potassium or magnesium, and the resulting acetylene derivative of formula XI is converted into an allene ester of formula X, where R is above, in the presence of a weak acid catalyst in the presence of a weak ortho ester. ) and ^(1Χ Γ) esters of the formula - wherein X is hydrogen and R is as defined above - to obtain a mixture. However, during the conversion, the C4-C5 double bond is also partially displaced so that the esters of formula (XI) (2Z, 4Z) and (XH1) (2E, 4Z), where R is as defined above, are also formed, The recovery of the ester of formula (I) wherein X is hydrogen and R is as described above is significantly complicated.

According to British Patent No. 1368,267, the esters of formula (I) wherein X is hydroxy or alkyl, R is as defined above, are prepared from the citronella halide of formula (XIII) which is prepared with a phosphonate anion of formula (III): R and FI ¹ are as defined above - condensed and then water or a mixture of the resulting 2Z, 4E ester of formula (XIV) where R is as defined above and 2Z, 4E ester of formula XV where R is as defined above they add the right alcohol. In this way, a mixture of esters of formula (XVI) and (XVII), where R is as defined above, R ³ is hydrogen or C 1-4 alkyl, is obtained.

The disadvantages of the process are, firstly, the preparation of the hardly accessible phosphonic acid esters of the general formula (III), where R and R * are as defined above, and the difficulty in separating the isomeric esters formed in the reaction.

In another process described in the above patent, an unsaturated ketone of formula XVIII is prepared with a carbanion of a phosphonic acid ester of formula VI wherein R and R ¹ are as defined above or with an ylide of formula VII wherein R and R * are as defined above-is reacted, then the resultant (XIV) and of formula (XV) esters - wherein R is as defined above - a mixture as described above using water or a suitable alcohol is additioned obtain the ester (1) and formula (Ia ^R) - wherein X is a mixture of hydroxy or alkoxy.

A disadvantage of these methods is also the difficulty in accessing the unsaturated ketone of formula (XVIII) and the formation of the isomeric mixture.

In a further process described in the above patent, the citronella of formula XIII is condensed with an acetylide of formula VIII wherein R ² is as defined above, and the resulting acetylene compound of formula XIX is reacted with an orthoester in the presence of a weak acid catalyst. ), where R is as defined above. The allene ester of formula (XX), where R is as defined above, is converted in a basic medium to a mixture of the esters of formula (XIV) and (XV), where R is as defined above. However, during the conversion, the C4-C5 double bond is partially displaced, resulting in the formation of esters of the formulas (XXI) and (XXH), where R is as defined above.

A disadvantage of this method is again the difficulty of recovering the desired ester of formula I - wherein X is hydroxy or alkoxy-23 - from the isomeric mixture.

In a further process described in the patent, water or a corresponding alcohol is added to the citronella XIII to produce an aldehyde XXIII where R ³ is hydrogen or alkyl and then with the phosphonate anion 111 R and R ¹ are as defined above, condensed to form a mixture of esters of formula XVI and XVII, wherein R and R ³ are as defined above.

The disadvantage of this method is also the difficulty in separating the resulting unwanted isomers.

No. 1409,321. According to British patent (I) esters of the formula - wherein X and R are as defined above -jutnak if formula (V) or the formula (XVIII) or formula (IX) - wherein R ³ is as defined above Ketones one of an ( From a haloacetic acid ester of formula XXV wherein X is chlorine or bromine, R is as defined above, by reacting a hydroxy ester of formula XXVI with a zinc organic salt wherein Z ¹ is hydrogen or OR ³ - wherein R ³ is as defined above, Z ² is hydrogen, or Z ¹ and Z ^{2 are taken} together to form a double bond, followed by dehydration of the esters of formula (I) and (TV) where R is as defined above in (XIV). and esters of formula (XV) wherein R is as defined above or a mixture of esters of formula (XVI) and (XVIII) wherein R is as defined above.

A disadvantage of these methods is also the difficulty in separating the resulting isomeric mixtures and the difficulty in accessing the starting ketones.

No. 3,873,586. In the findings of U.S. patent (I) képletűészterekhez - receive, if the (II) or (XIII) with the aldehyde or (XXIII) with aldehydes of the formula - -, wherein R ³ is as defined above - one of X and R is as defined above Is reacted with the dilithium salt of formula (XXVII) or (XXVIII) and isomerized to the resulting carboxylic acid of formula (XXIX), wherein Z * and Z ² are as defined above and R ⁴ is hydrogen, from which the acids XXX and XXXI - where Z 'and Z ² are as defined above, a mixture of the ester of formula (XXXII) and ester of formula (ΧΧΧΙΠ), where Z * and Z ² are as defined above, is reacted with thionyl chloride followed by alcohol.

The disadvantages of this method are the very low reaction temperature (-80 ° C), the use of the lithium salt, and the unwanted isomers of Formulas (XXXIV) and (XXXV) - where Z ^! and Z ² is as defined above and R ⁴ is hydrogen, which may be formed during the esterification into the unwanted esters of formulas (XXXIV) and (XXXV) - wherein Z ¹ and Z ² are as defined above, R ⁴ is R - R has the meanings given above. Thus, the desired ester of formula (I), wherein X and R are as defined above, is difficult to recover from the reaction mixture.

In another embodiment of the above patent, one of the aldehydes of formula (II) or (III) or the aldehydes of formula (XXIII) wherein R ³ is as defined above is a lithium salt of an ester (XXXVI) or (XXXVII) where R is alkyl. and then forming the hydroxy esters of formulas XXXVIII and XXXIX, wherein Z ¹ and Z ² are as defined above and R ⁴ is alkyl, and the lactone of formula XL, wherein Z ¹ and Z ² are as defined above, the mixture is separated by chromatography. The hydroxy esters of formulas (XXXVIII) and (XXXIX), wherein Z 'and Z ² are as defined above and R ⁴ is alkyl, are further processed as described above. And the lactones of formula XL, wherein Z ¹ and Z ² are as defined above, with an alkali metal hydroxide, into the salt of the hydroxy acids XXXVIII and XXXIX, wherein Z * and Z ² are as defined above and R is an alkali metal atom. —Convert, from which the hydroxy acids XXXV111 and XXXIX — wherein Z ¹ and Z ^J are as defined above, R ⁴ is hydrogen — are acidified and further processed as described above.

Another disadvantage of these methods is the use of the lithium salt and the separation of very complex reaction mixtures.

According to another embodiment of the present invention, an aldehyde of formula (II) or (XIII) or an aldehyde of formula (XX.I11) wherein R ³ is as defined above with an acrylic ester of formula (XLI) wherein Y is halogen and R is as defined above - is reacted with zinc in the presence, and then the resulting (XXXV1I1) and formula (XXXIX) hydroxy esters - in which Z ^1, Z ² and R are as defined above - is dehydrated to reach the (XXX11) and (XXXIII) esters of formula Wherein Z ¹ , Z ² and R are as defined above.

Another disadvantage of this method is the difficulty in separating the various unwanted isomers resulting from the reaction.

No. 3,910,1025. Lessons learned from U.S. patent by formula (XXI11) of the aldehyde of formula - wherein R ³ is as defined above - formula (VIII) with acetylene of general formula derivatives - wherein R ² represents a metal atom - is reacted with (XL11) hydroxy-acetylene derivatives of formula - wherein R ³ are as defined above - is treated with a an allene ester of formula (XL11I) trialkyl orthoacetate - made by treating organized into sodium hydroxide (XVI) and (XVII): - wherein R ³ and R are as defined above esters - wherein R and R ³ are as defined above - a mixture.

A disadvantage of this method is the difficulty in recovering the desired ester of formula I, wherein X is hydroxy or alkoxy and R is as defined above.

No. 727,624. According to the US patent, a mixture of esters of the formulas I and IV, where X and R are as defined above, is obtained when an unsaturated ketone of the formula V or a ketone of the formula XXIII, wherein R ³ is as defined above - ( They are reacted with ethoxyacetylene XLIV in the presence of boron trifluoride etherate to give a mixture of esters of formulas I and IV wherein X is as defined above and R is ethyl.

The patent teaches no separation of the resulting isomeric esters of formulas I and IV wherein X is as defined above and R is ethyl.

No. 654,606. According to U.S. Patent No. 4,198, a mixture of esters of formulas I and IV, wherein X is hydrogen and R is as defined above, is provided when the β-oxydihydrocitronellylacetone of formula XLV is reacted with the phosphonic acid ester of formula XI: wherein R and R ¹ is ethyl, and the reaction mixture is acylated with acetic anhydride. In this way, a mixture of ester XLV1 and lactone XLVI1 is obtained, which, without separation, is first formed into a salt with potassium tert.-butylate and then reacted with thionyl chloride and then with alcohol to form the esters I and IV. wherein X is a hydrogen atom and R is a mixture of the above. The patent does not teach us how to separate them.

In 1399196 br, U.K. patent shows (I) esters of the formula - wherein X and R are as defined above - can be provided that formula (II) or formula (XXIII) of the formula The aldehyde - wherein R ³ is as defined above - an ( LVI), where R ² is as defined above, is condensed in an alkaline medium, and then formed from the dicarboxylic acid salt of formula LVII, wherein X is the above -M is an alkali metal ion, to the corresponding dicarboxylic acid of formula LVII, wherein X is as defined above, - M is hydrogen by acidification. The dicarboxylic acid (LVII) thus obtained, wherein X is as defined above, M is hydrogen, with the help of tertiary amine in the presence or absence of copper ion or copper shavings, via a lactonone (LVHI), wherein X is above, acid - converted - wherein Z ¹ is hydrogen or an alkoxy group and Z ² is hydrogen.

The acid of formula XXXI, wherein Z 'and Z ² are as defined above, is isomerized to a mixture of the acids of formula XXXI and XXX, wherein Z ¹ and Z ² are as defined above, and then added to a solution of the mixture in a suitable solvent. purifying the ammonium salt of the carboxylic acid LIX - where X is as defined above and M is ammonium ion - by purifying ammonia, which is acidified and then reacted with thionyl chloride and a suitable alcohol to give the desired ester of formula I where X and R is as defined above.

The disadvantage of this method is that if any of the pure acids of formula LIX, where X is as defined above and M is hydrogen, are used in the esterification, they are always formed in the reaction.

2-8% of the undesired (IV) of formula 2Z, 4E isomer ester - wherein X and R are as defined above - and low ester (LX) - wherein R ³ is as defined above and (LX1) ester of the formula wherein R has the same meaning as above. In this way, the ester of formula (I), wherein X and R are as defined above, can be obtained with a maximum purity of 90%.

A further disadvantage of the method is that the chemicals (oxalyl chloride, thionyl chloride) used in the large-scale implementation of acid chloride production are highly corrosive and the resulting by-products (hydrochloric acid, sulfur dioxide) are pollutant pollutants.

No. 3,917,662. U.S. Pat. No. 6,011,123 discloses that the ammonium salts of formula (LIX) wherein X is as defined above and M is ammonium ion are heated with tetraalkoxy thionates of formula (LXII) where R is as described above directly to the esters of formula (I) Where X and R are as defined above.

However, the realization of this method under large-scale industrial conditions is ambiguous because the titanium compounds used are highly toxic and it is practically impossible to separate them completely from the product.

Surprisingly, it has been found that the compounds of formula I, wherein X and R are as defined above, can be readily prepared, without side reaction, in very high yields in high purity, provided that a salt of formula LIX - wherein X is as defined above M is sodium ion, potassium ion, calcium ion, aluminium ion, ammonium ion or ammonium ion substituted with ethyl, diethyl or dibenzyl group in a polar solvent with an alkyl halide of formula (LXIIl) wherein R is halogen at 10-60 ° C.

The polar solvent is preferably a dipolar aprotic solvent such as dimethylformamide, dimethylsulfoxide or hexamethylformamide, but the reaction is well carried out in alcohols such as methanol or butanol, ketones such as acetone, or in 1 to 25%, preferably .

As the salt of formula (LIX), where X and M are as defined above, salts with sodium or potassium, calcium and aluminum; or as alkyl substituted ammonium, ethyl ammonium, diethylammonium, dibenzylammonium salts.

The salts of formula (L.1X), wherein X is as defined above, M is as defined above, may be formed in situ in the reaction mixture from an acid of formula (LIX) wherein X is as defined above, M is as hydrogen. .

Examples of alkyl halides of the formula (LX1II) wherein R and Y are as defined above include methyl bromide, methyl iodide, ethyl bromide, ethyl iodide, propyl chloride, propyl bromide, propyl iodide, isopropyl chloride, isopropyl bromide, isopropyl iodide or butyl bromide.

For the simple preparation of acids of formula LIX and salts thereof, wherein X and M are as defined above, see Journal of Organic Chemistry 40, pp. 3-7. (1975), alkyl halides of the formula LX11I, wherein R and Y are as defined above, are commercially available.

The reaction may be carried out at from 10 to 60 ° C, preferably from 20 to 40 ° C, depending on the solvent used and the alkyl halide.

The invention is further illustrated by the following non-limiting Examples

Example 7

-methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid isopropyl ester

5.8 g of 0.02 mol of sodium salt of 11-methoxy-3,7,11-trimethyl 2E, 4E-dodecadienoic acid are dissolved in 50 ml

4-hexamethylphosphoramide, 10 g of isopropyl bromide are added and the reaction mixture is stirred for 3 days at room temperature. Water (50 mL) was added to the reaction mixture under cooling, and the mixture was extracted with ether (2 x 50 mL). The ethereal phase was basified to pH-9, washed with 8% aqueous sodium hydroxide and then basified with water. The solvent was evaporated to give 5.75 g (93%) of 11-methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid isopropyl ester which was 99% pure by gas chromatography.

IR: 2830, 1720, 1110, 1090 cm -1.

Example 2

3.7.11, Trimethyl-2E, 4E-dodecadienoic acid ethyl ester

5.1 g of 0.02 mol of the ammonium salt of 3,7,11-trimethyl-2E, 4E-dodecadienoic acid are dissolved in 50 ml of hexamethylphosphoramide, 2.2 g of triethylamine are added, and after stirring for 1 hour at room temperature, 10 g of ethyl g of potassium iodide and the reaction mixture was stirred at 40 ° C for 1 day. After cooling, 50 ml of water are added under cooling and the mixture is extracted with 2 x 50 ml of ether, the ethereal phase is made basic with 8% aqueous sodium hydroxide and washed with water to pH = 7. The ether phase was evaporated to give 4.95 g (93%) of ethyl 3,7,11-trimethyl-2E, 4E-dodecadienoic acid, which was 98% pure by gas chromatography. The infrared spectrum is the same, but absent the 2830 and 1090 methoxy absorption and the 1110 isopropyl ester band.

Example 3

-methoxy-3,7,11-trimethyl-2E, 4Edodecadienoic acid isopropyl ester

To 5.7 g of ammonium salt of 11-methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid are added 50 ml of dimethylformamide and 1.57 g of potassium carbonate. After stirring for 1 hour, 10 g of isopropyl bromide are added and the mixture is stirred at room temperature for 2 days. After cooling, 50 ml of water are added and the mixture is extracted with 2 x 50 ml of ether. The ethereal phase was made basic to pH 9. Wash with 8% aqueous sodium hydroxide and then with water to make it alkaline. The ethereal phase is evaporated to give 4.5 g (73%) of isopropyl ester of 11-methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid which is 97% pure by gas chromatography.

Example 4

-methoxy-3,7, H-trimethyl-2E, 4E-dodecadienoic acid isopropyl ester

To 5.7 g of the ammonium salt of 11-methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid was added 50 ml of dimethylsulfoxide, followed by 3.2 g of 25% aqueous sodium hydroxide and stirred for 1 hour at room temperature.

Thereafter, 10 g of isopropyl bromide are added to the reaction mixture and stirred for 3 days at room temperature. 5.85 g (94.5%) of 11-methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid isopropyl ester are obtained, which is 99% pure by gas chromatography.

Example 5

II-Methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid isopmpyl ester

11.35 g of 11-methoxy-3,7,11-tri-methyl-2E, 4E-dodecadenoic acid are dissolved in 50 ml of dimethylsulfoxide and 3.2 g of 25% aqueous sodium hydroxide are added. After stirring for 1 hour at room temperature, 10 g of isopropyl bromide are added to the reaction mixture and stirred for 3 days at room temperature. Water (50 mL) was added with cooling and the mixture was extracted with cyclohexane (2 x 50 mL). The organic layer was basified to pH 9 with 8% aqueous sodium hydroxide and washed with brine (10 mL) and water (10 mL). After evaporation of the solvent, 5.8 g (94%) of isopropyl ester of methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid are obtained, which is 99-100% pure by gas chromatography.

Example 6

-methoxy-3,7-11-trimethyl-2E, 4Edodecadienoic acid isopropyl ester

All proceed as in Example 5 except that 3.2 g of 25% aqueous sodium hydroxide is replaced by 10 g of 13.5% methanolic sodium methylate. Yield: 5.5 g (90%) of 11 methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid isopropyl ester, 98% pure by gas chromatography.

Example 7

-methoxy-3,7,11-trimethyl-2E, 4Edodecadienoic acid isopmpyl ester

In all of the procedures of Example 1, the starting material was 5.8 g of 11-methoxy-3,7,11 instead of the sodium salt of methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid. - potassium salt of trimethyl2E, 4E - dodecadienoic acid. Yield: 5.8 g (94%) of 11E-methoxy-3,7,11-trimethyl 2E, 4E-dodecadienoic acid isopropyl ester, 99% pure by gas chromatography.

Example 8

-methoxy-3,7,11-trimethyl-2E, 4Edodecadienoic acid isopropyl ester

In each case, Example 1 was repeated except that 5.8 g of starting material were used

Instead of the ethyl ammonium salt of 196 946 methoxy - 3,7,11 - trimethyl - 2E.4E - dodecadienoic acid, 9.3 g of the dibenzylammonium salt of 11 - methoxy - 3,7,11 trimethyl dodecadienoic acid are used. yield 5.5 g (90%) 11 - pure isopropyl ester, which is GC 99% - methoxy - 3,7,11 - tri methyl ₅ - 2E, 4E - dodecadienoate.

Instead of the sodium salt of methoxy - 3,7,11 - trimethyl - 2E, 4E - dodecadienoic acid, 6.15 g of calcium salt of 11 - methoxy - 3,7,11 - trimethyl - 2E, 4E - dodecadienoic acid are used. Yield: 5.7 g (93.5%) of 11-methoxy-3,7 -11-trimethyl-2E, 4E-dodecadienoic acid isopropyl ester, 99% pure by gas chromatography.

Example 9

-methoxy-3,7,11-trimethyl-2E, 4Edodecadienoic acid isopmpyl ester

In all of the procedures of Example 1, except that 5.9 g of 11-methoxy-3,7,11 sodium salt of methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid was used as starting material. - trimethyl 2E, 4E - aluminum salt of dodecadienoic acid. Yield 5.5 g (90%) of 11-methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid isopropyl ester, 99% pure by gas chromatography.

12. p ed

-methoxy-3,7,11-trimethyl-2E, 4Edodecadienoic acid isopmpyl ester

In all of the procedures of Example 10, except that 6.25 g of 11-methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid is replaced by 7.4 g of 11-methoxy-3.7 in the starting material. Triethylammonium salts of trimethyl 2E, 4E - dodecadienoic acid were used. Yield: 5.6 g (92%) of 11-methoxy-3.7,11

trimethyl 2E, 4E - dodecadienoic acid isopropyl ester is obtained which is 99% pure by gas chromatography.

Example 10 11-Methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid isopropyl ester

To the ethylammonium salt of 6.25 g of 11-methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid is added 50 ml of dimethylsulfoxide, and 3.2 g of 25% aqueous sodium oxide is stirred for 10 hours at room temperature and 10 g of isopropyl bromide are added. and stirred for 3 days at room temperature. The mixture was extracted with 2 x 50 mL of cyclohexane and the cyclohexane layer was basified to pH-9 with 8% aqueous sodium hydroxide and then basified with water. After evaporation of the solvent, 5.7 g (93.5%) of 11-methoxy-3,7,11-trimethyl-2E, 4E-dodecadienoic acid isopropyl ester are obtained, which is 99% pure by gas chromatography.

Example 11

11-methoxyl · 3.7, U-trimethyl-2E, 4E-dodecadienoic acid isopmpyl ester

In each case, the procedure of Example 10 was followed, except that 6.25 g of starting material 11 -

Claims (1)

Claims A process for the preparation of an unsaturated carboxylic acid ester of the formula (2E, 4E) wherein X is hydrogen or methoxy, R is a (1-4C) alkyl, characterized in that Hg / optionally a salt of formula (LIX) wherein M is sodium ion, potassium ion, calcium ion, aluminium ion, ammonium ion, ethylammonium ion, diethylammonium ion or dibenzylammonium ion - in a polar solvent, preferably dipolar aprotic solvent, especially in dimethylformamide, dimethylformamide, dimethylformamide, or by reaction with acetyl halide (LXIII) in which Y is halogen and R is as above, at a temperature of from 10 to 60 ° C, preferably from 20 to 40 ° C, and the resulting product is isolated from the reaction mixture in a known manner. ⁵ 2. A method according to claim 1, characterized such that said starting from: salts of formula I. (LIX) in a reaction mixture is formed in situ by appropriate the salt of formula (LIX) of the free carboxylic acid with the appropriate base reaction. 10 pieces of drawing