CS251361B1 - Process for the preparation of acylaminomalonic acid monoalkyl esters - Google Patents

Abstract

A method for preparing monoalkyl esters of acylaminomalonic acid by hydrolysis of dialkyl esters of acylaminomalonic acid of the general formula COOR' RCO-NH-CH > COOR * * where H' and R" are alkyl with a number of carbons C. to Cj and where R is H, alkyl with a number of carbons C. to C., phenyl or 2-chlorophenyl, 4-chlorophenyl, benzyl, catalyzed by esterases or proteinases, which consists in that the pH of the reaction mixture is maintained at the optimum value of 7.5 to 8.3 by adding ammonium carbonate or alkali metal bicarbonate and the hydrolysis product, monoalkyl ester of acylaminomalonic acid, is isolated after cooling to 0 to 5 °C and acidification with mineral acid to pH 1.5 to 3.0 by crystallization from the reaction mixture. Monoalkyl esters of acids are an important intermediate in the production of optically active amino acids, for example tryptophan.

Description

The invention relates to a process for the preparation of acylaminomalonic acid monoesters by enzymatic hydrolysis of acylaminomalonic acid with esterases or proteinases, preferably chymotrypsin.

The acylaminomalonic acid mono-esters of the general formula (I) / COOH

SCO - NH - CH 2 (I).

Wherein R is H, an alkyl having a carbon number of C to C11, phenyl, 2-chlorophenyl, and 4-chlorophenyl or benzyl, and wherein fi 'is an alkyl having a carbon number of C12 to C12; inter alia (especially in the case of the monoethyl ester of ecetamidomalonic acid, R = CH 3 and R 4 C 3 H 3) represent an important intermediate for the preparation of optically active tryptophan.

The methods known to date for the preparation of acylaminomalonic acid monoesters are based on partial hydrolysis of the respective diesters in aqueous ethanol / N.F. Albertson: J. Am.

Soc. 70, 1150 (1948), L. Berlinquet: Can.J.Chem. 32, 31, (1954), in absolute ethanol]

H. Hellmann, K. Teichmann, F. Ligens, Chem. Ber. 91, 2427 (1958) and hydrolysis catalysed by crownether (18-crown-6) compounds in dioxane D.H. Hunter, R.A. Perry: Synthesis 1977, 37, Synthesis 1981, D. H. Hunter, V. Patel, R. A. Perry: Cen. J. Chem. 58, 2271 (1980) //.

These methods are not suitable for industrial use. The inconvenience consists in insufficient conversion of hydrolysis, low yield and impure product. While 18-crown-r6 catalyzed hydrolysis is 100% conversion, the reaction requires the use of an equimolar amount of catalyst which is very expensive and difficult to recover.

The use of enzymes as specific catalysts represents a significant improvement in the hydrolysis of diesters of acylaminomalonic acid to the corresponding monoesters.

The diethyl ester of acetamidomalonic acid is described by / S. Cohen, G. Crossley, J.

Am. Chem. Soc. 86, 4999/1964 // (Λ-chymotrypsin-catalyzed hydrolysis, which proceeds stereepecifically to the first stage to form the monoethyl ester of acetamidomalonic acid. This monoethyl ester is no longer hydrolyzed, so the conversion is in the sense of the formation of monoester 100 56.

The hitherto used method of Isolation by the enzymatic reaction of the resulting acetamidomalonic acid monoethyl ester is, however, too complex and time consuming at a low reaction yield. This isolation method consists in acidifying the reaction mixture and extracting the monoester into an organic solvent. After drying and filtering the extract, the solvents are evaporated and the acetamidomalonic acid monoethyl ester is purified by crystallization. Said method of insulation, however, is not very suitable for industrial production.

The prior art processes and their disadvantages overcome the process for the preparation of acylaminomalonic acid monoesters of the general formula I, in which R and R 'are as defined above, by enzymatic hydrolysis of diesters of acylaminomalonic acid by esterases or proteinases. 5 to 8.3, which is maintained by the addition of ammonium carbonate or sodium or potassium bicarbonate, after which the hydrolysis product, acylaminomalonic acid monoester is isolated after cooling and acidification with a mineral acid to pH 1.5-3.0 by crystallization from the reaction mixture.

The resulting monoester of acylaminomalonic acid can be separated by ultrafiltration from the reaction mixture and chymotrypsin can be used in further repeated hydrolyses. Alternatively, for the multiple use of chymotrypsin, ee may apply chymotrypsin immobilized by any of the immobilization techniques used. Hydrolysis can be accomplished by Λ -chymotrypsin generated in the reaction mixture from the added chymotrypsinogen by the step amount of -chymotrypsin.

25.3 * 1

An advantage of the process according to the invention is, in comparison with the hitherto known processes, essentially the isolation of the monoester of acyleminomonic acid, in which the product of the partial hydrolysis crystallizes after cooling and acidification of the reaction mixture in high yield.

The advantage of the process of preparing the monoesters of the acylaminomalonic acid according to the invention lies mainly in the simplicity of the whole process, the possibility to work only with aqueous solutions, 100% conversion given by enzyme catalysis and the associated high yield of monoesters (90 to 95%). In other chemical processes, recrystallization is necessary, which is associated with the possibility of dacarboxylation of the crystallized monoester, and thus considerable losses and contamination of the product.

An advantage of the process according to the invention is also the possibility of re-use of applied chymotrypsin, whether free (including ultrafiltration) or immobilized. The advantages of the process according to the invention include the considerable simplicity of maintaining the pH of the reaction mixture by the addition of ammonium carbonate or potassium or sodium bicarbonate according to U.S. Pat.

No. 247444, which does not increase the volume of the reaction mixture, which would otherwise reduce the weight yield of the product (while maintaining the pH by means of the pH of the state by adding sodium hydroxide solution).

Another advantage of the process according to the invention is the possibility of carrying out the hydrolysis directly of the crude product of the acylation reduction of isonitrosomalone ester to Baney-Nickel, wherein the crude product of this reduction, acylaminomalonic acid diester, contains traces of nickel and aluminum ions.

In the following, the invention is illustrated in more detail by the examples without limiting it.

Example 1

The 4 parts by weight. water containing 0.01 wt. % technical preparation of .beta. -chymotrypsin and 0.0 wt. 1 part by weight of calcium chloride is added with stirring. diethyl acetamidomalonic acid diethyl ester. The reaction mixture is mixed at 20 [deg.] C., the progress of the reaction being readily controlled both by the gradual dissolution of the diethyl acetaninoasonic acid ester and, on the other hand, by the formation of carbon dioxide released by the neutralization of the acid formed.

After complete hydrolysis, the reaction mixture was cooled to 0 ° C to 5 ° C and acidified to pH 1.5 with concentrated hydrochloric acid. The crystallized non-ethyl acetenidomalate was sucked off, washed with ice water and dried at 20 ° C. Yield of pure product, i.e. acetamidomalonic acid monoethyl ester, m.p. 131 DEG -32 DEG C. is 94

Example 2

The 2 parts by weight. water containing 0.15 wt. technical preparation «z. % of dymotrypsin and 0.1 wt. of calcium chloride, 1 part of haot is gradually added with stirring. of diethyl acetamidomalonic acid ester and pK of the reaction mixture are maintained at 7.5-8.0 by addition of solid sodium bicarbonate.

After hydrolysis in all the diethyl ester, 80% of the reaction mixture is filtered through an ultrafilter and to the residue and again 2 parts by weight are added. of water and gradually, with stirring, 1 part by weight. of diethyl acetamidomalonic acid ester, the pH of the reaction mixture being maintained at pH 7.5 to 8.0 by the addition of sodium bicarbonate.

After complete conversion of the diethyl ester to the non-ethyl ester, 80% of the reaction filter is again filtered through an ultrafilter and the process repeated. 92-95% of the theoretical yield of acetamidomalonic acid monoethyl ester is obtained from the individual filtrates after cooling to 0-5 ° C and acidification to pH 1.5-2.0 with hydrochloric acid, m.p. , 32-3 ° C.

Example 3

The 4 parts by weight. water containing 0.001 wt. technical preparation <A -chymotrypsin, 0.05 SK wt. chymotrypsinogen e 0.05 SK wt. The mixture is stirred for 1 part by weight. potassium bicarbonate and 2 parts by weight of potassium bicarbonate; diethyl acetamidomalonic acid diethyl ester. The reaction is carried out as in Example 1. The yield of pure product, i.e., acetamyl malonic acid monoethyl ester, m.p. , 3, to 3 ° C, is 95 SK.

He attaches

To 4.5 parts by weight. water containing 0.01 wt. % of the technical preparation of? - -hymotrypsin and 0.01 SK wt. 1% by weight of calcium chloride was added with stirring. potassium bicarbonate and 2.5 parts by weight of potassium bicarbonate; of benzamidomaloaloic acid methyl ester. The procedure was as in Example 1. 93% of benzamidomalomic acid monoethyl ether was obtained.

to 76 ° C.

Example 5

The 5 parts mass. water containing 0.01 SK wt. of technical preparation <* · -chynotrypsin and 0.01 SK wt. 1 part by weight of calcium chloride is added with stirring. potassium bicarbonate and 2.6 parts by weight of potassium bicarbonate; of dimethyl phenylacetylaninomalonate. The procedure was continued as in Example 1. 94 SK of phenylacetyl-aminomalonate was obtained. , 27 ° C.

Example 6

The 5 parts mass. water containing 0.01 wt. 0.5 parts by weight, ammonium carbonate and 3 parts by weight of the technical preparation -hymotrypsim are added with stirring. 4-chlorobenzamidomalonic acid methyl ester. The procedure is as in Example 1. 95 SK of 4-chlorobenzamidomalonic acid monomethyl ester is obtained, m.p. Mp 135-136 ° C.

Example 7

In the same manner as in Example 6, the non-ethyl ester of 2-chlorobenzamidomalonic acid was obtained in 94 SK yield, m.p. Mp 120-222 ° C.

Example 8

To 5 parts water containing 25 SK wt. % methanol and 0.01 SK wt. technical preparation tA. -hynotrypsin and 1 part haot is added with stirring. % potassium bicarbonate; The dodecylamidomalonic acid dimethyl ester is further processed as in Example 1. 89 SK of the dodecylanldonalonic acid nonomethyl ether is obtained, m.p. 1.7-118 ° C.

Example 9

The 4 parts by weight. water containing 0.02 SK wt. of a suspension preparation of carboxylic esterase (EC 3.1.1.1.) from pork liver in 3.2 M ammonium sulphate, 1 part by weight is added under stirring. sodium bicarbonate and 2 parts by weight of sodium bicarbonate; formamidomalonic acid methyl ester. The reaction mixture was stirred at 20 ° C and pH 7.0-7.6 in analogy to Example 1. The reaction was continued as in Example 1. 90 SK of formamidomalonic acid monomethyl ester was obtained, m.p. 127-128 ° C.

Claims (1)

SUBJECT OF THE INVENTION A method for the contribution of monoalkyl acylaminomalonic acid esters by hydrolysis of dialkyl acylaminonalonic acid esters of the general formula: COOR ' RCO-NH-CH3 COOR wherein R 'and R' 'is an alkyl having a number of carbons of C to C 1 and wherein R is H, alkyl or a number of carbons of C to C 1, phenyl or 2-chlorophenyl, 4-chlorophenyl, benzyl catalyzed by esteroses or proteinases, characterized in that the pH of the reaction mixture is maintained at an optimum value of 7.5-8.3 by addition of ammonium carbonate or alkali metal hydrogen carbonate and the hydrolysis product, acylaminomalonic acid monoalkyl ester is isolated after cooling to 0-5 ° C and acidification with mineral acid to pH 1.5 to 3, crystallizing from the reaction mixture.