摘要:
The invention relates to a process for the preparation of N-protected-L-aspartyl-L-phenylalanine methyl ester by enzymatic coupling of an N-protected-L-aspartic acid and L- or DL-phenylalanine methyl ester in an aqueous solution with formation of a precipitate using a thermolysin-like protease enzyme, wherein a water-immiscible organic solvent is added to and blended with the reaction system during the formation of the precipitate in the course of the coupling reaction, which organic solvent has a relatively high affinity for the precipitate. The process is particularly suitable as a continuous process. The method results in lower enzyme deactivation during and after the enzymatic coupling reaction and in larger and thicker precipitated crystals.
摘要:
The invention relates to a process for the preparation of N-benzyloxycarbonyl-.alpha.-L-aspartyl-L-phenylalanine methyl ester by enzymatic coupling of N-benzyloxycarbonyl-L-aspartic acid and L-phenylalanine methyl ester in an aqueous medium with formation of a precipitate, the coupling reaction being effected with (virtually) equimolar quantities of N-benzyloxycarbonyl-L-aspartic acid and L-phenylalanine methyl ester under the influence of a neutral protease at an initial pH of from 4.5 to 6.0 and in the presence of from 3 to 25%, calculated as per cent by weight based on the total reaction mixture, of an alkali metal salt, alkaline earth metal salt or ammonium salt.
摘要:
A method for purifying a dipeptide ester by electrolysis in an electrolytic cell comprising an anode compartment, a cathode compartment and a central compartment partitioned by anion exchange membranes, which comprises supplying an aqueous dipeptide ester solution containing an inorganic acid to the central compartment defined by said anion exchange membranes, an aqueous solution containing a basic substance or an aqueous electrolyte solution containing a basic substance to the cathode compartment and an aqueous electrolyte solution to the anode compartment, supplying hydroxyl ions from the cathode compartment to the central compartment through the anion exchange membrane to neutralize the aqueous dipeptide ester solution containing the inorganic acid and removing anions of the inorganic acid in the aqueous dipeptide ester solution from the central compartment to the anode compartment through the anion exchange membrane.
摘要:
The invention provides a novel and efficient method for the elimination of protecting groups, e.g. benzyloxycarbonyl group, from a protected amino acid, peptide or derivative thereof having at least one functional group protected by a protecting group, e.g. a lower alkyl ester of N-benzyloxycarbonyl-.alpha.-L-aspartyl-L-phenylalanine by catalytic hydrogen reduction to produce free amino acid, peptide or derivative thereof. In contrast to the conventional procedures in which the reaction is carried out in a solvent dissolving both the starting compound and the product compound or a solvent dissolving the starting compound but not dissolving the product compound, the inventive method utilizes a binary two-phase reaction medium composed of water and an organic solvent not freely miscible with water such as toluene. The reaction takes place in the organic phase containing the starting compound dissolved and the catalyst dispersed therein whereas the reaction product which is water-soluble is smoothly and successively transferred into the aqueous phase so that advantages are obtained in the unexpectedly high yield of the product as well as in the easiness of handling the reaction mixture after completion of the reaction.
摘要:
A process for producing a halogen-containing ethylbenzene derivative represented by the general formula: ##STR1## where X is a halogen atom, and Y is a nitrile group, a carboxyl group, a lower alkoxycarbonyl group or an amidocarbonyl group, which comprises reacting a vinyl compound represented by the general formula:CH.sub.2 .dbd.CH--Y (II)where Y is as defined above, with a benzenediazonium salt and halogen ions in a solvent mixture comprising a lower alcohol and/or an ether, and water, under an acidic condition with a mineral acid, in the presence of a monovalent copper compound as a catalyst.
摘要:
An improvement in a method for manufacturing dipeptides from an N-substituted aspartic acid and a phenylalanine lower alkyl ester. The two starting materials are allowed to react with each other in the presence of an immobilized metallo-proteinase in an organic solvent immiscible with water. The enzyme can be recovered for reuse thereof. The loss of materials due to the hydrolysis of the phenylalanine lower alkyl ester is reduced, so that use of the phenylalanine lower alkyl ester in a nearly stoichiometric quantity suffices for the reaction to ensure an improved yield and reduction in cost of industrial production.
摘要:
A method for racemizing an optically active amino acid, which comprises heating the optically active amino acid in an aqueous solution under an alkaline condition in the presence of an alkali metal salt.
摘要:
A process for producing DL-phenylalanine by reacting an .alpha.-halogeno-.beta.-phenylpropionic acid represented by the general formula: ##STR1## where X is a halogen atom, or its salt, with ammonia, characterized in that the reaction is conducted while supplying the .alpha.-halogeno-.beta.-phenylpropionic acid or its salt into aqueous ammonia charged in a reactor in advance.
摘要:
A process for producing an .alpha.-halogeno-.beta.-phenylpropionic acid represented by the general formula: ##STR1## where X is a halogen atom, which comprises hydrolyzing under heating a halogen-containing ethylbenzene derivative represented by the general formula: ##STR2## where W is a cyano group, an amidocarbonyl group or a lower alkoxycarbonyl group, and X is as defined above, in an aqueous mineral acid solution under vigorous stirring.
摘要:
Addition compounds have the formula ##STR1## wherein R.sub.1 represents an aliphatic oxycarbonyl group, benzyloxycarbonyl group which can have nuclear substituents or benzoyl, aromatic sulfonyl or aromatic sulfinyl group; R.sub.2 represents methyl, isopropyl, isobutyl, isoamyl or benzyl group; R.sub.3 represents a lower alkoxyl, benzyloxy or benzhydryloxy group and n represents 1 or 2.The addition compounds are produced by reacting an N-substituted monoaminodicarboxylic acid having the formula ##STR2## with an amino carboxlic acid ester having the formula in an aqueous medium in the presence of a protease and reacting the resulting dipeptide ester with the amino carboxylic acid ester and separating the addition compound.The addition compounds can be decomposed into the constituent dipeptide esters and amino acid esters by the action of an acid.
摘要翻译:加成化合物具有式(I)其中R 1表示脂族氧羰基,可具有核取代基的苄氧基羰基或苯甲酰基,芳族磺酰基或芳族亚磺酰基; R 2表示甲基,异丙基,异丁基,异戊基或苄基; R3表示低级烷氧基,苄氧基或二苯甲氧基,n表示1或2.加成化合物通过使具有式(IV)的式(I)所示的N-取代的单氨基二羧酸与式 (V)在水性介质中,在蛋白酶存在下,使得到的二肽酯与氨基羧酸酯反应并分离加成化合物。 加成化合物可以通过酸的作用分解成组分二肽酯和氨基酸酯。