Abstract: A method for making a stabilized neutral metalloprotease enzyme composition is described in which a neutral metalloprotease and an aqueous solution are combined to obtain a solution or slurry thereof, whereby the stabilized neutral metalloprotease enzyme composition is obtained. The aqueous solution contains an N-protected amino acid, or an N-protected amino acid is added thereto. The invention also provides a stabilized neutral metalloprotease composition, and a method of transporting the stabilized neutral metalloprotease composition.

Abstract: 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.

Abstract: 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.

Abstract: A method for crystallizing .alpha.-L-aspartyl-L-phenylalanine methyl ester from a hot aqueous solution containing .alpha.-L-aspartyl-L-phenylalanine methyl ester by cooling is disclosed, which comprises (i) continuously supplying a hot aqueous solution of .alpha.-L-aspartyl-L-phenylalanine methyl ester having a concentration such that the content of L-aspartyl-L-aspartyl-L-phenylalanine methyl esters is less than 0.6% by weight based on the weight of .alpha.-L-aspartyl-L-phenylalanine methyl ester in said solution, or if the content of L-aspartyl-L-aspartyl-L-phenylalanine methyl esters is 0.6% by weight or more based on the weight of .alpha.-L-aspartyl-L-phenylalanine methyl ester in said solution, to a crystallization vessel the temperature of which is lowered to that corresponding to the solubility of .alpha.-L-aspartyl-L-phenylalanine methyl ester or less, and (ii) continuously discharging the formed slurry from the crystallization vessel.

Abstract: A method for preparing .alpha., .beta.-unsaturated carboxylic acids of the formulaR.sub.1 (R.sub.2)C.dbd.C(R.sub.3)CO.sub.2 Hwhere R.sub.1 to R.sub.3 can be hydrogen, fluorine, alkyl, or alkyl containing fluorine, but at least one of R.sub.1 to R.sub.3 is fluorine or alkyl containing fluorine. The method involves reacting an alkenyl halide containing fluorine having the general formulaR.sub.1 (R.sub.2)C.dbd.C(R.sub.3)Xwhere R.sub.1 to R.sub.3 are the same as above, and X is chlorine, bromine, or iodine with carbon dioxide in an aprotic polar organic solvent and in the presence of activated zinc. The activated zinc is activated by pretreatment with a mineral acid or acetic acid. At least one cation is present during the reaction which is an alkali metal ion, alkaline earth metal ion or ammonium ion. The cation is present in an amount of 0.01 to 50 gram atoms per one mol of alkenyl halide containig fluorine. The resulting product is hydrolyzed.

Abstract: Disclosed is a shaped zeolite catalyst used for liquid phase organic reactions. The shaped zeolite catalyst is composed of substantially spherical particles having a particle diameter substantially in the range of from 70 to 300 .mu.m, and which has fine pores having a pore volume of 0.4 to 1 cc per gram of the shaped catalyst and a median pore diameter based on the pore volume of 1,000 to 5,500 .ANG..

Abstract: 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.

Abstract: A 4,4'-bis(phthalimido)diphenyl sulfone compound having the formula: ##STR1## wherein X is a halogen atom, k=0 to 4, l=0 to 4, m=0 to 4 and n=0 to 4, provided k+l+m+n>1.

Abstract: A method for producing 4,4'-dibromobiphenyl, which comprises reacting biphenyl and from 2 to 3 mol times, relative to biphenyl, of bromine in a halogenated hydrocarbon solvent in the presence of a catalyst which is a simple substance of an element selected from the group consisting of antimony, titanium, tin and zinc, or a compound of the element.

Abstract: A process for producing dry .alpha.-L-aspartyl-L-phenylalanine methyl ester, which comprises drying wet crystals of .alpha.-L-aspartyl-L-phenylalanine methyl ester by means of an air having an absolute humidity of at least 0.015 kg/kg or at most 0.01 kg/kg.

Abstract: A process for producing stable .alpha.-L-aspartyl-L-phenylalanine methyl ester, which comprises heat-treating crystals of .alpha.-L-aspartyl-L-phenylalanine methyl ester having a water content of from 5 to 15% by weight based on wet crystals, at a temperature of higher than 50.degree. C. and lower than 80.degree. for at least 30 minutes.

Abstract: 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 ion exchange membranes, which comprises supplying an aqueous dipeptide ester solution containing organic acids to the central compartment defined by anion and cation exchange membranes or by anion exchange membranes and an aqueous electrolyte solution to the cathode and anode compartments, and electrically removing the organic acids from the central compartment to the anode compartment through the anion exchange membrane.

Abstract: A process for producing dry .alpha.-L-aspartyl-L-phenylalanine methyl ester having an improved solubility from wet crystals of .alpha.-L-aspartyl-L-phenylalanine methyl ester having a water content of at least 20% by weight, which comprises drying the wet crystals at a temperature of higher than 50.degree. C. to obtain moist crystals having a water content of less than 20 and more than 15% by weight, then drying the moist crystals at a temperature of not higher than 50.degree. C. to obtain semi-dry crystals having a water content of less than 5% by weight, and further drying the semi-dry crystals at a temperature of higher than 50.degree. C. to obtain dry crystals of .alpha.-L-aspartyl-L-phenylalanine methyl ester.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A process for producing a halogen-containing ethylbenzene derivative represented by the general formula: ##STR1## where X is a halogen atom, and W is a nitrile group, a carboxyl group, a lower alkoxycarbonyl group or an amidocarbonyl group, which comprises diazotizing aniline with a nitrite in a solution mixture comprising a hydrophilic organic solvent, an aqueous mineral acid solution and a vinyl compound represented by the general formula:CH.sub.2 .dbd.CH--W (II)where W is as defined above, to form a benzenediazonium salt, and reacting the benzenediazonium salt, without isolating it from the reaction system, with said vinyl compound in the presence of halogen ions and a copper compound as a catalyst.

Abstract: A process for producing an addition compound of N-benzyloxycarbonyl-.alpha.-L-aspartyl-L-phenylalanine methyl ester and phenylalanine methyl ester. Benzyloxycarbonylation of the amino group of L-aspartic acid by benzyloxycarbonylchloride in the presence of a base and esterification of phenylalanine containing its L-body by methanol in the presence of an acid are carried out and both the reaction solutions are admixed after residual methanol is removed from the esterification reaction solution. A proteolytic enzyme is added to the resulting mixture solution after it is adjusted to have a pH, value, at which no substantial deactivation of the enzyme occurs. The reaction of N-benzyloxycarbonyl-L-aspartic acid and phenylalanine methyl ester is carried out in the solution at a pH, at which the proteolytic enzyme exerts the enzymatic activity to deposit the addition compound which is then recovered.