Mitsui Toatsu Chemicals, Incorporated

Ryuichi Mita

Chojiro Higuchi

Akihiro Yamaguchi

Toshio Katoh

Takeshi Oura

Toshio Kato

Mitsumasa Umemoto

Nobuyuki Kawashima

Takao Takano

Naoki Sato

Hisamichi Murakami

Hideyuki Akieda

Shosuke Nagai

Masaharu Ohoka

Katsuya Sakai

Shousuke Nagai

Koichi Morinaga

Yoshinori Ide

Tsutomu Ishii

Masanobu Ajioka

Yukihiro Yoshikawa

Yoshitsugu Kono

Hitoshi Shimotori

Katsutoshi Ishikawa

Hideo Kawashima

Nobuhiro Kawashima

Hiroharu Tanikawa

Hironobu Horie

Sunao Maeda

Hiroshi Maeda

Chojiro H Iguchi

Nobuo Shimuta, Deceased

Mamoru Ueda

Yosiro Nagatake

Toyohiro Tajiri

Yuji Fukunaga

Yasuhiro Matsuki

Yuji Yanese

p-Aminophenyl acetate is isomerized to p-acetylaminophenol in the presence of an acid such as acetic acid or phosphoric acid.

Production of p-acetylaminophenol from p-aminophenyl acetate

A triethylene glycol derivative is added to p-dichlorobenzene so as to prevent consolidation and improve flowability of p-dichlorobenzene.

Process for preventing consolidation of p-dichlorobenzene

An improved process for producing allyl bromides by halogen exchange by reaction of an allyl chloride, with a metal bromide, wherein the reaction is conducted in an aprotic polar solvent. The allyl bromides obtained by the process of the invention are useful as intermediates for producing medicines, agricultural chemicals, dyes, and the like.

Process for producing allyl bromides

Pyrimidinyloxy(thio)quinoline derivatives represented by the formula (I) which exhibit an excellent controlling effect for plant diseases and are also safe for crop plants, preparation processes of the derivatives, and agri-horticultural fungicides comprising the derivatives as an active ingredient, are disclosed. ##STR1## In the formula (I), X is an oxygen atom or sulfur atom, Y is a hydrogen atom or halogen atom, Z is a hydrogen atom or methyl, R.sup.1 and R.sup.2 are methoxy or methyl, and n is an integer of 1 or 2.

Pyrimidinyloxy(thio)quinoline derivative, and agri-horticultural

A process for producing a p-hydroxyneophyl m-phenoxybenzyl ether represented by the general formula (II) ##STR1## (X.sub.1 and X.sub.2 are independently a hydrogen atom or a halogen atom) by subjecting a corresponding p-alkoxyneophyl m-phenoxybenzyl ether represented by the general formula (I) ##STR2## (R represents a lower alkyl group, and X.sub.1 and X.sub.2 have the same definitions as above) to ether cleavage, in which process the ether cleavage reaction is effected in an aprotic polar solvent, using a lower alkoxide of an alkali metal or an alkaline earth metal or using a metal hydroxide in the presence of a lower alcohol.

Process for producing p-hydroxyneophyl m-phenoxybenzyl ether

Crude pentachloronitrobenzene containing hexachlorobenzene and small amounts of acids is treated in the molten state or in a mixture solution of nitrobenzene or chloronitrobenzenes with an inorganic basic substance and then subjected to a distillation under reduced pressure.

Method for purifying pentachloronitrobenzene by solid base treatment

A higher yield of the difluorohalomethoxybenzene produced by the reaction of a metal phenolate with dibromodifluoromethane or bromochlorodifluoromethane can be obtained by conducting the addition of a metal alcoholate or a metal hydride as a reaction initiator to a solution or a suspension of an aprotic polar solvent containing the metal phenolate and dibromodifluoromethane or bromochlorodifluoromethane.

Preparation of a difluorohalomethoxybenzene

.alpha.-L-Aspartyl-L-phenylalanine methyl ester having low hygroscopicity is prepared by bringing a cake of .alpha.-L-aspartyl-L-phenylalanine methyl ester, which cake has been obtained by solid-liquid separation through a desired preparation process of .alpha.-L-aspartyl-L-phenylalanine methyl ester, into contact with an organic solvent of uniform phase so as to treat the cake with the organic solvent, subjecting the resulting mixture of the cake and organic solvent to solid-liquid separation to obtain a cake, and then drying the last-mentioned cake at a temperature not higher than 60.degree. C. The organic solvent is dry or contains water in an amount up to 30 wt.%.

Preparation process of .alpha.-l-aspartyl-l-phenylalanine methyl ester

.alpha.-L-aspartyl-L-phenylalanine methyl ester or the hydrohalide thereof is prepared by esterifying .alpha.-L-aspartyl-L-phenylalanine or .alpha.-L-aspartyl-L-phenylalanine which has been formed in situ by treating an N-protected-.alpha.-L-aspartyl-L-phenylalanine in an aqueous solution of sulfuric acid or a methanol-containing aqueous solution of sulfuric acid in the presence of an alkali metal halide or alkaline earth metal halide in a medium composed of sulfuric acid, water and methanol, thereby to allow the resulting .alpha.-L-aspartyl-L-phenyl-alanine methyl ester to precipitate as its corresponding hydrohalide, and then isolating the hydrohalide; and when the preparation of the methyl ester is desired, neutralizing the hydrohalide.

Preparation process of .alpha.-l-aspartyl-l-phenyl-alanine methyl ester

A method for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester having improved solubilization by the isolation thereof from an aqueous medium containing at least one additive selected from the group consisting of sodium alginate, sodium salt of carboxymethylcellulose, sodium starch glycolate and sodium polyacrylate.

Isolation of alpha-l-aspartyl-l-phenylalanine methyl ester from aqueous

This invention relates to an improved process for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester. More specifically, it relates to a process for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester which comprises treating, as a raw material, N-formyl-.alpha.-L-aspartyl-L-phenylalanine in methanol in the presence of an acid to form .alpha.-L-aspartyl-L-phenylalanine dimethyl ester, hydrolyzing the .alpha.-L-aspartyl-L-phenylalanine dimethyl ester by bringing it into contact with hydrochloric acid in the presence of methanol as desired, separating the thereby-precipitated .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride and neutralizing the hydrochloride. Further, this invention also provides a process for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester capable of using, as a raw material, N-formyl-.alpha.-L-aspartyl-L-phenylalanine which contains N-formyl-.beta.-L-aspartyl-L-phenylalanine in an amount of 30% by weight or less.

Preparation process of .alpha.-L-aspartyl-L-phenylalanine methyl ester

Disclosed herein is a process for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester or its hydrochloride from 5-benzyl-3,6-dioxo-2-piperazine acetic acid or its methyl ester, prepared without using L-penylalanine methyl ester which involves problems in its stability, as a raw material. Specifically, the process comprises: bringing 5-benzyl-3,6-dioxo-2-piperazine acetic acid in the presence of methanol or 5-benzyl-3,6-dioxo-2-piperazine acetic acid methyl ester in the presence or absence of methanol into contact with hydrochloric acid; isolating the thereby deposited .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride; and neutralizing said hydrochloride with an alkali as required. Preparation processes of 5-benzyl-3,6-dioxo-2-piperazine acetic acid or its methyl ester are also disclosed.

The present invention relates to a process for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester or its hydrochloride. .alpha.-L-aspartyl-L-phenylalanine methyl ester or its hydrochloride is prepared by a process comprising: condensating N-formyl-L-aspartic acid anhydride and L-phenylalanine in water or in water containing methanol at a pH in the range of 7-12 to form N-formyl-.alpha.-L-aspartyl-L-phenylalanine; acidifying the reaction mixture successively with hydrochloric acid in the presence of methanol without isolating the N-formyl-.alpha.-L-aspartyl-L-phenylalanine so as to bring it into contact with hydrochloric acid in the presence of methanol for reaction and thereby to deposit .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride; separating the .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride; and neutralizing said hydrochloride as required.

This invention relates to an improved process for preparing N-formyl-.alpha.- aspartyl phenylalanine. More specifically, it relates to a process for preparing N-formyl-.alpha.-aspartyl phenylalanine by condensating N-formyl aspartic acid anhydride and phenylalanine which comprises effecting the condensation reaction in a water medium while maintaining the pH during the reaction in the range of 7-12 and at a reaction temperature of 50.degree. C. or below.

Preparation process of N-formyl-.alpha.-aspartyl phenylalanine

A process for preparing an N-acylphenylalanine represented by the formula (II): ##STR1## wherein R.sub.3 and R.sub.4 mean individually a hydrogen atom or an alkyl, alkoxy, phenoxy, hydroxy or methylenedioxy group, and R denotes a methyl or phenyl group, which comprises catalytically reducing an N-acyl-.beta.-phenylserine represented by the formula (I): ##STR2## wherein R.sub.1 and R.sub.2 mean individually a hydrogen atom or an alkyl, alkoxy, phenoxy, benzyloxy or methylenedioxy group, and R has the same meaning as defined in the formula (II), in the presence of a reducing catalyst or both reducing catalyst and acid, in a solvent.

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Kawasaki, Japan

Ryuichi Mita