Sumitomo Chemical Company, Limited

Mamoru Shirahata

Yoji Sakito

Yujiro Kiyoshima

Kazuya Minamisaka

Atukazu Iwata

Yasunobu Miyamoto

Toshitsugi Uemura

Process for producing hexahydrothieno (3,4-D)immidazole-2,4-diones

A method for purifying O,S-dimethyl N-acetyphosphoramidothioate, which is characterized by subjecting a crude crystal of O,S-dimethyl N-acetylphosphoramidothioate to recrystallization by using a two-phase solvent system comprising water and an organic which is an aromatic hydrocarbon, an aliphatic carboxylic acid ester or aliphatic ketone, wherein the amount of water is 0.1 to 2 parts by weight and the amount of the organic solvent is 1 to 20 parts by weight to 1 part by weight of the crude O,S-dimethyl N-acetylphosphoramidothioate. A further method for purifying O,S-dimethyl N-acetylphosphoramidothioate, which is characterized by extracting O,S-dimethyl N-acetylphosphoramidothioate from an aqueous solution of crude O,S-dimethyl N-acetylphosphoramidothioate with an organic solvent which is a carbonate ester, an aliphatic carboxylic acid ester, an aliphatic ketone, an aliphatic alcohol or a mixture of two or more thereof, wherein the solubility of water in the organic solvent is in a range of from 1 to 20% by weight, and crystallizing O,S-dimethyl N-acetylphosphoramidothioate from the resulting organic phase.

Method for purifying O, S-dimethyl N-acetylphosphoramidothioate

Method for purifying O,S-dimethyl N-acetylphosphoramidothioate

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Oita, Japan

Mamoru Shirahata