Sumitomo Seika Chemicals Co., Ltd.

Nario Kimura

Hiroshi Goda

Naohiro Yoshikawa

Satoshi Kimura

Masaki Teramoto

Yuuji Matuzaki

Yoshihide Masuda

Katsuhiko Yoshida

The present invention is directed to novel 2,5-dichlorophenylthioglycolic acid derivative, a process for their production and a process for producing the desired product 2,5-dichlorophenylthioglycolic acid derived from said novel compounds. 2,5-dichlorophenylthioglycolic acid derivative of the present invention can be obtained by reacting 2,4,5-trichlorobenzensulfonates and thioglycolic acid in the presence of base, and said desired product can be obtained by desulfonating said compound in an aqueous solution of mineral acid. Novel 4-carboxymethylthio-2,5-dichlorobenzenesulfonates of the present invention can be used advantageously as an intermediate for the production of 2,5-dichlorophenylthioglycolic acid. The use of said intermediate makes it possible to obtain the desired product in a decreased process steps with high yield. In addition, it poses no problem of environmental pollution as pointed out with conventional methods because it uses no heavy metals.

2,5-dichlorophenylthioglycolic acid derivative and method for its

A method of producing a dibenzoxazolyl thiophene represented by the formula ##STR1## wherein R'' represents a hydrogen, an alkyl of 1-8 carbons, a cycloalkyl, a phenyl, a substituted phenyl or a benzyl, which includes: reacting a thiophene-2,5-dicarboxylic acid diester represented by the formula ##STR2## wherein R' represents a branched alkyl of 3-5 carbons, phenyl, or tolyl, with an aminophenol represented by the formula ##STR3## wherein R'' is the same as before, in the presence of an acid catalyst, wherein the acid catalyst is boric acid, phosphoric acid, polyphosphoric acid, zinc chloride, ferric chloride, or sulfuric acid.

Production of thiophene-2,5-dicarboxylic acid diesters,

There is disclosed a method of producing a thiophene-2,5-dicarboxylic acid diester represented by the formula ##STR1## wherein R' represents an alkyl of 1-8 carbons, a phenyl, a substituted phenyl or benzyl, which comprises:

Production of dibenzoxazolylthiophenes

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Hyogo, Japan

Nario Kimura