Abstract: 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.

Abstract: 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.

Abstract: 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:halogenating a tetrahydrothiophene-2,5-dicarboxylic acid diester represented by the formula ##STR2## wherein R' is the same as before, with a halogenating agent selected from the group consisting of halogens and sulfuryl halides in an amount of 2-4 moles per mole of the tetrahydrothiophene-2,5-dicarboxylic acid diester; and thendehydrohalogenating the resultant halogenated tetrahydrothiophene-2,5-dicarboxylic acid diester in the presence of an alcohol, a base, a metal or a metal ion.There is also disclosed a method of producing tetrahydrothiophene-2,5-dicarboxylic acid diester and dibenzoxazolyl thiophenes. Some of the thiophene-2,5-dicarboxylic acid diesters and tetrahydrothiophene-2,5-dicarboxylic acid diesters are novel.

Abstract: 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.

Abstract: 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:halogenating a tetrahydrothiophene-2,5-dicarboxylic acid diester represented by the formula ##STR2## wherein R' is the same as before, with a halogenating agent selected from the group consisting of halogens and sulfuryl halides in an amount of 2-4 moles per mole of the tetrahydrothiophene-2,5-dicarboxylic acid diester; and thendehydrohalogenating the resultant halogenated tetrahydrothiphpene-2,5-dicarboxylic acid diester in the presence of an alcohol, a base, a metal or a metal ion.There is also disclosed a method of producing tetrahydrothiophene-2,5-dicarboxylic acid diester and dibenzoxazolyl thiophenes. Some of the thiophene-2,5-dicarboxylic acid diesters and tetrahydrothiophene-2,5-dicarboxylic acid diesters are novel.