Production of dibenzoxazolylthiophenes

摘要

There is disclosed a method of producing a thiophene-2,5-dicarboxylic acid diester represented by the formula <IMAGE> (I') 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 <IMAGE> (II') 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 then dehydrohalogenating 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.