Synthesis of new spiropyrans from 2,5-dimethyl-1,3-benzodithiolium salts

New spiropyrans that have thermochromic properties were obtained by the condensation of 2,5-diniethyl-1,3-benzodlthiolium perchlorate with o-hydroxy aromatic aldehydes and subsequent treatment of the resulting 2-styryl derivatives with ammonia in ether.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 318–320, March, 1972.