Studies on arylhydrazones of ethyl arylsulfonylglyoxylates

The reaction of arylhydrazones of 4-arylthiosemicarbazides of arylsulfonylglyoxylic acid with ω-bromoacetophenone has given arylhydrazones of N-(3-aryl-4-phenyl-2-thiazolinylidene)hydrazides of arylsulfonylglyoxylic acids. The reaction of ethyl p-toluenesulfonate with o-aminothiophenol and o-phenylenediamine in polyphosphoric acid has given 2-(p-tolylsulfonyl)methylbenzothiazole and 2-(p-tolylsulfonyl)methylbenzimidazole. From 2-(p-tolylsulfonyl)methylbenzothiazole, a styryl and the corresponding carbocyanine with a substituted indoline have been obtained. The considerable hypsochromic shift of the absorption maxima of the latter is explained by the influence of the voluminous electronegative group SO₂R in the position α to the heterocyclic nuclei.