Dimethin and Tetramethin Merocyanines Derived from Thiazolones

Preparations of dimethin and tetramethin merocyanines from the fired acidic nucleus, 2-benzylthio-thi­azolone, and various variable basic nuclei, like quinoline-4, quinoline-2, pyridine-2, pyridine-4, benzoxazole, benzothiazole, and 4-phenyl -2-methylthiazole, are described.

With the help of the absorption data, certain generalisations on the influence of structural changes on absorption and the relative acidity of the thiazolone nucleus have been made.

The photographic sensitising properties of these dyes have also been studied.