Synthesis and characterization of 1, 3??bis??(2??dialkylamino??5??thiazolyl)??substituted squaraines and their 2??(dialkylamino) thiazole precursors

D Keil, H Hartmann

Index: Keil, D.; Hartmann, H. Liebigs Annalen, 1995 , # 6 p. 979 - 984

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Citation Number: 15

Abstract

Abstract By condensation of squaric acid (1) with 2-(dialkylamino)-substituted thiazoles 8 a novel type of heterocyclic-substitued squaraines of the general structure 9 was prepared in moderate yield mostly. The squaraines 9 obtained are sparingly soluble in the most organic solvents and exhibit, in these solvents, narrow absorption bands in the visible range at about 620–700 nm. In dispersed form, the absorption bands of the squaraines 9 are, however, ...