Studies on Cyanine Dyes. II

On Syntheses of Merocarbocyanine Dyes by Using Compounds Containing Active Methylene Radicals as Condensation Agents

Abstract

Merocarbocyanine dyes, similar to the dyes obtained from dye intermediates and ethoxymethylene cyanoacetate, cyanoacetamide or acetoacetate, were prepared by the reaction of orthoformate and quinaldine methiodide or 2-methylbenzothiazole ethiodide, using a large amount of cyanoacetate, cyanoacetamide, cyanoacetanilide, acetoacetate, or benzoylacetonitrile as an addition agent.