2-(4-alkylamido-2-hydroxyphenyl)benz-X-azoles as intermediates for the synthesis of dyes

Nineteen substituted 2-phenylbenz-X-azoles, which are intermediates for the synthesis of dyes, were prepared from p-aminosalicylic acid (PAS). Substituents in the phenyl ring are 2′-hydroxy and/or 4′-amino and 4′-alkylamido with alkyl chains ranging from C₁ to C₁₅. The preferred route of the synthesis is discussed. The melting points and the R_f values are correlated with the structure. An extensive discussion of the electronic absorption spectra, involving other compounds with the same general structure, is reported.