The synthesis of fused and pendant pyrazole heterocyclic compounds from 5‐amino‐3‐methyl‐1‐phenylpyrazole and their evaluation as fluorescent brightening agents

Abstract
5‐Amino‐3‐methyl‐1‐phenylpyrazole (1) has been condensed with EMME (2a) and EMCA (2b) and the resulting ethyl 5‐aminoacrylates (3a–b) cyclized to pyrazolo[3,4,‐b]pyridines (4a–b). 3‐Methyl‐1‐phenylpyrazol‐5‐yl diazonium salt (7), prepared from (1) was coupled with tobias acid (8) and 2‐methoxy‐6‐aminoquinoxaline (9) to get the corresponding O‐aminoarylazo and heterylazo dyes (10) which were oxidatively cyclized to 2‐N‐(3‐methyl‐1‐N‐phenylpyrazol‐5‐yl)‐1,2,3‐triazolo[4,5‐a] naphthalene and [4,5‐f] quinoxaline derivative (11). The spectral properties of the compounds (4a–b, 5, 6, 11a–b) were studied.