A Facile Environment-Friendly Synthesis of 7-(Naphthalen-1-yl)pyrazolo[1,5-a]pyrimidine Analogues via Aza-Michael Addition–Elimination–Cyclodehydration. X-Ray Crystallography and Structural Elucidation

The functionalization of 1-acetylnaphthalene (1) through the reaction with dimethylformamide dimethyl acetal resulted in the formation of 3-(dimethylamino)-1-(naphthalen-1-yl)prop-2-en-1-one (2) which reacted with substituted aminopyrazoles 3 in the presence of KHSO4 in aqueous media under ultrasonic irradiation, yielding novel substituted 7-(naphthalen-1-yl)pyrazolo[1,5-a]pyrimidine derivatives 4a and 4b. The structures of these compounds were confirmed by analytical and spectral data, as well as by X-ray crys­tallo­graphic analysis of compound 4b.