Studies on the Synthesis of 2-Alkyl-5-aryl-1,3,4-oxadiazolines from N-Acylhydrazones

Abstract

Reaction of N-acylhydrazones with benzyloxyacetyl chloride in the presence of i-Pr 2 EtN affords new 1,3,4-oxadiazolines in excellent yields (72-95%), under mild reaction conditions and in short reaction times. The structures of the products were confirmed by single-crystal X-ray diffractometry. A plausible reaction mechanism is proposed.

Construction of 1,3,4-oxadiazolines bearing CF3-quaternary centers via amino-assisted [3 + 2] cycloadditions

“…Over the past decades, many efforts have been made continuously by organic chemists targeting the access of the 1,3,4-oxadiazoline skeleton. The pioneering studies were the cyclizations of N -acylhydrazones under acylation conditions by using acetic anhydride 9 or acetyl chloride 10 (Scheme 1a, (1)). In 2014, Xu and co-workers published the synthesis of 2-imino-1,3,4-oxadiazolines via Pd-catalyzed oxidative annulation reactions of hydrazides with isocyanides (Scheme 1a, (2)).…”