Sodium Benzoate as a Mild Base Catalyst for the Tandem Michael-Aldol Self-Condensation of γδ-Unsaturated β-Ketoesters

Abstract

An ef®cient procedure has been developed for the tandem Michael-aldol selfcondensation of ,-unsaturated -ketoesters (1), using sodium benzoate as a mild base catalyst to furnish conjugated vinylcyclohexenonedicarboxylates (2) some of which show biological activity against ectoparasites in cattle.

One-pot, four-component synthesis of pyrano[2,3-c]pyrazoles catalyzed by sodium benzoate in aqueous medium

“…This compound is also well known for their application in food industry as a safe preservative and antimicrobial agent. Literature survey also reveals that sodium benzoate has been employed as an eco-friendly base catalyst for the synthesis of cyclic ketones, 44 arylmethylene isoxazol-5(4H)-ones, 45 and substituted olefins via Knoevenagel condensation. 46 In consideration of green chemical methodology, here we report the synthesis of pyranopyrazoles (5) starting from aryl aldehydes (1), hydrazines (2), ethyl acetoacetate (3), and malononitrile (4) using sodium benzoate as the mild basic catalyst in water (Scheme 1).…”