An Efficient Protocol for the Synthesis of Pyrazolo[1,5-c]quinazolines by a Staudinger–Aza-Wittig–Dehydroaromatization Sequence

Abstract

One-pot synthesis of azide-substituted dihydropyrazoles in isopropanol was performed using chalcones, hydrazine hydrate, and acyl chloride at 0℃, and its subsequent Staudinger-aza-Wittig-dehydroaromatization reactions with methyldiphenylphosphine were also investigated for further application in the construction of pyrazolo[1,5-c]quinazolines.

Hydrogen bond-promoted regio- and stereoselective synthesis of isoindoline derivatives through Pd-catalyzed isocyanide insertion reaction involving aziridines

“…To begin our investigation, a mixture of benzaldehydes 1 (2 mmol) and ketones 2 (2 mmol) was subjected to a solution of NaOH in an ice-bath of ethanol for 4 hours. The reactions yielded chalcones 3 , 17 which were then converted to the corresponding aziridines 4 successfully (Scheme 2). 18 All products 4 were isolated by column chromatography with overall yields of 70–85% (Table 1).…”