Acylation of aldo 1-pyrroline 1-oxides (4,5-dihydro-3H-pyrrole 1-oxides) and the oxidation of the resulting 3-acyloxy-1-pyrrolines (3-acyloxy-4,5-dihydro-3H-pyrroles)

Abstract

5,5-Dimethyl-1-pyrroline 1-oxide (DMPO), when treated with NaH (1 mol) followed by ethyl chloroformate, benzoyl chloride, pivaloyl chloride or 2-bromoisobutyryl bromide gave the corresponding 3-acyloxy-1-pyrrolines. With NaH (2–4 mol) followed by benzoyl chloride or 2-bromoisobutyryl bromide, DMPO gave the corresponding 2-(3′-acyloxy-1′-pyrrolin-3′-yl)-3-acyloxypyrrolidines. Acylation of the 3-phenyl and 3-methyl DMPOs also gave the corresponding 3-acyloxy-1-pyrrolines. Oxidation of the 3-acyloxy-1-pyrrolines with m-CPBA gave the corresponding oxaziridines in good yield. These oxaziridines were resistant to ring opening by acid hydrolysis, photolysis and thermolysis.