3-Hydroxy-1H-pyrrole

Abstract

Flash vacuum pyrolysis (FVP) of tert-butyl {[(2,2-di­methyl-4,6-dioxo-1,3-dioxan-5-ylidene)methyl]amino}acetate at 600 ˚C gives the unstable 3-hydroxy-1H-pyrrole in ca. 55% yield as the only significant product. It exists as the enol tautomer in di­methyl sulfoxide solution, and predominantly as the keto tautomer in water. 3-Hydroxy-1H-pyrrole reacts readily with mild electrophiles, exclusively at the 2-position. FVP of the product obtained from one such reaction with methoxymethylene-substituted ­Meldrum’s acid gives pyrano[3,2-b]pyrrol-5(1H)-one in 77% yield.