CHEMISTRY OF ETHYL 2-METHYL-4-OXO-Δ2-PYRROLINE-3-CARBOXYLATE AND RELATED COMPOUNDS

Abstract

Ethyl 2-methyl-4-oxo-Δ²-pyrroline-3-carboxylate (Ia) is oxidized by one-electron oxidizing agents to a colored dimer which has been synthesized by an alternative route. Acetylation of (Ia) and its N-methyl derivative (Ib) gives a variety of products some of which show unusual infrared absorptions. The products of dimerization of (Ia) and (Ib) in strong acid show nuclear magnetic resonance absorptions at variance with previously claimed structures and alternatives are suggested.