1, 6-Dihydro-3 (2H)-pyridinones. I. Facile Synthesis of N-Substituted 1, 6-Dihydro-3 (2H)-pyridinones

Abstract

The first synthesis of the N-substituted 1, 6-dihydro-3 (2H)-pyridinones (4 and 16) is described. 1-Benzyl-1, 2, 3, 6-tetrahydropyridine (9) was treated with ethyl chloroformate to give the urethane (6), which was oxidized to the epoxide (10) with perbenzoic acid. Regioselective hydrobromination of 10 afforded the 4-bromo-3-hydroxypiperidine (11). Acetylation of 11 followed by dehydrobromination with DBU yielded the 5-acetoxy-Δ³-piperideine (13), which was hydrolyzed to the alcohol (15). Basic hydrolysis of 15 and subsequent condensation with methanesulfonyl chloride gave the sulfonamide analogue (22). The allylic alcohols (15 and 22) were oxidized to give the 1, 6-dihydro-3 (2H)-pyridinones (4 and 16), respectively.