Preparación de alfa-Cetoles y su Aplicación en la Síntesis de Nuevas Oxazolin-2-onas

Abstract

Oxazolidinones are heterocyclic pharmacophores of relevance for a large number of drugs, due to their biological activity. This work describes an efficient methodology for obtaining substituted alpha-ketols 7 by Michael additions to the captodative olefin 6, and the subsequent basic hydrolysis. Condensation in a single step of these alpha-ketols 7 with several isocyanates leads to the substituted 4- oxazoline-2-ones 8 assisted by MW irradiation under solvent-free conditions. N O O R 8a, R = C6H4-p-OMe 8b, R = S-Ph 6 O O O O NO2 OH R 7a, R = p-OMe-C6H4- 7b, R = S-Ph 7c, R = m-OMe-C6H4-S- 7d, R = ter-butil-S- 7e, R = m-Me-C6H4-SCONDENSATION MICHAEL ADDITION TYPE R' Also, no chiral dihydropyranyloxazol-2-one 46a and chiral 46b, were efficiently prepared in high yields. Upon hydrogenation, the latter compounds were saturated to furnish the tetrahydropyranyl compounds 47a-b in good yields. R N O O O R N O O O 9a, R = C6H5 9b, R = 1-(R)-feniletil MW 48 46a, R = C6H5 46b, R = 1-(R)-feniletil R N O O O 47a, R = C6H5 47b, R = 1-(R)-feniletil