ONE-POT SYNTHESIS OF NOVEL (2-OXO-1,2-DIHYDROPYRIDIN-3-YL)-1,3,5-TRIAZINE DERIVATIVES FROM METHYL 2-(N-TRIPHENYLPHOSPHORANYLIDENE)AMINONICOTINATE ARYL ISOCYANATES AND PRIMARY AMINES - SEQUENTIAL AZA-WITTIG/CYCLOADDITION/RING-TRANSFORMATION REACTIONS

摘要

(2-Oxo-1,2-dihydropyridin-3-yl)-1,3,5-triazine derivatives 10 were obtained unexpectedly, in stead of [2,3-d]pyrimidine derivatives, by the intermolecular aza-Wittig reaction of methyl 2-(N-triphenylphosphoranylidene)aminonicotinate 3 with aryl isocyanates followed by attempted heterocyclization by use of prim-amines. A novel sequential aza-Wittig/cycloaddition/ring-transformation mechanism for the formation of 10 has been reported based on the isolation and characterization of the key intermediates, pyrido[1,2-a][1,3,5]triazines 15 formed via [4+2] cycloaddition of the initially produced carbodiimide with aryl isocyanates. (C) 1997 Elsevier Science Ltd. [References: 28]