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

Article abstract of DOI:10.1016/S0040-4020(97)10064-3

(2-Oxo-1,2-dihydropyridin-3-yl)-1,3,5-triazine derivatives 10 were obtained unexpectedly, in stead of pyrido[2,3-d]pyrimidine derivatives, by the intermolecular aza-Wittig reaction of methyl 2-(N- triphenylphosphoranylidene)aminonicotinate 3 with aryl isocyanates followed by attempted heterocylization 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.