Oxidative annulation of L-phenylalanine using I2/DMSO: an easy approach for chemoselective synthesis of 2,3,5-trisubstituted pyridines and 2,5-disubstituted oxazoles

A facile approach for chemoselective synthesis of 2,3,5-trisubstituted pyridines and 2,5-disubstituted oxazoles from L-phenylalanine and aryl methyl ketone using I2/DMSO has been developed. Two equivalents of L-phenylalanine reacted with aryl methyl ketone and I2/DMSO giving 2,3,5-trisubstituted pyridines and interestingly one equivalent of L-phenylalanine afforded 2,5-disubstituted oxazoles. This chemo-divergent approach has features of being transition metal-free, free from expensive ligands, additives and starting materials, and having a less toxic nitrogen source and broad substrate scope.

Pyrazolo-fused 4-azafluorenones as key reagents for the synthesis of fluorescent dicyanovinylidene-substituted derivatives

A green method for the three-component synthesis of an indeno[1,2-b]pyrazolo[4,3-e]pyridines library under microwave irradiation and their use in the preparation of novel fluorescent dicyanovinylidene-substituted derivatives is provided.