Syntheses of Functionalized N-(2-Pyridyl)-a-amino Acids and Esters by Ring Opening of Imidazo[1,2-a]pyridine

This report is devoted to the ring opening of the imidazole nucleus of functionalized imidazo [1,2-a] pyridines, by methanol in strong acid medium (HClO 4 ) leading to esters of N-(2-pyridyl)-α-amino acids in which the heterocyclic moiety bears a functional group. Direct obtention of this kind of compounds could be achieved by condensation of glyoxal derivatives with ethers of 2-amino-3-hydroxypyridine or with 2-amino-3(or 5)-nitropyridine in methanolic perchloric acid