PHOSPHARYLATED IMIDAZO[1,2-A]PYRIDINES

The reaction of phosphorus(III) halides with imidazo[1,2-a]pyridines i n the presence of bases leads to the formation of 3-phosphorylated imi dazo[1,2-a]pyridines. The reaction proceeds in high yield and requires no catalysts. In the compounds obtained, in contrast to phosphorylate d indolizines, the phosphorus-heterocycle bond is stable and nor cleav ed by dry hydrogen chloride, alcohols, or water. Imidazo[1, 2-a]pyridi nes with the phosphinic and phosphinous groups can be alkylated both a t the phosphorus and at the nitrogen atom of the heterocycle, the alky lation direction being dependent on the strength of the alkylation rea gent used. (C) 1995 John Wiley & Sons, Inc.