An easy photochemical approach to the synthesis of the food-borne carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine

Article abstract of DOI:10.1016/S0040-4039(97)10039-9

Mutations induced by substances formed during food cooking are a field of growing interest; for a better comprehension of the mechanism of action of these carcinogens, simple routes to their synthesis are needed. In this letter we describe an easy method for 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP) synthesis, starling from the commercially available 2,3- diaminopyridine 1 via the 2-amino-3-methylamino-5-phenylpyridine 5 formation. The key step of this approach is the one pot synthesis of 5 performed by photolysis of 2-amino-5-iodo-3-(N-methyl-N-tosylamino)pyridine 4 to obtain simultaneous phenylation and tosyl group removal. Compound 5 was then used as an intermediate to obtain the 1-methyl 6-phenylimidazo[4,5-b]pylidine 6 which was aminated to afford PhIP in good overall yields.