Synthesis of Melatonin Analogues Derived from Furo[2,3-b]-and [2,3-c]Pyridines by Use of a Palladium-Copper Catalyst System

摘要

2,3,5-Substituted furo[2,3-b]pyridine was synthesized by palladium-catlyzed reaction of 5-bromo-2-hydroxy-3-iodopyridine and phenylene with (Ph_3P)_2PdCl_2, CuI in the Et_3N. A carbonylative cyclization of 5-hydroxy-2-methoxy-4-(2-phenylethynyl)pyridine with carbon monoxide in methanol with PdCl_2, CuCl_2 under basic conditions, has been accomplished to prepare methyl 2,5-substituted furo[2,3-c]pyridine-3-carboxylate.