Synthesis of 4-methylfuro[3′,2′:5,6]benzofuro[3,2-c]pyridine

4-Methylfuro3′,2′:5,6]benzofuro3,2-c]pyridine ( 3 ) was synthetized from 2-acetylfuro3,2-f]benzob]furan ( 4 ) or from 2-acetyl-5,6-dihydrofuro3,2-f]benzob]furan ( 10 ). The key step involves a rearrangement-cyclization of azides 6 and 12 to form 4-methylfuro3′,2′:5,6]benzofuro3,2-c]pyridin-1(2H) one ( 7 ) and 8,9-dihydro-4-methylfuro3′,2′:5,6]benzofuro3,2c]pyridin-1(2H)-one ( 13 ). Introduction of an aminoalkyl chain on carbon 1 was effected by substitution of 1-chloro-4-methylfuro3′,2′:5,6]benzofuro3,2-c]pyridine ( 8 ).