FUROPYRIDINES .23. SYNTHESIS AND REACTIONS OF CHLOROPYRIDINE DERIVATIVES OF FURO[2,3-B]PYRIDINE, FURO[2,3-C]PYRIDINE AND FURO[3,2-C]PYRIDINE

Chlorination of the N-oxides of furo[2,3-b]- 1a, -[2,3-c]- 1b and -[3, 2-c]pyridine 1c with phosphorus oxychloride afforded compounds substit uted normally at the alpha- or gamma-position to the ring nitrogen, 2a , 2'a, 2b, 2c, 2'c and 2 '' c, and in addition, in the case of 1b, com pounds substituted on the furan ring, 2'b and 2 '' b. The structures o f these compounds were confirmed from their ir, nmr and mass spectra. The major chlorinated products 2a, 2b and 2c were converted to methoxy - 5a, 5b and 5c, N-pyrrolidyl- 7a, 7b and 7c, and phenylthiofuropyridi nes 8a, 8b, and 8c.