Synthesis and stereochemistry of new trihydrodiazabicyclo[3.m.n]alkano[4',5':1,2]pyrido[3,4-b]indole ring system

Article abstract of DOI:10.1002/jhet.5570300616

The classical Pictet-Spengler reaction of tryptamine with the isomeric N- benzylpiperidones 3a, 3b and N-benzylpyrrolidone 3c yielded the spiro derivatives of 1,2,3,4-tetrahydro-β-carboline 5a, 5b and 5c. Cyclocondensation of the spirotetrahydrocarboline with chloroacetic chloride and the subsequent reductive debenzylation afforded the new ring systems of trihydrodiazabicyclo[3.m.n]alkano[4',5':1,2]pyrido[3,4-b]indoles 8a, 8b, and 8c. The structures of the bicyclic systems 8a, 8b, and 8c were determined by using both, high-resolution ¹H and ¹³C nmr techniques and force field and MNDO calculations.