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Syntheses of benzo[b]‐ and benzo[j]phenanthridines
Author(s) -
Klemm L. H.,
Weisert Annekäte
Publication year - 1965
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570020104
Subject(s) - chemistry , phenanthridine , dehydrogenation , stereochemistry , oxime , medicinal chemistry , organic chemistry , catalysis
The isomeric lactams benzo[b]phenanthridine‐5(6H)‐one and benzo[j]phenanthridine‐6(5H)‐one were obtained in equal yields by Schmidt reaction on 11H‐benzo[b]fluoren‐11‐one (44% total) or by Beckmann reaction on 11H‐benzo[b]fluoren‐11‐one oxime (22% total). Reduction of the lactams with lithium aluminum hydride gave the 5, 6‐dihydro‐benzo[b]‐ and ‐[j]phenanthridines. Dehydrogenation of these dihydro derivatives produced the parent aromatic heterocycles benzo[b]‐ and benzo[j]phenanthridine in best overall yields of 20% and 12%, respectively. A few substituted benzophenanthridines were also prepared. Assignment of structures was based on ultraviolet, infrared, and n.m.r. spectra of the dihydro derivatives as well as on separate unequivocal synthesis of the isomeric benzophenanthridines.