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Synthesis of 1,4,5,6‐tetrahydropyrazolo[3,4‐ d ]pyrido[3,2‐ b ]azepine
Author(s) -
Albright J. Donald,
Du Xuemei
Publication year - 2000
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.5570370107
Subject(s) - azepine , chemistry , yield (engineering) , acrolein , acetic acid , stereochemistry , medicinal chemistry , organic chemistry , catalysis , materials science , metallurgy
The synthesis of 7,8‐dihydro‐5(6 H )‐quinolinone ( 3 ) from commercially available 3‐amino‐2‐cyclohexen‐1‐one ( 1 ) and 3‐(dimethylamino)acrolein ( 4 ) in 23% yield avoids the preparation of propynal ( 2 ). Conversion of 5‐(4‐methylphenylsulfonyl)‐6,7,8,9‐tetrahydro‐5 H ‐pyrido[3,2‐ b ]azepine ( 12 ) to 6‐(4‐methylphenylsulfonyl)‐1,4,5,6‐tetrahydropyrazolo[3,4‐ d ]pyrido[3,2‐ b ]azepine ( 24 ) is described. Removal of the N ‐(4‐methylphenylsulfonyl) group with 40% sulfuric acid in acetic acid gave the tricyclic azepine 26. Application of a similar series of reactions to 5‐(4‐nitrobenzoyl)‐6,7,8,9‐tetrahydro‐5 H ‐pyrido[3,2‐ b ]‐azepine ( 13 ) afforded 6‐(4‐nitrobenzoyl)‐1,4,5,6‐tetrahydropyrazolo[3,4‐ d ]pyrido[3,2‐ b ]azepine ( 25 ).