On the synthesis of protopine alkaloids.
For the synthesis of protopine alkaloids, we studied a reaction sequence based on a ring enlargement of indeno[2,1-a][3]benzazepines by a singlet oxygen oxygenation, followed by conversion of an amide carbonyl group of the resultant 10-membered keto-lactam to a methylene group, which is the last step for completion of the synthesis. The key substances, indeno[2,1-a][3]benzazepines, were prepared by Bischler-Napieralski cyclization of alkoxy-substituted 1-(2-bromobenzyl)-3-benzazepin-2-ones. Steric effects of the substituents in this synthesis were examined.
Wada
Yasuhiro
Y
Laboratory of Organic Synthesis, Division of Molecular Chemistry, School of Engineering, Hokkaido University, Sapporo 060-8628, Japan.
Kaga
Harumi
H
Uchiito
Shiho
S
Kumazawa
Eri
E
Tomiki
Miho
M
Onozaki
Yu
Y
Kurono
Nobuhito
N
Tokuda
Masao
M
Ohkuma
Takeshi
T
Orito
Kazuhiko
K
D001552:Benzazepines / Q000737:chemistry*; D053119:Benzophenanthridines / Q000138:chemical synthesis*; D001600:Berberine Alkaloids / Q000138:chemical synthesis*
D001552:Benzazepines; D053119:Benzophenanthridines; D001600:Berberine Alkaloids; C009093:protopine