Aristolactams, synthesis

Cohare and co-workers reported that aristolactam BU (22) was prepared, following Kupchen s method, by Perkin condensation of 6-bromo-3,4-di-methoxy phenyl acetic acid (119) and o-nitrobenzaldehyde (120) (Scheme 14). The 2-bromo-4,5-dimethoxy-2 -nitro-ds-stilbene-a-carboxylic acid (121) was obtained. The nitro group of 121 was reduced with ferrous sulfate and ammonium hydroxide, and the resulting 2-bromo-4,5-dimethoxy-2 -amino-cw-stilbene-a-carboxylic acid (122) without purification was submitted to the Pschorr phenanthrene synthesis to yield l-bromo-3,4-dimethoxyphen-anthrene-lO-carboxylic acid (123). The phenanthrylamine 124 was prepared from 123 via a Schmidt reaction, and, by treatment with n-butyllithium and CO2, 124, afforded 22 (42). 

A record number of new aporphine alkaloids, sixteen, has been isolated and characterized during the year under review. Even better methods for the synthesis of aporphines in high yields have been developed,1-3 and an interesting relationship between aporphines, morphinandienones, neoproaporphines, and spirinedienones has been pointed out.1 A novel and unusual alkaloid is eupolauramine (70), which is structurally related to the aristolactams but which incorporates an additional nitrogen atom in ring A.4... 

An alternate synthesis of an aristolactaro involves condensation of benzyne with the enelactam (74). The resulting aristolactam (75) was isolated in 227 yield. 

A recent synthesis of an aristolactam involves nitration at C-10 of the ester (84) derived from glaucine, followed by catalytic reduction and lactamization to provide... 

A partial synthesis of a tetrasubstituted aristolactam has been achieved from the tetramethoxyphenanthrene carboxylic acid 8, which had been derived from natural (+)-glaucine via Hofmann degradation followed by oxidation. ... 

SCHEME 7.19 Synthesis of Aristolactam BII (cepharanone B), Aristolactam BIB, Aristolactam FI (piperolactam A), A-methyl piperolactam A and Sauristolactam. Sonagashira coupling reaction. 

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