Aristolactam

Aristolactam (13) (in some papers, aristololactam) was first prepared by catalytic hydrogenation or zinc reduction in acetic acid from aristolochic acid I (25). It has been isolated from seveizl Aristolochic plants, including A. debilis and A. fangchi (24). Kupchan and Merianos isolated the first aristolactam iV-glucoside (19) from A. indica (37). 

Priestap has isolated a total of 12 aristolactams from A. argentina. These compounds all show a substitution pattern similar to that of the accompanying... 

The IR spectra are useful for detecting functional groups of Aristolochia alkaloids. Aristolochic acids show two characteristic bands at 1550 and 1350 cm due to the absorption of nitro group, and the carboxy OH group appears at 3000-2500 cm as a broad continuous absorption. Hydroxy derivatives of aristolochic acids or aristolactams show OH and NH absorptions at 3300-3500 and 3200-3400 cm The carboxy or lactam carbonyl is present at 1690 cm i. In general, the aromatic ring system shows stretches at 1625-1575 and 1525-1475 cm 1 as usual, and observation of the 900-700 cm region is often used for analysis of substitution type in aromatic derivatives 28). 

Maldonado and co-workers isolated an aristolactam taliscanine (21) from A. taliscana. Methylation of taliscanine was carried out by treatment with dimethyl sulfate and K2CO3 in acetone and yielded A -methyltaliscanine (76). Compound 76 was ozonized to give 77 and then further oxidized with C1O3-ACOH to give a carboxylic acid (79) (38). 

Tetramethoxy aristolochic acid (80) was obtained by nitration from the corresponding 3,4,6,7-tetramethoxy-phenanthrene-l-carboxylic acid (81), which was obtained from glaucine (82) via exhaustive Hofmann degradation (twice) followed by oxidation. Catalytic hydrogenation with Pd-C afforded the relevant aristolactam (83) (Scheme 10) (82). 

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). 

Aristolamide (11) A-(p-Hydrox-yphenethyl)-p-cuomaramide W-(p-Hydrox-yphenethyl)-fer-ulamide (moupinamide) Cepharanone A (aristolactam II) (14)... 

C. Aporphine, oxa-aporphine, and proaporphine alkaloids (including dioxoaporphine, aristolactams, and phenanthrene alkaloids)... 

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