| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1989: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1988: ¥1,600,000 (Direct Cost: ¥1,600,000)
|
|---|
| Research Abstract |
New type modified indole alkaloids in Thai Rubiaceous plant, Uncaria salaccensis --- From the titled plant four new seco indole alkaloids of hitherto unknown structure classes were isolated. Their structures were elucidated and synthetic studies were made. Thus the first alkaloid, salacin (US-6) was found to be a D- seco modified oxindole alkaloid which was regarded to be formed through oxidative cleavage of 20,21 enamine type double bond. Total synthesis of -salacin was carried out starting from condensation of oxytryptamine and the corresponding car aldehyde. Second and third alkaloids, US-7 and US-8, belonged to the same structural class as salacin. Attempts of chemical derivation from known natural alkaloids or total synthesis were made. Fourth alkaloid, US-9, was new type C-seco oxindole alkaloid and the structure was found to be 3-oxo-7-hydroxy-3,7-secorhyn- chophylline. Chemical derivation from rhynchophylline or isorhynchophylline proved the relative and absolute stereochemistry.
Modified endole alkaloids of Ophiorrhyza pumila of Rubiaceae --- New type modified indole alkaloids, pumiloside and deoxypumiloside, were found in Ophiorrhiza pumila. The stereo structure was proved through synthesis of pumiloside and its isomer at C-3, 3-epipumiloside. These compounds were long postulated and sought for in the nature as the key members in the "Poststrictosamide Biosynthetic Events" that follow the known intermediates, strictosidine and strictosamide. Further detailed study on the constituents of O. pumila gave an acidic gluco alkaloid and the structure was found to be strictosidic acid.
|
