Chemical Studies on Rubiaceous New Type Modified Indole Alkaloids

泰国红科植物Uncaria salaccensis的新型修饰吲哚生物碱——从该植物中分离到4个新的结构类别未知的次吲哚生物碱。对它们的结构进行了分析和合成研究。因此，第一个生物碱salacin （US-6）被发现是一个D- seco修饰的氧吲哚生物碱，它被认为是通过氧化裂解20,21烯胺型双键形成的。以羟色胺和相应的车醛为起始反应，进行了-salacin的全合成。第二和第三类生物碱US-7和US-8与salacin属于同一结构类。尝试从已知的天然生物碱进行化学衍生或全合成。第4种生物碱US-9为新型c -二羟基辛多碱生物碱，结构为3-氧-7-羟基-3,7-二羟基辛多碱。由蛇蛇碱或异蛇蛇碱的化学衍生证明了相对立体化学和绝对立体化学。茜草科苦麦草中吲哚类生物碱的改性——在苦麦草中发现了新型改性的苦麦草苷和脱氧苦麦草苷。通过对彪马皂苷及其c - 3,3 -彪马皂苷异构体的合成，证明了其立体结构。这些化合物长期以来一直被认为是自然界中“后strictosamide生物合成事件”的关键成员，继已知的中间体，strictosamide和strictosamide之后。进一步对其成分进行详细研究，得到一种酸性葡萄糖生物碱，其结构为strictosidic酸。

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.