Synthesis Of Paclitaxel Analogues ��. To A Diterpenoid Alkaloids Conversion Of The Synthesis Of Paclitaxel Analogues

On the basis of our previous work on the conversion of the norditerpenoid alkaloids into taxoids, this dissertation described further research on the ABC route. At the same time, we brought forward a new conversion stratagem, and study the key reaction primarily. In addition, we also study the debenzylation with NBS/HOAC.In the research of ABC route, chloronation of 19 possessing C(17)-NH2 with SOCl₂ in PhH did not give the desired 7,17-seco compound but compound 23 having Δ⁸⁽¹⁵⁾. This indicated that it is difficult to cleave 7,17-bond of ring B after the modification of ring A.In the study of the key reaction of ring B rearrangement, we successfully prepared the key compounds 40, 42 for enlarging of ring B from the compunds 34 and 39, whose ring B have not been modified. However, attempts are failed together with compounds 35 having 8,15-epoxy and 44. Such results indicated that the rearrangement is difficult when ring B was not modified.Due to the spatial resistance of substitute group in C(7), the key compound for rearrangement was not prepared by compounds 61 and 63 whose ring B were modified. After changing the strategy, compound 103 without substitute group in C(7) but having Δ⁸⁽¹⁵⁾ at the same time was obtained. But the attempts to synthesis the key compound for rearrangement was also failed. Compound 85 was used for rearrangement byTTN, to give unexpected 87 with o;/?-unsaturated ketone.Attempt to debenzylate of compound 131 with NBS/HOAC was studied and we got compound 133 having no benzyl successfully.In the course of our research mentioned above, 90 norditerpenoid alkaloids were prepared and 87 of them were new artificial compounds. Their structures were determined by spectral data (MS, *H and 13C NMR, DEPT, 'H-'H COSY, HMQC, HMBC) and chemical methods.