Total Synthesis of dl-Febrifugine and dl-Isofebrifugine.
作者:Yasuo TAKEUCHI、Hitoshi ABE、Takashi HARAYAMA
DOI:10.1248/cpb.47.905
日期:——
Racemic compounds (1 and 2) of the antimalarial agents febrifugine (d-1) and isofebrilugine (d-2) were synthesized using an unusual Claisen rearrangement of allyl enol ether (7) and the stereoselective reduction of 2-allyl-3-piperidone (8). This method is widely applicable to the synthesis of derivatives needed to study the structure-activity relationship of febrifugine.
The regioisomers (2a,b) of the piperidinering of febrifugine (1a) and isofebrifugine (1b) were synthesized from 4-allyl-3-piperidone (5). Reduction of 5 afforded a mixture of the trans and cis alcohols (6a,b) without diastereoselectivity; this result differentiated it from the reduction of 2-allyl-3-piperidone (14). The antimalarial activity of 2a,b and related compounds was tested.
type alkaloids, febrifugine (1) and isofebrifugine (2), isolated from Dichroa febrifuga roots, show powerful antimalarial activity against Plasmodium falciparum. Unfortunately, their emetic effect and other undesirable side effects have precluded their clinical use for malaria. Because of their antimalarial potency, analogues were searched for, with the goal of preserving the strong antimalarial activity