916236-90-3Relevant academic research and scientific papers
Novel, efficient total synthesis of natural 20(S)-camptothecin
Tang, Chao-Jun,Babjak, Matej,Anderson, Regan J.,Greene, Andrew E.,Kanazawa, Alice
, p. 3757 - 3759 (2006)
A modular approach to racemic and achiral camptothecinoids from the Padwa hydroxypridone which is based in part on a Claisen rearrangement and a Friedlander condensation was analyzed. The elements necessary for the construction of the chiral hydroxyl lactone derivative would be introduced by a Claisen rearrangement for the β substituent and a Heck coupling for the α substituent. Hydroxypyridone 3 was obtained in high yield from 2 pyrrolidinone and then converted into crotonate 4 in 96% yield through reaction with methyl 4 bromocrotonate. To cleave oxidatively the ethylidene group in 5a, it proved necessary to first deactivate the hydroxypyridone moiety by triflation and this permitted the desired scission to proceed selectively with ozone in dichloromethane to give keto ester 6 in 96% yield. Result shows that a new synthesis of 20 (S)-camptothecin has been developed which is both efficient and flexible.
