Synthetic studies on pseudoguaianolides. II. A total synthesis of (.+-.)-carpesiolin.
作者:KEISHIRO NAGAO、MASATO CHIBA、SANGWON KIM
DOI:10.1248/cpb.31.414
日期:——
A total synthesis of (±)-carpesiolin (3) is reported starting from the hydroazulenone (2), which is a key intermediate of helenanolide synthesis. For the introduction of the C6 to C8 functionalities, 2 was converted to the epoxy-alcohol (5). Its structure was confirmed by chemical and spectroscopic evidence. After construction of the γ-lactone ring, the tert-butyl protective group was removed from the ester (15) by acid-catalyzed thermolysis. However, this reaction was unexpectedly accompanied by concomitant 1, 3-acyl migration with inversion of the configuration at C4 to yield the hydroxy-ester (16), whose structure was established by analysis of its proton magnetic resonance spectrum and some chemical reactions. After manipulation of the protective group to give the tetrahydropyranyl ether (18), its conversion to (±)-carpesiolin was achieved by (i) introduction of the exo-methylene group onto the lactone ring, (ii) oxidation to the cyclopentanone (24), and (iii) deprotection of the C6 hydroxyl group.
作者:KEISHIRO NAGAO、MASATO CHIBA、ISOTAKA YOSHIMURA、SANGWON KIM
DOI:10.1248/cpb.29.2733
日期:——
Total synthesis of (±)-carpesiolin (1) is described using a new and general synthetic route to helenanolide sesquiterpenes. The scheme includes the stereocontrolled introduction of the C-10 α-methyl group in the perhydroindanone (3) and its conversion to the perhydroazulenone (4) via the regiospecific ring expansion reaction.
TREATMENT OF VIRAL INFECTIONS AND VIRALLY ASSOCIATED LESIONS WITH SEQUITERPENE LACTONES
申请人:The Board of Regents of the University of Texas System
公开号:US20210196676A1
公开(公告)日:2021-07-01
The present disclosure relates to the use of the sequiterpene lactones and Helenalin (H. tox) or its derivatives to treat viral infection and virally induced lesions, such as warts or wart-associated skin or mucosal lesion. A topical application, optionally using a skin covering such as gauze, a bandage, or a patch, can substantially reduce and even eliminate persistent, recurrent and/or treatment-resistant warts.