A Synthesis of the ABC Tricyclic Core of the Clionastatins Serves To Corroborate Their Proposed Structures
نویسندگان
چکیده
A synthesis of the ABC tricyclic ring system of the clionastatins, an unusual pair of highly chlorinated androstane steroids, has been accomplished. This work provides strong support for the original structural proposal. An unexpected substrate-dependent reversal in alkene chlorination diastereoselectivity was critical to success. This approach should be amenable to an eventual enantioselective synthesis of the natural products themselves.
منابع مشابه
Synthesis and Biological Evaluation of New Tricyclic Dihydropyridine Based Derivatives on Potassium Channels
The present study reports a microwave-assisted method for the synthesis of twelve novel tricyclic 1,4-dihydropyridine derivatives in which dimethyl-substituted cyclohexane and / or tetrahydrothiophene rings are fused to the DHP ring. The structures of the compounds were confirmed by spectral methods and elemental analysis. The potassium channel opening effects of the compounds were determined o...
متن کاملSynthesis and Biological Evaluation of New Tricyclic Dihydropyridine Based Derivatives on Potassium Channels
The present study reports a microwave-assisted method for the synthesis of twelve novel tricyclic 1,4-dihydropyridine derivatives in which dimethyl-substituted cyclohexane and / or tetrahydrothiophene rings are fused to the DHP ring. The structures of the compounds were confirmed by spectral methods and elemental analysis. The potassium channel opening effects of the compounds were determined o...
متن کاملDEVELOPMENT OF RELATION FOR THE SEISMICALLY BASE ISOLATED STRUCTURES USING MODIFIED ABC ALGORITHM
In this paper, the effective parameters on the ductility demand of the seismically base isolated structure are investigated, and then a relation between the strength reduction factor and the target ductility is presented. The investigation has been conducted by modelling the base isolated structure as a two degree of freedom model in the OpenSees software, and the possibility of yielding in the...
متن کاملFacile and Efficient Self-template Synthesis of Core-coronal-shell ZnO@ZIF-8 Nanohybrid Using Ascorbic Acid and its Application for Arsenic Removal
In the present contribution, a facile and efficient protocol for synthesis a nanohybrid structure of core-coronal-shell ZnO@ZIF-8 using ascorbic acid (ZnO@AA/ZIF-8) as a new adsorbent for arsenic removal from water has been represented. For this purpose, the ZnO nanospheres were synthesized by a green and simple method followed by coating with ascorbic acid (AA) to modify their surface to achie...
متن کاملHighly efficient synthesis of the tricyclic core of Taxol by cascade metathesis.
An efficient enantioselective synthesis of the ABC tricyclic core of the anticancer drug Taxol is reported. The key step of this synthesis is a cascade metathesis reaction, which leads in one operation to the required tricycle if appropriate fine-tuning of the dienyne precursor is performed.
متن کامل