ORGN 555 |
| A series of novel tetracyclic 6-thia-5a-aza-acephenanthrylene derivatives (III) was designed as the ligands to serotonin receptors. These tetracyclic compounds were synthesized by rigidization of the arylsulfonyl moiety through C-7 of indole, which was achieved under Heck conditions. Since the C-2 cyclized Heck product is sterically and thermodynamically preferred end product, the reaction yields were less. Additionally, it was essential to block the C-2 position of indole so as to drive the nucleophilic attack from C-7 of indole. Alternate synthetic strategy was therefore adopted where the site for Palladium – bromine exchange was reversed. This strategy of altering the Palladium-Bromine exchange site gave a way to synthesis of derivatives, which were forbidden by former route. The comparative reaction rates, purities of products, reaction time etc. indicates that the alternate site for palladium exchange is advantageous.
|
|
Heterocycles, Aromatics, Metal-Mediated Reactions and Syntheses, Materials, Devices, and Switches
8:00 PM-10:00 PM, Wednesday, 29 March 2006 Georgia World Congress Center -- Ex. Hall B4, Poster
Division of Organic Chemistry |
