Keetha Laxminarayana

New diterpenoids from Caesalpinia species and their cytotoxic activity.

Chemical investigation on Caesalpinia crista afforded two new diterpenoids, 6beta-cinnamoyloxy-7beta-acetoxyvouacapen-5alpha-ol and 6beta,7beta-dibenzoyloxyvouacapen-5alpha-ol and on Caesalpiniapulcherrima another new diterpenoid, 12-demethyl neocaesalpin F along with several known constituents. The structures of the new compounds were settled from their 1D and 2D NMR spectral data. The cytotoxicity of these compounds was measured on two different cancer cell lines.

Stereoselective total synthesis of a potent natural antifungal compound (6S)-5,6,dihydro-6-[(2R)-2-hydroxy-6-phenyl hexyl]-2H-pyran-2-one

A practical stereoselective synthesis of (6S)-5,6,dihydro-6-[(2R)-2-hydroxy-6-phenyl hexyl]-2H-pyran-2-one, a potent natural antifungal compound, is described. The sequence involves diastereoselective iodine-induced electrophilic cyclization, epoxide ring opening with a vinyl Grignard reagent and ring closing metathesis (RCM) as the key steps.

Zirconium tetrachloride mediated regioselective transformation of N-tosylaziridines into β -chlorosulfonamides

Regioselective ring opening of N-tosylaziridines has efficiently been carried out with ZrCl4 at room temperature to afford the corresponding β-chlorosulfonamides in high yields within a short reaction time.