(2R,3R)-[2’’,3’’:6,7]-[5-(2-hydroxypropan-2-yl)-4,5-dihydrofurano]-5,7,4’-trihydroxy 2,3-dihydroflavon- 3-ol, (2R,3R)-5,7,4’-tetrahydroxy-6-(2,3-dihydroxy-3-methylbutyl)-2,3-dihydroflavon-3-

International Conference on Stereochemistry

August 18-19, 2016 Sao Paulo, Brazil

Patrick Yves Ango

University of Yaound�© 1, Cameroon

Posters & Accepted Abstracts: Med chem

Abstract :

A phytochemical study of Ficus thonningii has led to the isolation of two previously unreported compounds, (2R,3R)- [2â��â��,3â��â��:6,7]-[5-(2-hydroxypropan-2-yl)-4,5-dihydrofurano]-5,7,4â��-trihydroxy-2,3-dihydroflavon-3-ol,(2R,3R)-5,7,4â��-tetrahydroxy- 6-(2,3-dihydroxy-3-methylbutyl)-2,3-dihydroflavon-3-ol together with sixteen known compounds: shuterin, naringenin, syringic acid, p-hydroxybenzoic acid, genistein, 5,7,3â��,4â��,5â��-pentahydroxyflavanone, luteolin, methylparaben, aromadendrin, garbanzol, dihydroquercetin, 5,7,3â��-trihydroxyflavanone, �²-sitosterol, sitosterolglucoside, lupeol acetate, and taraxerol. Their structures were elucidated on the basis of spectroscopic data. The new compounds and extracts displayed potent antioxidant activity. The stereochemistry of asymetric carbon of the news compounds was determined using CD experiment. In fact, the CD measurements of thonningii flavanonol A involving the underivatized dihydroflavanonol gave a positive Cotton effect in the 330 nm region and a negative Cotton effect at 276 nm, indicating a 2R absolute configuration and, also suggesting a 3R absolute configuration due to the coupling constant (J=12 Hz) between H-2 and H-3. Thus, thonningii flavanonol A was determined as (2R,3R)-[2â��â��,3â��â��:6,7]- [5-(2-hydroxypropan-2-yl)-4,5-dihydrofurano]-5,7,4â��-trihydroxy-2,3 dihydroflavon-3-ol. The (2R, 3R) absolute configuration of thonningii flavanonol B was also deduced from the coupling constant between H-2 and H-3 (J= 11.4 Hz) and the CD curve with a positive Cotton effect in the region of 336 nm and a negative Cotton effect at 276 nm. The structure of thonningii flavanonol B was determined as (2R,3R)-5,7,4â��-tetrahydroxy-6-(2,3-dihydroxy-3-methylbutyl)-2,3-dihydroflavon-3-ol, an unreported natural product.

Biography :

Email: dradeliselim@gmail.com