Isolation of phytochemicals from Dolichandrone atrovirens followed by semisynthetic modification of ixoside via azomethine ylide cycloaddition; computational approach towards chemo-selection.

Aims of the study were the phytochemical investigation and chemical transformation of isolated compounds of medicinal plant listed in 'Ayurveda' like Dolichandrone atrovirens , endemic to Indian subcontinents. From chloroform extract of D. atrovirens four compounds; Ursolic acid ( 1 ), Maslinic acid ( 2 ), Lupeol ( 3 ), β -sitosterol ( 4 ) and from methanol extract five compounds; β -sitosterol-3- O - β -D-glucopyranoside ( 5 ), 10- O - trans - p -Methoxycinnamoylcatalpol ( 6 ), Kaempferol-3- O - β -D-glucopyranoside ( 7 ), 6- O -[6"( S )-hydroxy-2",6"dimethyl-2"(E)-7"-octadienoyl] catalpol ( 8 ) and Ixoside ( 9 ) were isolated. Ixoside was used for the semi-synthetic modification via azomethine ylide cycloaddition leading to novel spiro-oxindolo-pyrrolizidine adduct. The structures of novel adducts were elucidated by analysis of IR, MS and 1 D/2D NMR data. Furthermore, to confirm the chemo selection of only one double bond, we performed density functional theory (DFT) calculation, which confirms the chemo selectivity. In addition, in-silico ADME studies and atom-additive approach based on SASA was also examined for the molecules which suggest that they may be potential future candidates for drug discovery.