G. Qadeer, N. H. Rama, Syed Tasleem Hussain Shah
Jul 20, 2007
Citations
0
Influential Citations
10
Citations
Journal
Arkivoc
Abstract
Dimethoxyhomophthalic acid is a key intermediate for the synthesis of highly biological active naturally and non-naturally occurring isocoumarins and 3,4-dihydroisocoumarins. It was synthesized efficiently in five steps from 3,5-dimethoxybenzaldehyde (1) via a series of reactions including synthesis of 3,5-dimethoxycinnamic acid (2) and 3-(3',5'-dimethoxyphenyl)propionic acid (3), cyclization of 3-(3',5'-dimethoxyphenyl)propionic acid (3) to 5,7-dimethoxy-1- indanone (4) and oxidative decomposition of methyl 2-hydroxy-2-(5,7-dimethyoxy-1-oxo-1H- inden-2(3H)-ylidene)acetate (5) to 3,5-dimethoxyhomophthalic acid (6). Natural isocoumarin, thunberginol B (3-(3',4'-dihydroxyphenyl)-6,8-dihydroxyisocoumarin) (10) was synthesized by the condensation of 3,5-dimethoxyhomophthalic acid (6) with 3,4-dimethoxybenzoic acid (7) followed by demethylation of intermediate (3-(3',4'-dimethoxyphenyl)-6,8- dimethoxyisocoumarin) (9). The synthesized compounds were purified by HPLC and characterized by elemental analysis, IR, 1 H NMR and mass spectrometry.