The general procedure for the synthesis of 5,7-dimethoxyindanone from 3,5-dimethoxyphenylpropionic acid was as follows: 3-(3,5-dimethoxyphenyl)propionic acid (2 g x 5) was dissolved in methanesulfonic acid (10 ml x 5) in a microwave treated vial (20 ml x 5). The reaction mixture was heated at 90°C for 10 min under microwave radiation. After completion of the reaction, the mixture was slowly poured into ice (250 g) and neutralized to pH 8-9 with 2 M NaOH solution, followed by extraction with EtOAc. The organic layers were combined and the target product 5,7-dimethoxyindanone (8.8 g, 96.2% yield) was obtained after concentration. The product was analyzed by LC-MS and showed m/e 193 (MH+).
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