5-Chlorocarbonylphthalide → 1-Oxo-1,3-dihydroisobenzofuran-5-carbaldehyde

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Reaction Steps

A mixture of 7 g (0.036 mole) of 5-chlorocarbonylphthalide, 50 ml of tetrahydrofuran, 0.1 ml of the quinoline/sulfur mixture and 1 g of 10% Pd/C is hydrogenated at 3.5 bar and 35÷40° C. for 3 hours. After 3 hours a stoppage of the hydrogen absorption is observed. Thus, the mixture is cooled, diluted with dichloromethane, filtered, and by a HPLC control the presence of equivalent amounts of alcohol and aldehyde is observed. The mixture is concentrated under vacuum and the residue is taken up with ethyl acetate. The crystalline product is filtered and dried to obtain 4 g of 5-formylphthalide with a purity (HPLC)=44% (yield 30%).

Provenance & Evidence