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

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Reaction Conditions

Reaction Steps

In a hydrogenator, 23 l of N,N-dimethylacetamide, 1.65 Kg (8.39 moles) of 5-chlorocarbonylphthalide (prepared for example as described in J. Chem. Soc., 1931, 867–871) and 200 g of 5% Pd/BaSO4 are charged Hydrogen is then charged at 3 bar thereinto and the mixture is heated at 60±3° C. for a total of 48 hours. The mixture is cooled and, after removal of the catalyst by filtration, the filtrate is concentrated under vacuum at 75° C. up to a solid residue. The product is dispersed with 8 l of deionized water and, at 5÷10° C. under stirring, the pH of the mixture is adjusted to 7.0÷7.5 by addition of 2.3 l of 10% ammonium hydroxide solution After a 30-minute stirring, the product is filtered, washed with deionized water and dried under vacuum at 50° C. to give 885 g (65%) of desired product having m.p.=163÷165° C. (in J. Chem Soc. 1925, page 2290 a m.p.=159÷160° C. is given).

Provenance & Evidence