Cl[CH:2]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[C:4](=[O:5])[O:3]1.O1CCCC1>[Ni].C(N(CC)CC)C>[C:4]1([C:6]2[C:11](=[CH:10][CH:9]=[CH:8][CH:7]=2)[CH2:2][O:3]1)=[O:5]A 1-liter lift magnet autoclave is charged with 110 g of 3-chlorophthalide, 10 g of nickel catalyst RCH 55/10 (commercial product of Farbwerke Hoechst AG) and 400 ml of tetrahydrofuran to which 66 g of triethylamine is added. After purging the air with nitrogen, hydrogen is pumped in to a pressure of 10 bars, and the temperature is raised, with stirring, to 65° C. The hydrogen consumption is compensated by additions in the range between 10 and 20 bars for a period of 41/2 hours. After the absorption of hydrogen ceases, the catalyst and precipitated salt are filtered out and the solvent is withdrawn. After distillation of the residue between 88° and 90° C. and 0.2 Torr, 77.5 g of phthalide is obtained, of a melting point of 71° C. (gas-chromatographic analysis 98.95%).
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