Water → 1,3-Dihydro-1-oxoisobenzofuran-5-carbonitrile

Participants

Reaction Conditions

Reaction Steps

Wet 5-carboxyphthalid (14 kg, approx. 6.3 kg dry, 35 mole) was suspended in sulfolane (23.5 kg). The water was removed by azeotropic distillation with toluene. Sulfamide (3.9 kg, 41 mole) and thionyl chloride (5.8 kg, 48 mole were added and the temperature was raised to 135-140° C. for 5 hours. At about 90° C. gas evolution took place. The mixture was allowed to cool to 90° C. and water (21.3 kg) was added. The temperature was held at 85-90° C. for 15 min and then the solution was cooled to 35° C. The crystals were filtered off and washed with water (14.2 kg). The title compound was crystallised from acetic acid. Yield: 3.8 kg, 68%. Purity: 99.5% (hplc, peak area).

Provenance & Evidence