Formaldehyde → 3-(5-Dimethylamino-3H-isobenzofuran-1-ylidene)-1-piperidin-1-ylmethyl-1,3-dihydro-indol-2-one

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Reaction Steps

A mixture of 3-(5-Dimethylamino-3H-isobenzofuran-1-ylidene)-1,3-dihydro-indol-2-one (550 mg, 1.88 mmol), paraformaldehyde (141 mg, 4.7 mmol) and piperidine (240 mg, 2.82 mmol) in 20 mL of EtOH was stirred at reflux for overnight and cooled to room temperature. The solid which formed on cooling was collected by filtration, washed with EtOH (5 mL) and dried under vacuum to give the title compound (655 mg, 89%) as bright yellow crystals.

Provenance & Evidence