Water → Ethyl 7-chloro-5-methyl-4-oxo-3-phenyl-3,5-dihydro-4H-pyridazino[4,5-b]indole-1-carboxylate

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Reaction Steps

4 ml (40.6 mmol) of phenylhydrazine are added at room temperature to a solution of 4.6 g (13.6 mmol) of ethyl 6-chloro-2-(ethoxycarbonyl)-1-methyl-α-oxo-1H-indole-3-acetate in 120 ml of acetic acid. The reaction mixture is stirred for 30 min at room temperature and then for 4 hours at reflux. The mixture is cooled and 350 ml of dichloromethane and 100 ml of water are added. The organic phase is separated by settling, washed with a saturated aqueous sodium hydrogencarbonate solution and then with water, dried over sodium sulphate, filtered and concentrated under reduced pressure and the residue is purified by chromatography on a column of silica gel. 4.1 g (10.7 mmol) of product are isolated.

Provenance & Evidence