Thionyl Chloride → HCID 15225717, compound

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Reaction Steps

12.73 g (0.035 mol) of α-Hydroxy-N,N,6,9-tetramethyl-2-phenyl-9H-imidazo[1,2-a]benzimidazole-3-acetamide are treated with 75 ml of thionyl chloride in 250 ml of dichloromethane for 24 h. The solvent is evaporated and the excess thionyl chloride is evaporated under reduced pressure. The residue is taken up in toluene and the mixture is again evaporated. The residue is taken up in 600 ml of dichloromethane, 22 g of Rongalite® are added and the mixture is stirred for 48 h. Insoluble matter is removed by filtration. The filtrate is washed with water, with an aqueous sodium bicarbonate solution and again with water. The organic phase is dried over sodium sulphate, and the solvent is evaporated under reduced pressure. 10.36 g of solid are isolated which are purified by silica gel column chromatography, eluting with a chloroform/methanol 90/10 mixture. 7.86 g of product are isolated of which 1.3 g are removed and dissolved in dichloromethane. The solution is filtered and the filtrate is evaporated under reduced pressure. The residue is treated with carbon black in methanol, the suspension is filtered, the methanol is evaporated under reduced pressure, and the residue is dried under vacuum. 0.9 g of white solid are obtained. Melting point: 222°-223° C.

Provenance & Evidence