HCID 19373119, compound → HCID 15222250, compound

Participants

Reaction Steps

13.7 g (0.0363 mol) of α-hydroxy-N,N,6,7,9-pentamethyl-2-phenyl-9H-imidazo[1,2-a]benzimidazole-3-acetamide are dissolved in 500 ml of dichloromethane. A slight insoluble matter is removed by filtration. 75 ml of thionyl chloride are added to the filtrate and the mixture is stirred for 3 h, allowed to stand overnight, and again stirred for 6 h. The solvent is evaporated under reduced pressure, as well as the excess thionyl chloride by means of toluene. The residue is dissolved in 500 ml of dichloromethane and 23.5 g of Rongalite® are added to this solution. The mixture is stirred for 48 h. The insoluble matter is removed by filtration, and the organic phase is washed with water, with sodium bicarbonate solution and then with water. It is dried over sodium sulphate and concentrated under reduced pressure. 12.23 g of product are obtained which are washed with ether and then purified by silica gel column chromatography, eluting with a chloroform/acetone 95/5 mixture. 6.16 g of product are obtained, of which 1.32 g are removed for two successive treatments with carbon black in methanol. 1.04 g of product are finally isolated. Melting point: 202°-206° C.

Provenance & Evidence