Water → HCID 86752431, compound

Participants

Reaction Steps

A mixture of dichloromethane (30 ml) and oxalyl chloride (1.5 ml, 16.5 mmol) is under stirring at -50° C. to -60° C. added dimethyl sulfoxide (2.8 ml, 36 mmol) diluted with dichloromethane (15 ml). The reaction mixture is stirred for 2 min. followed by addition within 10 min. of 2-hydroxymethyl-1-(1-imidazolylmethyl)-7-trifluoromethylimidazo[1,2-a]quinoxalin-4(5H)-one (Example 22) (1.65 g, 4.5 mmol) in dichloromethane (5 ml) and dimethylsulfoxide (10 ml). The stirring was continued for an additional 15 min. Triethylamine (12 ml, 86 mmol) was added and the reaction mixture was stirred for 5 min. and then allowed to warm up to room temperature. Water (300 ml) was added and the aqueous layer was reextracted with additional dichloromethane (4×100 ml). The organic layers were combined, washed with saturated sodium chloride solution (250 ml) and dried with anhydrous magnesium sulphate. The filtered solution was concentrated in vacuo to give crude 4-chloro-2-formyl-1-(1-imidazolylmethyl)-7-trifluoromethylimidazo[1,2-a]quinoxaline which was hydrolysed to the title compound in 10 min at 40° C. with glacial acetic acid (30 min.). The mixture was concentrated in vacuo and the residue diluted in water. Saturated sodium hydrogen carbonate was added and the aldehyde extracted with acetonitrile (6×250 ml) to give 830 mg (50%) of the title compound. M.p. >250° C.

Provenance & Evidence