Water → HCID 20093923, compound

Participants

Reaction Steps

4. 242 g of manganese dioxide are added to a warm solution of 22 g of 10-bromo-2,3-dihydroimidazo[1,2-c]quinazoline in 2 l of benzene in a reaction vessel which is provided with a water separator. The mixture is heated at reflux temperature for 15 h. Then, a further 8 g of maganese dioxide are added thereto and the mixture is heated at reflux temperature for a further 1 h. The hot reaction mixture is filtered over Dicalite. The filter cake is rinsed with 1 l of hot benzene, then again boiled up in 1.5 l of dichloromethane/ethanol 199:1 and again filtered. The filtered solutions are concentrated to about 1.51 in a vacuum. A byproduct crystallizes and is filtered off (1.65 g). The filtrate is chromatographed over a column of 2 kg of silica gel. A total of 12.0 g of the desired product is eluted with dichloromethane/ethanol 99:1. 11.7 g of 10-bromoimidazo[1,2-c]quinazoline of m.p. 215°-216° C. are obtained after crystallization from ethyl acetate.

Provenance & Evidence