Phosphorus pentachloride → 2-Methylquinazolin-5-amine

Participants

Reaction Steps

12.7 g (62 mmol) of 2-methyl-5-nitro-3H-quinazolin-4-one (M. T. Bogert, V. J. Chambers J. Org Chem. 1905, 649-658) and 37.5 g of phosphorus pentachloride are refluxed in 75 ml of phosphoryl chloride over 20 hours. After cooling, it is poured into saturated NaHCO3 solution and extracted with ethyl acetate. The organic phase is dried, and the solvent is removed. 14 g of 4-chloro-2-methyl-5-nitroquinazoline, of which 4.5 g (20.2 mmol) in 225 ml of ethyl acetate and 22.5 ml of triethylamine are dissolved, is obtained. 2 g of palladium on carbon is added, and it is stirred while being cooled with ice for 4 hours under a hydrogen atmosphere at normal pressure. Catalyst is removed from the solution by means of filtration through Celite, whereby it is rewashed with 200 ml of ethanol and concentrated by evaporation. After chromatography on silica gel with ethyl acetate-ethanol (0-10%), 530 mg of the product is obtained.

Provenance & Evidence