A mixture of 2-amino-5-mesityl-7-methyl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-one (142 mg, 0.50 mmol), N,N-diethylaniline (68 mg, 0.50 mmol), and phosphorus oxychloride (10 ml) was heated at 80° C. with stirring for 4 hours. The dark orange solution was allowed to cool to room temperature and concentrated in vacuo. Water (10 ml) was then added to the residue at 0° C. with vigorous stirring. Concentrated aqueous ammonium hydroxide was added and extracted with ethyl acetate (100 ml×2). The extracts were combined, washed with brine, dried over sodium sulfate and concentrated in vacuo. To a mixture of the residue and dimethylformamide (5 ml) was added sodium hydride (60% in oil, 50 mg, 1.25 mmol) at 0° C. and stirred for 0.5 hour. After stirring at room temperature for 0.5 hour, to the mixture was added a solution of n-PrI (213 mg, 1.25 mmol) and dimethylformamide (2 ml) at 0° C. and stirred for 0.5 hour. After stirring at room temperature for 1 hour, the mixture was diluted with water (20 ml) and extracted with ethyl acetate (50 ml×2). The extracts were combined, washed with brine, dried over sodium sulfate and concentrated in vacuo. The residue was purified by silica gel chromatography eluting with hexane/ethyl acetate (20:1) to give 59 mg (31%) of the title compound.
