To a solution of 0.050 g (0.233 mmole) 2-chloro-thieno[3,2-d]pyrimidine-7-carboxylic acid, 0.0714 g (0.466 mmole) of 1-methyl-1H-benzol[d]imidazol-4-amine, 0.122 mL (0.699 mmole) of N,N-diisopropylethylamine and 1.55 mL of dimethylformamide was added 0.111 g (0.256 mmole) of O-(benzotriazol-1-yl)-N,N,N′,N′-bis(tetramethylene)uronium hexafluorophosphate. The mixture was stirred at room temperature for over night. Water and dichloromethane were added. The aqueous layer was washed three times with dichloromethane. The combined organic layer was washed with aqueous sodium carbonate, brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. Purification by silica gel chromatography, eluting with hexanes-ethyl acetate (gradient 100:0-60:40) gave 0.050 g of 2-chloro-thieno[3,2-d]pyrimidine-7-carboxylic acid(2,4-dimethoxy-phenyl)-amide as a yellow solid.
