To a stirred solution of 5-benzyloxy-6-hydroxy-2-(1-pyrrolo[2,3-b]pyridin-1-yl-cyclopentylmethyl)-pyrimidine-4-carboxylic acid (2-hydroxyethyl)-methyl-amide (406) (210 mg, 0.42 mmol) in dichloromethane (30 mL) was added triphenyl phosphine (550 mg, 2.09 mmol) followed by diisopropyl azodicarboxylate (0.2 mL, 1.26 mmol) at room temperature and stirring was continued for 10 min (TLC, 5% methanol in ethyl acetate, Rf=0.2). The reaction mixture was concentrated under reduced pressure to get a crude product, which was purified by Prep-TLC plate (mobile phase 5% methanol in ethyl acetate) to get 9-benzyloxy-2-methyl-6-(1-pyrrolo[2,3-b]pyridin-1-yl-cyclopentylmethyl)-3,4-dihydro-2H-pyrazino[1,2-c]pyrimidine-1,8-dione (407) (60 mg, 30%) as a white solid.
