Into a round bottom flask 7-Azagramine 2 (5.38 g, 30.7 mmol), N,N-dimethylformamide (25.0 mL), and sodium hydride (1.35 g, 33.8 mol) were combined. Into the reaction was added triisopropylsilyl chloride (6.8 mL, 0.032 mol). The reaction was stirred at 20° C. for 12 hours. The reaction mixture was poured into water and extracted with ethyl acetate. The organic layer was washed with brine, dried over sodium sulfate, concentrated and purified with biotage to give compound 4 (6.0 g, yield=58.8%) as a colorless oil.
