Chlorotrimethylsilane → Tert-butyl 3-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-3-hydroxypiperidine-1-carboxylate

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Reaction Steps

7-Bromopyrrolo[2,1-f][1,2,4]triazin-4-amine (17.29 g, 81 mmol) was dissolved in THF (214 mL) under argon at room temperature. Chlorotrimethylsilane (20.60 mL, 17.63 g, 162 mmol, 2 eq.) was added, and the mixture was stirred at room temperature for 3 h. Then, it was cooled to 0° C., and 2-propyl magnesium chloride (170 mL of a 2.0 M solution in THF, 340 mmol, 4.2 eq.) was added. The mixture was stirred for further 3 h while warming up to room temperature. Then, tert-butyl 3-oxopiperidine-1-carboxylate (25.00 g, 121 mmol, 1.5 eq.) was added, and stirring was continued for another 16 h. The reaction was quenched with a 1:1 mixture of concentrated aqueous ammonium chloride solution and ice until the pH value reached 6-7. The mixture was extracted with two portions of ethyl acetate, and the combined organic extracts were dried over anhydrous sodium carbonate and concentrated to dryness. The title compound crystallized upon trituration of the residue with diethyl ether (50 mL). The crystals were washed with diethyl ether and dried to give 17.20 g (64% of th.).

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