Hydrochloric Acid → 9-Bromo-3,4,7,8-tetrahydro-[1,4]diazepino[7,1-a]isoquinoline-2,5-dione

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Reaction Conditions

Reaction Steps

methyl 2-(2-acetyl-5-bromo-1,2-dihydroisoquinolin-1-yl)acetate. To a stirred solution of 5-bromoisoquinoline (100 g, 481 mmol) in DCM (1900 mL) acetyl chloride (35.9 mL, 505 mmol) was dropped at RT and the solution was stirred for 60 min. The solution was cooled to −78° C. (yellow suspension) and then a solution of tert-butyl((1-methoxyvinyl)oxy)dimethylsilane (95 g, 505 mmol) in DCM (500 mL) was added in one portion. The resulting yellow solution was stirred at −78° C. for 1 h and then allowed to warm to rt overnight. 2N aqueous HCl (400 mL) was added and the reaction mixture was stirred for 10 min. The organic layer was separated and washed with brine (2×). The combined organic layers were dried with sodium sulfate, filtered and the solvent was removed under reduced pressure. The residue was dissolved in diethyl ether (1000 mL), charcoal was added and the mixture was filtrated through a pad of celite. The solvent was evaporated and the crude product was dried under high vacuo overnight to yield the title compound (147 g) which was used without further purification. UPLC-MS: MS 324.0/326.0 (M+H+); UPLC rt 1.03 min.

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