Hydrochloric Acid → 7-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3,4,5-tetrahydro-1,4-benzoxazepine hydrochloride

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Reaction Conditions

Reaction Steps

To a slurry of 1,1-dimethylethyl 7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3-dihydro-1,4-benzoxazepine-4(5H)-carboxylate (example 9, step 1) (3.3 g, 8.8 mmol) in methanol (25 mL) was added anhydrous hydrogen chloride (6.0 mL, 4 N in dioxane, 24 mmol). The reaction mixture was heated (60° C.) for 1.5 h and was concentrated. The resulting solid was suspended in ethyl ether (50 mL), collected by filtration and washed with ethyl ether (2×30 mL) to afford 7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,3,4,5-tetrahydro-1,4-benzoxazepine hydrochloride (1.4 g, 50% yield) as a white solid. MS (EI) for C15H22BNO3: 276 (MH+).

Provenance & Evidence