Potassium Hydroxide → 3-tert-butoxycarbonyl-7-chloro-6-mercapto-2,3,4,5-tetrahydro-1H-benzo[d]azepine

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Reaction Conditions

Reaction Steps

Dissolve 3-tert-butoxycarbonyl-7-chloro-6-dimethylcarbamoylthio-2,3,4,5-tetrahydro-1H-benzo[d]azepine (200 mg, 0.52 mmol) in methanol (10 mL) and add potassium hydroxide (0.934 g, 16.64 mmol). Heat at 60° C. for 4 h. Cool the reaction mixture to ambient temperature, add aqueous saturated ammonium chloride and concentrate in vacuo. Partition the residue between EtOAc and water. Dry the organic phase over anhydrous Na2SO4 and concentrate in vacuo to give 3-tert-butoxycarbonyl-7-chloro-6-mercapto-2,3,4,5-tetrahydro-1H-benzo[d]azepine (0.163 g). Dissolve the crude 3-tert-butoxycarbonyl-7-chloro-6-mercapto-2,3,4,5-tetrahydro-1H-benzo[d]azepine (0.163 g, 0.52 mmol) in anhydrous DMSO (5 mL) and add triethylamine (0.43 mL, 3.12 mmol) and 2,2-difluoro-2-phenylethyl trifluoromethanesulfonate (151 mg, 0.52 mmol). Heat the solution at 40° C. overnight. Cool to ambient temperature, add water and extract the aqueous phase twice with EtOAc. Dry the combined organic extracts over anhydrous Na2SO4, filter and concentrate in vacuo. Purify the crude mixture by chromatography on silica gel eluting with hexane and hexane/EtOAc (19:1, 9:1 and 4:1) to give 3-tert-butoxycarbonyl-7-chloro-6-(2,2-difluoro-2-phenyl-ethylthio)-2,3,4,5-tetrahydro-1H-benzo[d]azepine as oil (132 mg, 56%).

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