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 (12 mL) and add potassium hydroxide (0.935 g, 16.66 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 (0.16 g, 5.2 mmol). Dissolve the crude 3-tert-butoxycarbonyl-7-chloro-6-mercapto-2,3,4,5-tetrahydro-1H-benzo[d]azepine (0.16 g, 0.52 mmol) in anhydrous DMSO (5 mL) and add triethylamine (0.435 mL, 3.12 mmol) and 4-(3-cyano-benzoyl)benzyl bromide (289 mg, 0.96 mmol). Heat the solution at 40° C. overnight. Cool to ambient temperature, dilute the mixture with hexane/EtOAc (1:1, 100 mL), and wash the organic solution sequentially with brine and ice-cold water. Dry the organic layer over anhydrous Na2SO4, filter and concentrate in vacuo. Purify the crude mixture by chromatography on silica gel eluting with hexane and hexane/EtOAc (9:1, 4:1) to give 3-tert-butoxycarbonyl-7-chloro-6-[4-(3-cyanobenzoyl)-benzylthio]-2,3,4,5-tetrahydro-1H-benzo[d]azepine as oil (212 mg, 77%).

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