To a solution of 8-bromo-N-(2-chlorophenyl)-4,5-dihydrobenzo[b]thieno[2,3-d]oxepine-2-carboxamide in dry 1,4-dioxane was added Lawesson's reagent. The 50 mL round-bottom was sealed and heated at 80° C. for 3 h. The reaction mixture was cooled to room temperature and concentrated to give the crude thioamide. The bright yellow crude solid thus obtained was taken up in methanol and methylene chloride and treated with hydrazine. Reaction progress was monitored by LCMS. Upon completion, the mixture was diluted with saturated sodium bicarbonate and extracted with ethyl acetate. The combined organics were washed with brine, dried over sodium sulfate and concentrated to give crude 8-bromo-N-(2-chlorophenyl)-4,5-dihydrobenzo[b]thieno[2,3-d]oxepine-2-carbohydrazonamide as a yellow solid.
