Triethylamine → (2,4-Difluorophenyl)thiocarbamic acid O-(4-hydroxymethyl-5-oxo-2,3,4,5-tetrahydrobenzo[b]thiepin-4-ylmethyl)ester

To a solution of 4,4-bis(hydroxymethyl)-3,4-dihydro-2H-benzo[b]thiepin-5-one (720 mg, 3.02 mmol) in 38 ml of tetrahydrofuran were added, at room temperature, triethylamine (0.46 ml, 3.32 mmol) and 2,4-difluorophenyl isothiocyanate (985 μl, 7.55 mmol). The mixture was heated to reflux for 72 hours, concentrated and purified by column chromatography on silica gel (eluent: 1:2 ethyl acetate/hexane). The product was obtained in a yield of 170 mg (14%).