Diisopropylethylamine → 3-(8-Bromo-4,5-dihydrothiazolo[4,5-d]benzo[b]oxepine-2-yl)-4,4-dimethyloxazolidin-2-one

Triphosgene (148 mg, 0.500 mmol) was added to a mixture of 185 mg (0.500 mmol) of 2-(8-bromo-4,5-dihydrothiazolo[4,5-d]benzo[b]oxepine-2-ylamino)-2-methylpropan-1-ol and 0.522 ml (3.00 mmol) of diisopropylethylamine in 7.0 ml of methylene chloride. The reaction mixture was stirred for 3 hours and concentrated in vacuum. The residue was partitioned between ethyl acetate and 5% aqueous citric acid. The organic extracts were washed with water, brine, dried over magnesium sulfate and concentrated in vacuum. Yield 194 mg (98%). MS (ESI+): 396.3