1,4-Dioxane → 1,1-dimethylethyl 7-(4-amino-3-nitrophenyl)-2,3-dihydro-1,4-benzoxazepine-4(5H)-carboxylate

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Reaction Conditions

Reaction Steps

(4-{[(1,1-dimethylethyl)oxycarbonyl}-2,3,4,5-tetrahydro-1,4-benzoxazepin-7-yl)boronic acid (example 1, step 2) (2.22 g, 7.57 mmol) and 4-bromo-2-nitroaniline (1.56 g, 7.20 mmol) were taken into dioxane (20 mL), water (4 mL) and DIPEA (5.4 mL, 31 mmol) followed by addition of dichloro[1,1-bis(diphenylphosphino]ferrocenepalladium (II) dichloromethane adduct (322 mg, 0.39 mmol) and the mixture was heated to 95° C. for 2 h. The mixture was cooled to room temperature and partitioned with ethyl acetate and 10% aqueous citric acid. The biphasic mixture was filtered through a celite pad and the organic filtrate was washed once with 0.5M aqueous hydrochloric acid, brine then dried over anhydrous magnesium sulfate, filtered and concentrated. The residue was purified by silica gel chromatography to give 1,1-dimethylethyl 7-(4-amino-3-nitrophenyl)-2,3-dihydro-1,4-benzoxazepine-4(5H)-carboxylate (2.01 g, 69% yield) as a yellow crystalline solid.

Provenance & Evidence