Potassium Carbonate → 4-[4-Bromo-5-chloro-2-(2,3,4,5-tetrahydro-benzo[b]azepine-1-sulfonyl)-phenoxy]-butyric acid tert-butyl ester

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Reaction Conditions

Reaction Steps

To 4-bromo-5-chloro-2-(2,3,4,5-tetrahydro-benzo[b]azepine-1-sulfonyl)-phenol (0.83 g, 2 mmol) in dry DMF (8 mL), was added K2CO3 (0.69 g, 5 mmol), followed by the addition of t-butyl 4-bromobutyrate (0.58 g, 2.6 mmol). The mixture was heated at 62° C. for 15 hrs and partitioned between ethyl acetate (50 mL) and water (25 mL). The organic layer was separated, washed with brine (2×25 mL), and dried over MgSO4. After filtration, the solution was concentrated and purified by silica gel column chromatography eluting with ethyl acetate in hexanes (1/8) yielding 4-[4-bromo-5-chloro-2-(2,3,4,5-tetrahydro-benzo[b]azepine-1-sulfonyl)-phenoxy]-butyric acid tert-butyl ester as a pale yellow foam (1.05 g). MS: 501.8 (M+H-tBu)+; tR=11.2 min (method 2). NMR (CDCl3), δ, 8.060 (1H, s), 7.133-7.205 (3H, m), 7.011-7.067 (1H, m), 6.789 (1H, d, J=8.1 Hz), 4.086 (2H, t), 3.742 (2H, t), 2.826 (2H, m), 2.346 (2H, t), 1.827-1.959 (4H, m), 1.617-1.641 (2H, m), 1.431 (9H, s).

Provenance & Evidence