Cesium carbonate → HCID 86642123, compound

Participants

Reaction Steps

To a stirred solution of 4-[N-(tert-butoxycarbonyl)amino]phenol (3.1 g, 14.81 mmol) in DMF (40 mL) was added cesium carbonate (12.1 g, 37.02 mmol) and cyclobutyl bromide (2.0 g, 14.81 mmol). The reaction mixture was stirred at r.t. for 3 days, and then at 60° C. for 19 h. The reaction mixture was cooled to r.t., filtered and partitioned between water (50 mL) and Et2O (100 mL). The layers were separated, and the aqueous fraction was further extracted with Et2O (3×50 mL). The combined organic fractions were washed with brine (50 mL), dried (Na2SO4), filtered and concentrated in vacuo. Purification by column chromatography (SiO2, 5-8% EtOAc/hexanes) gave the title compound (1.6 g, 41%) as a white solid. δH (CDCl3) 7.24 (2H, d, J 8.9 Hz), 6.82-6.72 (2H, m), 6.31 (1H, br. s), 4.67-6.54 (1H, m), 2.52-2.36 (2H, m), 2.25-2.08 (2H, m), 1.94-1.78 (1H, m), 1.77-1.62 (1H, m), 1.53 (9H, s). LCMS (ES+) 208.0 ((M−tBu)+H)+, RT 3.10 minutes (Method 3).

Provenance & Evidence