Dimethylformamide → 3-{2-(1,3-Dioxo-1,3-dihydro-isoindol-2-ylmethyl)-4-[2-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxy]-phenyl}-propionic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A 2 L 3-neck flask was charged with 3-[2-(1,3-dioxo-1,3-dihydro-isoindol-2-ylmethyl)-4-hydroxy-phenyl]-propionic acid tert-butyl ester (67.9 g, 0.178 mol), toluene-4-sulfonic acid 2-(5-methyl-2-phenyl-oxazol-4-yl)-ethyl ester (76.6 g, 0.214 mol) and DMF (680 mL). Cesium carbonate (75.4 g, 0.231 mol) was added, and the reaction mixture was heated at 55° C. for 18 h. After cooling, ethyl acetate (890 mL) and DI water (1200 mL) were added, the mixture was agitated, and the layers were separated. The aqueous layer was back-extracted with ethyl acetate (740 mL). The organic layers were combined and washed with 1N NaOH (375 mL) then saturated NaCl solution (2×375 mL). The organic solution was dried (Na2SO4), filtered, and concentrated to an oil (107 g). The crude oil was dissolved in toluene (50 mL), and heptane was added (˜100 mL) until cloudiness remained even with agitation. The mixture was warmed to 50° C. on a rotary evaporator to yield a solution. Seed crystals were added, and rotation was continued at ambient temperature overnight. The product slurry was placed in the freezer overnight and filtered. The title compound was dried in a vacuum oven at 35° C. (71.4 g, 70.8%).

Provenance & Evidence