Cesium carbonate → 4-cyano-7-fluoro-N,N,5-trimethyl-6-(2-methyl-1,3-thiazol-4-yl)-1,3-benzoxazole-2-carboxamide

Participants

Reaction Conditions

Reaction Steps

Under nitrogen atmosphere, a toluene (100 ml) suspension of 6-bromoacetyl-4-cyano-7-fluoro-N,N,5-trimethyl-1,3-benzoxazole-2-carboxamide (I-128) (3.80 g, 10.3 mmol), thioacetamide (931 mg, 12.4 mmol) and cesium carbonate (4.36 g, 13.4 mmol) was stirred at 100° C. for 45 minutes. After cooling, the reaction liquid was filtered through Celite, the obtained filtrate was washed with water and saturated brine. Next, the organic layer was dried over anhydrous magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was subjected to silica, gel column chromatography, and the eluate with n-hexane/ethyl acetate (1:1, v/v) gave the entitled compound (2.31 g, 65%) as a yellow solid.

Provenance & Evidence