Cesium carbonate → 1-[5-Benzyloxy-7-(4-methyl-pyridin-2-yl)-benzothiazol-2-yl]-3-ethyl-urea

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-[5-Benzyloxy-7-bromo-benzothiazol-2-yl]-3-ethyl-urea (406 mg, 1.0 mmol), bis(neopentyl)glycolato diboron (452 mg, 2.0 mmol) and potassium acetate (294 mg, 3.0 mmol) in dimethyl sulfoxide (7 ml) was purged with nitrogen for 5 minutes. Bis(diphenylphosphino)ferrocene palladium(II)chloride complex (82 mg, 0.1 mmol) was added, the reaction mixture sealed and heated at 80° C. for 16 h. The reaction mixture was cooled to ambient temperature. 2-Bromo-4-methylpyridine (258 mg, 1.5 mmol) was added followed by aqueous cesium carbonate solution (3.7M, 0.405 ml, 1.5 mmol). The reaction mixture was purged with nitrogen for 5 minutes, treated with tetrakistriphenylphosphine palladium (0) (115 mg, 0.1 mmol), sealed and heated at 80° C. for 8 h. The reaction mixture was cooled to ambient temperature, diluted with ethylacetate (150 ml), washed with water (3×20 ml) followed by brine (25 ml) and dried (MgSO4). The solvent was removed in vacuo and the residue purified by flash silica chromatography eluting with 1:1 ethyl acetate:petrol ether to give 1-[5-Benzyloxy-7-(4-methyl-pyridin-2-yl)-benzothiazol-2-yl]-3-ethyl-urea as an off white solid (290 mg, 69%).

Provenance & Evidence