Water → 4-Isobutylaminobenzenesulfonic acid 2-tert-butoxycarbonylaminobenzothiazol-6-yl ester

Participants

Reaction Steps

A solution of 4-fluorobenzenesulfonic acid 2-tert-butoxycarbonylamino-benzothiazol-6-yl ester (intermediate 15) (1 g, 2.32 mmol), isobutylamine (517 mg, 7.07 mmol) and cesium carbonate (845 mg, 2.59 mmol) in 12 ml of DMSO is stirred at 80° C. overnight. 60 ml of water are added to the reaction medium. The mixture is extracted with ethyl acetate. The organic phase is washed with water and with saturated sodium chloride solution, dried over magnesium sulfate and then evaporated to dryness. The residue is washed with ethyl ether to give 880 mg of 4-isobutylaminobenzenesulfonic acid 2-tert-butoxycarbonylaminobenzothiazol-6-yl ester (beige-colored solid) in a yield of 80%.

Provenance & Evidence