Diisopropylamine → 4-Fluorobenzenesulfonic acid 2-(2-methoxy-acetylamino)benzothiazol-6-yl ester

Participants

Reaction Steps

A solution of 4-fluorobenzenesulfonic acid 2-aminobenzothiazol-6-yl ester (intermediate 16) (101.2 mg, 0.312 mmol), methoxyacetic acid (84.3 mg, 0.936 mmol), HBTU (355 mg, 0.936 mmol) and N,N-diisopropylamine (326 μl, 1.872 mmol) in 5 ml of dimethylformamide in a test tube, equipped with a magnetic bar, is stirred for 20 hours at room temperature. 100 ml of water are added and the reaction medium is extracted with ethyl acetate. The organic phase is dried over magnesium sulfate and evaporated. The residue obtained is taken up in ethyl acetate and purified on a Varian flash cartridge containing 5 g of silica of porosity 15-35μ, with a mixture of 1% methanol in dichloro-methane. After evaporating off the solvent, 89 mg of 4-fluorobenzenesulfonic acid 2-but-3-enoylaminobenzothiazol-6-yl ester are obtained (yellow oil) in a yield of 72%. LC/MS (method A1): [M+H]+: 397.11, retention time: 3.59 min.

Provenance & Evidence