1-Chloroethyl chloroformate → 7-[4-(1-Chloro-2-methylamino-ethylidene)-piperidin-1-yl]-1-cyclopropyl-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid trifluoroacetic acid salt

Participants

Reaction Steps

A solution of 161 (160 mg, 0.24 mmol) was dissolved in 1,2-dichloroethane (4 mL) and was treated with 1-chloroethyl chloroformate (0.8 mL, 7.3 mmol) under nitrogen. After 5 min, the reaction mixture was warmed to reflux temperature and the reaction mixture was allowed to stir for 3 h. The resulting mixture was allowed to cool to room temperature, and then it was concentrated in vacuo. The residue was dissolved in tetrahydrofuran (5 mL), adjusted to pH>7 by the addition of NaHCO3 and water at room temperature and stirred overnight. The resulting mixture was concentrated in vacuo and the residue purified by HPLC (reverse phase C-18 column, 35-90% acetonitrile/water containing 0.1% trifluoroacetic acid) to afford the trifluoroacetic acid salt of 72 (37 mg, 27%) as a yellow solid. MS 450 (M+H).

Provenance & Evidence