Triethylamine → 2,5-Difluoro-3-fluoromethyl-4-(4-ethoxycarbonyl-1-piperazinyl)nitrobenzene

Participants

Reaction Conditions

Reaction Steps

3,6-Difluoro-2-(4-ethoxycarbonyl-1-piperazinyl)-5-nitrobenzyl alcohol (1.5 g) is dissolved in dichloromethane (18 ml), and thereto is added dropwise a solution of diethylaminosulfur trifluoride (DAST) (0.7 ml) and triethylamine (0.78 ml) in dichloromethane (3 ml) over a period of 5 minutes while stirring at 0° C. in ice bath. The mixture is stirred at 0° C. for 1.2 hour, and thereto is further added DAST (0.3 ml). After 5 minutes, the reaction mixture is poured into ice water, and the organic layer is separated. The solvent is distilled off under reduced pressure, and the residue is purified by silica gel column chromatography (solvent, ethyl acetate:n-hexane=1:10→1:5 v/v) to give 2,5-difluoro-3-fluoromethyl-4-(4-ethoxycarbonyl-1-piperazinyl)nitrobenzene (1.1 g).

Provenance & Evidence