Water → HCID 18699436, Verbindung

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a stirred solution of 3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-iodopyrazole (3.0 g) in tetrahydrofuran (80 ml) at -80° C. under an atmosphere of nitrogen was added, at such a rate that the temperature of the reaction mixture did not exceed -73° C., n-butyllithium (2.78 ml of a 2.5M solution in hexanes). The mixture was stirred at -73° C. for 10 minutes and then a solution of methyl heptafluorobutyrate (1.07 ml) in tetrahydrofuran (5 ml) was then added at such a rate that the temperature of the reaction mixture did not exceed -75° C. Upon completion of the addition the mixture allowed to warm to room temperature over a period of 1.5 hours. Water (100 ml) was added and the mixture extracted twice with ethyl acetate (50 ml). The combined organic layers were dried (Na2SO4) and evaporated to give a pale yellow solid which was purified by column chromatography on silica gel (150 g) eluted with ether:hexane (3:2). Combination and evaporation of suitable fractions gave a yellow oil which was further purified by column chromatography on silica gel (150 g) eluted initially with hexane:ether (19:1), then hexane:ether (9:1) and finally hexane:ether (1:1). Combination and evaporation of suitable fractions gave the title compound as a pale yellow solid, m.p. 102-103° C.

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