Diethyl Ether → 3-Chloro-2-(4-chloro-2-fluorophenyl)-2,4,6,7-tetrahydro-thiopyrano[4,3-c]pyrazole-5-oxide

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Reaction Steps

1.6 parts of 85% m-chloroperbenzoic acid dissolved in 110 parts of chloroform were added dropwise for 1 hour to a stirred solution of 3-chloro-2-(4-chloro-2-fluorophenyl)-2,4,6,7-tetrahydro-thiopyrano[4,3-c]pyrazole dissolved in 75 parts of chloroform. The resulting solution was stirred 16 hours, washed 4 times with 40 parts of saturated aqueous NaHCO3, 2 times with water, dried with anhydrous magnesium sulfate, and solvent evaporated under a reduced pressure of 50 to 300 mm Hg. to give a pale yellow oil. The oil, when contacted with a mixture of ether and pentane, gave 1.2 parts of 3-chloro-2-(4-chloro-2-fluorophenyl)-2,4,6,7-tetrahydro-thiopyrano[4,3-c]pyrazole-5-oxide as a pale caramel-colored solid, m.p. 119°-122° C. This solid can be recrystallized from a mixture of methylene chloride, ether, and pentane to give m.p. 1221/2°-125° C.

Provenance & Evidence