Carbon Disulfide → Isopropyl (1,3-dithiol-2-ylidene)-(4-fluorophenyl)-acetate

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Reaction Steps

To a solution of isopropyl 4-fluorophenylacetate (98.1 g) in dimethylsulphoxide (1.2 g) there are added carbon disulphide (38.0 g) and then, slowly, a solution of potassium hydroxide (84.9 g) in water (150 ml). The mixture is stirred for 2 hours at 40° and cooled to room temperature. cis-1,2-Dichloroethylene (50 g) is added very slowly and the mixture is stirred at 45° for 2 hours. Water (1.5 l) and hexane (1 l) are added, the two phases are separated and the aqueous solution is extracted with hexane (3×1 l). The combined organic phases are washed with water (2×1 l), dried over magnesium sulphate and evaporated. The residue is crystallised from hexane. The product is dried in vacuo to constant weight to yield isopropyl (1,3-dithiol-2-ylidene)-(4-fluorophenyl)-acetate, m.p. 86°.

Provenance & Evidence