Hydrochloric Acid → (1RS)-cis-3-(Z-2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarbonyl chloride

Participants

Reaction Conditions

Reaction Steps

A 1 liter dry, clean jacketed split reaction vessel equipped with agitator, thermometer, condenser, nitrogen blanket and vent to a scrubber system was charged with toluene (450 ml) and agitated whilst 1R cis-Z 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl-cyclopropane carboxylic acid (89.4 gm=0.369 mol) was added followed by triethylamine (0.21 gm=2.1 mmol). The reaction mixture was then heated to 45° C., using oil circulation on the jacket, and thionyl chloride (62.0 gm=0.52 mol) was then charged over 105 minutes maintaining on temperature. The reaction mass was then agitated for 5 hours at 45° C. then tested by GLC for completion of reaction showing 2% residual acid. A further addition of thionyl chloride (4.4 gm=37 mmol) was then made and the reaction mass allowed to cool with stirring overnight. The following day, residual thionyl chloride, dissolved sulphur dioxide and hydrogen chloride gases were removed by distillation of about 320 ml toluene under vacuum. GC, GCMS and NMR analysis of the product were consistent with the structure of the acid chloride (IIIa). Yield, 175 gm of a 54% solution of the acid chloride in toluene, 97% theory. αD=+46° (c=0.012, DCM).

Provenance & Evidence