Ethyl orthoformate → (E)-3-(4-chloro-3-trifluoromethyl-styryl)-1,2,4-oxadiazole

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Reaction Steps

5.2 g (0.02 mol) of (E)-4-chloro-3-trifluoromethyl-cinnamamide oxime are introduced into 50 ml of triethyl orthoformate and 2 drops of boron trifluoride etherate are added at room temperature. The mixture is then stirred for 2 hours at reflux temperature and the entire batch is concentrated in vacuo. The residue is taken up in 100 ml of methylene chloride and washed in succession with 100 ml of 2N hydrochloric acid, saturated sodium carbonate solution and water. The organic phase is dried over sodium sulphate and the solvent is subsequently distilled off. 3.9 g (71.0 % of theory) of (E)-3-(4-chloro-3-trifluoromethyl-styryl)-1,2,4-oxadiazole are obtained.

Provenance & Evidence