Acetone Cyanohydrin → 3-[2-(2-Methoxy-ethoxymethyl)-6-trifluoromethyl-pyridine-3-carbonyl]-1,5-dimethyl-8-oxa-bicyclo[3.2.1]oct-6-ene-2,4-dione

Participants

Reaction Steps

146 mg (0.879 mmol) of 1,5-dimethyl-8-oxa-bicyclo[3.2.1]oct-6-ene-2,4-dione and 245 mg (0.879 mmol) of 2-(2-methoxy-ethoxymethyl)-6-trifluoromethyl-nicotinic acid (preparation as described in WO 01/94339) are dissolved in 29 ml of acetonitrile and treated at ambient temperature with 199 mg (0.966 mmol) of dicyclohexylcarbodiimide. The reaction mixture is stirred for 2 hours and then 0.184 ml (1.318 mmol) of triethylamine and 0.08 ml (0.879 mmol) of acetone cyanohydrin are added. Stirring is carried out for a further 16 hours at ambient temperature, followed by concentration under reduced pressure. The residue that remains behind is chromatographed over silica gel (eluant: toluene/ethanol/dioxane/triethylamine/water 20:8:4:4:1). The product-containing fraction is concentrated. The oily residue is again dissolved in fresh ethyl acetate and washed with 10 ml of dilute hydrochloric acid (pH 1), and then with water (2×) and sodium chloride solution (2×). After the solution has been dried over sodium sulfate and concentrated by evaporation under reduced pressure, 128 mg (34%) of 3-[2-(2-methoxy-ethoxymethyl)-6-trifluoromethyl-pyridine-3-carbonyl]-1,5-dimethyl-8-oxa-bicyclo[3.2.1]oct-6-ene-2,4-dione are obtained in the form of a yellow oil.

Provenance & Evidence