Pivaloyl chloride → Cyenopyrafen

Participants

Reaction Conditions

Reaction Steps

In a 10 L-reaction flask, 456 g (1.47 mol) of 3-oxo-2-(4-tert-butylphenyl)-3-(1,3,4-trimethylpyrazol-5-yl) propionitrile and 2738 g of xylene were added, the temperature was raised to 70° C., and 534 g (4.43 mol) of pivaloyl chloride was added dropwise under reflux over 10 hours while removing hydrogen chloride under a reduced pressure at 68 to 71° C./10 to 13 kPa. After reacting as such for 3 hours, 2181 g of a mixture of pivaloyl chloride and xylene was distilled off at 70° C. under a reduced pressure in order to remove excess pivaloyl chloride. After adding 456 g of warm water of 70° C., 228 g of 2.7% sodium hydrogen carbonate aqueous solution was added dropwise. After separating the resulting aqueous phase, the resulting organic phase was washed with 456 g of warm water of 70° C., the resulting aqueous phase was separated to obtain a xylene solution. A quantitative analysis with liquid chromatography showed that the xylene solution contained 555 g (yield 95.6%) of (2E)-3-(2,2-dimethylpropanoyloxy)-2-(4-tert-butylphenyl)-3-(1,3,4-trimethylpyrazol-5-yl) acrylonitrile. After distilling off xylene at 90° C., 1141 g of heptane was added, and crystallization was carried out by gradually cooling from 70° C. After aging at 0° C. for 1 hour, the resulting crystal was filtered, and dried to obtain 533 g (yield 91.9%) of (2E)-3-(2,2-dimethylpropanoyloxy)-2-(4-tert-butylphenyl)-3-(1,3,4-trimethylpyrazol-5-yl) acrylonitrile (melting point: 110° C.).

Provenance & Evidence