Ethyl orthoformate → 3-Cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-5-ethoxymethyleneamino-4-trifluoromethylthiopyrazole

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Reaction Steps

5-Amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylthiopyrazole (4.0 g) was added to triethyl orthoformate (19.0 ml) and p-toluene/-sulphonic acid (0.019 g) added. The mixture was heated under reflux for 21 hours cooled, and the triethyl orthoformate evaporated in vacuo to give a brown oil as residue. This was purified by chromatography eluting with a mixture of dichloromethane and hexane (1:1). Evaporation of the eluates in vacuo gave 3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-5-ethoxymethyleneamino-4-trifluoromethylthiopyrazole as a colourless solid, m.p. 70-71.5° C.

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