2-Chloro-4-(1H-pyrazol-1-yl)-5-(trifluoromethyl)pyrimidine

The reaction of 2,4-dichloro-5-(trifluoromethyl)pyrimidine with 1H-pyrazole gave two structural isomers in a 1:1 ratio that were separable by chromatography. The title compound, C8H4ClF3N4, was the first product to elute and was characterized in the present study to confirm that substitution by the pyrazolyl group had occurred at position 4. The molecule (with the exception of the F atoms) is essentially planar, with a mean deviation of 0.034 Å from the least-squares plane through all non-H and non-F atoms. The bond angles in the pyrimidine ring show a pronounced alternating pattern with three angles, including those at the two N atoms being narrower, and the remaining three wider than 120°.