Crystal structure of 1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-5-((4-trifluoromethyl) methyleneimino)-1H-pyrazole-3-carbonitrile, C19H8Cl2F6N4

Abstract

C 19H 8 Cl 2 F 6 N 4 ,triclinic, P 1 (no. 2), a =6.8064(7) Å, b =11.599(1) Å, c =13.421(1) Å, a =72.683(2)°, b =84.523(2)°, g =83.237(2)°, V =1002.4 Å 3 , Z =2, R gt(F) =0.085, wRref(F 2 ) =0.217, T =298 K. Source of materialFollowing the literaturemethod [1] the reactionof2,6-dichloro-4-(trifluoromethyl)aniline (10 mmol, 2.3 g) with asuspensionof sodium nitrite (10 mmol,0 .69 g) and sulfuric acid (3 ml), followed by reaction with asolutionofethyl 2,3-dicyanopropionate (10 mmol, 1.52 g) in acetic acid (5 ml), gave 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-pyrazole. The compound wasthen reacted with 4-trifluoromethylbenzaldehyde (10 mmol, 1.74 g) to give the title compound. Single crystals suitable for Xrayanalysis were obtained by slow evaporation from amethanol solution. Experimental detailsAll Hatoms were positioned geometrically and allowed to ride on their parent atoms atdistances of C sp2 -Hof 0.93 Åwith U iso = 1.2U eq (parent atom), C sp3 -Hof 0.97 Åwith U iso =1.5U eq (parent atom), and N-Hof 0.86 Åwith U iso =1.2U eq(parent atom).The large displacement parameters of the fluorine atoms and the high R values resulted from either intense thermalmotion or rotationaldisorder of the two trifluoromethylgroups. DiscussionThe incorporationoffluorine into molecules results in profound changes in the physicaland chemicalproperties [2]. The changes also affect the biologicalactivity of the molecules. Asaconsequence, trifluoromethyl-containing molecules have been found considerable utilization in pharmaceuticaland agrochemicalindustry [3,4]. The title compound is akey intermediate in the synthesis of trifluoromethyl-containing pyrazole derivatives,which are good insecticides [5]. The title compound contains two trifluoromethyl groups and consists of threedifferent rings, the first phenyl ring (C2 ® C7), the second phenyl ring (C13® C18) and the pyrazolyl ring (N2, N3, C9 ® C11), which are each almost planar. The dihedralangles of the pyrazolyl ring with the phenylrings C2 ® C7and C13® C18 are 19.2(2)°and 74.8(2)°, respectively. Inthe crystalstructure, all bond lengths and angles are normal, and there are no obvious p -p interactions between pyrazolyl ring and phenyl rings.