Crystal structure, spectroscopic studies and conformational analyses of 5-chloro-6-nitro-2-cyclohexylmethylbenzoxazole

Abstract

5-Chloro-6-nitro-2-cyclohexylmethylbenzoxazole (1) (C14H15O3N2Cl) has been studied by using an elemental analysis, IR, 1H NMR, X-ray analysis and AM1 semi-empirical quantum mechanical methods. It crystallizes in the monoclinic space group P21/c with a=8.6844(1), b=5.7169(1), c=28.8156(1)Å,β=92.063(1)°, V=1429.70(3)Å3,Z=4, Dc=1.369gcm−3,μ(MoKα)=0.276mm−1 and F(000)=616. The structure was solved by direct methods and refined to R=0.0542 for 953 reflections [I>2σ(I)]. The title compound is not planar. Minimum energy conformations from AM1 were calculated as a function of θ1(O1–C7–C8–C9), θ2(N2–C7–C8–C9), θ3(C7–C8–C9–C10) and θ4(C7–C8–C9–C14) varied every 5°. The optimized geometry of the crystal structure corresponding to the non-planar conformation is the most stable conformation in all calculations.