MOLECULAR-STRUCTURE OF HETEROCYCLES - NMR-SPECTROSCOPY, SEMIEMPIRICALMO CALCULATIONS AND X-RAY-DIFFRACTION OF 6,7-HEXAHYDRO-3-TRICHLOROMETHYL[2,1]BENZOISOXAZOLE

H-1 and C-13 NMR data, AMT calculations and X-ray diffraction in 3,3a, 4,5,6,7-hexahydro-3-trichloromethyl[2,1]benzo isoxazole (1), obtained from the cyclization of trichloroacetyl cyclohexanone with hydroxylami ne, are reported.H-1 and C-13 NMR data shown that only one pair of the diastereoisomers was obtained and the AM1 calculations indicated that 1a (3S3aS/3R3aR) is 2.63 kcal.mol(-1) more stable than 1b (3S3aR/3R3a S). The X-Ray diffraction data confirmed that only the structure la wa s obtained. Crystals of 1 (C8H10Cl3NO2, M-r = 258.52) were obtained fr om acetone-hexane solution. The compound crystallizes in the monaclini c space group P2(1)/c with the cell dimensions a = 10.153(2), b = 8.27 1(2) and c = 14.225(3) Angstrom, beta = 103.8(3)degrees, V = 1160.0(4) Angstrom(3), Z = 4, D-calcd. = 1.480 Mg/m(3), lambda(Mo-K alpha) = 0. 71073 Angstrom, = 0.764 mm(-1) F(000) = 528, T = 293(2) K, R = 7.31 % and R-W= 17.91 % for an F-2 refinement on unique data with 2082 reflec tions and 1994 independent (R-int = 6.70%) were collected.