Synthesis, spectral characterization, single crystal and conformational study of 1,5-dimethyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9-one derivatives

1,5-Dimethyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9-one 1 and their derivatives 2-8 were obtained by condensation of 2,6-dimethyl cyclohexanone, Ammonium acetate and substituted aromatic aldehydes and characterized by FT-IR, FT-Raman, H-1 NMR, C-13 NMR, GC-MS, HOMOCOSY, HSQC, NOESY, single crystal X-ray diffraction analysis and theoretical DFT calculation. Compound 1 crystallized in the Triclinic system, space group P-1 with a = 6.8950(5)angstrom, b = 11.5889(9)angstrom, c = 11.9172(9)angstrom, alpha = 76.277(4)degrees, beta = 78.000(3)degrees, gamma = 72.920(4)degrees, V = 874.41(12) angstrom(3) and Z = 2. 1,5-Dimethyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9-one 1 and their derivatives 2-8 were exist in boat-chair conformation with equatorial orientation of all the substituents at piperidine ring (two phenyl rings at C-2 and C-4 position, two methyl substituents at C-1 and C-5 position) of compound 1. In the crystal structure of compound 1, the molecules are connected by N-H center dot center dot center dot O=C intermolecular hydrogen bonds. The existence of boat-chair conformation was confirmed by single crystal X-ray diffraction analysis and theoretical DFT calculation. (C) 2012 Published by Elsevier B.V.