title: Molecular structure of two conformationally restrained fentanyl analogues: cis- and trans-isomers of N-(3-methyl-1-[2-(1,2,3,4-tetrahydro)naphthyl] -4-piperidinyl)-N-phenylpropanamide.
abstract: The X-ray crystallographic structures of two analogues of the potent analgetic fentanyl in which the N-phenethyl substituent is restrained through incorporation into a tetrahydronaphthyl ring system are reported. The tetrahydronaphthyl moiety exists in an equatorial conformation with respect to the piperidine ring which exists in the chair conformation. The propanilido group is also equatorial and antiperiplanar. The orientation of the N-phenyl group with respect to the N-acyl moiety is essentially invariant with an approximately 90 degrees dihedral angle. The implications of these conformations in the interaction of fentanyl-type analgetics with opiate receptors are discussed. The following data were obtained: cis-[C25H33N2O+]Cl- . 1/2 C2O4H2, triclinic, P-1; a = 7.005(7), b = 13.189(2), c = 14.312(4)A, alpha = 111.27(2), beta = 99.15(5), gamma = 93.52(4)0, V = 1205.9A, Z = 2, T = 110K, R = 0.0596, Rw = 0.0760; trans-[C25H33N2O+] C2O4H- . 1/2 C2O4H2 . 2 H2O, triclinic, P-1, a = 8.235(6), b = 10.546(8), c = 17.108(9)A, alpha = 107.72(5), beta = 95.73(5), gamma = 90.63(6)0, V = 1406.8A3, Z = 2, T = 110K, R = 0.0737, Rw = 0.0934.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D003460:Crystallization; D005283:Fentanyl / Q000031:analogs & derivatives* / Q000032:analysis / Q000138:chemical synthesis; D008968:Molecular Conformation; D013237:Stereoisomerism; D014961:X-Ray Diffraction
chemical_list: C047821:N-(3-methyl-1-(2-(1,2,3,4-tetrahydro)naphthyl)-4-piperidinyl)-N-phenylpropanamide; D005283:Fentanyl