Crystal Structure and Conformation Study of 3-Methyl-2, 6-bis (4-chlorophenyl) Piperidin-4-one Thiosemicarbazone Derivative

Abstract  

The 1, 3-dipolar cycloaddition reactions with trans azomethine ylide produce spirooxindole derivatives, which are active against certain bacterial pathogens. Spirooxindole ring systems have a very important place in medicinal chemistry because they are the central skeleton for numerous alkaloids and have potential biological activity. This newly synthesized target molecule, PSSPI was crystallized and its X-ray crystal structure has been derived. The crystallographic data of PSSPI are: C₃₄H₃₈N₂O₃; M.W = 522.7, Monoclinic, P2₁/a, with cell parameters a = 11.959(6) ?, b = 19.308(3) ?, c = 13.452(6) ?, β = 107.81(4)°; V = 2957(2) ?³, Z = 4, D _cal = 1.174 mg/m³, λ (Mo K _α ) = 0.71073 ?. Based on the crystal structure, the piperidine, pyrrolidine and cyclohexanone rings adopt half-chair, envelop and twisted sofa conformations respectively. The rings oxindole and cyclohexanone are parallel to each other but perpendicular to the pyrrolidine ring. C–H···N, C–H···O and N–H···O types of intra and intermolecular interactions control the molecules in the crystal packing.     

6,7‐Dihydrodibenzo[e,g]azulen‐8(5H)‐one and 12,13‐dihydrobenzo[e]­napth­[2,1‐g]­azulen‐14(11H)‐one

In the structures of the title compounds, 6,7‐di­hydro­dibenzo[e,g]­azulen‐8(5H)‐one, C₁₈H₁₄O, (I), and 12,13‐di­hydro­benzo[e]­napth­[2,1‐g]­azulen‐14(11H)‐one, C₂₂H₁₆O, (II), the azulene group is in a boat‐envelope conformation. The structures are stabilized by weak C—H?O interactions.     

Presence of pseudo‐peptide bond in the crystal structure of n‐(t‐butoxycarbonyl)‐ε‐n′‐benzyloxycarbony‐l‐lysyl‐l‐isoleucine (boc‐lys(obzl)‐ile)

The dipeptide Boc‐Lys(OBzl)‐Ile crystallizes in monoclinic space group P2₁ with cell parameters a = 5.003(1), b = 19.199(3), c = 15.270(2)Å, β =93.42(1)°, V = 1464.1(3)ų, Z = 2, D_cal = 1.117 Mg/m³ at T = 293 K. The structure was solved by direct methods and refined by full‐matrix least‐squares procedure to a final R = 0.096 and wR = 0.101 using 1379 reflections. The peptide unit is in trans conformation and the molecule takes up an extended conformation. In the lysine side chain, delocalization of electrons and pseudo peptide bond formation is observed at the interaction site of benzyloxycarbonyl group. Both N‐H…O and main chain C‐H…O hydrogen bonds stabilize the molecules in the unit cell in a parallel β‐sheet fashion. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)