Synthesis, reactivity and biological activity of novel bisbenzofuran-2-yl-methanone derivatives

Preparation of bisbenzofuran-2-yl-methanone (1), the corresponding ketoxime 4, semicarbazone and thiosemicarbazone 3a and 3b, ether derivatives of the ketoximes 5a-j and the alcohol 2 are described. These substances have been prepared in excellent yields. All the synthesized compounds except 5i have been tested against five different microorganisms and some of them were found to be active against some of the species studied.     

Ab initio and semiempirical computational studies on 1‐{(2E)‐2‐[(aminocarbonothioyl)hydrazono]‐2‐(3‐mesityl‐3‐methylcyclobutyl)ethyl}‐pyrrolidine‐2,5‐dione

The molecular geometry, vibrational frequencies, and gauge including atomic orbital (GIAO) ¹H‐ and ¹³C NMR chemical shift values of the title compound in the ground state have been calculated using the Hartree‐Fock (HF) and density functional theory (DFT) methods with 6‐31G(d) basis sets, and compared with the experimental data. The calculated results show that the optimized geometries can well reproduce the crystal structural parameters and the theoretical vibrational frequencies, and ¹H‐ and ¹³C NMR chemical shift values show good agreement with experimental data. To determine conformational flexibility, the molecular energy profile of the title compound was obtained by semiempirical (AM1) calculations with respect to the selected torsion angle, which was varied from ?180° to +180° in steps of 10°. The energetic behavior of the title compound in solvent media was examined using the B3LYP method with the 6‐31G(d) basis set by applying the Onsager and the polarizable continuum model (PCM). The results obtained with these methods reveal that the PCM method provided more stable structure than Qnsager's method. By using TD‐DFT method, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD‐DFT method and the experimental one is determined. The predicted nonlinear optical properties of the title compound are much greater than ones of urea. In addition, the molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis, NBO analysis and thermodynamic properties of the title compound were investigated using theoretical calculations. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012     

Structure of 2-(2-(anthracen-9-ylmethylene)hydrazinyl)-4-(3-methyl-3-phenylcyclobutyl)thiazole by combined X-Ray crystallographic and molecular modelling studies

A single crystal of 2-(2-(anthracen-9-ylmethylene)hydrazinyl)-4-(3-methyl-3-phenylcyclobutyl)thiazole (C₂₉H₂₅N₃S) containing anthracene, thiazole and cyclobutane rings has been synthesised. The synthesised crystal structure was characterised using IR, ¹H-NMR and ¹³C-NMR spectroscopic and X-Ray analysis techniques. In the crystal, neighbouring molecules formed chains along [110] by interconnecting with N–H···N hydrogen bonding and π–π interactions. The geometrical parameters of the title compound were optimised by Gaussian 09 software in the gas phase and Quantum-Espresso software under Periodic Boundary Conditions (PBC) in the solid phase. Theoretically, IR, NMR spectra, Mulliken, NPA and AIM atomic charges, Hirshfeld surface and frontier molecular orbitals (FMOs) of the title compound were examined. Using the Hirshfeld surface and two-dimensional (2D) fingerprint graphics, the presence of intermolecular interactions in the crystal packing were analysed. The energies of these interactions and their distribution on the crystal structure were shown graphically. In general, it was seen that theoretical calculations were consistent with X-Ray results.     

4‐Bromo‐2‐{[4‐(3‐mesityl‐3‐methyl­cyclo­butyl)thia­zol‐2‐yl]hydrazono­meth­yl}phenol,with N—H⋯N,C—H⋯π and π–π inter­actions

The title compound, C₂₄H₂₆BrN₃OS, crystallizes in the triclinic space group P, with two independent mol­ecules in the asymmetric unit. The mol­ecules adopt an E geometry about the azomethine C=N double bond. The structure is stabilized as dimers by N—H⋯N hydrogen bonding. C—H⋯π and π–π inter­actions are also effective in the crystal packing.     

Antimicrobial activity studies of the metal complexes derived from cyclobutane‐substituted thiazole carbamate ligands

Two novel monodentate carbamate ligands derived mainly from 4‐(1‐methyl‐1‐phenylcyclobutyl‐3‐yl)‐2‐aminothiazole and 4‐(1‐phenyl‐1‐methylcyclobutane‐3‐yl)‐2‐(N‐methyl)aminothiazole, have been prepared. The ligands and their metal complexes have been characterized by elemental analyses, IR, ¹³C, and ¹H NMR spectra, as well as UV–Vis, and magnetic susceptibility measurements. Both ligands contain 1 mole of water of crystallization and all complexes are mononuclear. Antimicrobial activities of the ligands and their complexes have been screened against the Bacillus subtitis IMG 22 (bacteria), Micrococcus luteus LA 2971 (bacteria), Escherichia coli DM (bacteria), Staphylococcus aureus COWAN I (bacteria), Saccharamyces cerevisiae UGA 102 (yeast), and Candida albicans CCM 314 (yeast). Thermal properties of the ligands and their complexes have been studied by thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC). © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:665–670, 2001     

X-Ray diffraction and vibrational spectroscopic study of 2-chloro-N-{4-[3-(2,5-dimethylphenyl)-3-methylcyclobutyl]-thiazol-2-yl}-acetamide

The title compound C₁₈H₂₁ClN₂SO crystallizes with Z = 4 in space group P2₁/c. The structure of the title compound was characterized by ¹H-NMR, ¹³C-NMR, IR and single crystal diffraction. There are an intermolecular N-H…O hydrogen bond and a C-H…π interactions in crystal packing. In addition to the molecular geometry and packing obtained from X-ray experiment, the molecular geometry and vibrational frequencies of the title compound in ground state have been calculated using density functional theory method DFT (B3LYP) with 6-31G (d, p) basis set. Calculated frequencies, bond lengths, angles and dihedral angles are in good agreement with the corresponding experimental data.     

(Benzo­furan‐2‐yl)(3‐methyl‐3‐phenyl­cyclo­butyl)­methanone

The structure of the title compound, C₂₀H₁₈O₂, consists of a dimeric arrangement of benzo­furan mol­ecules around an inversion centre, linked via C—H⋯O hydrogen bonds. There are also C—H⋯π ring interactions. All these interactions result in the formation of infinite chains parallel to the [100] axis. The cyclo­butane ring is puckered, with a dihedral angle of 29.03 (13)° between the two three‐atom planes.     

Benzoin 4‐ethyl­thio­semicarbazone

In the title compound, 2‐hydr­oxy‐1,2‐diphenyl­ethanone 4‐ethyl­thio­semicarbazone, C₁₇H₁₉N₃OS, the thio­semi­carbazone moiety is planar and has an E configuration. The planar phenyl rings make dihedral angles of 82.34 (8) and 8.07 (17)° with the plane of the thio­semicarbazone moiety. The crystal structure contains two intra­molecular (N—H⋯O and N—H⋯N) and one inter­molecular inter­action (O—H⋯S), as well as two C—H⋯π(benzene) inter­actions. Mol­ecules are stacked in columns running along the a axis. Mol­ecules in each column are connected to each other by means of linear O—H⋯S hydrogen bonds and C—H⋯π inter­actions. In addition, there are also C—H⋯π(benzene) inter­actions between the columns.     

Studies on the synthesis and reactivity of novel benzofuran-2-yl-[3-methyl-3-phenylcyclobutyl] methanones and their antimicrobial activity

Preparation in excellent yields of cyclobutyl benzofuran-2-yl- and naphthofuran- 2-yl-ketones, the corresponding ketoximes and thiosemicarbazones, ether derivatives of the ketoximes and thiazoles derived from the thiosemicarbazones are described. Two of the synthesized compounds have been tested against eight different microorganisms and found to be active against some of the species studied.