No abstract

No abstract

No abstract

1,2-Dithiol-3-thiones are a sulfur containing five membered heterocyclic compounds, which constitute an important class of biologically active compounds owing to their ability to release sulfhydryl (SH) group. In this research a new series of multi-cyclic compounds, containing 1,2-dithiol-3-thione moiety, was synthesized. To pursue this goal, five chalcones (1a-e) were synthesized via the condensation of 1-tetralone with aromatic aldehydes under the influence of 5% ethanolic sodium hydroxide solution. These chalcones were converted to β-ketoesters (2a-e) via its reaction with ethyl acetoacetate in presence of 5% ethanolic sodium hydroxide solution. The thionation of these β-ketoesters with phosphorous penta sulfide in xylene afforded the titled compounds (3a-d). The chemical structures of the synthesized compounds were elucidated by the physical and spectral (IR and NMR) data.

varing the positions and isotropic vibrational amplitudes of the C, 0, and Fe atoms led to R = 0.089. Six further cycles of least-squares refinement of the atomic parameters with anisotropic vibrational amplitudes for the C, O, and Fe atoms converged to R = 0.068. A difference Fourier map calculated at this stage revealed peaks of density appropriate to all hydrogen atoms. Keeping the vibrational amplitudes for the hydrogens fixed (B(H) = B(C) + 1.0 A)1 2 and refining with anisotropic IPs for all the C, O, and Fe atoms, we obtained a final R of 0.033. The atomic scattering factors were taken from the literature.12 All the calculations were performed on the FACOM M-200 computer in the computer center of Kyushu University with the (12) "International Tables for X-ray Crystallography"; Kynoch Press:

Carbon-13 NMR chemical shifts and 'J(CH), 'J(CH) and 'J(CH) coupling constants of selected saturated nitrogen heterocyclic molecules containing the acetylenic moiety have been determined. These NMR parameters have also been determined for the corresponding N-oxides and the Meisenheimer rearrangement products, the 0-allenylhydroxylamines. The effect of the N-oxidation on the chemical shifts of the ring and the acetylenic carbon atoms is discussed.

No abstract

The carbon-13 NMR spectra of some N-(2-or 4-nitrophenyl) tertiary amines and their corresponding N-oxides have been analysed. These N-oxides undergo thermal rearrangement to 0-arylhydroxylamines, for which the 13C NMR spectral assignments were also carried out. The N-oxidation effect on the aromatic and aliphatic fragments is calculated.