Normal Vibrations of Cyclohexanethione

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Infrared Spectra of Dithio- & Diseleno-carbamate Derivatives

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Non-bonded interactions in 2,2,4,4-tetramethyl-1,3-cyclobutanedithione and 2,2,4,4-tetramethyl-3-thio-1,3-cyclobutanedione

Electronic absorption and emission spectra as well as He(I) photoelectron spectra of 2,2,4,4-tetramethyl-1,3-cyclobutanedithione and 2,2,4,4-tetramethyl-1-3-thio-1,3-cyclobutanedione have been interpreted on the basis of molecular orbital calculations. The results show that the non-bonded orbital of the dithione is split owing to through-bond interaction, the magnitude of splitting being 0.4 eV. The π∗ orbital of the dithione appears to be split by about 0.2 eV. Electronic absorption spectra show evidence for the existence of four n-π∗ transitions, arising out of the splitting of the orbitals referred to above, just as in the case of 2,2,4,4-tetramethyl-1,3-cyclobutanedione. Electronic and photoelectron spectra of the thio-dione show evidence for weak interaction between the C=S and C&.zdbnd;O groups, probably via π∗ orbitals. Infrared spectra of both the dithione and the thio-dione are consistent with the planar cyclobutane ring; the ring-puckering frequency responsible for non-bonded interactions is around 67 cm−1 in both the dithione and the thio-dione, the value not being very different from that in the dione. The 1,3-transannular distance is also similar in the three molecules

A study of the nature of coordination in metal monothiocarbamates based on infrared spectroscopy and the HSAB concept

The nature of coordination in metal monothiocarbamates is shown to depend on the hardness or softness of the metal ton. Thus, the monothiocarbamate ion acts as a monodentate ligand with metal-sulphur bending when the metal ion is a soft acid while it acts as a bidentate ligand when the metal ion is a hard acid; it can exhibit either behaviour when the metal ion is a borderline acid. In dialkylt in and dialkylmonocholorot in complexes, the monothiocarbamate ion acts as a bidentate ligand with strong Sn-S bonding while in trialkyl-or triaryl-tin complexes it acts essentially as a monodentate ligand. Thus, R3Sn(I) seems to be a soft or borderline acid while R2Sn(II) is a hard acid

Synthesis, Characterization, and Biological Activity of 5-Phenyl-1,3,4-thiadiazole-2-amine Incorporated Azo Dye Derivatives

5-Phenyl-1,3,4-thiadiazole-2-amine has been synthesized by single step reaction. A series of heterocyclic azodyes were synthesized by diazotisation of 5-phenyl-1,3,4-thiadiazole-2-amine by nitrosyl sulphuric acid followed by coupling with different coupling compounds such as 8-hydroxyquinoline, 2,6-diaminopyridine, 2-naphthol, N,N-dimethyl aniline, resorcinol, and 4,6-dihydroxypyrimidine. The dyes were characterized by UV-Vis, IR, 1H-NMR, 13C NMR, and elemental analysis. The synthesized compounds were also screened for biological activity

Whole cell screen based identification of spiropiperidines with potent antitubercular properties

Abstract Whole cell based screens to identify hits against Mycobacterium tuberculosis (Mtb), carried out under replicating and non-replicating (NRP) conditions, resulted in the identification of multiple, novel but structurally related spiropiperidines with potent antitubercular properties. These compounds could be further classified into three classes namely 3-(3-aryl-1,2,4-oxadiazol-5-yl)-1′-alkylspiro[indene-1,4′-piperidine] (abbr. spiroindenes), 4-(3-aryl-1,2,4-oxadiazol-5-yl)-1′-alkylspiro[chromene-2,4′-piperidine] (abbr. spirochromenes) and 1′-benzylspiro[indole-1,4′-piperidin]-2(1H)-one (abbr. spiroindolones). Spiroindenes showed ≥4 log10 kill (at 2-12 μM) on replicating Mtb, but were moderately active under non replicating conditions. Whole genome sequencing efforts of spiroindene resistant mutants resulted in the identification of I292L mutation in MmpL3 (Mycobacterial membrane protein Large), required for the assembly of mycolic acid into the cell wall core of Mtb. MIC modulation studies demonstrated that the mutants were cross-resistant to spirochromenes but not to spiroindolones. This Letter describes lead identification efforts to improve potency while reducing the lipophilicity and hERG liabilities of spiroindenes. Additionally, as deduced from the SAR studies, we provide insights regarding the new chemical opportunities that the spiroindolones can offer to the TB drug discovery initiatives