Kinetic H/D exchange study of Co(III) coordination compounds of diazines using NMR spectroscopy

The Co(III) diazines complexes having composition (NH3) 5CoPhtz)(ClO4), (1) (Phtz = phthalazine), (NH 3)5CoPydz)(ClO4)3 (2) (Pydz = pyradazine), (NH3)5Co(3-Me-Pydz)(ClO4) 3 (3) (3-Me-Pydz = 3-methyl pyradazine) and (NH3) 5Co(3-MePhtz)(ClO4)3 (4) (3-MePhtz = 3-methyl phthalazine), (NH3)5Co(ImH)(ClO4), (5) (ImH = imidazole), (NH3)5Co(NMeIm)(ClO4) 3 (6) (N-MeIm = N-methylimidazole) undergo OD--catalyzed H/D exchange at the ortho position of the coordinated site. Rate constants for H/D exchange of these complexes at 25°C or 60°C were obtained in alkaline D2O solution using NMR spectroscopy. Reaction rate for (NH3)5CoPhtz)(ClO4)3, (NH 3)5CoPydz)(ClO4)3, (NH 3)5Co(3-MePydz)(ClO4)3 and (NH3)5Co(3-MePhtz)(ClO4)3 at 25°C are faster compared to (NH3)5Co(ImH)(ClO 4)3, (NH3)5Co(N-MeIm)(ClO 4)3 (7). However (NH3) 5CoImCo(NH3)5Br5 complex does not H/D exchange at 60°C even in strong alkaline D2O solution

Synthesis and biological activity of some heterocyclic compounds contains N-benzylidene heterocycle and beta-lactam moiety

A number of N-benzylidene heterocycle derivatives have been synthesized and their antibacterial activities tested. The new chemical structures synthesized compounds were verified on the basis of spectral and elemental methods of analyses.the antimicrobial activity of the compounds was done by disc diffusion method We synthesized two different types of compounds, a combination of compounds based on the structure of isatin and other compounds based on the structure of thiazole. Synthesis of thiazole was performed using green chemistry method and a three-step reaction was used in the synthesis of isatin compounds. We used the Stoell-Becker method to synthesize compounds based on the isatin structure. The synthesized product was characterized by its physical properties, melting point, TLC and then subjected to the in vitro antibacterial activities against gram-positive and gram-negative strains of microbe

Synthesis, structural characterization and biological activity of Cu(II), Co(II) and Ni(II) complexes derived from 2-(thiazol-2-ylimino)thiazolidin-4-one ligand

A novel series of metal complexes of 2-(thiazol-2-ylimino) thiazolidin-4-one ligand were prepared; the corresponding ligand was synthesized from reaction 2-Chloro-N-(thiazol-2-yl) acetamide with ammonium thiocyanate. The complexes are characterized by FTIR, UV-Vis, molar conductance and mass spectroscopy. The low molar conductance values indicate that the complexes are non-electrolytes.Spectroscopic studies confirmed that the ligand bonded to the metals through the sulphur atoms. Coordination number of copper and nickel complexes is four with square planar geometry, while the cobalt complex has octahedral geometry.In vitro antibacterial activity of ligand and its metal complexes was evaluated using well diffusion method and compared to the standard drug (tetracycline). The antibacterial activitywas examined against Escherichia coli, and pseudomonas aeruginosa, as gram negative bacteria and Staphylococcus aureus as gram positive bacteria. It was found that Nickel complex has the highest antibacterial activity among the synthesized compounds with Zone inhibition diameter in the range 25-29 mm

One-pot synthesis of tetrahydropyrimidines catalyzed by zeolite

A simple one-pot synthesis of various tetrahydro pyrimidines in the presence of NaY zeolite, as an efficient catalyst, is reported. The multicomponent reaction was carried out by a three-component coupling of 1,3-diketone, aldehyde and urea/thiourea in the presence of the catalyst to give 1(a-k). The catalyst could be reused several times. Further reaction of these pyrimidines with phosphorus oxychloride gave corresponding N-formylated compounds

An Efficient and Convenient Protocol for the Synthesis of Optically Active 1,2,4-Triazolo-[3,4-b]-[1,3,4]-Thiadiazole, 1,3,4-Oxadiazole and 1,3,4-Thiadiazole Derivatives having L-Amino Acid Moieties

A series of novel bis triazolothiadiazole, 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives attached to L-amino acid moieties were synthesized in good yields using a simple and practical method. The structure of all synthesized compounds was confirmed by IR, 1H NMR, 13C NMR spectroscopy and elemental analysis.Keywords: Amino acid, triazolothiadiazole, 1,3,4-oxadiazole, 1,3,4-thiadiazole, phosphorus oxychloride, triazol