Bohari M. Yamin

Synthesis and characterization of bis-thiourea having amino acid derivatives

In this article four new symmetric bis-thiourea derivatives having amino acid linkers were reported with good yield. Isophthaloyl dichloride was used as spacer and L-alanine, L-aspartic acid, L-phenylalanine and L-glutamic acid were used as linkers. Bis-thiourea derivatives were prepared from relatively stable isophthaloyl isothiocyanate intermediate. Newly synthesized bis-thiourea derivatives were characterized by FTIR, H-NMR, 13C-NMR and CHNS-O elemental analysis techniques. Characterization data was in good agreement with the expected derivatives, hence confirmed the synthesis of four new derivatives of bis-thiourea having amino acids.

Synthesis and crystal structure of 1,1’-Bis(2-bromobenzoyl thioureido)ethane

1,1’-Bis(2-bromobenzoylthioureido)ethane was synthesized from the reaction of 2-bromobenzoylisothiocyanate and ethylenediamine in acetonitrile. The compound was characterized by FT-IR, 1H, and 13C NMR spectroscopy techniques. Furthermor compound was found to crystallized in monoclinic system with space group of P2(1)/c. In each thiourea moiety the thiono group is trans to the benzoyl across their C-N bonds. The crystal structures are stabilized by N–H···S intermolecular hydrogen bonds to form infinite two dimensional network.

Synthesis, characterization and antioxidant study of N,N’-bis(2-chlorobenzamidothiocarbonyl)hydrazine

N,N’-bis(2-chlorobenzamidothiocarbonyl)hydrazine was synthesized from 2-chlorobenzoylisothiocyanate and hydrazine in acetone. The compound was characterized by infrared, 1H and 13C NMR, and UV-Vis spectroscopies. X-ray crystallography study showed the molecule adopt trans configuration at both N-N and C-N bonds. The compound showed high antioxidant activity, EC50 of 374.89 µM, compared to ascorbic acid (EC50 of 561.36 µM).

Synthesis, crystal structure and antioxidant evaluation of C-4-acetamidophenylcalix[4]pyrogallolarene

C-4-acetamidophenylcalix[4]pyrogallolarene was synthesized by an acid catalyzed condensation reaction of pyrogallol with 4-acetamidobenzaldehyde. The compound was characterized by IR, 1H and 13C NMR spectroscopy. Single crystal X-ray analysis revealed that the molecule crystallized in a triclinic system with space group Pī and the unit cell dimensions a= 12.2948(16) A, b= 13.4423(17) A, c= 13.5906(18) A, α =107.549(4)°, β =102.034(4)°, γ =90.535(4)°, Z= 1 and V= 2088.2(5) A3. The macrocyclic calix adopts a chair (C2h) conformation and the molecule is associated with eight DMSO molecules of crystallization. Antioxidant test by DPPH method showed that the compound exhibits good antioxidant activity of about 72%.

Synthesis, characterization and antibacterial studies of 2-chloro-5-fluoro-N-[dibenzyl carbamothioyl] benzamide thiourea

Synthesis, characterization and antibacterial studies of 2-chloro-5-fluoro-N-[dibenzyl carbamothioyl] benzamide thiourea has been reported. The compound characterized by using elementary analysis CHNS, IR, 1H NMR and 13C NMR spectroscopies. The compounds have been screened for their antibacterial studies.

Synthesis and characterization of Ni(II) complex with 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-dienium bromide

Nickel(II) complex have been synthesized by treating a 14-membered ring tetraaza macrocyclic compound, 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-dienium, bromide (Me6N4H4)Br2 with nickel acetate in metanol. The complex was characterized using elemental analysis, Fourier Transform Infrared (FTIR), Ultraviolet-Visible (UV-Vis), and single crystal diffraction (X-ray). The nickel atom coordinates through four nitrogen atoms in the ligand. Square planar geometry has been proposed for this complex.

Complexation of 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-dienium bromide with copper salts

Copper complexes have been synthesized with 14-membered macrocyclic 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-dienium bromide (Me6N4H4)Br2 as ligand having six methyl groups and two double bonds located in diagonal position. These complexes were characterized by microelemental analysis, Fourier Transform Infrared (FTIR) and Ultraviolet-Visible (UV-VIS) spectroscopies. The chemical analysis and spectroscopic data is supported by chemical crystallographic study showed that one of the synthesized copper complex with CuCl2 consists of [Cu(Me6N4H2)] dication, two bromide counter anions and 2 water molecules of crystallisation. Thermogravimetry Analysis (TGA) showed that the complex is stable up to about 200°C before gradually decomposed up to 400°C.

Synthesis, characterization and antibacterial study of tripodal tris-(N-benzoylthioureido)ethylamine

A new tripodal tris-(N-benzoylthiouredoethyl)amine has been successfully synthesized and characterized by spectroscopic technique such as FTIR, ESI MS, 1H and 13C NMR. The microanalysis data is in a good agreement with the expected molecular formula. The 1H NMR chemical shift for both amide and thioamide proton are at lower field than their normal value indicates the presence of the hydrogen bond between the carbonyl oxygen atom and thioamide hydrogen. This is possible when the benzoyl group adopt a trans configuration againts thione group along the C-N bond. The compound has been tested for antibacterial activity against three selected bacteria namely Staphylococcus aureus, Proteus vulgaris and Pseudomanas aeroginosa but there is no significant activities observed.