Thiazole Nitrogen Research Articles

Palladium and platinum famotidine complexes

The molecule of the well-known ulceration inhibitor, famotidine, is an excellent coordinator of transition metal ions. The guanidine, amine group and thiazole nitrogen, and the thioether sulphur are preferential sites to bind metal ions. Pd(II) and Pt(II) derivatives of famotidine have been synthesized and studied structurally. There is evidence that the palladium complex is a monomer while the platinum complex forms a dimer. Due to the interesting structure of the platinum complex several assays have examined the possible antitumour activity. Changes in DNA conformation induced by both complexes have been detected by CD, interstrand crosslinking interactions and electrophoretic mobility, but studies of the cytotoxicity of the platinum compound with U937 human leukemia cells and HeLA human womb carcinoma cells show only a small antiproliferative potential.

Platinum (II) and palladium (II) complexes derived from the anion of sulfathiazole [4, 2]; crystal structure of cis- [Pt (stz) 2 (PPh3) 2] · 3CHCl3

Reaction of the complexes cis- [PtCl2L2] [L = PPh3 or L2 = 1,1′-bis (diphenylphosphino) ferrocene (dppf) ] , or [PdCl2 (phen) ] [phen = 1,10-phenanthroline] with two mole equivalents of sulfathiazole (stzH) in methanol with excess triethylamine yields the complexes cis- [M (stz) 2L2] in good yields. The complexes have been characterised by elemental microanalysis, together with infrared, 1H and 31P NMR spectroscopies. A single-crystal X-ray structure determination on the complex cis- [Pt (stz) 2 (PPh3) 2] 3a shows that both stz ligands coordinate via the thiazole nitrogen atoms. Using positive-ion electrospray mass spectrometry (ESMS) all complexes yield strong molecular ions [M+H] + at low cone voltages. At higher cone voltages, loss of one stz ligand occurs, giving [L2M (stz) ] + ions. The complex cis- [PtCl (stz) (PPh3) 2] 4 was also prepared using a 1 : 1 mole ratio of reactants. Functionalisation of both primary arylamine groups of 3a can be accomplished using either acetic anhydride or trifluoroacetic anhydride, in pyridine solvent, and the derivatives 5 were characterised by 31P NMR spectroscopy, elemental analysis and ESMS.

Metal-drug interactions: synthesis and crystal structure of dichlorodithiabendazolecobalt(II) monohydrate

The crystal structure of dichlorodithiabendazolecobalt(II) monohydrate [CoCl 2(C 10H 7N 3S) 2·H 2O] has been determined from X-ray diffraction data using Mo Kα radiation. The crystals are monoclinic, P2 1/c with a = 15.328(5), b = 11.2131(8), c = 13.967(5) A ̊ , β = 114.27(1)° and Z = 4 . The structure was solved and refined to a final R value of 0.0332 with 3717 observed reflections. Two chlorine atoms and two thiabendazole ligands form an octahedral geometry around cobalt. Each thiabendazole, [2-(4-thiazolyl)-1 H-benzimidazole], is bidendate chelating and is bonded to cobalt through the nitrogen atoms of the thiazolyl and benzimidazole rings in cis configuration. The protonated nitrogen atom of the imidazole ring is trans to the thiazole nitrogen atom.

Ara-tiazofurin: conservation of structural features in an unusual thiazole nucleoside.

Tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide, NSC 286193) is a C-glycosyl thiazole nucleoside with antitumor activity. Crystal structures of tiazofurin and its alpha,2'-deoxy and xylo analogues all show close contacts between the thiazole sulfur (S) and the furanose ring oxygen (O1'). These contacts have been interpreted in terms of an attractive intramolecular S-O interaction in the thiazole nucleosides. Ara-tiazofurin (2-beta-D-arabinofuranosylthiazole-4-carboxamide, ara-T) is the inactive arabinose analogue of tiazofurin. The crystal structure of ara-T is reported. This structure provides evidence for an attractive S-O interaction not seen in the other thiazole nucleosides. The conformation about the C-glycosyl bond in ara-T is such that close contacts are formed between the thiazole sulfur and both O1' and the 2'-hydroxyl oxygen O2'. This conformation is interpreted in terms of an additional attractive interaction between S and O2'. This interpretation is supported by comparison of the conformation of ara-T with those of other ara-nucleosides. These findings provide further evidence for an attractive S-O interaction in the thiazole nucleosides. Ara-T also demonstrates a second conformational feature found in these compounds: the carboxamide nitrogen remains cis to the thiazole nitrogen. Implications of these potentially constrained conformational features are discussed in terms of the mechanism of activity of tiazofurin.

Structure of 4-phthalimido-N-(1,3-thiazol-2-yl)benzenesulfonamide

CITHllN304S2, M,=385.4, monoclinic, P2Jc, a = 7.955 (2), b = 6.501 (1), c = 35.859 (8) A, #= 116.92 (2) °, V= 1653.5 (5)A3,Z =4, Din = 1.560, D x = 1 548 Mg m -3, ~,(Cu Kt~) = 1.5418/~, /~ = 3.13 mm -1, F(000) = 792, T= 293 K, final R = 0.061 for 2116 observed reflections. The molecule exists as an imido tautomer with deprotonation of the sulfonamide nitrogen and protonation of the thiazole nitrogen. Centrosymmetrically related pairs of molecules dimerize through hydrogen bonds of the type N-H...O and N-H...N. The thiazole and the phthalimide rings form stacks amongst themselves. Introduction. Sulfonamides and their derivatives are well known antibacterial drugs. The present compound is a substituted sulfonamide with the substituents a thiazole at the sulfonamide nitrogen, N(1), and a phthalimide ring at the para position of the phenyl ring, and is used in the treatment of intestinal infections. The main advantage of this drug is that it does not build up in the blood because of its rapid excretion and poor absorption and hence large doses can be administered without danger of toxic effects. The X-ray structural study of the present compound has been carried out in continuation of our studies (Basak, Mazumdar & Chaudhuri, 1982, 1983, 1984; Basak, Chaudhuri & Mazumdar, 1984) of the substituted sulfonamides in order to obtain detailed structural information and also to study the effects of substituents on the molecular

Palladium(II) chelates of 1,1-dimethyl-3-(4-methyl-2-thiazolyl)thiourea and related thioureas.

Pd (II) chelates of 1, 1-dimethyl-3-(4-methyl-2-thiazolyl) thiourea and related N-(2-thiazolyl)-thioureas were prepared and their molecular structures were determined by means of spectroscopic, thermochemical, and X-ray crystallographic measurements, in order to establish the identity of the colored substances in the spectrophotometric determination of Pd (II) with the thiazolyl-thioureas. The results indicated that Pd (II) formed 1 : 2 chelates with the thiazolylthioureas and that the ligands were bidentate and coordinated through the thiourea sulfur and thiazole nitrogen atoms. The geometry of Pd (II) coordination was roughly square-planar and the configuration of the two thiazolylthiourea molecules was cis.

Metal complexes of 2-mercaptobenzothiazole

Metal complexes of 2-mercaptobenzothiazole (LH) have been prepared and investigated. The metal complexes obtained were of the types ML2 (M = Ni, Pd, Pt, Zn, Cd), CuL.LH, and AgL. The copper complex has been shown to contain copper(I). Evidence from the i.r. spectra shows that in all the complexes the ligand is coordinatedvia the thiazole nitrogen and the exocyclic sulfur atom. Adducts of both the nickel and cadmium complexes were obtained with several nitrogen heterocycles. The complex CdL2py2 (py = pyridine) is isostructural with the six-coordinate NiL2py2 and CoL2py2 which possess acis configuration.

The Crystal Structure of Bis[1-(2-thiazolylazo)-2-naphtholato]cobalt(III) Perchlorate

Abstract The crystal structure of bis[1-(2-thiazolylazo)-2-naphtholato]cobalt(III) perchlorate, [CoIII(C13H8N3OS)2]ClO4 was determined from X-ray reflection data collected by counter methods. The crystals are monoclinic, space group P21/c, with a=10.348(2), b=21.066(5), c=13.072(5) Å, β=112.35(3)°, and Z=4. The structure was determined by the heavy-atom method and refined by the least-squares technique to give an R value of 0.051 for 2696 observed reflections. The cobalt atom is six-coordinate and exhibits octahedral coordination. The 1-(2-thiazolylazo)-2-naphtholato group is coordinated as a terdentate ligand with the cobalt atom through the phenolic oxygen atom, the azo nitrogen atom adjacent to the naphthol ring and the thiazole nitrogen atom giving two five-membered chelate rings. Short intraligand contacts of 2.24(6) and 2.28(6) Å are observed between the azo nitrogen and naphthol hydrogen atoms.

The Crystal Structure of 1-(2-Thiazolylazo)-2-naphtholato diaquacopper(II) Perchlorate

Abstract The crystal structure of 1-(2-thiazolylazo)-2-naphtholatodiaquacopper(II) perchlorate, [CuII(TAN)(H2O)2]-ClO4, has been determined from three-dimensional X-ray data collected by counter methods. The crystals are monoclinic, with the space group P21/c; a=13.481(4), b=8.060(4), c=15.307(7) Å, β=95.58(4)°, and Z=4. The structure was refined to an R value of 0.086 for 952 non-zero reflections. The copper atom is five-coordinated and has a distorted square-pyramidal environment. The 1-(2-thiazolylazo)-2-naphtholato group (TAN) acts as a terdentate ligand, the phenolic oxygen, the azo nitrogen and the thiazole nitrogen atoms being coordinated to the copper atom to give two five-membered chelate rings. The remaining two positions are occupied by water molecules.

ChemInform Abstract: CRYSTAL STRUCTURE OF CHLORO‐1‐(2‐THIAZOLYLAZO)‐2‐NAPHTHOLATOPALLADIUM(II) DIOXANE SOLVATE

The crystals of chloro-1-(2-thiazolylazo)-2-naphtholatopalladium(II) dioxane solvate, [PdCl(TAN)]·C4H8O2, are orthorhombic and of space group Pbcm, with unit cell dimensions: a=8.44(2), b=30.97(4) and c=6.82(2) A and Z=4. The structure was determined by the heavy-atom method and refined by the least-squares procedure to give an R value of 0.097 for 1392 observed reflections. The crystallographic mirror plane normal to the c-axis coincides with the molecular plane of [PdCl(TAN)]. The 1-(2-thiazolylazo)-2-naphtholato group, i.e., TAN, is a terdentate ligand; the phenolic oxygen atom, azo nitrogen atom and thiazole nitrogen atom are coordinated to the palladium atom to form two five-membered chelate rinsgs. The fourth coordination position is occupied by a chlorine atom.

Crystal Structure of Chloro-1-(2-thiazolylazo)-2-naphtholatopalladium(II) Dioxane Solvate

Abstract The crystals of chloro-1-(2-thiazolylazo)-2-naphtholatopalladium(II) dioxane solvate, [PdCl(TAN)]·C4H8O2, are orthorhombic and of space group Pbcm, with unit cell dimensions: a=8.44(2), b=30.97(4) and c=6.82(2) Å and Z=4. The structure was determined by the heavy-atom method and refined by the least-squares procedure to give an R value of 0.097 for 1392 observed reflections. The crystallographic mirror plane normal to the c-axis coincides with the molecular plane of [PdCl(TAN)]. The 1-(2-thiazolylazo)-2-naphtholato group, i.e., TAN, is a terdentate ligand; the phenolic oxygen atom, azo nitrogen atom and thiazole nitrogen atom are coordinated to the palladium atom to form two five-membered chelate rinsgs. The fourth coordination position is occupied by a chlorine atom.

Complexes of thiazoles. Part IV. Acetamido-thiazoles as ambidentate ligands

Some complexes of 2-acetamidothiazole and 2-acetamidobenzothiazole with NiII and CuII have been prepared and three types of co-ordination behaviour distinguished on the basis of their i.r. spectra. The organic ligand donor atoms may be (a) carbonyl oxygen and thiazole nitrogen, (b) amide nitrogen and thiazole nitrogen, or (c) carbonyl oxygen, amide nitrogen, and thiazole nitrogen. Types (b) and (c) are of interest as examples of co-ordination via a non-deprotonated amide nitrogen atom.

Reaction of 2-(4'-Thiazolyl)benzimidazole (thiabendazole) with alkyl halides

2-(4?-Thiazolyl)benzimidazole (thiabendazole) is alkylated at a benzimidazole nitrogen by reaction with sodium hydride and an alkyl halide. With 1,3-dibromo-propane and 1,2-dibromoethane, the thiazole nitrogen is also alkylated to give quaternary salts containing the 6,7- dihydro-5H-thiazolo[3?,4?:1.2][1,4]diazepino-[8,9-a]benzimidazole and 5,6-dihydrothiazolo[3?,4?:1,2]pyrazino[7,8-a]benzimidazole ring systems respectively. The structures proposed for these tetracyclic products are supported by spectroscopic examination of the products formed by alkali fission of their thiazole rings.