Mesoionic tetrazolium-5-aminides: Synthesis, molecular and crystal structures, UV-vis spectra, and DFT calculations.

Tetrazolium-5-aminides have been prepared by the -butylation of 5-aminotetrazole and its -methyl derivatives by the BuOH/HClO system followed by the treatment of the tetrazolium salts by alkali. The mesoionic compounds have been found to show a higher reactivity of the exocyclic N atom in comparison with 5-aminotetrazoles. The compounds reacted with 1,2-dibromoethane and 5-(methylsulfonyl)-1-phenyl-1-tetrazole with substitution of bromine and methylsulfonyl groups giving the corresponding tetrazolium salts or conjugate aminides.

Mimics of Pincer Ligands: An Accessible Phosphine-Free -(Pyrimidin-2-yl)-1,2-azole-3-carboxamide Framework for Binuclear Pd(II) Complexes and High-Turnover Catalysis in Water.

We report for the first time cyclic phosphine-free "head to tail" N,N,N pincer-like (pincer complexes mimicking) -(pyrimidin-2-yl)-1,2-azole-3-carboxamide Pd(II) complexes with deprotonated amide groups as high-turnover catalysts (TON up to 10, TOF up to 1.2 × 10 h) for cross-coupling reactions on the background of up to quantitative yields under Green Chemistry conditions. The potency of the described catalyst family representatives was demonstrated in Suzuki-Miyaura, Mizoroki-Heck, and Sonogashira reactions on industrially practical examples.

5-(2-Mercaptoethyl)-1H-tetrazole: Facile Synthesis and Application for the Preparation of Water Soluble Nanocrystals and Their Gels.

A facile method for the preparation of the novel capping ligand 5-(2-mercaptoethyl)-1H-tetrazole for the stabilization of water-soluble nanocrystals was developed. This effective synthetic procedure is based on the cycloaddition of sodium azide to 3,3'-dithiobis(propionitrile) followed by the reductive cleavage of a S-S bond with triphenylphosphine. The structure of the synthesized compound was confirmed by single-crystal X-ray analysis.

The first organocopper tetrazole derivative: synthesis and characterization.

1-(5-Amino-3-azapentyl)tetrazole dihydrochloride (HL·2HCl) was prepared by heterocyclization of diethylenetriamine with triethyl orthoformate and sodium azide followed by treatment with potassium carbonate and hydrochloric acid. The reaction of CuCl2, HL·2HCl and triethylamine (NEt3) in a molar ratio of 1 : 1 : 3 in water was found to generate a novel organometallic tetrazole derivative Cu2L2Cl2. This compound is present as a binuclear centrosymmetric molecular complex, in which C-deprotonated tetrazole L acts as a chelating ligand via the two amino N and tetrazole ring C coordination sites and the two copper atoms are linked together through two tetrazole ring N(4)-C(5) bridges.

Copper(II) tetrafluoroborate complexes with the N(3),N(4)-bridging coordination of 1-(tert-butyl)-1H-tetrazole: synthesis, crystal structure and magnetic properties.

1-(tert-Butyl)-1H-tetrazole (L) reacts with copper(ii) tetrafluoroborate hexahydrate to give the complexes [Cu2L8(H2O)2](BF4)4 (1) or [Cu3L6(H2O)6](BF4)6 (2) depending on the reaction conditions. These complexes, as well as compound L, were characterized using single crystal X-ray analysis. Complex 1 was found to comprise a dinuclear complex cation [Cu2L8(H2O)2](4+) (the Ci symmetry point group), with six tetrazole ligands L showing monodentate N(4)-coordination, and two ligands L providing two tetrazole ring N(3),N(4) bridges between the copper(ii) cations; water molecules complete the distorted octahedral coordination of the metal ions.

Gold(I) thiotetrazolates as thioredoxin reductase inhibitors and antiproliferative agents.

Gold(i) complexes with phosphane and thiotetrazolate ligands were prepared and investigated as a new type of bioactive gold metallodrugs. The complexes triggered very efficient inhibition of the enzyme thioredoxin reductase (TrxR), which is an important molecular target for gold species. Strong cytotoxic effects were observed in MDA-MB-231 breast adenocarcinoma and HT-29 colon carcinoma cells, and the complexes also caused strong effects in vincristine resistant Nalm-6 leukemia cells.

Synthesis, characterization, and biological evaluation of new tetrazole-based platinum(II) and palladium(II) chlorido complexes--potent cisplatin analogues and their trans isomers.

Two series of tetrazole-containing platinum(II) and palladium(II) chlorido complexes, trans-[ML(2)Cl(2)] (M=Pt, Pd) and cis-[PtL(2)Cl(2)]·nH(2)O (n=0, 1), where L is 1- or 2-substituted 5-aminotetrazole, have been synthesized and thoroughly characterized. Configuration of platinum(II) complexes obtained from the reaction of 5-aminotetrazoles with K(2)PtCl(4) has been found to vary depending on the nature of tetrazole derivatives and reaction conditions. According to in vitro cytotoxic evaluation, only platinum complexes display noticeable antiproliferative effect, and their cytotoxicity depends strongly on their geometry and hydrophobicity of the carrier ligands.

2-tert-Butyl-5-(2-pyridyl)-2H-tetrazole as a chelating ligand in the direct synthesis of novel Cu(II) and heterobimetallic Cu(II)/Mn(II) complexes.

For the first time, a representative of the 2,5-disubstituted tetrazoles, namely, 2-tert-butyl-5-(2-pyridyl)-2H-tetrazole (L), has been found to participate in oxidative dissolution of copper powder in homometalic systems Cu0–L–NH4X–DMSO (X = Cl, SCN, ClO4) and heterobimetallic ones Cu0–Mn(OAc)2–L–NH4OAc–Solv (Solv = DMSO, DMF), providing the formation of molecular homometallic complexes [CuL2Cl2] (1), [CuL2(SCN)2] (2), and [CuL2(H2O)](ClO4)2 (3), heterobimetallic complex [Cu2MnL2(OAc)6] (4) from DMF solution and its mixture with complex [Cu2MnL2(OAc)6]·2DMSO (5) from DMSO solution. Free ligand L and complexes 1–4 were characterized by elemental analysis, IR spectroscopy, thermal and X-ray single crystal analyses, whereas complex 5 was characterized by X-ray analysis only. Compounds 1–3 are mononuclear complexes, with chelating coordination mode of L via the tetrazole ring N4 and pyridine ring N7 atoms.

2-Ethyl-6-methylpyridin-3-ol and its salt bis(2-ethyl-3-hydroxy-6-methylpyridinium) succinate.

The title compounds, C(8)H(11)NO, (I), and 2C(8)H(12)NO(+)·C(4)H(4)O(4)(2-), (II), both crystallize in the monoclinic space group P2(1)/c. In the crystal structure of (I), intermolecular O-H···N hydrogen bonds combine the molecules into polymeric chains extending along the c axis. The chains are linked by C-H···π interactions between the methylene H atoms and the pyridine rings into polymeric layers parallel to the ac plane.

Two succinic acid derivatives of 2-ethyl-6-methylpyridin-3-ol.

Crystals of bis(2-ethyl-3-hydroxy-6-methylpyridinium) succinate-succinic acid (1/1), C(8)H(12)NO(+)·0.5C(4)H(4)O(4)(2-)·0.5C(4)H(6)O(4), (I), and 2-ethyl-3-hydroxy-6-methylpyridinium hydrogen succinate, C(8)H(12)NO(+)·C(4)H(5)O(4)(-), (II), were obtained by reaction of 2-ethyl-6-methylpyridin-3-ol with succinic acid.

An X-ray powder diffraction study of cis-dichloridobis(2-methyl-2H-tetrazol-5-amine-κN(4))platinum(II), a tetrazole-containing analogue of cisplatin.

The structure of the title compound, cis-[PtCl(2)(C(2)H(5)N(5))(2)], was analysed using in-house X-ray powder diffraction data at room temperature. The structure was solved by direct methods and refined using Rietveld analysis. A slightly distorted square-planar coordination geometry is formed around the Pt atom by two Cl atoms and two ring N atoms of the 2-methyl-2H-tetrazol-5-amine ligands, which are in a cis configuration.

Copper(II) chloride and bromide complexes with 2-methyl-2H-tetrazol-5-amine: an X-ray powder diffraction study.

The complex catena-poly[[dibromidocopper(II)]-bis(mu-2-methyl-2H-tetrazol-5-amine)-kappa(2)N(4):N(5);kappa(2)N(5):N(4)], [CuBr(2)(C(2)H(5)N(5))(2)](n), (I), and the isotypic chloride complex catena-poly[[dichloridocopper(II)]-bis(mu-2-methyl-2H-tetrazol-5-amine)-kappa(2)N(4):N(5);kappa(2)N(5):N(4)], [CuCl(2)(C(2)H(5)N(5))(2)](n), (II), were investigated by X-ray powder diffraction at room temperature. The crystal structure of (I) was solved by direct methods, while the Rietveld refinement of (II) started from the atomic coordinates of (I). In both structures, the Cu atoms lie on inversion centres, adopting a distorted octahedral coordination of two halogen atoms, two tetrazole N atoms and two 5-amine group N atoms.

A tetrazol-5-yl analogue of glycine, 5-ammoniomethyl-1H-tetrazolide, and its copper(II) complex.

A nonclassical tetrazole isostere of glycine, viz. zwitterionic 5-ammoniomethyl-1H-tetrazolide, C(2)H(5)N(5), (I), crystallizes in the chiral P3(1) space group, similar to gamma-glycine. The crystal packing of (I) is determined by a set of classical hydrogen bonds, forming a three-dimensional network that is practically the same as that in gamma-glycine.

Stereoselective synthesis of 9alpha-hydroxylated ecdysteroids.

Treatment of ecdysteroids with excess of TBAF in THF was shown to proceed with stereoselective oxidation at the 9alpha position of the carbon skeleton. The stereochemistry of the products was confirmed by X-ray analysis. Using this method, 9alpha-hydroxyecdysteroids were obtained in good yield.

catena-Poly[cobalt(II)-di-μ-chlorido-κCl:Cl-μ-1,5-dimethyl-1H-tetra-zole-κN:N]: an X-ray powder investigation.

The asymmetric unit of the title compound, [CoCl(2)(C(3)H(6)N(4))](n), contains two Co atoms, both lying on inversion centres, two Cl atoms and one 1,5-dimethyl-tetra-zole ligand. The coordination polyhedra of both Co atoms adopt flattened octa-hedral geometry, with two N atoms from two ligands in axial positions and four Cl atoms in equatorial sites. Neighbouring Co atoms are linked together via two bridging Cl atoms and one tetra-zole ring to form polymeric chains running along the a axis.

trans-Dichloridotetrakis-[1-(2-hydroxy-ethyl)-1H-tetrazole-κN]cobalt(II).

The title cobalt(II) complex, [CoCl(2)(C(3)H(6)N(4)O)(4)], was obtained from metallic cobalt by direct synthesis. There are two Co atoms in the asymmetric unit, each lying on an inversion centre and adopting a distorted octa-hedral coordination. Classical and non-classical hydrogen bonds are responsible for formation of a three-dimensional polymeric network in the crystal.

Synthesis of 5,10-seco analogs of testosterone.

A number of 5,10-seco analogs of testosterone has been synthesized starting from products of the radical oxidation of 3beta,17beta-diacetoxy-5alpha-androstan-5alpha-ol. The obtained compounds possess a flexible 10-membered ring with substituents (O, -OH) at C-3 and C-5. Similar derivatives with an (E)- and (Z)-Delta(1(10))-double bond have been prepared also.

Two derivatives of 1,5-disubstituted tetrazoles: 1-(4-nitrophenyl)-1H-tetrazol-5-amine and {(E)-[1-(4-ethoxyphenyl)-1H-tetrazol-5-yl]iminomethyl}dimethylamine.

The geometric features of 1-(4-nitrophenyl)-1H-tetrazol-5-amine, C(7)H(6)N(6)O(2), correspond to the presence of the essential interaction of the 5-amino group lone pair with the pi system of the tetrazole ring. Intermolecular N-H..

Synthesis and molecular structure of 14,15-pyrrolidino-and 14,16-ethano derivatives of estrone.

Hydrolysis of 3-methoxy-16alpha-nitro-14,17-ethenoestra-1,3,5(10)-trien-17beta-yl acetate under weakly basic conditions leads to formation of 3-methoxy-2'-oxopyrrolidino-[4',5':14beta,15beta]-estra-1,3,5 (10)-trien-17-one, the structure of which has been confirmed by X-ray analysis and some chemical transformations. The reactivity of 3-methoxy-16alpha-nitro-14,17-ethanoestra-1,3,5(10)-trien-17beta-yl acetate under various conditions of basic hydrolysis has been investigated. The derived compounds have been identified by means of NMR spectroscopy and X-ray analysis.

catena-Poly[[bis-[1-(2-hydroxy-ethyl)-1H-tetra-zole-κN]copper(II)]-di-μ-chlorido]: a powder study.

The crystal structure of the title polymeric complex, [CuCl(2)(C(3)H(6)N(4)O)(2)](n), was obtained by the Rietveld refinement from laboratory X-ray powder diffraction data collected at room temperature. The unique Cu(II) ion lies on an inversion center and is in a slightly distorted octa-hedral coordination environment. In the hydroxy-ethyl group, all H atoms, the O atom and its attached C atom are disordered over two positions; the site occupancy factors are ca 0.

An X-ray powder investigation of catena-poly[copper(II)-di-mu-chloro-kappa41:2Cl-mu-1,5-dimethyl-1H-tetrazole-kappa2N3:N4].

The crystal structure of the polymeric title complex, [CuCl2(C3H6N4)]n, has been solved from laboratory X-ray powder diffraction data collected at room temperature. The structural model obtained was refined with the Rietveld method using geometric soft restraints. There are two Cu atoms, two Cl atoms and one 1,5-dimethyltetrazole ligand in the asymmetric unit.

Bis(1-methyl-1H-tetrazol-5-yl)diazene and two its copper(I) chloride complexes poly[[[mu-1,2-bis(1-methyl-1H-tetrazol-5-yl)diazene-kappa4N',N4:N,N4']dicopper(I)]-di-mu-chloro] and catena-poly[[chlorocopper(I)]-mu-1,2-bis(1-methyl-1H-tetrazol-5-yl)diazene-kappa4N',N4:N,N4'].

While bis(1-methyl-1H-tetrazol-5-yl)diazene, C4H6N10, (I), has no crystallographically imposed symmetry, in the two title chlorocopper(I) complexes, [Cu2Cl2(C4H6N10)]n, (II), and [CuCl(C4H6N10)]n, (III), the organic ligands lie across centres of inversion; in (III), the Cu and Cl atoms additionally lie about a twofold rotation axis in the space group P2/c. Complex (II) forms a two-dimensional coordination polymer containing tetrahedrally coordinated Cu(I) atoms, and complex (III) forms a one-dimensional coordination polymer containing five-coordinate square-pyramidal Cu(I) atoms.

Isolation and structure elucidation of new radical oxidation products of 5-hydroxy steroids.

Three new products have been isolated from the lead-tetraacetate version of the hypoiodite oxidation of 3beta,17beta-diacetoxy-5-hydroxy-5 alpha-androstane. Along with the expected 1(10)-unsaturated 5,10-seco steroidal 5-ketones, the fragmentation reaction gave two epimeric C-4 iodides. Their structural assignment was based on X-ray data of one of them ((4R,10S)-4-iodo-3beta,17beta-diacetoxy-5,10-secoandrostan-5-one).

Coordination polymers formed by bridging 2-substituted tetrazole ligands: poly[[dichlorocopper(II)]-di-mu2-2-propyl-2H-tetrazole-kappa2N1:N4] and poly[[dichlorocopper(II)]-di-mu2-2-allyl-2H-tetrazole-kappa2N1:N4].

Two polymeric complexes, [CuCl2L2]n, where L is 2-propyltetrazole (C4H8N4) or 2-allyltetrazole (C4H6N4), are the first coordination polymers of 2-substituted tetrazoles in which only the tetrazole rings bridge neighbouring Cu atoms. In both complexes, the Cu atoms lie on inversion centres and are six-coordinated in tetragonally distorted octahedral geometries, CuCl2N4, with two N1 tetrazole ring atoms in the axial positions and two Cl atoms and two N4 tetrazole ring atoms in the equatorial sites. The Cl atoms do not participate in the polymeric layer formation.

Bis[1,3-bis(2-methyltetrazol-5-yl-kappaN4)triazenido-kappaN2]nickel(II).

The title compound, [Ni(BMTT)2], where BMTT is 1,3-bis(2-methyltetrazol-5-yl)triazenide (C4H6N11), presents a molecular complex with tridentate ligands. The tridentate mode of the ligand is realised through the central N atom of the triazene group and two N atoms of the two tetrazole rings. The [Ni(BMTT)2] molecule is the meridional isomer, with crystallographic 4 symmetry in space group P4(2)/n.