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At least 19 recordsLinked to original sources
PubMed2005

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.

Journal Article↗
PubMed1976

Synthesis of tetrazole ribonucleosides and their evaluation as antiviral agents. 2. 5-Amino-1-(beta-D-ribofuranosyl)-1H-tetrazole and 5-amino-2-(beta-D-ribofuranosyl)-2H-tetrazole.

Synthesis of 5-amino-1-(beta-D-ribofuranosyl)-1H-tetrazole and 5-amino-2-(beta-D-ribofuranosyl)-2H-tetrazole is described. X-Ray crystallography was first used to establish the stereochemical configuration of the two isomers. By conducting 13C NMR analysis on these isomers with known structures, i.e., N1beta, a correlation is developed for determining the N-ribosyl attachment site of tetrazole ribonucleosides. Results are also presented on antiviral testing of these synthetic 5-aminotetrazole ribonucleosides against influenza A2/Asian/J305 virus infection in mice.

Amitrole↗
PubMed2006

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.

Journal Article↗
PubMed1996

Inhibitors of acyl-CoA:cholesterol O-acyltransferase. synthesis and pharmacological activity of (+/-)-2-dodecyl-alpha-phenyl-N-(2,4,6-trimethoxyphenyl)-2H-tetrazole-5- acetamide and structurally related tetrazole amide derivatives.

A series of tetrazole amide derivatives of (+/-)-2-dodecyl-alpha-phenyl-N-(2,4,6-trimethoxyphenyl)-2H-tetrazole-5- acetamide (1) was prepared and evaluated for their ability to inhibit acyl-CoA: cholesterol O-acyltransferase (ACAT) in vitro and to lower plasma total cholesterol in vivo. For this series of compounds, our objective was to systematically replace substituents appended to the amide and tetrazole moieties of 1 with structurally diverse functionalities and assess the effect that these changes have on biological activity. The ensuing structure-activity relationship (SAR) studies identified aryl (7b) and heteroaryl (7f,g) replacements for 2,4,6-trimethoxyphenyl that potently inhibit liver microsomal and macrophage ACAT in vitro and exhibit good cholesterol lowering activity (56-66% decreases in plasma total cholesterol at 30 mg/kg), relative to 1, when compared in the acute rat model of hypercholesterolemia. Replacement of the alpha-phenyl moiety with electron-withdrawing substituents (13e-h), however, significantly reduced liver microsomal ACAT inhibitory activity (IC50 > 1 microM). This is in contrast to electron-donating substituents (13ij,m-q), which produce IC50 values ranging from 5 to 75 nM in the hepatic microsomal assay. For selected tetrazole amides (1, 7b, 13n,o), reversing the order of substituents appended to the 2- and 5-positions in the tetrazole ring (36a-d), in general, improved macrophage ACAT inhibitory activity and provided excellent cholesterol-lowering activity (ranging from 65% to 77% decreases in plasma total cholesterol at 30 mg/kg) in the acute rat screen. The most potent isomeric pair in this set of unsubstituted methylene derivatives (13n and 36a) caused adrenocortical cell degeneration in guinea pigs treated with these inhibitors. In contrast, adrenal glands taken from guinea pigs treated with the corresponding alpha-phenyl-substituted analogs (7b and 36c) were essentially unchanged compared to untreated controls. Subsequent evaluation of 7b and 36c in a rabbit bioassay showed that both compounds and/or their metabolities were present in plasma after oral dosing. Unlike 7b and 36c, compound 1 and related 2,4,6-trimethoxyanilides (13j, 30c,d) showed poor oral activity in the rabbit bioassay. Nevertheless, in cholesterol-fed rabbits, both systemically available (7b, 36c) and poorly absorbed inhibitors (1, 36d) were more effective in lowering plasma total cholesterol than the fatty acid amide CI-976.

Animals↗
PubMed1995

[3'-(Tetrazol-2''-yl-3'-deoxythymidine and its 5''-substituted form: synthesis and conformation in the crystalline state. Substrate properties of 3'-(tetrazol-2''-yl)-3'-deoxythymidine-5'-triphosphate in relation to DNA polymerases].

5''-Derivatives of 3'-(tetrazole-2''-yl)-3'-deoxythymidines were synthesized by interaction of 5'-benzoyl-2',3'-anhydrothymidine with tetrazole or its 5-derivatives followed by debenzoylation. Structures of two of them, 3'-(tetrazole-2''-yl)-3'-deoxythymidine and 3'-(5''-methyltetrazole-2''-yl)-3'-deoxythymidine, elucidated by X-ray analysis, revealed anti conformation of thymine about the glycosidic bond and 2'-endo-3'-exo-conformation of the sugar residue with gauche+ orientation with respect to C4'-C5'-bond. 3'-(Tetrazole-2''-yl)-3'-deoxythymidine 5'-triphosphate demonstrated poor substrate properties for the avian myeloblastosis virus reverse transcriptase and none for several other DNA polymerases.

Base Sequence↗
PubMed1986

Synthesis and quantitative structure-activity relationships of antiallergic 2-hydroxy-N-1H-tetrazol-5-ylbenzamides and N-(2-hydroxyphenyl)-1H-tetrazole-5-carboxamides.

The synthesis and antiallergic activity of a series of 2-hydroxy-N-1H-tetrazol-5-ylbenzamides and isomeric N-(2-hydroxyphenyl)-1H-tetrazole-5-carboxamides is described. A relationship between structure and intravenous antiallergic activity in the rat passive cutaneous anaphylaxis (PCA) test has been established using a Hansch/Free-Wilson model and used to direct studies toward potent derivatives. The contribution of physicochemical properties to activity is discussed. One member of this series, N-(3-acetyl-5-fluoro-2-hydroxyphenyl)-1H-tetrazole-5-carboxamide (3f), which was selected for further evaluation, has an ID50 value of 0.16 mg/kg po and is 130 times more potent than disodium cromoglycate (DSCG) on intravenous administration.

Animals↗
PubMed1984

Synthesis of 5-aryl-2H-tetrazoles, 5-aryl-2H-tetrazole-2-acetic acids, and [(4-phenyl-5-aryl-4H-1,2,4-triazol-3-yl)thio]acetic acids as possible superoxide scavengers and antiinflammatory agents.

A series of 5-aryl-2H-tetrazoles, 5-aryl-2H-tetrazole-2-acetic acids, and [(4-phenyl-5-aryl-4H-1,2,4-triazol-3-yl)thio]acetic acids were synthesized and tested in vitro for superoxide scavenging activity, in vivo in the carrageenan-induced rat paw edema assay, and in the reverse passive Arthus reaction. The hydroxy-substituted compounds were effective as in vitro scavengers of superoxide but were not effective as in vivo antiinflammatory agents.

Acetates↗
PubMed1993

Pharmacological profile of a highly potent and long-acting angiotensin II receptor antagonist, 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4- yl]methyl]-1H-benzimidazole-7-carboxylic acid (CV-11974), and its prodrug, (+/-)-1-(cyclohexyloxycarbonyloxy)-ethyl 2-ethoxy-1-[[2'-(1H-tetrazol-5- yl)biphenyl-4-yl]methyl]-1H-benzimidazole-7-carboxylate (TCV-116).

The angiotensin II (AII) antagonistic action of 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl-1H-benzi mid azole-7 - carboxylic acid (CV-11974) was examined in in vitro assay systems, including AII receptor binding assay using membrane fractions of bovine adrenal cortex or rabbit aorta and AII-induced contraction assay using rabbit aortic strips, and CV-11974 and its prodrug, (+/-)1-(cyclohexyloxycarbonyloxy)ethyl 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H- benzimidazole-7-carboxylate (TCV-116), were examined in an in vivo system of AII-induced pressor response in conscious rats. DuP 753 or EXP3174 (the main active metabolite of DuP 753) was used as the reference compound. CV-11974 inhibited the binding of [125I] AII to the bovine adrenal cortical membrane and rabbit aortic membrane with IC50 values of 1.12 x 10(-7) and 2.86 x 10(-8) M, respectively. Similar results were obtained with EXP3174. CV-11974 interacted with AII in these membrane fractions with subtype 1 receptor in a competitive manner. CV-11974 at 10(-5) M did not affect the binding of [125I]AII to subtype 2 (AT2) receptor in bovine cerebellum. CV-11974 selectively inhibited the AII-induced contraction of rabbit aortic strips in a noncompetitive manner (pD' 2, 9.97); it had no effects on the contraction induced by norepinephrine, KCl, serotonin, prostaglandin F2 alpha or endothelin. EXP3174 showed a pD'2 value of 8.95 for the AII-induced contraction. CV-11974 given intravenously and TCV-116 given orally inhibited the AII-induced pressor response in rats with ID50 values of 0.033 mg/kg and 0.069 mg/kg, respectively. These effects of CV-11974 and TCV-116 were 12 and 48 times more potent than those of EXP3174 and DuP 753, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex↗
PubMed2006

5-(pyrrolidin-2-yl)-1H-tetrazole and 5-[(pyrrolidin-2-yl)methyl]-1H-tetrazole: proline surrogates with increased potential in asymmetric catalysis.

Catalytic enantioselective methodology has dramatically been enriched by the re-discovery of the simple amino acid proline as a chiral catalyst in the year 2000. Although no catalyst offers such a simple and broad access to quite complex reaction products, as does proline, its synthetic potential is not unrestricted, what is especially connected to its poor solubility in organic media. Exchange of the carboxylic moiety by a tetrazole unit leads to proline surrogates, that by far outperform proline with respect to yield, enantioselectivity, reaction time, substrate and solvent scope, catalyst loading, and stoichiometry of the compounds used in excess. These factors are discussed and critically compared with selected representative proline-catalyzed reactions.

Catalysis↗
PubMed1999

Interpenetrated and Noninterpenetrated Three-Dimensional Networks in the Polymeric Species Ag(tta) and 2 Ag(tta) small middle dotAgNO(3) (tta=tetrazolate): The First Examples of the µ(4)-eta(1):eta(1):eta(1):eta(1) Bonding Mode for Tetrazolate.

A twofold interpenetrated neutral three-dimensional network with rectangular channels (left) and a noninterpenetrated three-dimensional cationic framework (right) are the stuctural motifs observed in the simple salt Ag(tta) and in the double salt 2 Ag(tta) small middle dotAgNO(3), respectively. These compounds exhibit the first examples of the µ(4)-eta(1):eta(1):eta(1):eta(1) bonding mode for tetrazolate (tta).

Journal Article↗
PubMed2004

Synthesis of fused tetrazole derivatives via a tandem cycloaddition and N-allylation reaction and parallel synthesis of fused tetrazole amines.

A method for the synthesis of novel fused tricyclic tetrazoles from allylic bromides generated by the recently discovered DiazAll reaction has been developed. This new tandem reaction comprises a cycloaddition between a nitrile and (TMS)N(3) followed by an intramolecular N-allylation. The variation of functionalities in the benzene moiety was well-tolerated, and only a moderate difference in yield and degree of purity was noticed. An exo-methylene group in these new compounds permitted further derivatization. Structural resemblance with substances which possess important pharmacological properties motivated the synthesis of a series of ketones and a small library of amines.

Journal Article↗
PubMed1992

Modification of the distal histidyl imidazole in myoglobin to N-tetrazole-substituted imidazole and its effects on the heme environmental structure and ligand binding properties.

The mechanism of N-tetrazole ring formation at the distal histidyl imidazole of sperm whale myoglobin (Mb) has been studied by nitrogen-15 (15N) NMR spectroscopy by utilizing 15N-labeled cyanogen bromide (BrCN) and azide ion (N3-). The 15N-NMR spectrum of BrC15N-modified Mb + N3- afforded two hyperfine-shifted 15N resonances, both of which are identical with the resonance positions of two of the three 15N resonances for BrCN-modified Mb + 15NN2-. This unusual spectral feature is due to the formation of the N-tetrazole ring attached to the distal histidyl imidazole and the scrambling of the labeled nitrogen originated from N3- or BrCN over the tetrazole ring upon coordination to the ferric heme iron. The ferric iron-bound N-tetrazole ring comes off upon reduction to the ferrous state, and the stable CO complex of tetrazole-modified Mb (tetrazole-Mb) is formed. Electronic absorption and 1H-NMR spectra of deoxy and carbonmonoxy forms of tetrazole-Mb are slightly altered from those of native Mb by the modification, while the most significant effect is exerted on the C-O stretching frequency of iron-bound CO. The C-O stretching band for tetrazole-MbCO is observed at 1966 cm-1 in contrast to 1945 cm-1 for native MbCO, suggesting that the geometry of iron-bound CO in tetrazole-Mb is relatively upright which is characteristic of the "open" conformer. This result corresponds to the 15-fold increase of the CO association rate constant by the N-tetrazole modification of the distal His. The oxy form of tetrazole-Mb is readily autoxidized to its ferric state, indicating that hydrogen bonding between the distal His and iron-bound oxygen is essential for stable O2 binding to the heme iron.

Animals↗
PubMed2005

Effect of heteroatom insertion at the side chain of 5-alkyl-1H-tetrazoles on their properties as catalysts for ester hydrolysis at neutral pH.

[reaction: see text] Herein we introduce tetrazole and its suitably designed derivatives as powerful ester-cleaving reagents. By first performing a detailed ab initio computational study, we found that, in the side chain of 5-alkyl-1H-tetrazoles, introduction of a heteroatom (e.g., N, O, or S at the alpha-position of the tetrazole ring) raises the charge on the tetrazole nucleus significantly. All calculations have been performed using restricted Hartree-Fock (RHF) and hybrid ab initio/DFT (B3LYP) methods employing 6-31G* and 6-31+G* basis sets. To estimate the nucleophilicity of these reagents, the charges on conjugate bases of various tetrazole derivatives have been calculated using natural population (NBO) analysis in gas phase and in water. Free energy of protonation (fep) of the 1H-tetrazole derivatives (1-7), free energy of solvation, deltaG(aq), and the corresponding pKa values have been calculated by self-consistent reaction field (SCRF) methods applying the polarized continuum model (PCM). Since the calculation indicates that incorporation of heteroatom leads to enhanced nucleophilicity in their deprotonated anionic tetrazole forms, a series of 5-substituted 1H-tetrazole derivatives have been synthesized. These compounds indeed catalyze the hydrolysis of p-nitrophenyl diphenyl phosphate (PNPDPP) and p-nitrophenyl hexanoate (PNPH) efficiently in cationic cetyl trimethylammonium bromide (CTABr) micelles at pH 7.0 and 25 degrees C. The pseudo-first-order rate constants (k(obs)) were determined for each catalyst against both substrates. The experimental and theoretical results show that, to achieve better k(obs) values for the cleavage of PNPDPP and PNPH under micellar conditions, charge on the N- atom (nucleophile) of conjugate base is important. Replacing the alpha-CH2 in alkyl substituent with S (3), NH (4), or O (5) enhances the accumulation of charge on N- in conjugate bases of tetrazoles and subsequently increases their intrinsic nucleophilic reactivity toward hydrolytic reactions. Significantly large rate enhancements were observed for the cleavage of PNPDPP and PNPH at pH 7.0 in the presence of catalytic system 5/CTABr over background (only CTABr). Tetrazole 4 (alpha-isomer) showed 4-5-fold superior reactivity over 6 (beta-isomer) under identical conditions. Natural charges obtained from NBO analysis (B3LYP/6-31+G*) are -0.94 and -0.852 on N- in the conjugate bases of 4 and 6, respectively. This also predicts that 4 is a better nucleophile than 6. All the newly synthesized tetrazole derivatives in micellar media display true catalytic properties by cleaving several fold excess of substrates.

Catalysis↗