Tetrazole

IC50: Not available.

Tetrazole is the simplest compound belonging to tetrazoles family, a class of synthetic organic heterocyclic compound consists of a 5-member ring of four nitrogen and one carbon atom. Tetrazoles have commonly been believed to have similar properties to carboxylic acids, and therefore make themselves excellent bioisosteres. Moreover, several pharmaceutical agents, for instance, losartan and candesartan (Angiotensin II receptor blockers), are considered as tetrazoles. Tetrazoles are often adopted in medicinal chemistry as a substitute for carboxylic acids because they share very similar proton dissociation properties. [1]

In vitro: The acidity constant of tetrazole was detected and reported as 4.9. Four of the six angiotension II receptor antagonists clinically effective for treating hypertension contained a tetrazole. MTT, dimethyl thiazolyl diphenyl tetrazolium bromide, was regarded as a well-known tetrazole applied to quantify the respiratory activity of live cells. Some tetrazoles could also be used in DNA assays. [2]

In vivo: So far, no in vivo data has been reported.

Clinical trial: So far, no clinical trial has been conducted.

References:
[1]Berner S, Mühlegger K and Seliger H.  Studies on the role of tetrazole in the activation of phosphoramidites. Nucleic Acids Res. 1989 Feb; 17 (3): 853–864
[2]Satchell JF and Smith BJ.  Calculation of aqueous dissociation constants of 1,2,4-triazole and tetrazole: A comparison of solvation modelsy. Phys Chem Chem Phys. 2002; 4: 4314-8.

Two new metal-organic frameworks based on tetrazole-heterocyclic ligands accompanied by in situ ligand formation.[Pubmed:28224149]

Dalton Trans. 2017 Mar 7;46(10):3223-3228.

Based on the same in situ formed ligand, two new MOFs, namely {[Zn2(HL)2].0.5DMF.H2O}n (1) and {[Cd2(HL)2].1.5H2O}n (2) (H3L = 5-[(2H-tetrazol-5-yl)amino]isophthalic acid), have been solvothermally synthesized and structurally characterized by elemental analysis, IR, PXRD, and single-crystal X-ray diffraction. During the self-assembly process, the original ligand H2ATBDC (5-(5-amino-1H-tetrazol-1-yl)-1,3-benzenedicarboxylic acid) undergoes the Dimroth rearrangement to form a new ligand H3L, consequently contributing to the construction of the two new MOFs. Structural analysis reveals that both 1 and 2 possess a three-directional intersecting channel system and pts topology. The major structural difference between them is the metal coordination, which displays four- and six-coordinated modes in 1 and 2, respectively, and results in diverse channels and different stabilities. Moreover, the adsorption properties of 1a (i.e., the desolvated 1) have been studied, and the results show that 1a possesses moderate capability of gas sorption for N2, CO2, and CH4 gases, along with high selectivity ratios of 102 and 20 for CO2/N2 (15 : 85) and CO2/CH4 (50 : 50) at 273 K, respectively.

Tetrazole Derivatives as Promising Anticancer Agents.[Pubmed:28356016]

Anticancer Agents Med Chem. 2018 Feb 7;17(14):1856-1868.

Tetrazole cycle is a promising pharmacophore fragment frequently used in the development of novel drugs. This moiety is a stable, practically non-metabolized bioisosteric analog of carboxylic, cis-amide, and other functional groups. Over recent 10-15 years, various isomeric forms of Tetrazole (NH-unsubstituted, 1H-1- substituted, and 2H-2-substituted Tetrazoles) have been successfully used in the design of promising anticancer drugs. Coordination compounds of transition metals containing Tetrazoles as ligands, semisynthetic tetrazolyl derivatives of natural compounds (biogenic acids, peptides, steroids, combretastatin, etc.), 5-oxo and 5- thioTetrazoles, and some other related compounds have been recognized as promising antineoplastic agents. This review presents a comprehensive analysis of modern approaches to synthesis of these Tetrazole derivatives as well as their biological (anticancer) properties. The most promising structure types of Tetrazoles to be used as anticancer agents have been picked out.

5-(2-Pyridil)-1H-tetrazole complexes with Mo(iv) and W(iv) cyanides.[Pubmed:28271109]

Dalton Trans. 2017 Mar 21;46(12):4030-4037.

The reactions of Tetrazole ligand derived from 2-cyanopyridine with K3Na[Mo(CN)4O2].6H2O and K3Na[W(CN)4O2].6H2O in water-ethanol solution result in isolation of two new complexes with the following formulae: (PPh4)2[Mo(CN)3O(pdt)].2H2O (1) (Hpdt = 5-(2-pyridil)-1H-Tetrazole) and (PPh4)2[W(CN)3O(pdt)].3H2O (2). The complexes were characterized by elemental analysis, single crystal X-ray structure measurements, IR and UV-Vis spectroscopy, cyclic voltammetry measurement as well as thermogravimetric measurement. The X-ray crystal structure measurements indicated the presence of two coordination isomers in a single crystal. The pyridine nitrogen occupies both trans and/or cis position to the M[double bond, length as m-dash]O bond, which is explained by similar pK of pyridine and Tetrazole nitrogen. The DTG measurements indicate the stabilization of Tetrazole upon coordination.

A Novel High-Density Phase and Amorphization of Nitrogen-Rich 1H-Tetrazole (CH2N4) under High Pressure.[Pubmed:28218236]

Sci Rep. 2017 Feb 20;7:39249.

The high-pressure behaviors of nitrogen-rich 1H-Tetrazole (CH2N4) have been investigated by in situ synchrotron X-ray diffraction (XRD) and Raman scattering up to 75 GPa. A first crystalline-to-crystalline phase transition is observed and identified above ~3 GPa with a large volume collapse ( approximately 18% at 4.4 GPa) from phase I to phase II. The new phase II forms a dimer-like structure, belonging to P1 space group. Then, a crystalline-to-amorphous phase transition takes place over a large pressure range of 13.8 to 50 GPa, which is accompanied by an interphase region approaching paracrystalline state. When decompression from 75 GPa to ambient conditions, the final product keeps an irreversible amorphous state. Our ultraviolet (UV) absorption spectrum suggests the final product exhibits an increase in molecular conjugation.