Chemistry of tetrazoles

A review on the alkylation and related electrophilic reactions at endocyclic nitrogen atoms in the chemistry of tetrazoles has been published <00H(53)1421>. 

J. Wiley, NY (1967), 1-104 28a)H.Moris-son, Chemistry of Tetrazole Explosive Derivatives , IntSymp Utilization of Pyrot Expl Elements in Space Systs, Tarbes (Fr), Dunod (July 1968) 29) T. Fiechowicz, New Priming... 

Azotetrazoie (or Bis-5,5 -azotetrazole). See in Voi 1, A659-R to A660-L and the following Addnl Refs 1) H. Morisson, Chemistry of Tetrazole Explosives Derivatives , IntSymp on Utilisation Des Elements Pyrotechniques et Expiosifs Dans Les Systemes Spatiaux , Tarbes (Fr), Dunod (1968) translated by M. Blais, US Army ARRADCOM, Dover (1970) [The impact sensy of various bis-5-azotetrazole salts is presented in Table 7, below... 

Advances in the chemistry and technology of tetrazole production achieved by the Russian scientific schools have been presented . The principal lines of development in the medicinal chemistry of tetrazoles up to the 1980s are considered in a review <1980MI151>. The material accumulated in this important field up to the... 

The chemistry of tetrazol derivatives was reviewed by Bensen (192). The simplest and most versatile derivative is 5-aminotetrazol (Vol. Ill, p- 210). It is usually obtained by the method of Stolle and Schick [151] from cyanoguani-dine and sodium azide in an acid medium ... 

Ostrovskii VA, Trifonov RE, Popova EA (2012) Medicinal chemistry of tetrazoles. Russ Chem Bull Int Ed 61 768-780... 

Despite the weak basicity of isoxazoles, complexes of the parent methyl and phenyl derivatives with numerous metal ions such as copper, zinc, cobalt, etc. have been described (79AHC(25) 147). Many transition metal cations form complexes with Imidazoles the coordination number is four to six (70AHC(12)103). The chemistry of pyrazole complexes has been especially well studied and coordination compounds are known with thlazoles and 1,2,4-triazoles. Tetrazole anions also form good ligands for heavy metals (77AHC(21)323). 

The synthesis and chemistry of pyrazoles, imidazoles, and 1,2,3-triazoles were actively pursued in 2006. A review on the cross-coupling reactions on azoles with two and more heteroatoms for pyrazoles and imidazoles has been published <06EJO3283>. Publications relating to 1,2,4-triazole and tetrazole chemistry were not particularly well represented this year. The solid-phase and combinatorial chemistry of these ring systems have not been investigated compared to past years. No attempt has been made to incorporate all the exciting chemistry or biological applications that have been published this year. 

Major advancements in the chemistry of pyrazoles, imidazoles, triazoles, tetrazoles, and related fused heterocyclic derivatives continued in 2000. Solid-phase combinatorial chemistry of pyrazoles and benzimidazoles has been particularly active. Synthetic routes to all areas continue to be pursued vigorously with improvements and applications. Notably, metal-promoted and cross-coupling reactions of all classes seemed to be a dominant theme in 2000. Applications of pyrazole-, imidazole-, and 1,2,3-benzotriazole-containing reagents to a wide array of synthetic applications remained active. 

The [3+2] cycloaddition of azides to double and triple bond systems has found considerable interest over the last couple of years. The reaction can either be performed under thermal conditions or by copper(i) catalysis <2001AG(E)2004, 2002AG(E)2596>. In an attempt to broaden the chemistry of such cycloaddition processes, Sharpless et al. reported the generation of tetrazole derivatives 61 by an intramolecular process (Scheme 12). In... 

Another common theme that authors use to establish importance involves environmental impacts. For example, an environmental slant is used in the first sentence of the cyclodextrin article (P3, exercise 6.7), where the study of cyclo-dextrins is justified based on their role in soil remediation. The importance of work that benefits air or water quality and/or promotes green chemistry can also be stressed. Work is also viewed as important if it has cross-disciplinary applications. For example, in the Introduction section of the tetrazole article, the authors stress the importance of tetrazoles in coordination chemistry, medicinal chemistry, and in various materials science applications and point out their role as useful intermediates in the preparation of substituted tetrazoles ... 

The most likely explanation is as outlined in Scheme 3. Following a well-known stereoelectronic effect , wherein addition of nucleophiles to triple bonds places the developing new lone pair trans to the incoming nucleophile, a fast addition of azide ion to the diazonium ion would give the Z-diazoazide (21) which cannot form a pentazole. This is analogous to the stable imidoyl azide of tetrazole chemistry. Rapid loss of N2 from this produces the first N2 evolution. 

The transformation 401 - 406 by Schotten-Baumann benzoylation is a mysterious reaction, the mechanism of which is not obvious. Clearly a change in oxidation level has occurred, but related changes are known, and this is an incompletely understood aspect of the chemistry of for-mazans (393) and the corresponding tetrazolium cations. In contrast, the reaction of the salt with p-toluenesulphonyl chloride yields the meso-ionic l,2,3,4-tetrazol-5-imine (411) directly. 

The preparation and chemistry of organic azides have been intensively investigated since about 1960 because of their importance in preparative heterocyclic chemistry and as a source of nitrenes [1]. Many nitrogen-containing heterocycles such as carbazoles, furoxans, azepines, A2-triazolines, triazoles [2], tetrazoles [3], aziridines [4, 5], and azirines have been obtained by either the addition or the decomposition of azides. 

An extensive review of the chemistry of aliphatic and aromatic azides is given by Boyer and Canter [167] and Gray [168]. Organic azides are subject to various reactions such as the Bergmann degradation and the synthesis of peptides, the well known Curtius rearrangement, the Darapsky synthesis of a-aminoacids [169], for synthesis of triazoles [170], tetrazoles ( Schmidt reaction ) [169] and [171] etc. These reactions lie beyond the scope of the present book. 

Reviews of the coordination chemistry of this type of ligand have been published for pyrazoles24 and imidazoles,25 and to a lesser extent for the triazoles26 and tetrazoles.27 Many azole ligands are commercially available or are easily synthesized by a variety of condensation and ring-closure reactions.4-6... 

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