Recent Developments in Tetrazole Chemistry. A Review

Wittenberger, Steven J.

doi:10.1080/00304949409458050

Cited by 281 publications

(112 citation statements)

References 83 publications

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“…4 It has been held that 5-substituted-1H-tetrazoles (RCN 4 H) may serve as a nonclassical isostere for the carboxylic acid moiety (RCO 2 H) in biologically active molecules. 4,[8][9][10][11][12][13] The term "nonclassical isosterism" (used interchangeably with the term "bioisosterism") refers to the concept in which functional groups that have similar physicochemical properties may be interchangeable, resulting in similar biological properties. In fact, the number of patent claims and publications related to medicinal uses of tetrazoles continues to grow rapidly.…”

Section: Introductionmentioning

confidence: 99%

Photochemistry and Vibrational Spectra of Matrix-Isolated 5-Ethoxy-1-Phenyl-1H-Tetrazole

et al. 2007

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A combined matrix isolation FT-IR and theoretical DFT(B3LYP)/6-311++G(d,p) study of the molecular structure and photochemistry of 5-ethoxy-1-phenyl-1H-tetrazole (5EPT) was performed. A new method of synthesis of the compound is described. Calculations show three minima, very close in energy and separated by low-energy barriers (less than 4 kJ mol -1 ), in the ground-state potential energy profile of the molecule. The method of matrix isolation enabled the reduction of the number of populated conformational states in the experiment at low temperature due to the effect known as conformational cooling. As a result, the spectrum of the as-deposited matrix of 5EPT closely matches that of the most stable conformer predicted theoretically, pointing to the existence of only this conformer in the low-temperature matrixes. In this structure, the dihedral angle between the two rings, phenyl and tetrazole, is ca. 30°, whereas the ethyl group stays nearly in the plane of the tetrazole ring and is as far as possible from the phenyl group. In situ UV irradiation (λ > 235 nm) of the matrix-isolated 5EPT induced unimolecular decomposition, which led mainly to production of ethylcyanate and phenylazide, this later compound further reacting to yield, as final product, 1-aza-1,2,4,6-cycloheptatetraene. Anti-aromatic 3-ethoxy-1-phenyl-1H-diazirene was also observed experimentally as minor photoproduct, resulting from direct extrusion of molecular nitrogen from 5EPT. This species has not been described before and is now characterized by infrared spectroscopy for the first time.

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Section: Introductionmentioning

confidence: 99%

Photochemistry and Vibrational Spectra of Matrix-Isolated 5-Ethoxy-1-Phenyl-1H-Tetrazole

et al. 2007

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“…[22][23][24] Being an analog and metabolically stable substitute of a carboxyl group, the tetrazole ring is extensively used in molecular design and in the synthesis of modied amino acids and peptidomimetics. 22,25 This area of chemistry has strong impact since the last two decades emphasizing on the popular synthesis and applications of tetrazoles.…”

Section: 12mentioning

confidence: 99%

N,N-Dimethylpyridin-4-amine (DMAP) based ionic liquids: evaluation of physical properties via molecular dynamics simulations and application as a catalyst for Fisher indole and 1H-tetrazole synthesis

et al. 2017

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The last few decades have seen a rapid increase in the use of ionic liquids (ILs) as a green alternative to traditional solvents in organic synthesis. The use of ILs as catalysts has also increased in recent years.Herein we the report synthesis of new N,N-dimethylpyridin-4-amine (DMAP) based ionic liquids (ILs) as new and efficient catalysts for the facile synthesis of indoles (via Fischer indole synthesis), and 1H-tetrazoles (via click chemistry). The method is environmentally friendly, requiring only minimum catalyst loading (0.2 equiv. for Fischer indole synthesis). In the case of 1H-tetrazole formation (via click chemistry), the reaction was carried out under a solvent free environment. Moreover, thermal studies (TGA, DTG and DSC) of DMAP-ILs (2, 3) have also been carried out to elicit their stability for temperature dependent reactions. Application of molecular dynamics simulations provided valuable insights into the structural and transport properties of these ionic liquids. An MP2 method was applied to evaluate the stability of the compound via binding energy calculations.

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“…as an oxidant. This reaction is performed under ambient conditions and proceeds through C À C bond cleavage.Keywords: alcohols; azides; copper; regioselectivity; tetrazoles Metal-mediated transformations are useful and indispensable strategies for C À C and C À heteroatom bond forming reactions in organic synthesis.[1] In addition, C À N bond forming strategies are not only challenging but have a great impetus as they provide avenues for the synthesis of biologically active and therapeutically useful heterocycles.[2] Among the heterocyles, tetrazole and its derivatives form a vital class of nitrogencontaining molecules [3] due to their well-known biological activities [4] as well as vast applications in pharmaceuticals [5a] and material sciences.[5c] Traditionally, 1,5-disubstituted tetrazoles are prepared by (i) the reaction of nitriles with alkyl or aromatic azides, [6] (ii) the reaction of ketones [7] or oximes [8] with sodium azide or hydrazoic acid and (iii) the reaction of amides [9] with sodium azide in the presence of PCl 5 or triflic anhydride, etc. Gold-catalyzed synthesis of tetrazoles using alkynes has been recently reported by Echavarren and Gaydou.…”

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confidence: 99%

Copper‐Catalyzed Oxidative Transformation of Secondary Alcohols to 1,5‐Disubstituted Tetrazoles

2014

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A mild and convenient oxidative transformation of secondary alcohols to 1,5-disubstituted tetrazoles is uncovered by employing trimethylsilyl azide (TMSN 3 ) as a nitrogen source in the presence of a catalytic amount of copper(II) perchlorate hexaA C H T U N G T R E N N U N G hydrate [CuA C H T U N G T R E N N U N G (ClO 4 ) 2 . 6 H 2 O] (5 mol%) and 2,3-dichloro-5,6-dicyano-para-benzoquinone (DDQ) (1.2 equiv.) as an oxidant. This reaction is performed under ambient conditions and proceeds through C À C bond cleavage.Keywords: alcohols; azides; copper; regioselectivity; tetrazoles Metal-mediated transformations are useful and indispensable strategies for C À C and C À heteroatom bond forming reactions in organic synthesis.[1] In addition, C À N bond forming strategies are not only challenging but have a great impetus as they provide avenues for the synthesis of biologically active and therapeutically useful heterocycles.[2] Among the heterocyles, tetrazole and its derivatives form a vital class of nitrogencontaining molecules [3] due to their well-known biological activities [4] as well as vast applications in pharmaceuticals [5a] and material sciences.[5c] Traditionally, 1,5-disubstituted tetrazoles are prepared by (i) the reaction of nitriles with alkyl or aromatic azides, [6] (ii) the reaction of ketones [7] or oximes [8] with sodium azide or hydrazoic acid and (iii) the reaction of amides [9] with sodium azide in the presence of PCl 5 or triflic anhydride, etc. Gold-catalyzed synthesis of tetrazoles using alkynes has been recently reported by Echavarren and Gaydou.[10] Recently, Jiao and coworkers developed a method to synthesize 1,5-disubstituted tetrazoles using 1,3-diphenylpropene, [11] which requires precursors that are relatively difficult to access and require multistep synthetic sequences. [12] Additionally, this protocol uses a large excess of TMSN 3 (5.5 equiv.), harsh reaction conditions (80 8C), and requires additives and long reaction times.In continuation of our investigations on the utility of azides in C À N bond forming reactions, especially leading to the formation of nitriles, [13] and in the light of Jiaos work, [11] we anticipated that secondary alcohols in the presence of a Cu salt, an excess of trimethylsilyl azide (TMSN 3 ) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), may form the corresponding azide in situ and then undergo a rearrangement to form the nitrilium ion, which may be trapped in a [2+3] cycloaddition fashion by the excess azide present in the reaction medium (Scheme 1). Herein, we present our detailed investigation for converting secondary alcohols directly to 1,5-disubstituted tetrazoles in a one-pot fashion under ambient conditions. We began our study by investigating the Cu-catalyzed reaction of (E)-1,3-diphenylprop-2-en-1-ol 1a with TMSN 3 as a nitrogen source and DDQ as an oxidant (Table 1). Preliminary studies were carried out using Cu(I) and Cu(II) salts such as CuCl, CuBr, CuI, These are not the final page numbers! ÞÞ COMMUNICATIONS

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Recent Developments in Tetrazole Chemistry. A Review

Cited by 281 publications

References 83 publications

Photochemistry and Vibrational Spectra of Matrix-Isolated 5-Ethoxy-1-Phenyl-1H-Tetrazole

Photochemistry and Vibrational Spectra of Matrix-Isolated 5-Ethoxy-1-Phenyl-1H-Tetrazole

N,N-Dimethylpyridin-4-amine (DMAP) based ionic liquids: evaluation of physical properties via molecular dynamics simulations and application as a catalyst for Fisher indole and 1H-tetrazole synthesis

Copper‐Catalyzed Oxidative Transformation of Secondary Alcohols to 1,5‐Disubstituted Tetrazoles

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