Application of mass spectrometry to the study of prototropic equilibria in 5-substituted tetrazoles in the gas phase; experimental evidence and theoretical considerations

Rażyńska, Anna; Tempczyk, Anna; Maliński, Edmund; Szafranek, Janusz; Grzonka, Zbigniew; Hermann, Péter

doi:10.1039/p29830000379

Cited by 42 publications

(18 citation statements)

References 2 publications

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“…In addition, tetrazole compounds have a significant role in medicinal chemical research [4]. In the gas phase, experimental results provide information about the existence of two tautomeric forms for tetrazole and its derivatives [5][6][7]. On the other hand, theoretical calculations have shown that, in the gas phase, the 2H continues to be the lowest energy tautomer on the semiempirical, [8] ab initio HF, [9,10] and DFT levels [11].…”

Section: Introductionmentioning

confidence: 99%

Density functional theory study of intermolecular interactions of cyclic tetrazole dimers

Chermahini

Ghaedi²,

Teimouri³

et al. 2008

Journal of Molecular Structure: THEOCHEM

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Section: Introductionmentioning

confidence: 99%

Density functional theory study of intermolecular interactions of cyclic tetrazole dimers

Chermahini

Ghaedi²,

Teimouri³

et al. 2008

Journal of Molecular Structure: THEOCHEM

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“…[20][21][22] On the other hand, in solution, 1H-and 2H-tautomers coexist, and the relative proportion of the more polar 1H-form increases with increasing solvent polarity. 23,24 In the gas phase, the existence of 1H-tetrazole has been suggested by microwave spectroscopy, 25 but this has not been confirmed by photoelectron spectroscopy 26 or mass spectrometry 27 studies.…”

Section: Introductionmentioning

confidence: 99%

Tautomeric equilibrium and hydrogen shifts in tetrazole and triazoles: Focal-point analysis and ab initio limit

Balabin

2009

The Journal of Chemical Physics

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High-level ab initio electronic structure calculations, including extrapolations to the complete basis set (CBS) limit, were performed, and highly precise relative energies of five-member N-heterocycles were determined. Nitrogen-containing heterocycles studied included tautomers of tetrazole (CH(2)N(4)) and triazoles (C(2)H(3)N(3)). Valence focal-point analysis of 1H-tetrazole, 2H-tetrazole, 5H-tetrazole, 1H-1,2,3-triazole, 2H-1,2,3-triazole, 1H-1,2,4-triazole, and 4H-1,2,4-triazole and a number of transition state (TS) calculations were performed, using energy values determined by CCSD(T)/aug-cc-pVTZ, MP3/aug-cc-pVQZ, and MP2/aug-cc-pV5Z. An accuracy of 0.10-0.25 kcal mol(-1) (35-87 cm(-1)) was obtained for comparison of tautomer energy differences. Relative CCSD(T)/CBS energies of 2.07, 3.98, and 6.25 kcal mol(-1) for 1H-tetrazole, 1H-1,2,3-triazole, and 4H-1,2,4-triazole, respectively, were calculated. Use of electron correlation methods resulted in markedly different convergence behaviors for triazole and tetrazole tautomers. Similarly, differences in convergence were observed for TSs with respect to corresponding minima structures. It was confirmed that the MP2 method predicts an acyclic structure for 5H-tetrazole. The same was not observed for the corresponding TS geometry. Comparison with density functional theory (B3LYP) and model chemistry methods (CBS-4M and CBS-QB3) is reported.

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“…2). Tetrazolic acids and especially tetrazolate anions have high capacity for hydrogen bond formation in the interaction with other molecules (Rażyńska et al, 1983). Hansch and Leo reported that tetrazolate ions are almost 10 times more lipophilic than the corresponding carboxylic anions (1995).…”

Section: Introductionmentioning

confidence: 99%

Oxytocin analogues with amide groups substituted by tetrazole groups in position 4, 5 or 9.

Manturewicz

Grzonka²,

Borovičková³

et al. 2007

Acta Biochim Pol

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Eleven oxytocin analogues substituted in position 4, 5 or 9 by tetrazole analogues of amino acids were prepared using solid-phase peptide synthesis method and tested for rat uterotonic in vitro and pressor activities, as well as for their affinity to human oxytocin receptor. The tetrazolic group has been used as a bioisosteric substitution of carboxylic, ester or amide groups in structure-activity relationship studies of biologically active compounds. Replacement of the amide groups of Gln(4) and Asn(5) in oxytocin by tetrazole analogues of aspartic, glutamic and alpha-aminoadipic acids containing the tetrazole moiety in the side chains leads to analogues with decreased biological activities. Oxytocin analogues in which the glycine amide residue in position 9 was substituted by tetrazole analogues of glycine had diminished activities as well. The analysis of differences in rat uterotonic activity and in the affinity to human oxytocin receptors of analogues containing either an acidic 5-substituted tetrazolic group or a neutral 1,5- or 2,5-tetrazole nucleus makes it possible to draw some new conclusions concerning the role of the amide group of amino acids in positions 4, 5 and 9 of oxytocin for its activity. The data suggest that the interaction of the side chain of Gln(4) with the oxytocin receptor is influenced mainly by electronic effects and the hydrogen bonding capacity of the amide group. Steric effects of the side chain are minor. Substitution of Asn(5) by its tetrazole derivative gave an analogue of very low activity. The result suggests that in the interaction between the amide group of Asn(5) and the binding sites of oxytocic receptor hydrogen bonds are of less importance than the spatial requirements for this group.

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Application of mass spectrometry to the study of prototropic equilibria in 5-substituted tetrazoles in the gas phase; experimental evidence and theoretical considerations

Cited by 42 publications

References 2 publications

Density functional theory study of intermolecular interactions of cyclic tetrazole dimers

Density functional theory study of intermolecular interactions of cyclic tetrazole dimers

Tautomeric equilibrium and hydrogen shifts in tetrazole and triazoles: Focal-point analysis and ab initio limit

Oxytocin analogues with amide groups substituted by tetrazole groups in position 4, 5 or 9.

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