Theoretical study of the azido-tetrazole isomerization

Burke, Luke A.; Elguero, José; Leroy, Georges; Sana, M.

doi:10.1021/ja00423a009

Cited by 90 publications

(36 citation statements)

References 4 publications

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“…11 Another example demonstrating the efficiency of the method for a high-dimensional chemical system is the RHFr4-31G computation of the SP of the isomerization path from azidoazomethine to 1 H-tetrazole. 35 …”

Section: 10mentioning

confidence: 99%

Searching for saddle points of potential energy surfaces by following a reduced gradient

et al. 1998

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The old coordinate driving procedure to find transition structures in chemical systems is revisited. The well‐known gradient criterion, ∇E(x)=0, which defines the stationary points of the potential energy surface (PES), is reduced by one equation corresponding to one search direction. In this manner, abstract curves can be defined connecting stationary points of the PES. Starting at a given minimum, one follows a well‐selected coordinate to reach the saddle of interest. Usually, but not necessarily, this coordinate will be related to the reaction progress. The method, called reduced gradient following (RGF), locally has an explicit analytical definition. We present a predictor–corrector method for tracing such curves. RGF uses the gradient and the Hessian matrix or updates of the latter at every curve point. For the purpose of testing a whole surface, the six‐dimensional PES of formaldehyde, H2CO, was explored by RGF using the restricted Hartree–Fock (RHF) method and the STO‐3G basis set. Forty‐nine minima and saddle points of different indices were found. At least seven stationary points representing bonded structures were detected in addition to those located using another search algorithm on the same level of theory. Further examples are the localization of the saddle for the HCN⇌CNH isomerization (used for steplength tests) and for the ring closure of azidoazomethine to 1H‐tetrazole. The results show that following the reduced gradient may represent a serious alternative to other methods used to locate saddle points in quantum chemistry. © 1998 John Wiley & Sons, Inc. J Comput Chem 19: 1087–1100, 1998

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Section: 10mentioning

confidence: 99%

Searching for saddle points of potential energy surfaces by following a reduced gradient

et al. 1998

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“…The cyclization of u-diazoimines 1 may occur via HeteroEkttroCyclic (HEC) mechanism as well (16)(17)(18).…”

Section: Resultsmentioning

confidence: 99%

Study of Polyfunctional Diazo Compounds Reactivity in Heterocyclization by the Method of Intramolecular Competitive Reactions

Бакулев¹,

Morzherin²,

Dankova³

et al. 1993

Bulletin des Soc Chimique

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New method for the study of reactivity of highly reactive compounds was proposed and applied to determine the effect of substituents in adiazoacetamidines, and -imidales. The introduction of electronreleasing groups to the nitrogen atom of the amidine, and imidate functions was shown to increase the reactivity of the substances studied. The resultsobtained are in good agreement with the heteroelectrocyclic mechanism suggested for the cyclization of these compounds. INTRODUCTIONDiazo compounds 1-3. bearing C=N-(1). C=S-(2) and C=Sa (3) bonds at the a-position are with a few exceptions very unstable and undergo ringclosure into heterocycles 4-6 under the conditions of their generation. These substances are intermediates in the synthesis of imino(thio, se1eno)ketenes and carbenes, in the preparation of 1.2,3-triazoles 4. thia(se1ena)diazoles 5(6) (1-3) and in rearrangements of I .2,3-triazoles

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“…De telles isomCrisations peuvent s'envisager soit comme des rkactions Clectrocycliques (5) soit comme des cycloadditions dipolaires-1,5 (6) soit encore comme des cycloadditions-1,3 au cours de I'attaque d'un azide sur une imine (7). Un calcul effectuC par la mkthode LCAO-SCF sur le modble le plus simple (R' = R2 = H, cf.…”

Section: Facteurs Structurauxunclassified

“…tion s'apparente plutat au rCactif (I.A.) (quoique plus polarid) qu'au produit (T) (7). Ce rCsultat thCorique s'accorde aussi bien avec le postulat de Hammond (prkdiction d'ktats de transition "reactant-like" pour les systbmes rkactifs) qu'avec de nombreux rksultats de la littkrature (ainsi qu'avec nos observations) qui montrent en g6-nCral une plus grande stabilitC pour la forme tktrazole (7,8).…”

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Réactivité du nucléophile azoture vis-à-vis de cations hétérocycliques aromatiques. VIII. Réarrangement de β-tétrazolo-trans-benzalacétophénones

Cherton¹,

Bazinet²,

Bolze³

et al. 1985

Can. J. Chem.

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β-Tetrazolyl-trans-benzalacetophenones (T) isomerize upon heating into the corresponding azido-azomethines (A). These non-isolable products undergo various transformations depending on the reaction conditions. With organic bases such as triphenylphosphine or pyridine, their interception can occur. In aromatic solvents, a rearrangement involving loss of nitrogen leads to five-membered diazoted heterocycles:-N-benzoyl imidazoles and pyrazoles, via intermediate diazirines and oxazepines. Protic solvents have been found to facilitate the isomerisation of tetrazoles into azidoazomethines. Solvolysis of the azidooxazine and in some cases of the oxazinium species resulting from the equilibrium and reaction:[Formula: see text]are then observed.

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Theoretical study of the azido-tetrazole isomerization

Cited by 90 publications

References 4 publications

Searching for saddle points of potential energy surfaces by following a reduced gradient

Searching for saddle points of potential energy surfaces by following a reduced gradient

Study of Polyfunctional Diazo Compounds Reactivity in Heterocyclization by the Method of Intramolecular Competitive Reactions

Réactivité du nucléophile azoture vis-à-vis de cations hétérocycliques aromatiques. VIII. Réarrangement de β-tétrazolo-trans-benzalacétophénones

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