Rearrangement of (1,2,4-Triazol-4-yl)ethanols to (1,2,4-Triazol-1-yl)ethanols

Bentley, T. William; Howle, Lisa M.; Wareham, Peter J.; Jones, Ray V. H.

doi:10.1016/s0040-4020(01)80464-6

Cited by 13 publications

(6 citation statements)

References 9 publications

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“…The proposed mechanism resembles one reported by Bentley et al for the rearrangement of 4-(β-hydroxyethyl)-1,2,4-triazole [2] and finds further support in the work by other groups. [3] The mechanism outlined in Scheme 2 accounts for the formation of the cross-over products 4 and 5.…”

Section: Resultssupporting

confidence: 86%

Thermal Rearrangement of 4-Alkyl-4H-1,2,4-triazoles to 1-Alkyl-1H-1,2,4-triazoles − A Study of the Mechanism by Cross-over Experiments

Gautun

Carlsen

2000

Eur. J. Org. Chem.

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Section: Resultssupporting

confidence: 86%

Thermal Rearrangement of 4-Alkyl-4H-1,2,4-triazoles to 1-Alkyl-1H-1,2,4-triazoles − A Study of the Mechanism by Cross-over Experiments

Gautun

Carlsen

2000

Eur. J. Org. Chem.

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“…Quantum-chemical calculations by the ab initio method on the RHF/6-31G* basis [14] for the isomeric ethyl triazolylbutyrates showed a higher stability (by 25.14 kJ/mol) for 4-(1,2,4-triazol-1-yl)butyrate 3b in comparison with 4-(1,2,4-triazol-4-yl)butyrate 3c. According to the data obtained experimentally the stability of 1,1-diphenyl-2-(1,2,4-triazol-1-yl)ethanol is greater by 17.45 kJ/mol than that of 1,1-diphenyl-2-(1,2,4-triazol-4-yl)ethanol [13]. No wonder that under distillation conditions at temperatures greater than 100 o C the 1-substitution product 3b is distilled preferentially from the mixture of isomers.…”

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confidence: 83%

“…As it is known, products of 1-substitution are mainly formed on alkylation of 1,2,4-triazole as being the thermodynamically most stable [13]. Quantum-chemical calculations by the ab initio method on the RHF/6-31G* basis [14] for the isomeric ethyl triazolylbutyrates showed a higher stability (by 25.14 kJ/mol) for 4-(1,2,4-triazol-1-yl)butyrate 3b in comparison with 4-(1,2,4-triazol-4-yl)butyrate 3c.…”

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confidence: 99%

Preparation of 4-(azol-1-yl)butyric acids by the interaction of azoles with γ-butyrolactone

Alekseenko

Попков

2007

Chem Heterocycl Compd

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The interaction of salts of imidazole, 1,2,4-triazole, benzimidazole, and 2-benzylbenzimidazole with γ-butyrolactone has been studied. Ab initio quantum-chemical calculations showed a preference for N-alkylation on interaction of azolates with γ-butyrolactone.It is known that many azolylalkanoic acids possess high biological activity, for example 8-(imidazol-1-yl)octanoic acid displays antiaggregation properties [1,2]. 4-(Imidazol-1-yl)butyric acid is a GABA agonist [3]. High immunomodulating activity is displayed by estimulocel, 3-(benzimidazol-2-yl)propionic acid [4]. ω-Azolylalkanoic acids serve as starting materials for the synthesis of antiaggregation preparations [5].The preparation of azolylalkanoic acids by the interaction of azolates and esters of ω-haloalkanoic acids with subsequent hydrolysis has been known for a long time [1-3, 6]. The interaction of heterocycles with γ-butyrolactone is comparatively seldom used for their N-alkylation [7][8][9][10][11]. The direction of cleavage the lactone at the acyl-oxygen or alkyl-oxygen bond is determined by the acid-base properties of the azole. Preference of fission of the alkyl-oxygen bond is aided by the use of the azolate, more nucleophilic than the azole, or an increase in temperature [7]. Products of N-alkylation of heterocycles are obtained in this way, viz. imidazol-1-yl-, pyrrol-1-yl-, and indol-1-ylbutyric acids [8][9][10].The condensation of imidazole, 1,2-4-triazole, benzimidazole, and 2-benzylbenzimidazole with γ-butyrolactone has been studied in the present work.The interaction of imidazole with γ-butyrolactone in the presence of sodium sulfate catalyzed by concentrated sulfuric acid at 180 o C, by analogy with the procedure given in a patent [12], led to significant resinification of the reaction mixture. The imidazolide of 4-(imidazol-1-yl)butyric acid was isolated in insignificant yield (16%) from the reaction mixture by high vacuum distillation, on hydrolysis of which the corresponding acid was obtained in 15% yield. On interacting the sodium salt of imidazole with a small excess of γ-butyrolactone at 120 o C in the absence of solvent 4-(imidazol-1-yl)butyric acid (2a) is formed in 50% yield. The use of the potassium salt of imidazole did not lead to an increase in yield. On carrying out the interaction in a boiling mixture of xylenes the yield of acid 2a was increased to 67%. 4-(Benzimidazol-1-yl)-and 4-(2-benzylbenzimidazol-1-yl)butyric acids (2d,e) were obtained analogously by the interaction of the sodium salts of benzimidazole and 2-benzylbenzimidazole with γ-butyrolactone at 180°C in the absence of solvent in yields of 52 and 42% respectively (Scheme 1). __________________________________________________________________________________________ D. Mendeleyev

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“…However, we noticed that the 4H-triazole isomer 2b undergoes a rearrangement to give the corresponding 1H-triazole derivative 2a, as described by Bentley et al for 1,2,4-triazol-4-ylethanols. 13 The mechanism proposed for such a rearrangement involves the electron releasing effect of the 7-hydroxy group, which by mesomerism, leads to the formation of the triazole anion (Fig. 3).…”

Section: Chemistrymentioning

confidence: 99%