1H, 13C and 15N NMR spectroscopy and tautomerism of nitrobenzotriazoles

Ларина, Л. И.; Milata, Viktor

doi:10.1002/mrc.2366

Cited by 25 publications

(16 citation statements)

References 37 publications

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“…When we undertook this project, the current state of the art in the area of synthesis of regioselectively substituted aminobenzotriazoles was rather underdeveloped. There were only a few papers regarding the synthesis of alkylated 5‐nitrobenzotriazole which was considered to be the precursor for derivatives of 5‐aminobenzotriazole …”

Section: Resultsmentioning

confidence: 99%

“…Their characteristic HN−N=N pattern combined with proton tautomerism results in the existence of two heterocyclic systems with distinct topologies . They are assigned to be of 1H or 2H type which exhibit different spectroscopic, physical, chemical and biological properties. Many 1H ‐ and 2H ‐benzotriazoles have attracted attention because of their application in agriculture, medicine (e. g. drugs Vorozole and Alizapride), and chemical industry .…”

Section: Introductionmentioning

confidence: 99%

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A Modular Synthesis of N‐Benzotriazole Ureas Using Alkylation of 5‐Nitrobenzotriazole

2016

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N‐Alkylations of monosubstituted benzotriazoles yield isomeric products with distinct topology, i. e. 1H‐ or to 2H‐isomers. Therefore, the molecular shape of these compounds varies and this results in distinct biological and physical properties. Herein, a protocol for the simple synthesis of various alkyl‐aminobenzotriazoles using 5‐nitrobenzotriazole is reported. This synthetic approach furnishes 2‐alkyl‐5‐nitro‐2H‐benzotriazoles as major products in most of the attempted cases. All three obtained isomers were separable from each other by standard column chromatography. In addition, three alternative approaches furnishing selectively substituted alkyl‐amino‐1H‐benzotriazoles are described. Finally, a library of sixty‐eight N‐benzotriazoylureas and six N‐benzotriazoylthioureas was synthesized by reactions with either isocyanates (phenyl chloroformate) or isothiocyanates.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Modular Synthesis of N‐Benzotriazole Ureas Using Alkylation of 5‐Nitrobenzotriazole

2016

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“…Establishing the structure of the compounds using nuclear quadrupole spectroscopy 35 Cl and the assignment of signals in the experimental spectra without attracting quantum chemical calculations in many cases quite is difficult. 35 Cl NQR frequencies at 77 K (ν, MHz) and signal-to noise ratio (s/n) in the spectra of chloro-containing 1,2,4-triazoles (1-6) and imidazoles (7)(8)(9)(10)(11)(12).…”

Section: Chlorinated Five-membered Azolesmentioning

confidence: 99%

“…The35 Cl NQR frequencies at 77 K (ν, MHz) and signal-to noise ratio (s/n) in the spectra of chloro-containing 1,2,4-triazoles (1-6) and imidazoles(7)(8)(9)(10)(11)(12).…”

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confidence: 99%

Nuclear Quadrupole Resonance Spectroscopy: Tautomerism and Structure of Functional Azoles

Ларина

2019

Crystals

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The Nuclear Quadrupole Resonance spectroscopy data of functionalized azoles (imidazoles, triazoles and corresponding benzazoles) are reviewed and critically discussed. The possibility of studying the tautomerism of azoles by the NQR method is considered.Crystals 2019, 9, 366 2 of 12 transfer of a chlorine atom between 1-chlorobenzimidazole and benzimidazole in a CCl 4 /CH 3 OH/K 2 CO 3 medium [52,53]. A similar chlorotropic rearrangement was observed in the equilibrium exchange process between 1-chloroindole and 3-chloro-3H-indole, i.e., the fast intermolecular transformations of 1-chloroindole to 3-chloroindole in the related media were detected [53]. The base-promoted intermolecular mechanism rationalizes chlorotropic processes in N-chlorosubstituted azoles. NQR spectroscopy data are missing.X-ray single-crystal analysis of 1,2,4-triazole (Scheme 1) have revealed a crystalline state of the asymmetric 1H(2H)-tautomer (A, C) [54,55]. Quantum-chemical (ab initio) calculations of 1,2,4-triazole tautomers suggest the prevailing of 1H(2H)-1,2,4-triazole in gas phase as compared to 4H-1,2,4-tautomer by~7 kcal/mol [56][57][58][59], that agrees with experimental data [60,61].

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“…A set of proton-carbon couplings for 4(7)nitro-and 5(6)-nitrobenzotriazoles and their methyl derivatives has been measured by Larina and Milata, 246 who studied the tautomerism of these compounds by 1 H, 13 C and 15 N spectroscopy. n J HC couplings (n ¼ 1-3) have been measured and calculated by¸Senyel et al 247 for 3-piperidino-propylamine.…”

Section: Three-bond Couplings To Hydrogenmentioning

confidence: 99%

Applications of spin-spin couplings

Trela¹

1994

Nuclear Magnetic Resonance

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¹H, ¹³C and ¹⁵N NMR spectroscopy and tautomerism of nitrobenzotriazoles

Cited by 25 publications

References 37 publications

A Modular Synthesis of N‐Benzotriazole Ureas Using Alkylation of 5‐Nitrobenzotriazole

A Modular Synthesis of N‐Benzotriazole Ureas Using Alkylation of 5‐Nitrobenzotriazole

Nuclear Quadrupole Resonance Spectroscopy: Tautomerism and Structure of Functional Azoles

Applications of spin-spin couplings

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