✦ LIBER ✦

NMR Studies of the Equilibria Produced by 6- and 8-Substituted Tetrazolo[1,5-a]pyridines

✍ Scribed by Piotr Cmoch; Lech Stefaniak; Graham A. Webb

Publisher: John Wiley and Sons
Year: 1997
Tongue: English
Weight: 238 KB
Volume: 35
Category: Article
ISSN: 0749-1581
DOI: 10.1002/(sici)1097-458x(199704)35:4<237::aid-omr63>3.0.co;2-l

No coin nor oath required. For personal study only.

✦ Synopsis

1H, 13C and 15N NMR data are reported for nine tetrazoles. Five of these compounds are found to exhibit valence tautomeric equilibrium between the tetrazole and azide forms. The position of this equilibrium at 298 K is found to be dependent on the solvent and the position and nature of the substituent. More polar solvents favour the tetrazole form. Protonation studies on the two forms using TFA as a solvent are reported. The favoured site of protonation is found to be N-4 for the azide form and N-1 for the tetrazole form.

📜 SIMILAR VOLUMES

1H, 13C and 15N NMR and IR studies of ha

1H, 13C and 15N NMR and IR studies of halogen-substituted tetrazolo[1,5-a]pyridines

✍ P. Cmoch; H. Korczak; L. Stefaniak; G. A. Webb 📂 Article 📅 1999 🏛 John Wiley and Sons 🌐 English ⚖ 85 KB 👁 1 views

The tetrazole-azide tautomerization of some halogen-substituted tetrazolo [1,5-a]pyridines was examined by IR spectroscopy at ambient temperature and by 1 H, 13 C and 15 N NMR spectroscopy at various temperatures. The tetrazolopyridines can exhibit equilibrium between the azide and the tetrazole for

Studies with polyfunctionally substitute

Studies with polyfunctionally substituted heteroaromatics: A facile route for the synthesis of polyfunctionally substituted N-aminopyridines, 1,2,4-triazolo[1,5-a]pyridines and isoquinolines

✍ Abdel Haleem Mostafa Hussein 📂 Article 📅 1997 🏛 John Wiley and Sons 🌐 English ⚖ 187 KB 👁 1 views

The reactions of formaldehyde and acetaldehyde with active methylene compounds, followed by reaction with cyanoacetic acid hydrazide 2, afforded N-aminopyridine-2-one derivatives 5a-f. In contrast, the reactions of cyanoacetic acid hydrazide 2 with aliphatic aldehydes and cyanothioacetamide afforded

Conformational analysis of substituted 5

Conformational analysis of substituted 5,6,7,8-tetrahydrodibenzo[a,c]cyclo-octene: comparison of 1H NMR, molecular mechanics and semiempirical methods

✍ Parviz Rashidi-Ranjbar; Jamshid Najafpour; Farideh Piri 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 80 KB

The 6-Mono-and trans-6,7-di-substituted derivatives of 5,6,7,8-tetrahydrodibenzo[a,c]cyclo-octene exist in solution in two different conformations. The experimental DG o values obtained from 1 H NMR spectra are compared with the DE steric and DG values calculated by molecular mechanics and semiempir

Specificity of base substitution mutatio

Specificity of base substitution mutations induced by the dietary carcinogens 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in Salmonella

✍ W.H. Koch; R.W. Wu; T.A. Cebula; J.S. Felton 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 132 KB 👁 1 views

The base pair substitution mutational profiles in-position (CCCrCTC; 96-99% of total). Base substiduced by the heterocyclic amine cooked food muta-tution mutagenesis induced by heterocyclic amines gens PhIP and IQ in Salmonella typhimurium strains related to PhIP is generally SOS-dependent, requir-T

Through-space transmission of polar subs

Through-space transmission of polar substituent effects in the bicyclo[1.1.1]pentane ring system as monitored by 119Sn NMR chemical shifts: a 13C and 119Sn NMR study of 3-substituted-(X)bicyclo[1.1.1]pent-1-yltrimethylstannanes

✍ William Adcock; Alexander R. Krstic 📂 Article 📅 1997 🏛 John Wiley and Sons 🌐 English ⚖ 279 KB 👁 2 views

A series of 3-substituted(X)bicyclo [ 1.1.1 ] pent-1-yltrimethylstannanes (3) were synthesized and their 119Sn and 13C NMR spectra were recorded. The 119Sn substituent chemical shifts (SCS) and the one-bond carbon-tin coupling constants [ 1J(13C,119Sn) ] were analyzed in terms of possible substituen

Synthesis and 1H and 13C NMR study of th

Synthesis and 1H and 13C NMR study of the stereochemistry of (E )-2-acetyl-3-aryl-7-arylidene-3,3a,4,5,6,7-hexahydroindazoles

✍ V. Vijayabaskar; S. Perumal; S. Selvaraj; M. J. E. Hewlins 📂 Article 📅 1999 🏛 John Wiley and Sons 🌐 English ⚖ 113 KB 👁 2 views

The reaction of 2,6-diarylidenecyclohexanones with hydrazine hydrate in glacial acetic acid resulted in the formation of diastereomers of (E)-2-acetyl-3-aryl-7-arylidene-3,3a,4,5,6,7-hexahydroindazoles. The relative conÐgurations of these diastereomers were unambiguously assigned using 1H and 13C NM