Detail of "5918-93-4"

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The annular tautomerism of imidazoles and pyrazoles: The possible existence of nonaromatic forms

All Rights Reserved. The annular tautomerism of imidazoles and pyrazoles: The possible existence of nonaromatic forms. Alkorta, Ibon; Elguero, Jose; Liebman, Joel F. (Instituto de Quimica Medica (C.S.I.C.), Madrid E-28006, Spain). Structural Chemistry, 17(4), 439-444 (English) 2006 Springer. CODEN: STCHES. ISSN: 1040-0400. DOCUMENT TYPE: Journal CA Section: 22 (Physical Organic Chemistry) DFT (B3LYP/6-31G*) and G3//B3LYP (usually referred as G3B3 in the literature) calcns. have been carried out on annular tautomers of C- and/or N-functionalized imidazoles (both the arom. 1H- and nonarom. 2H-) and pyrazoles (the arom. 1H- and 2H-, and nonarom. 3H- and 4H-). 5918-93-4 is also in the experiment. The aromaticity of 1H-imidazole and 1H- and 2H-pyrazole results in these species being more stable than their nonarom. tautomers. However, this stability is reversed when the hydrogen on the azole nitrogen or methylene carbon is substituted by OH or by F, e.g., in increasing order of stability we find 1-fluoro-1H-imidazole < 2-fluoro-2H-imidazole (< 2-fluoro-1H-imidazole). These results are related to a recent report of a highly substituted imidazole that exists in the "nonarom." 2H-tautomeric form, and discussed subsequently in a purely thermochem. context. .

Vibrational spectra of imidazoline-2-one and of imidazoline-2-thione and its N-methyl derivative

Vibrational spectra of imidazoline-2-one and of imidazoline-2-thione and its N-methyl derivative. Shunmugam, R.; Sathyanarayana, D. N.; Anagnostopoulos, Augoustinos (Dep. Inorg. Phys. Chem., Indian Inst. Sci., Bangalore 560012, India). Can. J. Spectrosc., 28(5), 150-5 (English) 1983. CODEN: CJSPAI. ISSN: 0045-5105. DOCUMENT TYPE: Journal CA Section: 73 (Optical, Electron, and Mass Spectroscopy and Other Related Properties) The laser Raman and IR spectra of imidazoline2-one, imidazoline-2-thione, and 1-methyl-imidazoline-2-thione were measured. 5918-93-4 and 7782-39-0 which are cas registry numbers of substances are two of reagents here. The vibrational assignments are supported by means of N-Du labeling and S-methylation studies, as well as comparison with the spectra of related compds. Further support is derived from the Raman depolarization measurements and the IR spectrum in polarized light of oriented cryst. samples of 1-methylimidazoline-2-thione. .