Aufspaltung des Imidazolrings

Bamberger, Eug.; Berlé, B.

doi:10.1002/jlac.18932730216

Cited by 39 publications

(21 citation statements)

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“…The problem of benzimidazoles' nitration (Table 4) is not so simple. The preferred nitration site of the 1H-tautomer (4a) is the 6-position, in agreement with experimental data, [43][44][45] whereas the less stable (ca 30 kcal/mol) 2H-tautomer (4b) prefers the 4(7)-position. If the protonated benzimidazolium cations are considered, the less stable (ca 40 kcal/mol) 1,2-H-tautomer (4c) prefers the positions 4, 5 and 7, whereas the more stable 1,3-H-benzimidazolium (4d) prefers the experimentally confirmed [43][44][45] 5(6)-position.…”

Section: Introductionsupporting

confidence: 87%

Quantum-chemical studies of benzazoles nitration

Breza¹,

Milata²

2005

Arkivoc

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The H-tautomers of benzotriazole, benzimidazole, and their N-methyl-derivatives, as well as of their cations have been investigated by using the MP2/cc-pVDZ treatment. The atomic reactivity indices for electrophilic reactions (nitration) in the optimized geometries of the compounds under study have been evaluated as the electron density of the highest occupied molecular orbital. Both the benzotriazoles and their protonated cations prefer nitration in the 4-and/or 7-positions in agreement with experimental data. Only the more stable tautomers of 1H-benzimidazole nitrated in the 6-position, and the 3H-protonated cations of 1,3-H-benzimidazolium and 1-methyl-3H-benzimidazolium nitrated in the 5-and 6-positions, in full agreement with experiment. The results imply the importance of the protonated benzdiazolium cations for the nitration.

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Section: Introductionsupporting

confidence: 87%

Quantum-chemical studies of benzazoles nitration

Breza¹,

Milata²

2005

Arkivoc

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“…From the isomers of indigo, 2‐[1,3‐dioxo‐2‐indanyline)benzimidazolines, which were prepared in 1893 in Munich by Bamberger and Berlè ,, a series of similar N,O ‐chelate complexes was accessible (Scheme ). The heterocycles are not indigoid dyes, but the complexes thereof may be of interest – according to fundamental studies by Kaim – as potential redox active species.…”

Section: Pyrrolindigo and Structural Isomers Of Indigo As Ligandsmentioning

confidence: 99%

Metal Complexes of Indigo and of Some Related Ligands

Beck

Sünkel

2020

Zeitschrift anorg allge chemie

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While the first coordination compounds of indigo were reported over 100 years ago, a systematic study of the coordination chemistry of this important dye and also its structural “relatives” remained silent for over half a century. Only in the last two decades of the 20th century research on this topic started again keeps on growing ever since. It could be established, mainly by X‐ray crystallography, but also by many other modern spectroscopic techniques, that deprotonated indigo, and its deprotonated oxidized and reduced forms act as mono‐ and bidentate chelate ligands in metal complexes

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“…0-Methylquinoline, on the other hand, is unreactive toward oxalic ester (79). Another example is furnished by a, rw-dimethylbenzimidazole in which only the -methyl group condenses with benzaldehyde (6): Schlenk and Bergmann (66) have shown that the peculiar activity of the hydrogen atoms of the methylene group characteristic of the first members of this series is present also in the higher vinylogs. These act upon sodium triphenylmethyl to convert it to triphenylmethane, thus behaving as compounds possessing active hydrogen atoms.…”

Section: Compoundsmentioning

confidence: 99%