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N-Heterocyclic Carbenes of 5-Haloindazoles Generated by Decarboxylation of 5-Haloindazolium-3-carboxylates
Syntheses and properties of 5-fluoro-, chloro- bromo-, and iodo-substituted 1,2-dimethyl indazolium-3-carboxylates as new representatives of pseudo-cross-conjugated heterocyclic mesomeric betaines
Recent Advances in the Chemistry of Indazoles
Indazoles are of considerable interest due to the broad variety of their biological activities. This overview summarizes structures of pharmacologically interesting indazoles published during the
Addition reactions and redox esterifications of carbonyl compounds by N-heterocyclic carbenes of indazole.
TLDR
Model reactions such as redox esterifications of aromatic aldehydes with sodium alcoholates in the presence of 1,2-dimethylindazolium salt and oxidations of sodium benzylates by 1, 2-dimethylamine salt to aldeHydes lend support to a Cannizzaro-type mechanism of this reaction.
N-Heterocyclic Carbenesof Indazole: Ring Enlargement Reactions by α-HaloKetones and Dehalogenations of Vicinal Dihalides
On decarboxylation, l,2-dimethylindazolium-3-carboxylate forms the N-heterocyclic carbene, l,2-dimethylindazol-3-ylidene, which deprotonates α-halo ketones. The resulting indazolium salt and the
Imidazol-2-and-4-ylidene by decarboxylation. Studies on the cross-conjugated mesomeric betaine-alkaloid norzooanemonine and its pseudo-cross-conjugated isomer.
TLDR
Calculations were performed to characterize the different types of conjugation in the imidazolium-carboxylates to prove the structure of which was proved by independent syntheses.
Translation of pseudo-cross-conjugation into chemistry: cycloadditions of mesomeric betaines to the new ring system spiro[indazole-3,3'-pyrrole].
TLDR
A combination of NMR techniques such asheteronuclear single quantum coherence (HSQC), heteronuclear multiple bond correlation (HMBC), nuclear Overhauser enhancement spectroscopy (NOESY), and 1H/15N correlations were applied to elucidate the structures of the cycloadducts.
N‐Heterocyclic Carbene Induced Cycloaddition Reactions of Indazoles with Acetylenes To Form a New Ring System
Thermal decarboxylation of the mesomeric betaine 1,2-dimethylindazolium-3-carboxylate resulted in the formation of the N-heterocyclic carbene indazol-3-ylidene which deprotonated a second molecule of
Pseudo-Cross-Conjugated Mesomeric Betaines and N-Heterocyclic Carbenes of Indazole
1.2-Dimethylindazolium-3-carboxylates are pseudo-cross-conjugated mesomeric betaines (PCCMB) and derivatives of the indazole alkaloid Nigellicin. They decarboxylate on heating to give intermediary
Quantum mechanical study and vibrational spectra of indazolium-3-carboxylate and its decarboxylation product, the N-heterocyclic carbene indazol-3-ylidene.
TLDR
This paper has studied the carbene generation by decarboxylation of 1,2-dimethyl indazolium-3-carboxylate, using vibrational (infrared and Raman) spectroscopy and quantum chemistry calculations, and investigates the effect of 5-halogen substitution on thecarbene generation.
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