A straightforward synthesis of some fused aza-arenes via nucleophilic displacement of a ring hydrogen atom in nitroarenes by aromatic hydrazone anions

Uehata, Koji; Kawakami, Takuto; Suzuki, Hitomi

doi:10.1039/b105230f

Cited by 14 publications

(8 citation statements)

References 15 publications

(33 reference statements)

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“…Substituted nitrobenzenes reacted with aromatic hydrazones in the presence of sodium hydride by cyclocondensation to 3‐arylindazoles via nucleophilic substitution of the ortho hydrogen atom by the hydrazone anion, followed by replacement of the nitro group. On reaction of 4‐chloronitrobenzene ( 82 ), the chloro substituent remained intact to give 84 (Scheme ) 105…”

Section: Syntheses Of 1h‐indazolesmentioning

confidence: 99%

Recent Advances in the Chemistry of Indazoles

2008

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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 last decade, as well as syntheses, reactions, and functionalizations. Recent advances in the chemistry of N‐heterocyclic carbenes of indazole (indazol‐3‐ylidenes) and indazolium salts are also reported.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

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Section: Syntheses Of 1h‐indazolesmentioning

confidence: 99%

Recent Advances in the Chemistry of Indazoles

2008

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“…Quinolines with a NO 2 substituent at the benzenoid part of the bicyclic ring scaffold are suited for a variety of synthetic transformations, such as reduction to aminoquinolines, 19 vicarious nucleophilic substitution of an adjacent hydrogen atom with various strongly nucleophilic carbanions and heteroanions, 20 21 conversion into 3-aryl-1 H -pyrazolo[3,4- f ]quinolines and/or 3-aryl[1,2,4]triazino[6,5- f ]quinolines by cyclocondensation with aromatic aldehyde hydrazone anions, 21a and the use as electron-poor dienophiles in Diels–Alder reactions. 22…”

Section: Table 1 Preparation Of 8- 7- and 6-nitro-substituted 4-trifluoromethylquinolines 3 mentioning

confidence: 99%

Reactions of 1-Trifluoromethylprop-2-yne 1-Iminium Salts with Nitroanilines: Synthesis of 4-Trifluoromethylnitroquinolines and 1,2,3-Trisubstituted 5-Trifluoromethylpyrroles

et al. 2021

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A variety of 4-CF3-quinolines bearing an aryl (or cyclopropyl, tert-butyl, trimethylsilyl) group at C-2 and a nitro group at ring position 6, 7 or 8 have been prepared in good to high yields from 3-substituted 1-CF3-prop-2-yne 1-iminium triflate salts and o-, m- or p-nitroaniline. These reactions include an aza-Michael reaction at room temperature followed by an intramolecular electrophilic aromatic substitution step, which requires additional thermal activation in most cases. In contrast, the conjugate addition of 2,4-dinitroanilines at the acetylenic iminium ions proceeds much more slowly and some of the adducts can be converted thermally into 2-(2,4-dinitrophenyl)-5-CF3-pyrroles. Analogously, 2-(4-pyridyl)-5-CF3-pyrroles were obtained from 3-aryl-1-CF3-propyne iminium salts and 4-aminopyridinium triflate. A novel variation of the Truce-Smiles rearrangement is probably involved in the formation of these pyrroles.

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“…1H-Indazoles 303 can also be obtained in moderate yield from the reaction of nitroarenes with aromatic hydrazones in alkaline medium (Scheme 8.90) [273]. The presence of electron-withdrawing groups in both reagents is required for the formation of 1H-indazoles 303.…”

Section: Formation Of One C3àc3a Bondmentioning

confidence: 99%