Nitration of Indoles. V. Nitration of Electronegatively Substituted Indoles. Synthesis of the Four bz, 3-Dinitroindoles<sup>1</sup>

Noland, Wayl­and E.; Rush, Kent R.

doi:10.1021/jo01339a014

Cited by 34 publications

(9 citation statements)

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“…From a synthetic standpoint, starting with a dinitroindole ring was ideal and it was also necessary that the nitro substituents were positioned meta to each other. The nitration of indoles has been well studied, primarily by Noland, Smith, and Rush. − From these studies it was clear that the desired 4,6-dinitroindole is not possible via direct nitration of indole.…”

Section: Resultsmentioning

confidence: 99%

The Synthesis of Vinylogous Amidine Heterocycles

LaBarbera

Skibo

2013

J. Org. Chem.

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We report herein a convenient synthetic methodology for the conversion of meta-dinitro heterocyclic rings to iminoquinones with vinylogous amidine functionality. These structures are found in nature, particularly in marine organisms, and may be important for the pigments and biological activity observed with such marine secondary metabolites. Using benzimidazole and indole ring systems we show the versatility of these vinylogous amidines for organic synthesis, including the following: transamination substitution reactions with virtually any primary amine, regional control of the substitution with substituents between the vinylogous amidine, and hydrolytic properties that can be controlled or optimized based on the properties of the chosen ring system. Taken together, this versatile chemistry and functionalization of organic molecules may be useful in the preparation of a variety of chemical products such as drug pharmacophores or assembling macromolecular structures.

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Section: Resultsmentioning

confidence: 99%

The Synthesis of Vinylogous Amidine Heterocycles

LaBarbera

Skibo

2013

J. Org. Chem.

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“…During the synthesis of Indole-3-aldehyde, James and Snyder observed that that the most reactive position on indole for electrophilic aromatic substitution is C-3, which is 10 13 times more reactive than benzene [43]. However, a noteworthy exception took place when Noland, Smith, and Rush, carried out nitration of 2-Phenylindole under acidic conditions [44][45][46][47][48][49][50][51][52]. Electrophilic nitration took place at C-5 (carbocyclic ring), because C-3 of pyrrole ring is protonated.…”

Section: Product Analysis Under Kinetic Conditionsmentioning

confidence: 99%

Trichloroisocyanuric acid and NaNO2 mediated nitration of indoles under acid-free and Vilsmeier–Haack conditions: synthesis and kinetic study

et al. 2019

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This study deals with the synthetic and kinetic aspects of trichloroisocyanuric acid (TCCA) and NaNO 2 mediated nitration of indoles in aqueous acetonitrile media under acid-free and Vilsmeier-Haack conditions (using N,N′-dimethyl amides) conditions. Nitration of indoles revealed second order kinetics, with a first order dependence on [indole] and [nitrating agent] ([TCCA]/[NaNO 2 ], [(TCCA-DMF)]/[NaNO 2 ] or [(TCCA-DMA)]/[NaNO 2 ], in which [NaNO 2 ] far excess over other reagents). Reactions followed overall second order kinetics with first order in [reagent] and [indole] under the experimental conditions. Isokinetic temperature (β) values were obtained from Leffler's equation for different kinetic protocols (β = 303 K (TCCA-NaNO 2 ); 303 K (TCCA-DMF)/NaNO 2 ; and 244 K (TCCA-DMA)/NaNO 2 ). These values are the experimental temperature range (303-323 K) indicating that the entropy factors are probably more important in controlling the reaction.

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“…However, literature searches revealed that the only published examples of diaminoindoles are 2,3-diaminoindole and 6,7-diaminoindole . Some dinitroindoles are known; however, conversion of these to diaminoindoles has not been reported. A 2-substituted 3-amino-4-nitroindole is also known .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of a Series of Diaminoindoles

2021

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A selection of 3,4-diaminoindoles were required for a recent drug discovery project. To this end, a 10-step synthesis was developed from 4-nitroindole. This synthesis was subsequently adapted and used to synthesize 3,5-; 3,6-; and 3,7-diaminoindoles from the corresponding 5-, 6-, or 7-nitroindole. These novel intermediates feature orthogonal protecting groups that allow them to be further diversified. This is the first reported synthesis of these types of compounds.

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Nitration of Indoles. V. Nitration of Electronegatively Substituted Indoles. Synthesis of the Four bz, 3-Dinitroindoles¹

Cited by 34 publications

References 0 publications

The Synthesis of Vinylogous Amidine Heterocycles

The Synthesis of Vinylogous Amidine Heterocycles

Trichloroisocyanuric acid and NaNO2 mediated nitration of indoles under acid-free and Vilsmeier–Haack conditions: synthesis and kinetic study

Synthesis of a Series of Diaminoindoles

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Nitration of Indoles. V. Nitration of Electronegatively Substituted Indoles. Synthesis of the Four bz, 3-Dinitroindoles1

Cited by 34 publications

References 0 publications

The Synthesis of Vinylogous Amidine Heterocycles

The Synthesis of Vinylogous Amidine Heterocycles

Trichloroisocyanuric acid and NaNO2 mediated nitration of indoles under acid-free and Vilsmeier–Haack conditions: synthesis and kinetic study

Synthesis of a Series of Diaminoindoles

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Nitration of Indoles. V. Nitration of Electronegatively Substituted Indoles. Synthesis of the Four bz, 3-Dinitroindoles¹