22401-71-4

Upstream product

• 98-53-3 4-tercbutyl-cyclohexanone 
• 100-63-0 phenylhydrazine 
• 59-88-1 phenylhydrazine hydrochloride 
• 1227476-15-4 Azobenzene 
• 1076-82-0 2-bromo-4-tert-butylcyclohexanone 
• 62-53-3 aniline 

Downstream Products

• 22401-72-5 3-(tert-butyl)-9-methyl-2,3,4,9-tetrahydro-1H-carbazole 
• 22401-74-7 3-(1,1-dimethylethyl)-9H-carbazole 

Relevant academic research and scientific papers

Direct Synthesis of Indoles from Azoarenes and Ketones with Bis(neopentylglycolato)diboron Using 4,4′-Bipyridyl as an Organocatalyst

Multifunctionalized indole derivatives were prepared by reducing azoarenes in the presence of ketones and bis(neopentylglycolato)diboron (B2nep2) with a catalytic amount of 4,4′-bipyridyl under neutral reaction conditions, where 4,4′-bipyridyl acted as an organocatalyst to activate the B-B bond of B2nep2 and form N,N′-diboryl-1,2-diarylhydrazines as key intermediates. Further reaction of N,N′-diboryl-1,2-diarylhydrazines with ketones afforded N-vinyl-1,2-diarylhydrazines, which rearranged to the corresponding indoles via the Fischer indole mechanism. This organocatalytic system was applied to diverse alkyl cyclic ketones, dialkyl, and alkyl/aryl ketones, including heteroatoms. Methyl alkyl ketones gave the corresponding 2-methyl-3-substituted indoles in a regioselective manner. This protocol allowed us to expand the preparation of indoles having high compatibility with not only electron-donating and electron-withdrawing groups but also N- and O-protecting functional groups.

Tetrahydrocarbazoles by mechanochemical Fischer indolisation

The Fischer indolisation (FI) typically proceeds in the presence of a Br?nsted or Lewis acid in an organic solvent at elevated temperatures. Herein, we report that tetrahydrocarbazoles (THCs) are accessible by mechanochemical FI at ambient temperature. Using phenylhydrazine hydrochlorides in the presence of silica is critical for this solid-state variant of the FI.

Ene-hydrazide from enol triflate for the regioselective Fischer indole synthesis

Ene-hydrazide prepared from enol triflate undergoes a Fischer indolization reaction to give the corresponding indole with complete regioselectivity. The starting enol triflate is readily accessed in regiochemically defined form from the ketone precursor via various well-established methods. This new protocol was successfully applied to the synthesis of desbromoarborescidine A, a natural β-carboline alkaloid, difficult to prepare with conventional Fischer indole synthesis.

Novel SO3H-functionalized ionic liquids catalyzed a simple, green and efficient procedure for Fischer indole synthesis in water under microwave irradiation

Novel SO3H-functionalized ionic liquids were successfully applied as catalysts for one-pot Fischer indole synthesis under microwave irradiation and in a water medium. Various types of indoles were prepared using single-carbonyl ketones/aldehydes or cyclohexandiones with aryhydrazine hydrochlorides in 86-96% yields in water under microwave irradiation. The indole products could be conveniently separated from the reaction mixture through filtration, and the catalytic system of [(HSO3-p)2im] [CF3SO3]/H2O could be reused directly without any treatment. The entire process is simple, time saving, and environmentally friendly.

A microwave-assisted, propylphosphonic anhydride (T3P) mediated one-pot Fischer indole synthesis

A rapid, mild, and high yielding protocol for the Fischer indolization of arylhydrazines with T3P under microwave irradiation is described. Significant features of this method include short reaction times and preparative ease.

Fischer indole synthesis catalyzed by novel SO3H-functionalized ionic liquids in water

Novel SO3H-functionalized ionic liquids bearing two alkyl sulfonic acid groups in the imidazolium cations were designed and successfully applied as catalysts for the one-pot Fischer indole synthesis in water medium. The sequence of the catalytic activity observed in the transformation was in good agreement with the Bronsted acidity order determined by the Hammett method. Various types of indoles from single-carbonyl ketones/aldehydes and cyclohexandiones were provided in 68-96% yields using the catalytic system of [(HSO3-p)2im][HSO4]/H2O. The indole products could be conveniently separated from the reaction mixture by filtration and the dissolved catalyst could be regenerated by treatment with a strongly acidic cation exchange resin, which meant the whole process was performed in water without using any organic solvents.

Fischer indole synthesis in bronsted acidic ionic liquids: A green, mild, and regiospecific reaction system

A novel one-pot Fischer indole synthesis approach has been developed by using Bronsted acidic ionic liquids as dual solvent-catalysts. Yields of 83-97 % were obtained after reaction in BMImHSO4 at 70-110°C in 0.5-6 h, and exclusive formation of 2,3-disubstituted indoles was observed in the reaction of alkyl methyl unsymmetrical ketones. The indoles produced could be conveniently separated from the reaction mixture without any volatile organic solvents, and the BMImHSO4 could be readily reused without efficiency loss after simple treatment involving only 1 equiv. of HCl for neutralization followed by filtration. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.

RIGID AMINES

A monomer for use in manufacturing a conjugated polymer, the monomer having a structure as shown formula (2): Ar1, Ar2 and Ar3 are independently selected from optionally substituted aryl or heteroaryl, X1 and X3 both independently comprise a leaving group capable of participating in polymerisation and Z represents a direct bond or an optionally substituted bridging atom.

Microwave-assisted one-pot synthesis of 1,2,3,4-tetrahydrocarbazoles

A series of 1,2,3,4-tetrahydrocarbazoles 3a-m were synthesized by the reaction of substituted 2-bromocyclohexanones 2a-c with appropriate anilines 1a-i under microwave irradiation without any other catalysts. Copyright Taylor & Francis Group, LLC.

Fischer indole synthesis in the absence of a solvent

The traditional Fischer synthesis of indoles has been investigated and it has been shown that the reaction proceeds in good yield in the absence of a solvent.