38445-36-2

Usage

Physical state

Colorless to light yellow liquid

Odor

Strong, unpleasant

Natural occurrence

Found in feces, a byproduct of bacterial breakdown of tryptophan in the intestines

Production

Also produced in small quantities during the combustion of tobacco

Use

Used in some perfumes to impart a leather-like smell

Classification

Volatile organic compound

Environmental impact

Contributes to the odor of livestock manure and sewage

Health concerns

Linked to certain metabolic disorders and considered a potential environmental pollutant

Upstream product

• 4757-69-1 2-methyl-3-phenyl-1H-indole 
• 74-88-4 methyl iodide 
• 673-32-5 1-Phenylprop-1-yne 
• 6832-87-7 2-bromo-N-methylaniline 
• 100-61-8 N-methylaniline 
• 614-00-6 N-methyl-N-nitrosoaniline 
• 1227083-53-5 N-methyl-1,1-diphenylpropan-1-amine 
• 4226-57-7 2,2-diphenylbutanoic acid 
• 5311-82-0 1-methyl-1-phenyl-2-propylidenehydrazine 
• 618-40-6 1-Methyl-1-phenylhydrazine 
• 875-79-6 1,2-dimethylindole 
• 591-50-4 iodobenzene 
• 16668-99-8 bis(phenyl)iodonium trifluoroacetate 
• 58109-40-3 diphenyliodonium hexafluorophosphate 

Downstream Products

• 75834-30-9 2-Methoxy-3,4-dimethyl-2-phenyl-3,4-dihydro-2H-benzo[1,4]oxazine 
• 75834-28-5 6-Methoxy-1,2-dimethyl-3-phenyl-1H-indole 

Relevant academic research and scientific papers

Zinc-promoted hydrohydrazination of terminal alkynes: An efficient domino synthesis of indoles

(Chemical Equation Presented) Indole click chemistry: The quest for better catalysts for the intermolecular hydrohydrazination to indoles leads to zinc salts. A simple one-pot synthesis forms indoles from arylhydrazines and terminal alkynes. The pharmacologically relevant indole building blocks are selectively formed in the presence of zinc triflate (Zn(OTf)2) or ZnCl 2 (see scheme).

One-Pot Tandem ortho-Naphthoquinone-Catalyzed Aerobic Nitrosation of N-Alkylanilines and Rh(III)-Catalyzed C-H Functionalization Sequence to Indole and Aniline Derivatives

The nitroso group served as a traceless directing group for the C-H functionalization of N-alkylanilines, ultimately removed after functioning either as an internal oxidant or under subsequent reducing conditions. The unique ability of o-NQ catalysts to aerobically oxidize the N-alkylanilines without using solvents and stoichiometric amounts of oxidants has rendered the new opportunity to develop the telescoped catalyst systems without a need for directly handling the hazardous N-nitroso compounds.

A Copper-Catalyzed Aerobic [1,3]-Nitrogen Shift through Nitrogen-Radical 4-exo-trig Cyclization

A novel radical [1,3]-nitrogen shift catalyzed by copper diacetate under an oxygen atmosphere (1 atm) has been developed for the construction of a diverse range of indole derivatives from α,α-disubstituted benzylamine. In this reaction, oxygen was used as a clean terminal oxidant, and water was produced as the only by-product. Five inert bonds were cleaved, and two C?N bonds and one C?C double bond were constructed in one pot during this transformation. This unique method demonstrated broad application protential for the late-stage modification of biologically active natural products and drugs. Mechanistic investigations indicate that a unique 4-exo-trig cyclization of an aminyl radical onto a phenyl ring is involved in the catalytic cycle.

An Admix Approach to Determine Counter Anion Effects on Metal-Free Arylation Reactions with Diaryliodonium Salts

A method to determine the effect of counter anions in metal-free arylation reactions of diaryliodonium salts is described. This approach avoids the independent synthesis of individual diaryliodonium salts and potentially enables assessment of a large number of different counter anions, including those that are synthetically challenging to install. Diaryliodonium tosylate salts serve as a general precursor for this approach, and an azide arylation reaction was used to develop this strategy. Further optimization and representative scope of azide arylation is demonstrated in yields that range from 74-95% (89% average). The use of this method as a screening tool has also been validated with arylation reactions of three different nucleophiles employing diphenyliodonium tosylate.

Rhodium(III)-catalyzed synthesis of indoles from 1-alkylidene-2- arylhydrazines and alkynes via C-H and N-N bond cleavages

1-Alkylidene-2-arylhydrazines undergo annulative coupling with internal alkynes in the presence of a rhodium(III) catalyst and a copper(II) salt. The reaction proceeds through cleavage of the C-H and N-N bonds of hydrazines to afford 1,2,3-trisubstituted indole derivatives.

Bis(amidate)bis(amido) titanium complex: A regioselective intermolecular alkyne hydroamination catalyst

An efficient and selective bis(amidate)bis(amido) titanium precatalyst for the anti-Markovnikov hydroamination of alkynes is reported. Hydroamination of terminal and internal alkynes with primary alkylamines, arylamines, and hydrazines is promoted by 5-10 mol % of Ti catalyst. Various functional groups are tolerated including esters, protected alcohols, and imines. The in situ generated complex shows comparable catalytic activity, demonstrating its synthetic versatility for benchtop application. Applications of this catalyst for the synthesis of amino alcohols and a one-pot procedure for indole synthesis are described. A mechanistic proposal that invokes turnover-limiting protonolysis is presented to rationalize the observed regioselectivities.

On water phosphine-free palladium-catalyzed room temperature C-H arylation of indoles

Get on top of your chemistry! An "on water", palladium-catalyzed, phosphine-free direct C-H arylation of indoles, with iodoarenes at 25-30°C, is disclosed (see scheme; TBDMS=N-tert-butyldimethylsilyl ether; SEM=N-2-(trimethylsilyl)ethoxymethyl; Bn=benzyl, Piv=pivabyl). The mildness of the reaction conditions permits the tolerance of a variety of N1-protected indoles.

Metal-free direct arylations of indoles and pyrroles with diaryliodonium salts

Chemical equations presented. Direct arylations of indoles and pyrroles with differently substituted diaryliodonium salts were shown to efficiently proceed in the absence of metal catalysts.

Palladium-catalyzed indole, pyrrole, and furan arylation by aryl chlorides

The palladium-catalyzed direct arylation of indoles, pyrroles, and furans by aryl chlorides has been demonstrated. The method employs a palladium acetate catalyst, 2-(dicyclohexylphosphino)-biphenyl ligand, and an inorganic base. Electron-rich and electron-poor aryl chlorides as well as chloropyridine coupling partners can be used, and arylated heterocycles are obtained in moderate to good yields. Optimization of base, ligand, and solvent is required for achieving best results.

Regiochemistry of the microwave-assisted reaction between aromatic amines and α-bromoketones to yield substituted 1H-indoles

The scope and regioselectivity of the Bischler (or Bischler-Moehlau) reaction between aromatic amines and α-bromoketones has been studied by computational and experimental techniques. It has been found that in many cases the reaction yields are improved under microwave irradiation and working in the absence of solvent. When di- and trisubstituted amines are used as substrates the regioselectivity of the reaction is different to that obtained with the corresponding primary anilines. The reaction between benzene-1,2-diamine and α-bromoacetophenones under the same conditions yields 2-substituted quinoxalines instead of indoles. Finally, when pyridin-2-amines and pyrimidine-2-amines are allowed to react with the corresponding α-bromoacetophenones, the corresponding imidazo[1,2-a]pyridines and imidazo[1,2-a]pyrimidines are obtained, respectively. The Royal Society of Chemistry.