91-55-4

Basic information

• Product Name: 2,3-Dimethylindole
• Synonyms: 2,3-DIMETHYLINDOLINE;2,3-DIMETHYLINDOLE;2,3-DIMETHYL-1H-INDOLE;2,3-dimethyl-1h-indol;2,3-dimethyl-indol;Indole, 2,3-dimethyl-;2,3-DIMETHYLINDOLE, 97+%;1H-Indole, 2,3-dimethyl-
• CAS NO: 91-55-4
• Molecular Formula: C₁₀H₁₁N
• Molecular Weight: 145.2
• EINECS: 202-076-2
• Product Categories: Intermediates of Dyes and Pigments;Indoles and derivatives;Indole;Indoles;Simple Indoles;Building Blocks;Heterocyclic Building Blocks;Heterocycle-Indole series
• Mol File: 91-55-4.mol
• Article Data: 127

Chemical Properties

• Melting Point: 105-107 °C(lit.)
• Boiling Point: 285 °C(lit.)
• Flash Point: 285°C/750mm
• Appearance: /Solid
• Density: 1.0641 (estimate)
• Vapor Pressure: 0.434mmHg at 25°C
• Refractive Index: 1.6030 (estimate)
• Storage Temp.: under inert gas (nitrogen or Argon) at 2–8 °C
• PKA: 17.87±0.30(Predicted)
• BRN: 116662
• CAS DataBase Reference: 2,3-Dimethylindole(CAS DataBase Reference)
• NIST Chemistry Reference: 2,3-Dimethylindole(91-55-4)
• EPA Substance Registry System: 2,3-Dimethylindole(91-55-4)

Safety Data

• Safety Statements: 24/25
• WGK Germany: 3
• RTECS: NL7185000
• TSCA: Yes
• Hazardous Substances Data: 91-55-4(Hazardous Substances Data)

Usage

Uses

Used in Chemical Research:
2,3-Dimethylindole is used as a research compound for studying the mechanism of oxidation by peroxodisulphate and peroxomonosulphate anions, leading to the formation of 2-methylindole-2-carbaldehyde. This research helps in understanding the chemical reactions and transformations involving indole derivatives.
Used in Mass Spectrometry Analysis:
2,3-Dimethylindole is utilized in the study of the behavior of methylindoles in the Agilent multimode ion source by atmospheric pressure chemical ionization mass spectrometry. This application aids in the development of analytical techniques and methods for the identification and characterization of indole-based compounds.

InChI:InChI=1/C10H11N/c1-7-8(2)11-10-6-4-3-5-9(7)10/h3-7H,1-2H3

Upstream product

• 22120-50-9 2,3-dimethyl-2,3-dihydro-1H-indole 
• 22582-52-1 3-acetyl-2-methylindole 
• 124-41-4 sodium methylate 
• 64-17-5 ethanol 
• 6243-71-6 3-methyl-butan-2-one-phenylhydrazone 
• 5435-44-9 (E)-3-Ureido-but-2-enoic acid ethyl ester 
• 28128-12-3 (methyl)(phenyl)aminoacetone 
• 142-04-1 aniline hydrochloride 
• 4091-39-8 3-chloro-2-butanone 
• 62-53-3 aniline 
• 106-99-0 buta-1,3-diene 
• 542-11-0 aniline hydrobromide 
• 62557-43-1 3-bromolevulinic acid 
• 800369-80-6 3-anilino-3-methyl-4-phenyl-butan-2-one 

Downstream Products

• 37914-61-7 2,3-dimethyl-3-methoxyindolenine 
• 19013-49-1 2-ethyl-3-methylindole 
• 103865-85-6 1-<(3-methyl-2-indolyl)methyl>-4-phenylurazole 
• 103865-84-5 1-(2,3-dimethyl-3H-indol-3-yl)-4-phenylurazole 
• 126799-37-9 3-But-3-enyl-2,3-dimethyl-3H-indole 
• 107389-18-4 2-[Bis-(2,3-dimethyl-1H-indol-6-yl)-methyl]-benzoic acid methyl ester 
• 120105-05-7 bis<4-dimethylaminophenyl>(2,3-dimethylindol-1-yl)methane 
• 107389-14-0 C₂₈H₂₈N₂ 
• 107389-11-7 C₂₇H₂₅N₃O₂ 
• 107389-15-1 C₃₀H₃₂N₂O₃ 
• 57240-61-6 N-ethyl-2,3-dimethylindole 
• 31676-43-4 N-acetyl-2,3-dimethylindole 
• 107389-20-8 C₂₇H₂₆N₂ 
• 107389-17-3 2-[Bis-(2,3-dimethyl-1H-indol-6-yl)-methyl]-phenol 

Relevant articles and documents

α-Substituted β-mercapto ketone based synthesis of 3-alkyl-3-[(alkylsulfanyl)methyl]-2-methyl-3H-indoles

[Figure not available: see fulltext.] A novel approach to the synthesis of 3-(alkylsulfanylmethyl)-substituted 1H-indoles was developed based on the Fischer indole synthesis involving accessible β-mercapto ketones. Heterocyclization of 3-[(alkylsulfanyl)methyl]alkan-2-ones and phenylhydrazine by the action of ZnCl2 in MeOH or EtOH gave previously unknown 3-alkyl-3-[(alkylsulfanyl)methyl]-2-methyl-3H-indoles.

Study of catalytic hydrogenation and dehydrogenation of 2,3-dimethylindole for hydrogen storage application

2,3-Dimethylindole (2,3-DMID), a candidate with a hydrogen storage capacity of 5.23 wt%, was studied as a new liquid organic hydrogen carrier (LOHC) in detail in this report. Hydrogenation of 2,3-DMID was conducted over 5 wt% Ru/Al2O3 by investigating the influences of temperature and hydrogen pressure. 100% of fully hydrogenated product, 8H-2,3-DMID can be achieved at 190 °C and 7 MPa in 4 h. Dehydrogenation of 8H-2,3-DMID was performed over 5 wt% Pd/Al2O3 at 180-210 °C and 101 kPa. It is found that dehydrogenation of 8H-2,3-DMID followed first order kinetics with an apparent activation energy of 39.6 kJ mol-1. The structures of intermediates produced in the 8H-2,3-DMID dehydrogenation process were analyzed by DFT calculations.

Chiral-Phosphoric-Acid-Catalyzed C6-Selective Pictet-Spengler Reactions for Construction of Polycyclic Indoles Containing Spiro Quaternary Stereocenters

Compared with the well-established asymmetric Pictet-Spengler reactions on the pyrrole ring of indoles, the catalytic asymmetric Pictet-Spengler reaction on the benzene ring of indoles has been rarely studied. Herein the C6-selective Pictet-Spengler react

Synthesis of indoles through acceptorless dehydrogenative coupling catalyzed by nickel on silica-alumina

The high atom-economical formation of indoles from anilines and diols was described with affordable and easy to handle Ni/SiO2-Al2O3. After optimization, 2,3-dimethylindole was isolated with an excellent 98% yield in neat conditions. The scope of the reaction was studied and 13 indoles were isolated in 16–80% yields.

Acceptorless dehydrogenative condensation: synthesis of indoles and quinolines from diols and anilines

The use of diols and anilines as reagents for the preparation of indoles represents a challenge in organic synthesis. By means of acceptorless dehydrogenative condensation, heterocycles, such as indoles, can be obtained. Herein we present an experimental and theoretical study for this purpose employing heterogeneous catalysts Pt/Al2O3and ZnO in combination with an acid catalyst (p-TSA) and NMP as solvent. Under our optimized conditions, the diol excess has been reduced down to 2 equivalents. This represents a major advance, and allows the use of other diols. 2,3-Butanediol or 1,2-cyclohexanediol has been employed affording 2,3-dimethyl indoles and tetrahydrocarbazoles. In addition, 1,3-propanediol has been employed to prepare quinolines or natural and synthetic julolidines.

One-pot, three-component Fischer indolisation-N-alkylation for rapid synthesis of 1,2,3-trisubstituted indoles

A one-pot, three-component protocol for the synthesis of 1,2,3-trisubstituted indoles has been developed, based upon a Fischer indolisation-indoleN-alkylation sequence. This procedure is very rapid (total reaction time under 30 minutes), operationally straightforward, generally high yielding and draws upon readily available building blocks (aryl hydrazines, ketones, alkyl halides) to generate densely substituted indole products. We have demonstrated the utility of this process in the synthesis of 23 indoles, benzoindoles and tetrahydrocarbazoles bearing varied and useful functionality.

Palladium-catalyzed dearomative allylation of indoles with cyclopropyl acetylenes: access to indolenine derivatives

A palladium-catalyzed redox-neutral allylic alkylation of indoles with cyclopropyl acetylenes has been disclosed. Various 1,3-diene indolenine framework bearing a quaternary stereocenter at the C3 position were synthesized straightforwardly in good to excellent yields with high regio- and stereoselectivities. The reaction could be further expanded to the dearomatization of naphthols to synthesize functionalized cyclohexadienones with 1,3-diene motifs. The reaction exhibited high atom economy and good functional group tolerance.

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.

A Highly Dispersed Copper Nanoparticles Catalyst with a Large Number of Weak Acid Centers for Efficiently Synthesizing the High Value-Added 3-Methylindole by Aniline and Biomass-Derived Glycerin

Abstract: An excellent catalyst with a large number of weak acid centers and highly dispersed copper nanoparticles embedded in mesoporous SBA-15 carrier was successfully constructed for the purpose of efficient conversion of aniline with biomass-derived glycerin to the high value-added 3-methylindole, in which the catalyst of Cu/SBA-15 was modified with Al2O3, La2O3 and CoO in sequence. The modified carrier and the copper-based catalysts were studied by scanning electron microscopy and energy-dispersive X-ray (SEM–EDX) spectroscopy, nitrogen physical adsorption, ammonia temperature programmed desorption (NH3-TPD), hydrogen temperature programmed reduction (H2-TPR), powder X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric and differential thermal analysis (TG–DTA) and inductively coupled plasma (ICP) emission spectroscopy. The research found that the Cu/CoO/La2O3/Al2O3/SBA-15 catalyst exhibited a very good catalytic performance with 3-methylindole yield up to 73.3% and selectivity reaching 86.4%. Besides, only a 3.9% yield decreased after the catalyst was circulated seven times. The characterizations revealed that Al2O3 could enhance the polarity of the carrier, thereby the interaction between the active component and the composite carrier was strengthened and the dispersion of copper was increased significantly. Adding La2O3 to Cu/SBA-15-Al2O3 could weaken the acidity and inhibit the formation of carbon deposits. CoO promoter could increase the number of weak acid centers, which was conducive to a good dispersion of active component and the high selectivity of 3-methylindole. Furthermore, the reaction pathway of gas-phase synthesis of 3-methylindole from glycerin and aniline on Cu/CoO/La2O3/Al2O3/SBA-15 was explored. Graphic Abstract: [Figure not available: see fulltext.]

Rhenium(I)-Catalyzed C-Methylation of Ketones, Indoles, and Arylacetonitriles Using Methanol

A ReCl(CO)5/MeC(CH2PPh2)3 (L2) system was developed for the C-methylation reactions utilizing methanol and base, following the borrowing hydrogen strategy. Diverse ketones, indoles, and arylacetonitriles underwent mono-and dimethylation selectively up to 99% yield. Remarkably, tandem multiple methylations were also achieved by employing this catalytic system.