36729-21-2

Upstream product

• 114570-16-0 (2,3-Dimethyl-benzo[g]indol-1-yl)-oxo-acetic acid ethyl ester 
• 134-32-7 1-amino-naphthalene 
• 2028-63-9 but-3-yn-2-ol 
• 121198-11-6 (E)-N-(2-butenyl)-1-naphthylamine 
• 513-85-9 2.3-butanediol 
• 2243-56-3 1-naphthylhydrazine hydrochloride 
• 78-93-3 butanone 

Relevant academic research and scientific papers

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.

Catalytic Synthesis of Substituted Indoles and Quinolines from the Dehydrative C-H Coupling of Arylamines with 1,2- and 1,3-Diols

The cationic ruthenium-hydride complex catalyzes the dehydrative C-H coupling reaction of arylamines with 1,2-diols to form the indole products. The analogous coupling of arylamines with 1,3-diols afforded the substituted quinolines. The catalytic method directly forms these coupling products in a highly regioselective manner without generating any toxic byproducts.

Improved indole syntheses from anilines and vicinal diols by cooperative catalysis of ruthenium complex and acid

By developing a new and efficient dinuclear catalyst [Ru(CO) 2(Xantphos)]2 [Xantphos = 4,5-bis(diphenylphosphino)-9,9- dimethyl-9H-xanthene], an improved synthesis of indole from vicinal diols and anilines by cooperative catalysis of ruthenium complex and p-TSA (para-toluenesufonic acid) has been demonstrated. The presented synthetic protocol allows assembling a wide range of products in an efficient manner. Comparing to the existed protocols, our indole syntheses can be achieved at lower reaction temperature, in shorter reaction time, and with improved substrate tolerance.

Iridium- and ruthenium-catalysed synthesis of 2,3-disubstituted indoles from anilines and vicinal diols

A straightforward and atom-economical method is described for the synthesis of 2,3-disubstituted indoles. Anilines and 1,2-diols are condensed under neat conditions with catalytic amounts of either [Cp*IrCl2] 2/MsOH or RuCl3·xH2O/phosphine (phosphine = PPh3 or xantphos). The reaction does not require any stoichiometric additives and only produces water and dihydrogen as byproducts. Anilines containing methyl, methoxy, chloro and fluoro substituents can participate in the cyclocondensation. Meta-substituted anilines give good regioselectivity for 6-substituted indoles, while unsymmetrical diols afford excellent regioselectivity for the indole isomer with an aryl or large alkyl group in the 2-position. The mechanism for the cyclocondensation presumably involves initial formation of the α-hydroxyketone from the diol. The ketone subsequently reacts with aniline to generate the α-hydroxyimine which rearranges to the corresponding α-aminoketone. Acid- or metal-catalysed electrophilic ring-closure with the release of water then furnishes the indole product.

N-Heterocyclization of naphthylamines with 1,2- And 1,3-Diols catalyzed by an iridium Chloride/BINAP system

Benzoquinoline derivatives were successfully synthesized by iridium-catalyzed N-heterocyclization of naphthylamines with diols. For instance, the reaction of 1-naphthylamine with 1,3-propanediol catalyzed by IrCl3 combined with BINAP as a ligand produced 7,8-benzoquinoline in quantitative yield. The VV-heterocyclization reaction was found to be markedly influenced by the ligands employed. Benzoindoles were also synthesized by the same strategy from napthylamines with 1,2-diols. A reaction mechanism for the N-heterocyclization of naphthylamines with 1,3-diols by IrCl3 was proposed.

Thermal cyclization of N-[2-(2-propenyl)-1-naphthyl] ketenimines: Intramolecular Diels-Alder reaction versus [1,5] hydrogen migration. Synthesis of dibenz[b,h]acridines and benzo[h]quinolines

The thermal treatment of N-(2-propenyl)-1-naphthylamines provided the expected aza-Claisen rearranged products, 2-(2-propenyl)-1-naphthylamines and benz[g]indoles, these last derived from an intramolecular hydroamination reaction on those primary products. The 2-(2-propenyl)-1-naphthylamines were converted into their triphenylphosphazene derivatives, which by aza-Wittig reaction with disubstituted ketenes yielded N-[2-(2-propenyl)-1-naphthyl] ketenimines. The heating of these ketenimines in boiling toluene induced their cyclization either via an intramolecular Diels-Alder reaction, to afford dibenz[b,h]acridines, or via [1,5] hydrogen migration from the sp3 carbon atom of the propenyl substituent to the central carbon atom of the ketenimine fragment, followed by a 6π electrocyclic ring closure, to give benzo[h]quinolines.

PROCESSES FOR PREPARATION OF FUSED PYRROLES

The invention provides processes for the preparation of fused pyrroles, preferably indoles, which permit the use of inexpensive aromatic amines themselves as the raw material and attain high atomic efficiency and high regioselectivity. Specifically, a process for the preparation of fused pyrroles, e.g., indoles bearing methyl at the 3-position of pyrrole ring and R1(or R2) of the general formula (4) at the 2-position thereof, or 3,3-disubstituted indoles bearing R1and R2at the 3-position of pyrrole ring and methyl at the 2-position thereof, characterized by reacting an alkynol of the general formula (4) with an aromatic primary amine in the presence of a ruthenium complex, more preferably with an acid or an ammonium salt thereof being made to coexist. .[In the general formula (4), R1and R2are each independently hydrogen, optionally substituted alkyl, or optionally substituted aryl, or alternatively R1and R2may be united to form an alkylene chain.]

A practical one-pot synthesis of 2,3-disubstituted indoles from unactivated anilines

2-Substituted-3-methyl indoles are synthesized with good regioselectivity from readily available substrates and catalysts, i.e. the reaction of anilines with propargyl alcohols in the presence of 0.36-1 mol% Ru3(CO)12.

NITROGENOUS HETEROCYCLES. 6. REACTIONS OF ORGANOMAGNESIUM DERIVATIVES OF 7-AZA- AND BENZOINDOLES WITH DIETHYL OXALATE AND THE REACTIVITY OF ETHOXALYLINDOLES

The reactions of organomagnesium derivatives of 2-methyl- or 2,3-dimethyl-7-azaindoles and 2,3-dimethylbenz- or -indoles with diethyloxalate, and the reactivity of the resulting ethoxalylindoles towards phenylmagnesium bromide, have been examined.It has been shown that the course of the reaction is dependent on the solvent and the structures of the starting materials.