Synthesis Of Nitrogen-containing Heterocyclic Compounds Research Articles

Advances in the synthesis of nitrogen-containing heterocyclic compounds by in situ benzyne cycloaddition.

Nitrogen-containing heterocyclic compounds are prevalent in various natural products, medicines, agrochemicals, and organic functional materials. Among strategies to prepare nitrogen-containing heterocyclic compounds, pathways involving benzyne intermediates are attractive given that they can readily assemble highly diverse heterocyclic compounds in a step-economical manner under transition-metal-free conditions. The synthesis of nitrogen-containing heterocyclic compounds from benzyne intermediates offers an alternative strategy to the conventional metal-catalyzed activation approaches. In the past years, chemists have witnessed the revival of benzyne chemistry, mainly attributed to the wide application of various novel benzyne precursors. The cycloaddition of benzynes is a powerful tool for the synthesis of nitrogen-containing heterocyclic compounds, which can be constructed by [n + 2] cyclization of benzyne intermediates in situ generated from benzyne precursors under mild reaction conditions. This review focuses on the application of cycloaddition reactions involving in situ benzynes in the construction of various nitrogen-containing heterocyclic compounds.

Recent Developments in the Synthesis of Five- and Six-membered N-heterocycles from Dicarbonyl Compounds

Various diketones such as 1,2-diketones, 1,3-diketones, 1,4-diketones, β - diketones and dicarbonyl compounds are used in the synthesis of core heterocyclic compounds such as pyrazoles, isoxazoles, triazoles and quinolones. They play an important role in synthetic organic chemistry. The diketones and dicarbonyl compounds also act as chelating ligands for the lanthanides and a large number of transition metals in material chemistry. 50% of drugs contain nitrogen heterocyclic compounds, so organic chemists have made efforts for the synthesis of nitrogen-containing heterocyclic compounds. This review article has compiled different methodologies for the synthesis of five- and six-membered nitrogencontaining heterocyclic compounds.

Lipase‐mediated multicomponent synthesis of 1H‐Pyrazolo[1,2‐b]phthalazine‐5,10‐dione derivatives in a binary solvent medium

A new method for the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives via lipase from the Aspergillus niger-catalyzed multicomponent reaction of aldehydes, malononitrile, and phthalhydrazide is reported herein for the first time. This novel method holds several advantages, including its efficiency, environmental friendliness, simple workup procedure, and good yield (70-86%). The effects of temperature, organic solvents, and water content were investigated. This protocol has the potential to replace traditional chemical synthesis routes for the synthesis of nitrogen-containing heterocyclic compounds.

DIETHYL OXALATE AND ACETONE REACTION WITH SUBSEQUENT INTERACTION WITH SUBSTITUTED 7-AMINOINDOLES

The study described in the article is a continuation of scientific research on the problem of finding convenient methods for the synthesis of nitrogen-containing heterocyclic compounds with biological activity. This article describes the synthesis of tricyclic nitrogen-containing substances based on the interaction of oxalic acid, acetone and sodium diethyl ether with subsequent introduction of 2,3-dimethyl- or 1,2,3-trimethyl-7-aminoindoles into the reaction system in the presence of acetic acid. The synthesis is carried out in two stages. Both stages are carried out under one-reactor synthesis conditions, where toluene is used as a solvent. So by condensation of acetone with diethyloxalate in the presence of sodium, followed by the action of 1,2,3-trimethyl-7-aminoindole in acetic acid, previously unknown ethyl ester (2Z)-4-oxo-2-[(1,2), 3-trimethyl-1H-indole-7-yl)amino]-2-pentanoic acid with a yield of 28%. Subsequently, the synthesized compound was subjected to acid cyclization (boiling in trifluoroacetic acid, 72 °С), as a result of which 1,2,3,6-tetramethyl-1H-pyrrolo[3,2-h]quinoline-8-carboxylic acid ethyl ester was obtained with a yield of 36%. In the case of the use of 2,3-dimethyl-7-aminoindole, unsubstituted in the first position, (2Z)-5,6-dimethyl-2-(2-oxopropylidene)-1,2-dihydro-3-pyrrolо[1,2,3-de]quinoxalin-3-one with a yield of 37%. Monitoring the progress of the reaction and the purity of the obtained compounds was carried out chromatographically. The structural features of the synthesized compounds were established using UV spectroscopy and 1H NMR spectrometry. In the experimental 1H NMR spectra, the signals of the proton-containing groups of ethyl esters of indolyl carboxylic and pyrroloquinoline of carboxylic acids, as well as pyr-rolo[1,2,3-de]quinoxaline, with comparable integral intensity values are found in the expected region.

Copper-Catalyzed Amination of C(sp3)-H bonds: From Anilides to Indolines.

Copper-catalyzed oxidative intramolecular cyclization of o-alkylated anilines via cleavage of C(sp3)-H and N-H bonds for the production of indolines is described. This approach provides a straightforward strategy for the synthesis of nitrogen-containing heterocyclic compounds through the functionalization of unactivated C(sp3)-H bonds with high site selectivity. The present catalytic system shows high preference for functionalization of unactivated C(sp3)-H bonds over C(sp2)-H bonds, leading to C-N bond formation.

A simple one-pot preparation of 3,3a-dihydro-5H-pyrano[3,3a-c]isoxazol-5-ylideneethanal from 4-vinyloxyphenyl azide: an example of aromatic azide photooxidation for the synthesis of nitrogen-containing heterocyclic compounds

Photolysis of 4-vinyloxyphenyl azide in the presence of oxygen in acetonitrile leads to the formation of a fused heterocyclic compound due to the ability of the intermediates of this reaction to undergo a unique domino reaction sequence. The rate constants and activation parameters of some elementary stages of the process are measured by flash photolysis.

Unexpected course of Beckmann rearrangement of taraxerone oxime with Ac2O/AcOH

The chemistry of pentacyclic taraxerane-type triterpenoids has not been extensively studied. In the course of our synthesis of nitrogen-containing heterocyclic compounds from taraxerone using Beckmann rearrangement with Ac2O/AcOH as the rearrangement agent, unexpected synthetic pathways were discovered leading to new types of modified taraxerane skeletons.

Synthesis of Nitrogen-containing Heterocyclic Compounds by Ring Enlargement Reactions through Bicyclic Cyclopropane Intermediates (Review)

Papers on the synthesis of nitrogen-containing heterocyclic compounds by ring enlargement reactions based on the formation of an annelated cyclopropane ring by intramolecular alkylation followed by cleavage of the zero bridge in the obtained [n.1.0] bicyclic systems are reviewed.

SYNTHESIS OF NITROGEN-CONTAINING HETEROCYCLIC COMPOUNDS BY RING ENLARGEMENT REACTIONS THROUGH BICYCLIC CYCLOPROPANE INTERMEDIATES

Papers on the synthesis of nitrogen-containing heterocyclic compounds by ring enlargement reactions based on the formation of an annelated cyclopropane ring by intramolecular alkylation followed by cleavage of the zero bridge in the obtained [ n .1.0] bicyclic systems are reviewed. Authors: A. A. Fesenko and A. D. Shutalev English Translation in Chemistry of Heterocyclic Compounds , 2013, 49 (6), pp 827-848 http://link.springer.com/article/10.1007/s10593-013-1318-x

Synthesis of nitrogen-containing heterocyclic compounds by photooxidation of aromatic azides

It is shown that the photolysis of certain aromatic azides in the presence of oxygen leads to the formation of nitrogen-containing heterocyclic compounds via a domino reaction sequence.

Copper(II) Acetate Promoted Intramolecular Carboamination of Alkenes: An Efficient Synthesis of Pentacyclic Sultams

Copper(II) acetate promoted intramolecular carboamination reactions of 5-allyl-N-sulfonylated coumarins and quinolones have been described. The hitherto unreported pentacyclic sultams, obtained by the oxidative cyclization in high yields, are potential intermediates in the synthesis of nitrogen-containing heterocyclic compounds.

Use of Tetramethylthiuram Disulfide in Synthesis of Nitrogen-containing Heterocyclic Compounds

We have developed a method for synthesis of aryl isothiocyanates by means of thiocarbamoylation of aromatic amines by tetramethylthiuram disulfide followed by degradation of the intermediate N(1)-aryl-N,N-dimethylthiourea by concentrated HCl. We have shown that thiocarbamoylation of 4-amino-5-ethyl-4H-1,2,4-triazole-3-thiol occurs at the 2 position of the triazole ring, while thiocarbamoylation of 4-amino-3-methyl-6-phenyl-4,5-dihydro-1,2,4-triazin-5-one leads to the dihetaryl-substituted thiourea. We consider the possibility of using N(1)-aryl-N,N-dimethylthioureas as analogs of isothiocyanates in reactions with N-nucleophiles.

Environment-friendly synthesis of nitrogen-containing heterocyclic compounds

A novel environment-friendly vapour phase synthesis of different classes of nitrogen-containing heterocyclic compounds was developed using non-hazardous, commercially available and low cost feeds. 2-Methyl-8-ethylquinoline (MEQUI) was obtained from 2-ethylaniline (2-ETAN) and ethylene glycol (EG) or chloroethanol (CE), operating at high temperature in the presence of acid-treated K10 montmorillonite or ZnCl 2/K10 montmorillonite. At lower temperatures and using copper chromite catalysts, 7-ethylindole (7-ETI) or 5-ethylindole (5-ETI) were obtained from 2-ETAN or 4-ethylaniline (4-ETAN), respectively, and EG; excess of alkylaniline was required to avoid the formation of polyalkylated by-products. Mixing SiO 2 with the best copper chromite, made it possible to operate with higher LHSV values, thus improving the yield in alkylindoles. Finally, N-(2-ethylphenyl)pyrrole (EPP) and N-(2-ethylphenyl)pyrrolidine (EPD) were synthesised using a commercial copper chromite catalyst and feeding 2-ETAN and 2,3-dihydrofuran (DHF), EPP being favoured by high temperatures and absence of water in the feed. The possible reaction pathway for each synthesis is proposed, to evidence the key features of the best catalysts identified.

Synthesis of nitrogen-containing heterocyclic compounds using perfluoro-2-methylpent-2-ene and perfluoro-5-azanon-4-ene

Reactions of perfluoro-2-methylpent-2-ena or perfluoro-5-azanon-4-ene with a range of bidentate nitrogen nucleophiles (urea, acet-, benz-, 4-nitrobenz-amidine hydrochloride, 2-aminopyridine, 2-aminobenzimidazole, guanidine) in the presence of Et 3N or KOH effectively provided partially fluorinated heterocycles of pyrimidine, 2H-pyrido[1,2-a]pyrimidine and [1,3,5]triazine derivatives. The structure of 2-pentafluoroethyl-3-trifluoromethyl-pyrido[1,2-a]pyrimidin-4-one was further confirmed by the X-ray crystallographic analysis.

Synthesis of nitrogen-containing heterocyclic compounds based on?-haloketones (review)

In this review, we systematize data on methods for synthesis of nitrogen-containing heterocyclic compounds cyclocondensation of α-haloketones with different compounds.

Some peculiarities in synthesis of nitrogen-containing heterocyclic compounds on zeolite catalysts

Acid properties of some zeolite catalysts have been studied using IR spectroscopy and compared with data on the selectivity of their catalytic effect in the synthesis of nitrogen-containing compounds from monoethanolamine.

Syntheses of Nitrogen-containing Heterocyclic Compounds by the Use of Cyclopropenium Salt

Syntheses of Nitrogen-containing Heterocyclic Compounds by the Use of Cyclopropenium Salt

Syntheses of nitrogen-containing heterocyclic compounds. XLI. Reaction of diazaphenanthrenes and their N-oxides with methylsulfinyl carbanion.

Syntheses of nitrogen-containing heterocyclic compounds. XLI. Reaction of diazaphenanthrenes and their N-oxides with methylsulfinyl carbanion.

含窒素複素環化合物の合成研究(第37報)2-Phenylquinoline 1-Oxide類およびPhenyl-1,8-naphthyridine類の合成とその抗菌性について

含窒素複素環化合物の合成研究(第37報)2-Phenylquinoline 1-Oxide類およびPhenyl-1,8-naphthyridine類の合成とその抗菌性について

Syntheses of nitrogen-containing heterocyclic compounds. XLIV. Syntheses of 5-substituted 1,6-naphthyridine derivatives using the Reissert compound of 1,6-naphthyridine (author's transl)

1, 6-Naphthyridine-5-carboxamide (VI), 1, 6-naphthyridine-5-carboxylic acid (VII), and benzaldehyde were obtained by acid hydrolysis of 5-benzoyl-5, 6-dihydro-1, 6-naphthyridine-5-carbonitrile (III). Reaction of III with a Grignard reagent (CH3MgBr, PhMgBr) gave 1, 6-naphthyridine-5-carbonitrile (IX) by reaction with methylmagnesium bromide, and IX, VI, and α, α-diphenyl-5-(1, 6-naphthyridine) methanol (X) by reaction with phenylmagnesium bromide. Alkylation of III with methyl iodide, using a phasetransfer catalyst, gave 6-benzoyl-5, 6-dihydro-1, 6-naphthyridine-5-carbonitrile (XIII), and alkaline hydrolysis of XIII afforded 5-methyl-1, 6-naphthyridine (II). Reaction of III with 3, 4-dimethyoxbenzyl chloride gave 5-(3, 4-dimethoxybenzyl)-1, 6-naphthyridine (XV).