Alexander Karchava - Academia.edu (original) (raw)
Papers by Alexander Karchava
Russian Chemical Reviews, 2021
Arylation methods based on the generation and use of aryl radicals have been a rapidly growing fi... more Arylation methods based on the generation and use of aryl radicals have been a rapidly growing field of research in recent years and currently represent a powerful strategy for carbon – carbon and carbon – heteroatom bond formation. The progress in this field is related to advances in the methods for generation of aryl radicals. The currently used aryl radical precursors include aryl halides, aryldiazonium and diaryliodonium salts, arylcarboxylic acids and their derivatives, arylboronic acids, arylhydrazines, organosulfur(II, VI) compounds and some other compounds. Aryl radicals are generated under mild conditions by single electron reduction or oxidation of precursors induced by conventional reagents, visible light or electric current. A crucial role in the development of the radical arylation methodology belongs to photoredox processes either catalyzed by transition metal complexes or organic dyes or proceeding without catalysts. Unlike the conventional transition metal-catalyzed ...
Russian Chemical Reviews, 2022
Khimiya Geterotsiklicheskikh Soedinenii, 2008
Khimiya Geterotsiklicheskikh Soedinenii, 2010
Chemistry of Heterocyclic Compounds, 2020
This review article covers literature data from the last 5 years regarding the various applicatio... more This review article covers literature data from the last 5 years regarding the various applications of 1,4-diazabicyclo[2.2.2]octane (DABCO) in organic chemistry. The frequent use of DABCO as a base, catalyst, and reagent has been reflected in the large number of publications, therefore our review will be published in 4 parts. The first part of the review is dedicated to the use of DABCO as catalyst for Morita–Baylis–Hillman and Knoevenagel reactions. Authors: Dmitry I. Bugaenko, Alexander V. Karchava, Marina A. Yurovskaya*
Chemistry of Heterocyclic Compounds, 2019
In this minireview, we consider the reactivity of fluorescent probes on the basis of coumarin der... more In this minireview, we consider the reactivity of fluorescent probes on the basis of coumarin derivatives for the purpose of detecting biogenic thiols (cysteine, homocysteine, glutathione) and thiophenols. References are provided to literature sources from the last 5 years.
Chemistry – A European Journal, 2019
The visible-light-induced arylation of tertiary phosphines with aryl(mesityl)iodonium triflates t... more The visible-light-induced arylation of tertiary phosphines with aryl(mesityl)iodonium triflates to produce the quaternary phosphonium salts occurs under mild, metal, and catalyst-free conditions. Photo-excited EDA-complexes between diaryliodonium salts and phosphines supposedly enable this transformation, that difficult to achieve through the traditional ground-state reactions. Demonstrating high functional group tolerance, broad scope, and complete selectivity of the aryl group transfer, particularly the method is compatible with sterically congested phosphines, which are challenging under metal-based catalytic methods.
Organic Letters, 2018
Employing DABCO as a substrate, aryl(mesityl)iodonium triflates are introduced as arylating agent... more Employing DABCO as a substrate, aryl(mesityl)iodonium triflates are introduced as arylating agents for a tertiary sp3-nitrogen. Mild conditions and exceptional selectivity of the aryl group transfer allow unprecedented N-aryl-DABCO salts to be obtained, bearing substituents of different electronic natures. This metal-free methodology has no analogy among known transition-metal-based reactions. The utility of isolated N-aryl-DABCO salts is demonstrated for the preparation of flibanserin.
Russian Chemical Bulletin, 2017
The review summarizes the data on the synthesis of O-hetarylhydroxylamine derivatives (mainly oxi... more The review summarizes the data on the synthesis of O-hetarylhydroxylamine derivatives (mainly oximes) published since the 1960s.
Organic Letters, 2018
A new protocol for the preparation of N-substituted indole-3-carboxylates has been developed. The... more A new protocol for the preparation of N-substituted indole-3-carboxylates has been developed. The key C-N bond formation occurs under transition-metal-free conditions employing a t-BuOK/DMF system without special initiators or additives. Across a number of substrates, indoles were afforded in yields higher or comparable to those obtained under transition-metal-catalyzed conditions. While demonstrating high functional group tolerance, new conditions are particularly attractive for manufacturing halogenated indoles that cannot be made in a pure form using other metal-based catalytic methods.
Russian Chemical Reviews, 2019
Published data of the last 10 years concerning the development of new and upgrading of known appr... more Published data of the last 10 years concerning the development of new and upgrading of known approaches to indole synthesis are integrated and analyzed. Modern versions of the classical syntheses such as the Fischer synthesis, Nenitzescu synthesis, Ullmann reaction, Leimgruber – Batcho synthesis, Reissert synthesis, Bartoli reaction, Madelung synthesis and Cadogan – Sundberg reaction are considered. The presented new approaches include transformations of heterocycles, synthesis from o-alkynylanilines, reductive cyclization of nitrobenzene derivatives, synthesis with the use of arynes and catalysis by N-heterocyclic carbenes. The final Section summarizes original methods for the synthesis of indoles other than those listed above; they are classified in terms of the nature of the forming bond (C–C, C–N). Rarely used methods based on benzene ring construction in pyrrole derivatives are discussed separately. The bibliography includes 246 references
The Journal of Organic Chemistry, 2017
The N-(2-pyridyl)-N'-ethylpiperazines are important structural motifs in several medicinally ... more The N-(2-pyridyl)-N'-ethylpiperazines are important structural motifs in several medicinally relevant compounds. Known synthetic methods toward these structures are multistep and generally based on the SNAr-chemistry; their applicability is significantly limited to substrates containing electron-withdrawing groups. Here, we describe a new methodology for a rapid and modular access to this privileged scaffold. Importantly, the developed protocol proved to be very general and efficient for the substrates containing substituents of different electronic nature. An operationally simple, metal-free, one-pot synthetic procedure involves the initial reaction of activated heterocyclic N-oxides with DABCO, followed by in situ treatment of the resultant quaternary N-(2-pyridyl)-DABCO salts with nucleophiles, resulting in ring-opening. The method features mild reaction conditions, high positional selectivity, and excellent functional-group tolerance. The utility of our approach is demonstrated by the late-stage site-selective functionalizations of complex molecules; a rapid modular assembly of MC2050, a potent PARP-1 inhibitor; and gram-scale preparations.
Encyclopedia of Reagents for Organic Synthesis, 2017
RSC Advances, 2013
ABSTRACT Readily accessible o-bromobenzylketones and primary alkyl amines and anilines were used ... more ABSTRACT Readily accessible o-bromobenzylketones and primary alkyl amines and anilines were used for the construction of substituted indoles in good to excellent yields. The sequence involves a titanium-mediated reaction of ketones with amines to afford imines and subsequent intramolecular cyclization into indoles employing copper catalysis. The two-step protocol allows for the preparation of indoles bearing both N-alkyl and N-aryl groups as well as N-unsubstituted indoles without isolation of the intermediates and is tolerant of a wide range of functionality.
ChemInform, 2003
Indole derivatives Indole derivatives R 0140 Synthesis of Derivatives of 2-(Indol-1-yl)propionic ... more Indole derivatives Indole derivatives R 0140 Synthesis of Derivatives of 2-(Indol-1-yl)propionic Acids.-The method for the preparation of N-substituted derivatives of indole from N-phenylalanine includes Fischer cyclization of the corresponding arylalkylhydrazones.
Tetrahedron: Asymmetry, 1995
... All rights reserved 09574166 95 9.50+0.00 09574166(95)003797 Indoles from 3Nitropyridinium Sa... more ... All rights reserved 09574166 95 9.50+0.00 09574166(95)003797 Indoles from 3Nitropyridinium Salts1: A new Route to Chiral Indoles and lndolines Alexander V.Karchava", Marina A.Yurovskaya ... 2. (a) Yurovskaya MA , Chertkov VA, Afanasyev AZ, Ienkina FV, Bundel' Yu.G. Khim ...
Tetrahedron: Asymmetry, 1998
Recent advances in the stereoselective synthesis of nitrogen containing heterocyclic compounds us... more Recent advances in the stereoselective synthesis of nitrogen containing heterocyclic compounds using the reduction of endocyclic double carbon-nitrogen bond are surveyed.
Tetrahedron, 2011
Starting from ortho-bromosubstituted phenoxyacetates or (phenythio)acetates and primary amines, v... more Starting from ortho-bromosubstituted phenoxyacetates or (phenythio)acetates and primary amines, various N-substituted 4H-1,4-benzoxazine-and 4H-1,4-benzothiazine-2-carboxylates were synthesized in moderate to high yields by using a Cu(I)-catalyzed Ullmann-type cyclization as a key step. The method is simple to operate, tolerates many functional groups and does not require any additives.
![Research paper thumbnail of Stereoselective synthesis of 4-substituted 1,2,3,4,10,10a-hexahydropyrazino[1,2-a]indoles](https://attachments.academia-assets.com/85500621/thumbnails/1.jpg)
](Russian Chemical Bulletin, 2005
Chemistry of Heterocyclic Compounds, 2008
Although few in number, indole derivatives containing a 1,1-dimethylpropen-2-yl (isopropenyl) fra... more Although few in number, indole derivatives containing a 1,1-dimethylpropen-2-yl (isopropenyl) fragment on the nitrogen atom are extremely interesting from the viewpoint of the medicinal chemistry of a class of naturally occurring compounds showing diverse biological properties. Some of these show anticancer, antifungal, antibiotic, anti-inflammatory, and antiviral activity [1-4]. The simplest member of the N-isopropenyl indole alkaloids is methyl 1-(1,1-dimethylprop-2-en-1-yl)-1H-indole-3-carboxylate (1) which is isolated from the Aporpium caryae basidiomycetes fungus and shows clear antifungal activity [4]. Compound 1 also serves as the synthetic precursor of other biologically active, naturally occurring indole derivatives i.e. methyl 1-(2,3-dihydroxy-1,1,-dimethylprop-2-en-1-yl)-and 1-(1,1-dimethyl-2,3-epoxyprop-2-en-1-yl)-1H-indole-3-carboxylates. Despite the relative structural simplicity of compound 1 its synthesis is not a trivial problem in view of the impossibility of directly introducing an isopropenyl substituent at position 1 of the indole. Up to this time the preparation of this compound involved two "indirect" synthetic strategies. The first of these consists of five stages (overall yield 60%) and is based on initial preparation of an N-isopropenylindoline, oxidation to the corresponding indole, and the introduction of a methoxycarbonyl group at position 3 in the final synthetic step [1, 2]. The second strategy consists of seven stages (overall yield 22%) and includes the preliminary transformation of an N-(1-ethoxycarbonyl)ethyl substituent in the N-indole to N-isopropenyl and then the introduction of the methoxycarbonyl substituent at position 3 [3]. We propose a novel, simple, and efficient method for the synthesis of compound 1 based on the use of the method reported recently by us to prepare N-substituted 1H-indole-3-carboxylic acids via a copper (I) iodide-catalyzed intramolecular Ullman reaction [5]. Refluxing equimolar solutions of methyl α-formyl-(o-bromophenyl)acetate (2) and the commercially available 1-methylbutyn-3-yl-2-amine in methanol gave the enamine 3 needed for cyclization and used in the following step without further purification. We have previously shown that cyclization of enamines prepared from α-branched primary aliphatic amines under standard conditions (CuI (5 mol %), K 3 PO 4 (2 equiv.), 80ºC) occurs slowly, full conversion of starting enamine needing a prolonged reaction time (10-20 h) and the indole yield did not exceed 50% [5]. An analogous situation has been seen in the cyclization of enamine 3, the yield of the N-isopropenyl indole 4 not exceeding 36% under these conditions. Increasing the reaction temperature to 140ºC caused only a minor increase in the yield to 50%.
Russian Chemical Reviews, 2021
Arylation methods based on the generation and use of aryl radicals have been a rapidly growing fi... more Arylation methods based on the generation and use of aryl radicals have been a rapidly growing field of research in recent years and currently represent a powerful strategy for carbon – carbon and carbon – heteroatom bond formation. The progress in this field is related to advances in the methods for generation of aryl radicals. The currently used aryl radical precursors include aryl halides, aryldiazonium and diaryliodonium salts, arylcarboxylic acids and their derivatives, arylboronic acids, arylhydrazines, organosulfur(II, VI) compounds and some other compounds. Aryl radicals are generated under mild conditions by single electron reduction or oxidation of precursors induced by conventional reagents, visible light or electric current. A crucial role in the development of the radical arylation methodology belongs to photoredox processes either catalyzed by transition metal complexes or organic dyes or proceeding without catalysts. Unlike the conventional transition metal-catalyzed ...
Russian Chemical Reviews, 2022
Khimiya Geterotsiklicheskikh Soedinenii, 2008
Khimiya Geterotsiklicheskikh Soedinenii, 2010
Chemistry of Heterocyclic Compounds, 2020
This review article covers literature data from the last 5 years regarding the various applicatio... more This review article covers literature data from the last 5 years regarding the various applications of 1,4-diazabicyclo[2.2.2]octane (DABCO) in organic chemistry. The frequent use of DABCO as a base, catalyst, and reagent has been reflected in the large number of publications, therefore our review will be published in 4 parts. The first part of the review is dedicated to the use of DABCO as catalyst for Morita–Baylis–Hillman and Knoevenagel reactions. Authors: Dmitry I. Bugaenko, Alexander V. Karchava, Marina A. Yurovskaya*
Chemistry of Heterocyclic Compounds, 2019
In this minireview, we consider the reactivity of fluorescent probes on the basis of coumarin der... more In this minireview, we consider the reactivity of fluorescent probes on the basis of coumarin derivatives for the purpose of detecting biogenic thiols (cysteine, homocysteine, glutathione) and thiophenols. References are provided to literature sources from the last 5 years.
Chemistry – A European Journal, 2019
The visible-light-induced arylation of tertiary phosphines with aryl(mesityl)iodonium triflates t... more The visible-light-induced arylation of tertiary phosphines with aryl(mesityl)iodonium triflates to produce the quaternary phosphonium salts occurs under mild, metal, and catalyst-free conditions. Photo-excited EDA-complexes between diaryliodonium salts and phosphines supposedly enable this transformation, that difficult to achieve through the traditional ground-state reactions. Demonstrating high functional group tolerance, broad scope, and complete selectivity of the aryl group transfer, particularly the method is compatible with sterically congested phosphines, which are challenging under metal-based catalytic methods.
Organic Letters, 2018
Employing DABCO as a substrate, aryl(mesityl)iodonium triflates are introduced as arylating agent... more Employing DABCO as a substrate, aryl(mesityl)iodonium triflates are introduced as arylating agents for a tertiary sp3-nitrogen. Mild conditions and exceptional selectivity of the aryl group transfer allow unprecedented N-aryl-DABCO salts to be obtained, bearing substituents of different electronic natures. This metal-free methodology has no analogy among known transition-metal-based reactions. The utility of isolated N-aryl-DABCO salts is demonstrated for the preparation of flibanserin.
Russian Chemical Bulletin, 2017
The review summarizes the data on the synthesis of O-hetarylhydroxylamine derivatives (mainly oxi... more The review summarizes the data on the synthesis of O-hetarylhydroxylamine derivatives (mainly oximes) published since the 1960s.
Organic Letters, 2018
A new protocol for the preparation of N-substituted indole-3-carboxylates has been developed. The... more A new protocol for the preparation of N-substituted indole-3-carboxylates has been developed. The key C-N bond formation occurs under transition-metal-free conditions employing a t-BuOK/DMF system without special initiators or additives. Across a number of substrates, indoles were afforded in yields higher or comparable to those obtained under transition-metal-catalyzed conditions. While demonstrating high functional group tolerance, new conditions are particularly attractive for manufacturing halogenated indoles that cannot be made in a pure form using other metal-based catalytic methods.
Russian Chemical Reviews, 2019
Published data of the last 10 years concerning the development of new and upgrading of known appr... more Published data of the last 10 years concerning the development of new and upgrading of known approaches to indole synthesis are integrated and analyzed. Modern versions of the classical syntheses such as the Fischer synthesis, Nenitzescu synthesis, Ullmann reaction, Leimgruber – Batcho synthesis, Reissert synthesis, Bartoli reaction, Madelung synthesis and Cadogan – Sundberg reaction are considered. The presented new approaches include transformations of heterocycles, synthesis from o-alkynylanilines, reductive cyclization of nitrobenzene derivatives, synthesis with the use of arynes and catalysis by N-heterocyclic carbenes. The final Section summarizes original methods for the synthesis of indoles other than those listed above; they are classified in terms of the nature of the forming bond (C–C, C–N). Rarely used methods based on benzene ring construction in pyrrole derivatives are discussed separately. The bibliography includes 246 references
The Journal of Organic Chemistry, 2017
The N-(2-pyridyl)-N'-ethylpiperazines are important structural motifs in several medicinally ... more The N-(2-pyridyl)-N'-ethylpiperazines are important structural motifs in several medicinally relevant compounds. Known synthetic methods toward these structures are multistep and generally based on the SNAr-chemistry; their applicability is significantly limited to substrates containing electron-withdrawing groups. Here, we describe a new methodology for a rapid and modular access to this privileged scaffold. Importantly, the developed protocol proved to be very general and efficient for the substrates containing substituents of different electronic nature. An operationally simple, metal-free, one-pot synthetic procedure involves the initial reaction of activated heterocyclic N-oxides with DABCO, followed by in situ treatment of the resultant quaternary N-(2-pyridyl)-DABCO salts with nucleophiles, resulting in ring-opening. The method features mild reaction conditions, high positional selectivity, and excellent functional-group tolerance. The utility of our approach is demonstrated by the late-stage site-selective functionalizations of complex molecules; a rapid modular assembly of MC2050, a potent PARP-1 inhibitor; and gram-scale preparations.
Encyclopedia of Reagents for Organic Synthesis, 2017
RSC Advances, 2013
ABSTRACT Readily accessible o-bromobenzylketones and primary alkyl amines and anilines were used ... more ABSTRACT Readily accessible o-bromobenzylketones and primary alkyl amines and anilines were used for the construction of substituted indoles in good to excellent yields. The sequence involves a titanium-mediated reaction of ketones with amines to afford imines and subsequent intramolecular cyclization into indoles employing copper catalysis. The two-step protocol allows for the preparation of indoles bearing both N-alkyl and N-aryl groups as well as N-unsubstituted indoles without isolation of the intermediates and is tolerant of a wide range of functionality.
ChemInform, 2003
Indole derivatives Indole derivatives R 0140 Synthesis of Derivatives of 2-(Indol-1-yl)propionic ... more Indole derivatives Indole derivatives R 0140 Synthesis of Derivatives of 2-(Indol-1-yl)propionic Acids.-The method for the preparation of N-substituted derivatives of indole from N-phenylalanine includes Fischer cyclization of the corresponding arylalkylhydrazones.
Tetrahedron: Asymmetry, 1995
... All rights reserved 09574166 95 9.50+0.00 09574166(95)003797 Indoles from 3Nitropyridinium Sa... more ... All rights reserved 09574166 95 9.50+0.00 09574166(95)003797 Indoles from 3Nitropyridinium Salts1: A new Route to Chiral Indoles and lndolines Alexander V.Karchava", Marina A.Yurovskaya ... 2. (a) Yurovskaya MA , Chertkov VA, Afanasyev AZ, Ienkina FV, Bundel' Yu.G. Khim ...
Tetrahedron: Asymmetry, 1998
Recent advances in the stereoselective synthesis of nitrogen containing heterocyclic compounds us... more Recent advances in the stereoselective synthesis of nitrogen containing heterocyclic compounds using the reduction of endocyclic double carbon-nitrogen bond are surveyed.
Tetrahedron, 2011
Starting from ortho-bromosubstituted phenoxyacetates or (phenythio)acetates and primary amines, v... more Starting from ortho-bromosubstituted phenoxyacetates or (phenythio)acetates and primary amines, various N-substituted 4H-1,4-benzoxazine-and 4H-1,4-benzothiazine-2-carboxylates were synthesized in moderate to high yields by using a Cu(I)-catalyzed Ullmann-type cyclization as a key step. The method is simple to operate, tolerates many functional groups and does not require any additives.
Russian Chemical Bulletin, 2005
Chemistry of Heterocyclic Compounds, 2008
Although few in number, indole derivatives containing a 1,1-dimethylpropen-2-yl (isopropenyl) fra... more Although few in number, indole derivatives containing a 1,1-dimethylpropen-2-yl (isopropenyl) fragment on the nitrogen atom are extremely interesting from the viewpoint of the medicinal chemistry of a class of naturally occurring compounds showing diverse biological properties. Some of these show anticancer, antifungal, antibiotic, anti-inflammatory, and antiviral activity [1-4]. The simplest member of the N-isopropenyl indole alkaloids is methyl 1-(1,1-dimethylprop-2-en-1-yl)-1H-indole-3-carboxylate (1) which is isolated from the Aporpium caryae basidiomycetes fungus and shows clear antifungal activity [4]. Compound 1 also serves as the synthetic precursor of other biologically active, naturally occurring indole derivatives i.e. methyl 1-(2,3-dihydroxy-1,1,-dimethylprop-2-en-1-yl)-and 1-(1,1-dimethyl-2,3-epoxyprop-2-en-1-yl)-1H-indole-3-carboxylates. Despite the relative structural simplicity of compound 1 its synthesis is not a trivial problem in view of the impossibility of directly introducing an isopropenyl substituent at position 1 of the indole. Up to this time the preparation of this compound involved two "indirect" synthetic strategies. The first of these consists of five stages (overall yield 60%) and is based on initial preparation of an N-isopropenylindoline, oxidation to the corresponding indole, and the introduction of a methoxycarbonyl group at position 3 in the final synthetic step [1, 2]. The second strategy consists of seven stages (overall yield 22%) and includes the preliminary transformation of an N-(1-ethoxycarbonyl)ethyl substituent in the N-indole to N-isopropenyl and then the introduction of the methoxycarbonyl substituent at position 3 [3]. We propose a novel, simple, and efficient method for the synthesis of compound 1 based on the use of the method reported recently by us to prepare N-substituted 1H-indole-3-carboxylic acids via a copper (I) iodide-catalyzed intramolecular Ullman reaction [5]. Refluxing equimolar solutions of methyl α-formyl-(o-bromophenyl)acetate (2) and the commercially available 1-methylbutyn-3-yl-2-amine in methanol gave the enamine 3 needed for cyclization and used in the following step without further purification. We have previously shown that cyclization of enamines prepared from α-branched primary aliphatic amines under standard conditions (CuI (5 mol %), K 3 PO 4 (2 equiv.), 80ºC) occurs slowly, full conversion of starting enamine needing a prolonged reaction time (10-20 h) and the indole yield did not exceed 50% [5]. An analogous situation has been seen in the cyclization of enamine 3, the yield of the N-isopropenyl indole 4 not exceeding 36% under these conditions. Increasing the reaction temperature to 140ºC caused only a minor increase in the yield to 50%.