Nucleophilic attack on the unsubstituted carbon atom of azines and nitroarenes as an efficient methodology for constructing heterocyclic systems

Чупахин, О. Н.; Beresnev, D. G.

doi:10.1070/rc2002v071n09abeh000747

Cited by 31 publications

(4 citation statements)

References 40 publications

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“…On the other hand, these transformations widen the concept of recyclization mechanism in the heterocyclic series by the SN(ANRORC) (Addition-Nucleophile-Ring Opening-Ring Closure) type. Numerous examples of these recyclizations have been investigated and generalized in recent reviews 15,16 by academician Chupakhin for the series of 1,2,4-triazine ring.…”

Section: Methodsmentioning

confidence: 99%

Synthesis and structure of 5-acylhydrazine-3,3,5-trimethylisoxazolidines

Еrshov¹,

Добродумов²,

Грибанов³

2004

Arkivoc

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Section: Methodsmentioning

confidence: 99%

Synthesis and structure of 5-acylhydrazine-3,3,5-trimethylisoxazolidines

Еrshov¹,

Добродумов²,

Грибанов³

2004

Arkivoc

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“…This abil ity of azines is behind convenient routes to complex fused heterocyclic systems that are of particular interest from the viewpoint of biological activity. [2][3][4] However, publications devoted to the reactivities of phosphorylthioacetamides are scarce. [5][6][7][8] To the best of our knowledge, they are mainly concerned with (1) alky lation reactions that occur at the sulfur atom 5, 6 and sub sequently afford biologically active amidines, (2) the Hantzsch synthesis of phosphorus containing thiazoles, 7 and (3) regioselective condensation with dimethyl acetylenedicarboxylate yielding phosphorus containing thiazolidin 4 ones.…”

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confidence: 99%

Phosphorylthioacetamides in the synthesis of annulated quinoxalines

et al. 2007

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Diethoxyphosphorylthioacetamide in the reaction with 2,3 dichloroquinoxaline acted as a thionating reagent, giving diethoxyphosphorylacetonitrile and 2 chloro 3 [(3 chloro 2 quinoxalinyl)thio]quinoxaline. Reactions of phosphorylthioacetamides with N methylquin oxalinium iodide in alcohol media in the presence of a base proceeded stereoselectively to afford cis 3 phosphoryl 1,3,3a,4,9,9a hexahydro 2H pyrrolo[2,3 b]quinoxaline 2 thiones.Key words: phosphorylthioacetamides, 2,3 dichloroquinoxaline, N methylquinoxalinium iodide, annulation, 1,3,3a,4,9,9a hexahydro 2H pyrrolo[2,3 b]quinoxaline 2 thiones.Thioamides of carboxylic acids are widely employed as key precursors for the synthesis of various five and six membered heterocycles. 1 In particular, azines con taining two and more heteroatoms are known to undergo annulation in the presence of thioamides of carboxylic acids (and some other bisnucleophilic reagents). This abil ity of azines is behind convenient routes to complex fused heterocyclic systems that are of particular interest from the viewpoint of biological activity. 2-4However, publications devoted to the reactivities of phosphorylthioacetamides are scarce. 5-8 To the best of our knowledge, they are mainly concerned with (1) alky lation reactions that occur at the sulfur atom 5,6 and sub sequently afford biologically active amidines, (2) the Hantzsch synthesis of phosphorus containing thiazoles, 7 and (3) regioselective condensation with dimethyl acetylenedicarboxylate yielding phosphorus containing thiazolidin 4 ones. 8 Limited data on the chemical prop erties of compounds of this class are largely due to the lack of convenient methods for their preparation.A recently developed, convenient method for the syn thesis of phosphorylthioacetamides with various types of the surrounding of the P atom made these organophos phorus compounds easily accessible. 9 Here we present data on their application as annulating agents in reactions with azines. Diethoxy and diphenylphosphorylthio acetamides 1a,b were chosen as the starting organophos phorus substrates and easily accessible 2,3 dichloro quinoxaline and N methylquinoxalinium iodide, as azine components.Condensation of thioamides RC(S)NH 2 (R = H, Me, and Ph) with 2,3 dichloroquinoxaline has been re ported 10-12 to give 2 substituted thiazolo[4,5 b]quinoxa lines, although the physicochemical constants of the re sulting 2 methyl derivative do not coincide (the melting points of the samples differ by more than 200 °C). Sur prisingly, thioamide 1a in a reaction with 2,3 dichloro quinoxaline 2 acted as a thionating agent. As a result of the reaction of equimolar amounts of the reactants in ethanol in the presence of triethylamine as an acceptor of HCl, 2 chloro 3 (3 chloroquinoxalin 2 ylthio)quin oxaline 3, the starting thioamide 1a, and diethoxy phosphorylacetonitrile were isolated instead of the ex pected thiazolo[4,5 b]quinoxaline (Scheme 1). Scheme 1

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“…Depending on the nature of the group replaced by nucleophile and the mechanism of new bond formation, these cyclizations may be regarded as S H N -S H N [1-3], A N -A N [4-9], A N -S H N [7-9], A N -S N ipso [10, 11], or S N H -S N ipso [11,12]. As a rule, the key stage in these multistep processes is attack on unsubstituted carbon atom in the heteroring.…”

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confidence: 99%

Ring-Chain Transformations of Dihydroisoxazolo[4,5-b]quinoxaline

Boguslavskii

Ponizovskii²,

Кодесс

et al. 2005

Russ J Org Chem

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Ring-chain transformation of 3-hydroxyiminomethyl-1-methylquinoxalinium iodide into 9-methyl-9,9a-dihydroisoxazolo [4,5-b]quinoxaline was studied. The isoxazole ring in the latter was cleaved by the action of alcohols.In the recent years, methods for the synthesis of fused azine systems were developed on the basis of tandem reactions of azines and azinium ions with difunctional nucleophiles. Depending on the nature of the group replaced by nucleophile and the mechanism of new bond formation, these cyclizations may be regarded as S H N -S H N [1-3], A N -A N [4-9], A N -S H N [7-9], A N -S N ipso [10, 11], or S N H -S N ipso [11,12]. As a rule, the key stage in these multistep processes is attack on unsubstituted carbon atom in the heteroring. Here, information on the properties of σ H adducts and conditions of their formation is very important for understanding their reactivity. Studies on σ H adducts derived from azines and nucleophiles are often complicated due to reversibility of the corresponding processes, whereas cyclic adducts of 1,4-diazines with difunctional nucleophiles are more stable. There are published data on equilibrium addition of S-, O-, and N-nucleophiles to 1-alkylquinoxalinium salts [13][14][15]; furthermore, isolation of stable crystalline σ H adducts derived from 1-ethyl-2,3-dicyanopyrazinium ion has been reported in a few publications [16].We previously reported on tandem reactions of 1,4-diazines and their quaternary salts containing an exocyclic carbonyl group with difunctional nucleophiles, resulting in fusion of five-, six-, and sevenmembered heterorings to the pyrazine ring. These cyclizations occur as intramolecular nucleophilic substitution of hydrogen and give rise to aromatic systems [7][8][9]12]. In the present communication we report on specific features of isoxazole ring fusion and properties of the dihydroisoxazolo[4,5-b]quinoxaline system. It is known that 2-quinoxalinecarbaldehyde oximes are capable of being involved in intramolecular nucleophilic substitution of hydrogen [8] or other readily departing groups [17,18] with formation of isoxazolo[4,5-b]quinoxalines. We examined ring-chain transformations of N-alkyl-2-hydroxyiminomethylquinoxalinium salts.2-Quinoxalinecarbaldehyde oxime (I) [8] was treated with methyl iodide in DMF to give quinoxalinium salt II (Scheme 1). The 1 H NMR spectrum of salt II contained a three-proton signal at δ 4.73 ppm from the N-methyl group; its position is typical of N-methyl-N N NOH

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Nucleophilic attack on the unsubstituted carbon atom of azines and nitroarenes as an efficient methodology for constructing heterocyclic systems

Cited by 31 publications

References 40 publications

Synthesis and structure of 5-acylhydrazine-3,3,5-trimethylisoxazolidines

Synthesis and structure of 5-acylhydrazine-3,3,5-trimethylisoxazolidines

Phosphorylthioacetamides in the synthesis of annulated quinoxalines

Ring-Chain Transformations of Dihydroisoxazolo[4,5-b]quinoxaline

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