Convenient synthesis of some new substituted pyrazolyl-1,3,4-oxadiazoles and pyrazolyl-1,2,4-triazoles

Elkholy, Yehya M.; Ali, Korany A.; Farag, Ahmad M.

doi:10.1002/jhet.5570430508

Cited by 16 publications

(5 citation statements)

References 25 publications

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“…This would be accompanied by cyclodehydration, leading eventually to the aminotriazoline derivative 13. This hypothesis is consistent with our earlier report [54] and with other similar observations [55][56][57].…”

Section: Chemistrysupporting

confidence: 94%

Regioselective synthesis and biological evaluation of some novel thiophene-containing heterocyclic scaffolds as potential chemotherapeutic agents

Gaber

Bagley

2011

Eur. J. Chem.

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KEYWORDSIn the reaction of 2-amino-3-carbethoxythiophene derivative 2b with hydrazine hydrate the respective aminocarbohydrazide 3 was isolated. Treatment of the latter product with carbon disulfide in alkaline medium caused a heterocyclization to give 1,3,4-oxadiazole-2-thione 5 rather than 3-amino-2-thioxothieno[2,3-d]pyrimidin-4-one 4, which could be obtained on treatment of carbohydrazide 3 with thiourea. The structure of products 4 and 5 was proved by spectroscopic methods and chemical transformations. Derivatization led to two novel series of condensed and uncondensed thiophenes, which were of significant interest for biological study. Since compound 4 contains two adjacent reactive functional groups, it reacted readily with different electrophilic reagents to provide a series of thieno[2,3-d]pyrimidin-4-one derivatives with annelated bridgehead nitrogen heterocycles 8-11, whereas a second series of 3-heteroaryl-substituted thiophenes 13-17 was obtained by thioamide functionalization in 1,3,4-oxadiazole derivative 5 using various chemical reagents. The new thiophene-based derivatives were evaluated for their preliminary antimicrobial activity against a representative panel of Gram-positive and Gram-negative bacteria as well as fungi strains. The compounds tested displayed different levels of inhibitory effects, with the assays carried out on two pathogenic bacteria and two pathogenic fungi. Of these compounds, the monocyclic aminothiophene derivative 15 showed the highest effect on pathogenic bacteria, while the tricyclic condensed thiophene derivative 8 was observed to have the same inhibitory effect against pathogenic mould (Aspergillus flavus) as the reference drug Amphotericin B. For those derivatives belonging to first series of condensed thiophenes with annelated bridgehead nitrogen heterocycles, it has been observed that the antibacterial effect was in general found to be significantly higher than the corresponding uncondensed analogues. Although most of the condensed and uncondensed thiophenes under investigation showed generally remarkable in vitro antibacterial activity, unfortunately, no significant antifungal activity was observed with any of the compounds tested except for 8. Surprisingly, compound 8 displayed an excellent effect on fungus (A. flavus) on the one hand, whereas the lowest effect on bacteria on the other. The attachment of a triazolothiadiazine moiety to a thiophene ring could be considered as a promising strategy for the development of new therapeutic antibacterial agents related to the aminothiophene system. Thienopyrimidinone Cyclocondensation Cyclodesulfurization Hydrazinolysis Alkylation Antimicrobial activity

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Section: Chemistrysupporting

confidence: 94%

Regioselective synthesis and biological evaluation of some novel thiophene-containing heterocyclic scaffolds as potential chemotherapeutic agents

Gaber

Bagley

2011

Eur. J. Chem.

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“…3-Imino(hydrazono)-3H-furan-2-ones are convenient initial compounds for the creation of new derivatives of the aroyl-and pivaloylpyruvic acids (APA and PPA) [1,2], as well as new heterocyclic systems [3][4][5][6][7]. Preparation of 3-imino(hydrazono)-3H-furan-2ones can be carried out both from the already existing furan cycle [8][9][10][11][12][13][14], and methods of intramolecular cyclization of 2-imino(hydrazono)-4-oxobutanoic acids [15][16][17][18][19]. 3-Imino(hydrazono)-3H-furan-2-ones have several reactive centers in its structure, due to which it becomes possible to change the direction of the attacking reagent, depending on the nature of the substituents in the furan cycle and imino(hydrazono)function.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Biological Activity of Substituted 2-[2-(Diphenylmethylene)hydrazinyl]-5,5-dimethyl-4-oxohex-2-enoates

et al. 2021

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The synthesis of new substituted 2-[2-(diphenylmethylene)hydrazinyl]-5,5-dimethyl-4-oxohex-2-enoates is described. The synthesis from commercially available starting materials included the preparation of 5,5-dimethyl-2,4-dioxohexanoic acid via Claisen condensation of 3,3-dimethylbutan-2-one (pinacolone) and diethyl oxalate in the presence of sodium methanolate. The resulting acid reacted with (diphenylmethylene)hydrazine to form 2-[(diphenylmethylene)hydrazono]-5,5-dimethyl-4-oxohexanoic acid. The initial 5-(tert-butyl)-3-[(diphenylmethylene)hydrazono]furan-2(3H)-one was obtained by a known literary method: intramolecular cyclisation of 2-[(diphenylmethylene)hydrazono]-5,5-dimethyl-4-oxohexanoic acid under the action of propionic anhydride. 5-(tert-Butyl)-3-[(diphenylmethylene)hydrazono]furan-2(3H)-one entered the decyclization reaction under the action of primary aromatic alcohols to form substituted 2-[2-(diphenylmethylene)hydrazinyl]-5,5-dimethyl-4-oxohex-2-enoates. The presence of equimolar quantities of triethylamine was important; otherwise, the reaction proceeded with low yields. The isolation of target compounds was carried out by fi ltration of the resulting sediment followed by recrystallization. The structure of the compounds obtained was confi rmed by the 1 H and 13 C NMR spectroscopy methods. The resulting substituted esters exist in a solution of deuterated chloroform in one tautomeric form, in contrast to the previously studied solutions of deuterated DMSO, where up to four tautomeric forms were observed. Analgesic and anti-infl ammatory activity of new and previously synthesized compounds of this series has been studied. Analgesic activity was evaluated by the "Hot Plate" test on outbred white mice of both sexes with intraperitoneal injection. Anti-infl ammatory activity was studied on a carrageenan-induced paw edema model with oral administration of the studied substances. One compound possesses both high analgesic and high anti-infl ammatory effects, which causes the prospects for its use as a pharmacologically active substance.

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“…Chromanones and pyridines represent an important heterocyclic family in numerous applications, such as biological activity, chemical sensors, and optical switches . To date, there are many approaches to pyridine synthesis including coupling of 1,5‐dicarbonyl compounds or 1,3‐dicarbonyl compounds and aldehyde with ammonia, or 1,3‐dicarbonyl compounds with 3‐aminoenones or nitriles . Many other reactions are used for the preparations of pyridines, among them a multicomponent condensation reaction that is particularly attractive, because it decreases the reaction steps and times; in addition, it allows varying the nature of substituent at many positions of the heterocycles, which gives access to a large family of derivatives with improved biological activity …”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10] To date, there are many approaches to pyridine synthesis including coupling of 1,5-dicarbonyl compounds or 1,3-dicarbonyl compounds and aldehyde with ammonia, or 1,3-dicarbonyl compounds with 3-aminoenones or nitriles. [11,12] Many other reactions are used for the preparations of pyridines, among them a multicomponent condensation reaction that is particularly attractive, because it decreases the reaction steps and times; in addition, it allows varying the nature of substituent at many positions of the heterocycles, which gives access to a large family of derivatives with improved biological activity. [10][11][12] Even greater potential of chromeno-pyridine conjugates in the field of biological activity can be revealed upon their attachment to macrocyclic calixarene molecules, which are known as a nontoxic scaffold for attachment of various pharmacophore .…”

Section: Introductionmentioning

confidence: 99%

“…[11,12] Many other reactions are used for the preparations of pyridines, among them a multicomponent condensation reaction that is particularly attractive, because it decreases the reaction steps and times; in addition, it allows varying the nature of substituent at many positions of the heterocycles, which gives access to a large family of derivatives with improved biological activity. [10][11][12] Even greater potential of chromeno-pyridine conjugates in the field of biological activity can be revealed upon their attachment to macrocyclic calixarene molecules, which are known as a nontoxic scaffold for attachment of various pharmacophore . [13] In addition, a challenging problem in calixarene functionalization is the direct attachment of heterocyclic units on the upper and lower rims.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microwave‐assisted synthesis and heterocyclic functionalization of chromenopyridines on calixarene scaffold

Ali

Hafez

Elsayed

et al. 2020

Journal of Heterocyclic Chem

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A three‐component one‐pot condensation reaction of chroman‐4‐one with ethyl 2‐cyanoacetate and various aldehydes in the presence of ammonium acetate afforded a series of 2‐oxo‐4‐phenyl‐1,5‐dihydro‐2H‐chromeno[4,3‐b]pyridine‐3‐carbonitrile. These heterocycles have been converted to chloropyridine derivatives and appended to macrocyclic calix[4]arene scaffold through aromatic nucleophilic substitution under microwave irradiation. In this study, the microwave‐assisted functionalization of the lower rim of calix[4]arene has been considered the only appropriate tool because the conventional heating did not lead to any new product after 72 hours of heating under thermal condition.

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Convenient synthesis of some new substituted pyrazolyl-1,3,4-oxadiazoles and pyrazolyl-1,2,4-triazoles

Cited by 16 publications

References 25 publications

Regioselective synthesis and biological evaluation of some novel thiophene-containing heterocyclic scaffolds as potential chemotherapeutic agents

Regioselective synthesis and biological evaluation of some novel thiophene-containing heterocyclic scaffolds as potential chemotherapeutic agents

Synthesis and Biological Activity of Substituted 2-[2-(Diphenylmethylene)hydrazinyl]-5,5-dimethyl-4-oxohex-2-enoates

Microwave‐assisted synthesis and heterocyclic functionalization of chromenopyridines on calixarene scaffold

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