Recent Advances in Ring Transformations of Five-Membered Heterocycles and Their Fused Derivatives

Hajós, György; Riedl, Zsuzsanna; Kollenz, G.

doi:10.1002/1099-0690(200109)2001:18<3405::aid-ejoc3405>3.0.co;2-y

Cited by 44 publications

(7 citation statements)

References 71 publications

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“…Recyclizations are unique as a possibility for obtaining functionalized compounds but often have narrow preparative limits, since they are extremely sensitive to the stability of the initial rings and the effect of substituents [1][2][3][4][5][6]. For example, phenylhydrazones of 2-aroylmethyl-1H-benzimidazoles 1a-f are not inclined to remake the heterocyclic ring on acid catalysis, but undergo Fischer indolization [7].…”

mentioning

confidence: 70%

Recyclization on interaction of arylhydrazones of 2-aroylmethyl-1H-benzimidazoles with ethyl isothiocyanate

Dzvinchuk

Lozinskii

2006

Chem Heterocycl Compd

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Recyclizations are unique as a possibility for obtaining functionalized compounds but often have narrow preparative limits, since they are extremely sensitive to the stability of the initial rings and the effect of substituents [1][2][3][4][5][6]. For example, phenylhydrazones of 2-aroylmethyl-1H-benzimidazoles 1a-f are not inclined to remake the heterocyclic ring on acid catalysis, but undergo Fischer indolization [7]. However compounds of type 1 (and of the related type 2) are readily recyclized under the conditions of an acylation reaction, by the action of aroyl chlorides or anhydrides of carboxylic acids they give 5-(2-acylaminoanilino)-1,3-diarylpyrazoles [8-10]. According to our hypothesis and with data of quantum-chemical calculations [11], such a conversion is possibly caused by the direction of the acylation reaction to the benzimidazole nitrogen atom of the initial compounds, with the intermediate formation of the corresponding highly reactive acylbenzimidazolium derivative, which spontaneously undergoes rearrangement as a result of intramolecular nucleophilic attack at its position 2 of the hydrazone amino group. Initiation of an analogous recyclization by weak electrophiles of the isothiocyanate type remains unknown and was studied in the present work for this reason.We started from two series of compounds, the phenylhydrazones of 2-aroylmethylbenzimidazoles 1a-f and arylhydrazones of 2-phenacylbenzimidazole 2a-c. We used ethyl isothiocyanate as the second component of the reaction.It was found that the reactants interact at a molar ratio of 1:2 on boiling in pyridine. The isothiocyanate is probably added at the benzimidazole nitrogen atom with the intermediate formation of benzimidazolium derivatives 3, 4, the recyclization of which may proceed further through spiranes of structure 5, 6. However it does not stop at the stage of forming 5-(2-thioureidoanilino)pyrazoles 7, 8. Under the reaction conditions one further cyclocondensation readily occurs, which leads to the previously unknown 1-(1,3-diaryl-1H-pyrazol-5-yl)-1,3-dihydro-2H-benzimidazole-2-thiones 9a-f and 10a-c.

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confidence: 70%

Recyclization on interaction of arylhydrazones of 2-aroylmethyl-1H-benzimidazoles with ethyl isothiocyanate

Dzvinchuk

Lozinskii

2006

Chem Heterocycl Compd

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“…1,3,4-thiadiazoline, 1,2,4-triazoles, and 1,3,4-oxadiazoles are heterocycles related to biological properties such as antifungal, anti-inflammatory, antimalarial, anti-HIV activity, anti-TB properties, antimicrobial, anticancer, antiviral, antineoplastic, CNS depressant, and tyrosinase inhibitory activities [ 103 , 104 , 105 , 106 ]. Yusuf, Kaur, and Jain (2014) carried out the cyclization of bis tiosemicarbazones in the presence of acetic anhydride under reflux conditions to obtain 1,3,4-thiadiazoline [ 107 ].…”

Section: Synthetic Methods For Highly Active Compounds Against Fox Speciesmentioning

confidence: 99%

A Compendium of the Most Promising Synthesized Organic Compounds against Several Fusarium oxysporum Species: Synthesis, Antifungal Activity, and Perspectives

2021

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Vascular wilt caused by F. oxysporum (FOX) is one of the main limitations of producing several agricultural products worldwide, causing economic losses between 40% and 100%. Various methods have been developed to control this phytopathogen, such as the cultural, biological, and chemical controls, the latter being the most widely used in the agricultural sector. The treatment of this fungus through systemic fungicides, although practical, brings problems because the agrochemical agents used have shown mutagenic effects on the fungus, increasing the pathogen’s resistance. The design and the synthesis of novel synthetic antifungal agents used against FOX have been broadly studied in recent years. This review article presents a compendium of the synthetic methodologies during the last ten years as promissory, which can be used to afford novel and potential agrochemical agents. The revision is addressed from the structural core of the most active synthetic compounds against FOX. The synthetic methodologies implemented strategies based on cyclo condensation reactions, radical cyclization, electrocyclic closures, and carbon–carbon couplings by metal–organic catalysis. This revision contributes significantly to the organic chemistry, supplying novel alternatives for the use of more effective agrochemical agents against F. oxysporum.

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“…[ 15 ] Great efforts have, therefore, been made to discover and optimize new reactions/methodologies to facilitate the construction of heterocycles. [ 16 17 ] The extensive use of heterocyclic compounds may be recognized to a huge range of reaction types available that aid subtle structural as well as physicochemical modifications in the heterocyclic compounds. [ 18 19 ] Thus endeavor toward the understanding of interactive potency of heterocyclic compounds are extracting significance, especially expedient synthesis leading to N-heteoaromatics, which are potent inhibitors of lymphocyte apoptosis and often form the framework of deoxyribonucleic acid intercalating agents.…”

Section: Introductionmentioning

confidence: 99%

Rationalized design, synthesis and pharmacological screening of amino acid linked spiro pyrrolidino oxyindole analogs through environment friendly reaction

Das¹,

Bhattacharya²,

Kundu³

2013

J Adv Pharm Technol Res

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Introduction:The development of newer synthetic approaches toward the synthesis of polynuclear heteroaromatics and their application in the synthesis of some biologically active compounds has been discussed in this study.Materials and Methods:The synthesis of novel spiro pyrrolidino oxindoles was performed for the construction of amino acid linked polynuclear heteroaromatics by cycloaddition reaction. This reaction method is one of the most important methods for the construction of spiro pyrrolidino oxindole from the commercially available starting material isatin. Then the synthesized compounds were subjected for evaluation of nitric oxide scavenging and cytotoxic effects against tumor cell lines.Results:All the six synthesized compounds demonstrated promising antioxidant and cytotoxic effects in vitro.Conclusion:Form the present study, it can be concluded that the synthesized compounds are fruitful in terms of their chemical purity, structural novelty, marked biological activities (antioxidant and cytotoxic) in vitro and last of all the lucid and picturesque synthetic methodology to synthesize the molecules in a in a non-hazardous and environmental friendly way.

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Recent Advances in Ring Transformations of Five-Membered Heterocycles and Their Fused Derivatives

Cited by 44 publications

References 71 publications

Recyclization on interaction of arylhydrazones of 2-aroylmethyl-1H-benzimidazoles with ethyl isothiocyanate

Recyclization on interaction of arylhydrazones of 2-aroylmethyl-1H-benzimidazoles with ethyl isothiocyanate

A Compendium of the Most Promising Synthesized Organic Compounds against Several Fusarium oxysporum Species: Synthesis, Antifungal Activity, and Perspectives

Rationalized design, synthesis and pharmacological screening of amino acid linked spiro pyrrolidino oxyindole analogs through environment friendly reaction

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