Iodine-catalysed oxidative cyclisation of acylhydrazones to 2,5-substituted 1,3,4-oxadiazoles

Majji, Ganesh; Rout, Saroj Kumar; Guin, Srimanta; Gogoi, Anupal; Patel, Bhisma K.

doi:10.1039/c3ra44897e

Cited by 54 publications

(25 citation statements)

References 68 publications

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“…Although plethora of protocols have been well documented for the construction of 1,3,4‐oxadiazole scaffold, several of them are encountered with a major setback from the stand point of eco‐friendly concerns, involvement of either strong acidic or corrosive reagents . Hence, the synthesis of hitherto target compounds was accomplished by using the molecular iodine as per Scheme …”

Section: Resultsmentioning

confidence: 99%

“…Respective individual condensation between the compounds 5, 6 with appropriate aromatic aldehyde (ArCHO) for 6 h afforded the key intermediate 7, 8 which have been carried forward without further purification . Lastly, oxidative cyclisation of composites 7, 8 with molecular iodine in presence of oxidant hydrogen peroxide at 60 °C for 10 h generated the title compounds 9 , 10 (Figure ) in good yields . Lipophilicity values (presented in blue) for the derivatives 9, 10 are presented in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…Due to their in vivo performance, enhanced pharmacokinetics, metabolic profile, presence of toxophoric linkage ‐N=C−O‐ these motifs are considered to be biologically improved pharmacophores . Literature is flooded with the construction of this scaffold and nearly 686 patents have been filed since last decade thus highlighting/capturing accelerated interest from several research groups due to the myriad applications of this system . Symmetrically and unsymmetrically 2,5‐disubstituted‐1,3,4‐oxadiazoles are encompassed with an array of broad spectrum of activities such as analgesic, antidiabetic, anticancer, antifungal, anti‐inflammatory, antitubercular, antibacterial, antiepileptic, anti‐HIV, ulcerogenic, hypoglycemic, sedative, hypnotic and insecticidal agents .…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of 2,5‐Disubstituted‐1,3,4‐oxadiazole Derivatives and Their Evaluation as Anticancer and Antimycobacterial Agents

et al. 2017

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A series of regioisomeric (2,5‐dimethoxybenzoic acid, veratric acid) analogues were prepared by swapping the carboxylic motif to its oxadiazole bioisostere and have been screened for in vitro anticancer studies by using MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) colorimetric assay. All of them were well characterized by spectroscopic techniques. Among the screened compounds, 9 i (2‐(2,5‐dimethoxyphenyl)‐5‐(5‐phenylthiophen‐2‐yl)‐1,3,4‐oxadiazole) demonstrated superior activity against MDA231 cells. Products 9 i displayed excellent activity against DU145, HCT15 and 10 i (2‐(3,4‐dimethoxyphenyl)‐5‐(5‐phenylthiophen‐2‐yl)‐1,3,4‐oxadiazole) against MDA231 cells. Structure of 10 c (2‐(3,4‐dimethoxyphenyl)‐5‐(2,4,6‐trimethoxyphenyl)‐1,3,4‐oxadiazole) was further authenticated through single crystal X‐ray diffraction. Analogue 9 i have come out to be the best anticancer and antimycobacterial agent.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis of 2,5‐Disubstituted‐1,3,4‐oxadiazole Derivatives and Their Evaluation as Anticancer and Antimycobacterial Agents

et al. 2017

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“…The oxidative cyclization of N-aryl and N-alkyl hydrazones to construct 2,5-substituted 1,3,4-oxadiazoles has been reported (Scheme 62). [74] N-Aryl and N-alkyl hydrazones are prepared by treating benzoyl hydrazide with variousa romatica nd aliphatic aldehydes. N-Aryl hydrazones possessing EDGs in the aryl ring of the precursor aldehyde give better resultst han those with EWGs.…”

Section: Heteroatom Activation To Form Ah Etàibond As Ak Ey Intermediatementioning

confidence: 99%

Metal‐Free Cross‐Dehydrogenative Coupling (CDC): Molecular Iodine as a Versatile Catalyst/Reagent for CDC Reactions

Parvatkar

Manetsch

Banik

2018

Chemistry An Asian Journal

102

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The development of ecofriendly methods for carbon-carbon (CÀC) and carbon-heteroatom (CÀHet) bond formation is of great significance in modern-dayr esearch. Metal-free cross-dehydrogenative coupling (CDC) has emerged as an important tool for organic and medicinal chemists as am eanst of orm CÀCa nd CÀHet bonds, as it is atom economical and more efficient and greenert han transition-metalc atalyzed CDC reactions. Molecular iodine (I 2 )i s recognized as an inexpensive, environmentally benign, and easy-to-handle catalyst or reagentt op ursueC DCs under mild reactionc onditions, with good regioselectivities and broad substrate compatibility.T his review presentst he recentd evelopmentso fI 2 -catalyzed CÀC, CÀN, CÀO, and CÀ S/CÀSe bond-forming reactions for the synthesis of various important organic molecules by cross-dehydrogenative coupling.Scheme1.Strategies for CÀCa nd CÀHet bond formation by CDC.[a] Dr. Scheme5.Synthesis of substituted indolizines.Scheme6.Synthesis of (E)-or (Z)-2-methylthio-1,4diones.Scheme7.Synthesis of indolo[2,3-b]carbazoles.Scheme8.Synthesis of p-amino phenyl diketones.Scheme9.Synthesis of functionalized cyclopropanes.Scheme10. Photooxidative coupling of thiophenesw ith carbonyls.Bz = benzoyl.Scheme65. Synthesis of 2-aminobenzothiazoles. PTSA = para-toluenesulfonic acid.Scheme66. Synthesis of b-decarbonylated sulfones.Scheme67. Synthesis of diheteroaryl thioethers.

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“…19,20 Do ponto de vista da Química Medicinal, substâncias contendo este heterociclo podem possuir atividades biológicas de interesse, tais como: antitumoral, agonista de receptores benzodiazepínicos, analgésico, diurético, bactericida, dentre outros. 21 A preparação do anel 1,3,4-oxadiazol pode acontecer via ciclodesidratação de diacil hidrazidas, 22 oxidação de acil hidrazonas, 23 reação entre acil hidrazida e ortoésteres, 24 rearranjo de diaril-tetrazinas 25 e reações entre tetrazóis e cloreto de acila (reação de Huisgen), 26 …”

Section: Heterociclos 134-oxadiazolunclassified

Abordagem Didática Para O Desenvolvimento De Moléculas Bioativas: Regra Dos Cinco De Lipinski E Preparação De Heterociclo 1,3,4-Oxadiazol Em Forno De Micro-Ondas Doméstico

Santos¹,

Gonsalves²,

Araújo³

2017

Quim. Nova

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. In Brazil, the development of new chemical entities (NEQ) is still limited to small advances in the academic and public research sectors, the authors understand that this is a sector of the pharmaceutical industry that needs encouragement. Accepting that education transforms society, educate students in the development of bioactive molecules, it's a way to stimulate the national pharmaceutical industry to invest in the sector. Thus, this work brings a didactic sequence, applicable in undergraduate courses, which exemplifies some stages of development of the NEQ through its rational planning. The synthesis of a 1,3,4-oxadiazole heterocycle was planned and its potentiality assessed through the Lipinski's Rule of Five (RO5), using the ChemSpider ® database. Once in accordance with RO5, the heterocycle was prepared using a simple and accessible methodology, using microwaves for domestic use as heating source. The 2-phenyl-5-(pyridin-4-yl)-1,3,4-oxadiazole was synthesized by oxidative cyclization of acylhydrazone and an overall yield of 90%. So was possible to demonstrate in a practical way some steps for the development of a substance with potential biological activity and thus to attract greater interest of undergraduate students by this follow-up of the Medicinal Chemistry. INTRODUÇÃODo ponto de vista econômico, as inovações podem se tornar o diferencial para a competitividade de empresas e países. Dentro deste cenário, a indústria farmacêutica é uma das mais lucrativas em razão da busca constante por produtos inovadores. Existem quatro estágios tecnológicos na indústria farmacêutica, sendo estes: Estágio I -Pesquisa e Desenvolvimento (P&D); Estágio II -Produção de Farmoquímicos; Estágio III -Produção de Especialidades Farmacêuticas; e Estágio IV -Marketing e Comercialização das Especialidades Farmacêuticas. A descoberta de novas moléculas com potencial terapêutico (novas entidades quí-micas -NEQ) faz parte do Estágio Tecnológico I, uma atividade que compreende a pesquisa básica de screening, o desenho molecular e os estudos farmacológicos. 1No Brasil, tanto as indústrias nacionais quanto as subsidiárias de multinacionais atuam apenas nos Estágios Tecnológicos III e IV, ou seja, há formulação de medicamentos e comercialização, contudo, praticamente quase a totalidade das matérias-primas deve ser importada. Embora o país possua uma indústria de medicamentos bastante desenvolvida, sua capacidade tecnológica para gerar inovações ainda não é satisfatória, ficando as atividades de P&D basicamente restritas a setores acadêmicos e públicos de pesquisa. 1 A Química Medicinal é uma área de estudo que visa o desenvolvimento de novos fármacos, e assim, fornece meios para a obtenção de NEQ. A síntese orgânica colabora com este processo promovendo a obtenção das moléculas propostas. A formação de recursos humanos capacitados para o desenvolvimento de NEQ é uma maneira de colaborar com o setor nacional de P&D de fármacos, área considerada estratégica do ponto de vista social, econômico e político. Considerando que, de 70 a 8...

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Iodine-catalysed oxidative cyclisation of acylhydrazones to 2,5-substituted 1,3,4-oxadiazoles

Abstract: An environmentally benign synthesis of 2,5-disubstituted 1,3,4-oxadiazoles has been developed starting from N-aroylhydrazones and N-acetylhydrazones at room or ambient temperature using a catalytic quantity of iodine in the presence of an aqueous hydrogen peroxide oxidant.

Cited by 54 publications

References 68 publications

Synthesis of 2,5‐Disubstituted‐1,3,4‐oxadiazole Derivatives and Their Evaluation as Anticancer and Antimycobacterial Agents

Synthesis of 2,5‐Disubstituted‐1,3,4‐oxadiazole Derivatives and Their Evaluation as Anticancer and Antimycobacterial Agents

Metal‐Free Cross‐Dehydrogenative Coupling (CDC): Molecular Iodine as a Versatile Catalyst/Reagent for CDC Reactions

Abordagem Didática Para O Desenvolvimento De Moléculas Bioativas: Regra Dos Cinco De Lipinski E Preparação De Heterociclo 1,3,4-Oxadiazol Em Forno De Micro-Ondas Doméstico

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