III.—Oxidation of benzalthiosemicarbazone

Young, George W.; Eyre, William

doi:10.1039/ct9017900054

Cited by 38 publications

(14 citation statements)

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“…Since the late XIX century different reactions involving 1,3,4-thiadiazoles have been reported in the literature. [28][29][30][31][32][33][34][35] One of the first authors to report a synthesis of a thiadiazole was Bush in 1894, 29 who reacted hydrazine sulfate and carbon disulfide in the presence of an alcoholic solution of potassium hydroxide. According to Losanitch, 29 the development of 1,3,4-thiadizole chemistry is linked to the discovery of hydrazines.…”

Section: Methodologies For the Synthesis Of 134-thiadiazolementioning

confidence: 99%

“…This last step provided 74a-q with yields of 20 -70 % (Table 9) Table 9. Synthesis of 1,3,4-thiadiazoles from thiosemicarbazide and POCl3 or PPA 63 The authors reported good performance in the oxidation of 5-nitrofurfural thiosemicarbazone (83) with ferric chloride, 28,53,58 however when thiosemicarbazones derived from 2-furfural and 2-pyridine-carboxaldehyde were used, the yields obtained were less than 40 %. The authors associated the lower yield obtained in the reaction with furfural, compared to 5nitrofurfural, with the nitro group which prevents the acid cleavage of the furan ring.…”

Section: Scheme 15 Synthesis Of 2-amino-134-thiadiazoles Employing I2mentioning

confidence: 99%

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Synthesis of 1,3,4-Thiadiazole Derivatives and Microbiological Activities: A Review

Aguiar¹,

Barbosa²

2019

Rev. Virtual Quim

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Síntese de Derivados de 1,3,4-Tiadiazol e Atividades Microbiológicas: Uma Revisão Resumo: A resistência bacteriana associada a diferentes antibióticos é uma limitação para o tratamento de infecções e isto tem estimulado o desenvolvimento de novos agentes antimicrobianos. Neste aspecto, novos derivados de 1,3,4-tiadiazol-2,5-dissubstituídos, os quais apresentam diversificada atividade biológica, têm sido o foco de vários projetos de pesquisa nos anos recentes. Este artigo destaca as principais metodologias para a síntese deste heterociclo utilizando acilidrazinas, ditiocarbazatos, tiossemicarbazidas, 1,3,4oxadiazóis. Adicionalmente, derivados de 1,3,4-tiadizol-2,5-dissubstituídos com ação antimicrobiana são reportados.

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Section: Methodologies For the Synthesis Of 134-thiadiazolementioning

confidence: 99%

Section: Scheme 15 Synthesis Of 2-amino-134-thiadiazoles Employing I2mentioning

confidence: 99%

Synthesis of 1,3,4-Thiadiazole Derivatives and Microbiological Activities: A Review

Aguiar¹,

Barbosa²

2019

Rev. Virtual Quim

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“…Many methods have been described for the synthesis of 1,3,4-thiadiazole compounds, in the literature. In these methods, the following substances appear as starting materials: thiosemicarbazites [6][7][8], thiocarbazides [9], dithiocarbazates [10,11], thioacylhydrazines [12], acylhydrazines [13], bitolyure derivatives [14]. Oruç et al (2004), synthesized the 2,5-disubstitued-1,3,4-thiadiazole derivatives and evaluated for anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv using the BACTEC 460 radiometric system and, they reported that 2-phenylamino-5-(4-fluorophenyl)-1,3,4thiadiazole has a greater inhibitory potential than the other compounds tested [15].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Charactezation of Some New 1,3,4-Thiadiazole Compounds Derived from α-methyl Cinnamic Acid and their DFT Studies

Gür¹,

Şener²

2017

ANADOLU UNIVERSITY JOURNAL OF SCIENCE AND TECHNOLOGY a - Applied Sciences and Engineering

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Some novel 1,3,4-thiadiazole compounds derived from α-methyl cinnamic acid was synthesized, in this study. The structures of these compounds were elucidated by using spectroscopic methods such as FT-IR spectroscopy, 1 H-NMR spectroscopy, 13 C-NMR spectroscopy. Then, the absorption characteristics of the compounds were also examined by using UV-Vis spectrophotometer. In addition, the geometrical and electronic properties as well as Ultraviolet Visible analyzes of the compounds were theoretically done by using the density functional theory. The electronic configurations of the compounds substituted fluoro, chloro and methoxy have been investigated and how to effect chemical reactivity parameters to this configuration have been analyzed by using frontier molecular orbital energies. The calculated values obtained by B3PW91 with 6-311++G basis set and B3LYP with cc-PVTZ basis set are in good agreement with the experimental data. The results show that the UV-Vis absorptions are noticeably influenced by the o-, m-or p-positions of Cl, F and methoxy substituents. The methoxy substituent has more effect on the LUMO energies when compared to the Cl and F substituents. Moreover, positions of the substituents in the isomeric compounds were found to influence the molecular electronegativity and absorption wavelength. The absorption wavelength has the greatest value as the electronegativity of the isomer structures in the p-position of the substituents is smaller.

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“…Substrates 1a-z were prepared according to literature reports. 21,23,35 Dichloromethane was purified by refluxing with CaH 2 for three hours and distilling. …”

Section: Methodsmentioning

confidence: 99%

Oxidative cyclization of aldehyde thiosemicarbazones induced by potassium ferricyanide and by tris(p-bromophenyl)amino hexachloroantimoniate. A joint experimental and computational study

Meo¹,

Gruttadauria²,

Noto³

2005

Arkivoc

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The oxidative ring closure reaction of some aryl-substituted thiosemicarbazones induced by "bona fide" one-electron abstracting agents was investigated, by means of both experimental and computational techniques. The corresponding 1,2,4-triazole derivatives were the only cyclization products observed. The occurrence of two slightly different mechanistic pathways for the reaction is discussed. Keywords:Oxidative cyclization, thiosemicarbazones, 1,2,4-triazoles IntroductionThe cyclization of suitable open-chain organic molecules is a classical and very popular approach to the synthesis of heterocyclic derivatives, owing to both the large variety of heterocycles accessible through this way, and the large variety of conditions under which the reaction can be performed.1,2 Noticeably, when more than one product can be obtained at the same time in a particular reaction, good to excellent selectivities can often be achieved (and sometimes reverted) by means of a suitable choice of the cyclizing agent and conditions. [2][3][4][5] Frequently, such cyclization reactions are induced by acidic media or electrophilic reagents. In the latter case, this might involve de facto a formal oxidation of the organic substrate, as an implicit consequence of the process (the cyclo-etherification or lactonization of unsaturated alcohols and acids induced by halogens or sulfinyl and selanyl halides provides a typical case). 3,[5][6][7][8][9][10][11][12][13] In other occasions, the cyclization mechanism involves a plain oxidation stepelectron abstraction or dehydrogenation -prior to the actual ring closure step. Examples of these reactions have been recently reviewed. Aldehyde semicarbazones and thiosemicarbazones 1 are typical substrates which may undergo ring closure processes induced by an oxidizing agent, to afford the corresponding 1,2,4-triazole 2 and 1,3,4-oxa-or -thiadiazole 3 derivatives (Scheme 1). There is now enough evidence that the reaction may follow very different courses, depending on the substrate structure (in particular on the alkyl or aryl substituent groups placed on its main molecular framework) and on the oxidizing agent used. In particular, we have been interested in the oxidation of aryl-substituted thiosemicarbazones induced by high-valent (Fe) metal salts. [19][20][21][22][23] Despite the apparent similarity of these reagents, surprisingly we observed that very different results -both in terms of reaction regiochemistry and yields, and in terms of reaction kinetics -can be achieved by the use of different salts, depending on the hardness/softness of the metal cation (or, more properly, of the solvated metal-counteranion complex), as well as on its intrinsic oxidizing strength. On the grounds of a careful analysis of all available data, we proposed 2a,22,23 (Scheme 2) that the formation of the 1,2,4-triazole ring could be induced by an attack of the oxidizing agent on the tail thioamide-like moiety of the molecule, followed by a single electron transfer (s.e.t.) step and then by a rate-limiting ring clo...

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III.—Oxidation of benzalthiosemicarbazone

Cited by 38 publications

References 0 publications

Synthesis of 1,3,4-Thiadiazole Derivatives and Microbiological Activities: A Review

Synthesis of 1,3,4-Thiadiazole Derivatives and Microbiological Activities: A Review

Synthesis and Charactezation of Some New 1,3,4-Thiadiazole Compounds Derived from α-methyl Cinnamic Acid and their DFT Studies

Oxidative cyclization of aldehyde thiosemicarbazones induced by potassium ferricyanide and by tris(p-bromophenyl)amino hexachloroantimoniate. A joint experimental and computational study

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