The synthesis of 5-amino-4-arylazo-3-methyl-1H-pyrazoles and 5-aryl-3-methylpyrazole[3,4-e][1,2,3,4]tetrazines

The methods of synthesis, structure, reactivity, and synthetic utility of pyrazole-3(5)-diazonium salts are reviewed here for the first time, with emphasis on heterocyclization reactions of these compounds.More than one hundred years have passed since α-diazo derivatives of pyrazole were discovered. A substantial amount of knowledge has been accumulated over this time regarding the stability, structure, and transformations of these compounds. However, the chemistry of pyrazole-3(5)-diazonium salts developed rapidly only in the second half of the 20th century, with many studies performed in various countries, in particular Germany, Egypt, Russia, and Japan. Unfortunately, no systematic review has been compiled for the wide range of data about pyrazole-3(5)-diazonium salts. Some aspects regarding the properties of these compounds have been discussed in reviews and monographs on other topics [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17].

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“…[125]. The mechanism of this reaction was proposed to involve the delocalized zwitterion 53 as intermediate [126].…”

Section: Intramolecular Azo Couplingmentioning

confidence: 98%

Chemistry of Pyrazole-3(5)-Diazonium Salts (Review)*

Ledenyova

Didenko

Shikhaliev

2014

Chem Heterocycl Comp

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“…3,4 5-Aminopyrazoles are very important class of heterocycles due to their biological and pharmacological activities. 5,6 These compounds often exhibit antiinflammatory, herbicidal, fungicidal, bactericidal, and antipyretic activities. [6][7][8][9][10][11][12] The aminopyrazole compounds have been easily obtained by the reaction of nitrile derivatives with hydrazine, and are very useful as precursors for the synthesis of fused heterocyclic ring systems.…”

Section: Introductionmentioning

confidence: 99%

“…5,6 These compounds often exhibit antiinflammatory, herbicidal, fungicidal, bactericidal, and antipyretic activities. [6][7][8][9][10][11][12] The aminopyrazole compounds have been easily obtained by the reaction of nitrile derivatives with hydrazine, and are very useful as precursors for the synthesis of fused heterocyclic ring systems. 13,14 Reactions of aminopyrazoles with electrophilic reagents give rise to various fused annulated heterocyclic systems, including pyrazolo[1,5-a]pyrimidines which are synthetic analogs of purines.…”

Section: Introductionmentioning

confidence: 99%

SYNTHESIS OF SOME NEW HETEROARYLBISAZO DYES DERIVED FROM p-AMINOAZOBENZENE

Ameen¹,

Fadda²

2018

ECB

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Several novel arylbisazopyrazolo[1,5-a]pyrimidines were synthesized from diazotization of 4-aminoazobenzene and coupling with malononitrile and then refluxed with hydrazine hydrate to give 3,5-diamino-4-arylbisazo-1H-pyrazole.The later compound was diazotized and coupled with bifunctional reagents to produce novel heteroarylbisazo dyestuffs. Structural characterization of these novel dyes was carried out using IR, 1 H NMR, and mass spectroscopy.

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“…It has been known for many years that the azo compounds are the most widely used class of dyes due to their versatile application in various fields such as the dyeing of textile fiber, the coloring of different materials, colored plastic, and advanced applications in organic synthesis. Some of these compounds are also applied in medicine due to their biological and pharmacological activities which exhibit an anti-inflammatory, fungicidal, bactericidal, plant growth regulating properties, antipyretic, and protein kinase inhibitors [1][2][3][4][5][6][7][8][9][10]. Some azopyrimidine derivatives also find application in dyes and complexes [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…Although a number of articles have been published concerning the synthesis of pyrimidine and azopyrimidine derivatives, those containing an azotetrazolo pyrimidine system of pyrimidines have not yet been reported. In continuation of our work, we report here the synthesis of 5-amino-tetrazolo[1,5-a]pyrimidin-7-ol (I) and its disperse arylazo dyes (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). The spectral characteristics of prepared compounds are also reported.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Some Novel Arylazo Disperse Dyes Derived from 5-Amino-tetrazolo[1,5-a]pyrimidin-7-ol as Coupling Component and Investigation of Their Absorption Spectra

Liu

Chen

et al. 2013

J. Heterocyclic Chem.

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5‐amino‐tetrazolo[1,5‐a]pyrimidin‐7‐ol (I) was synthesized by reaction of 5‐amino‐tetrazole with ethyl cyanoacetate in excellent yield. A series of novel 5‐amino‐6‐arylazotetrazolo[1,5‐a]pyrimidin‐7‐ol dyes were prepared by linking o‐, m‐, p‐anisidine, o‐, m‐, p‐chloroaniline, o‐, m‐, p‐nitroaniline, o‐, m‐, p‐toluidine and aniline to 5‐amino‐tetrazolo[1,5‐a]pyrimidin‐7‐ol (I). The structure of these dyes were confirmed by UV‐vis, FTIR and 1H NMR spectroscopic techniques and elemental analysis. The effect of varying pH and solvent upon the absorption ability of 5‐amino‐6‐arylazotetrazolo[1,5‐a]pyrimidin‐7‐ol sudstituted with electron‐withdrawing and electron‐donating groups at their o‐, m‐, p‐position was examined.

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The synthesis of 5-amino-4-arylazo-3-methyl-1H-pyrazoles and 5-aryl-3-methylpyrazole[3,4-e][1,2,3,4]tetrazines

Cited by 20 publications

References 12 publications

Chemistry of Pyrazole-3(5)-Diazonium Salts (Review)*

Chemistry of Pyrazole-3(5)-Diazonium Salts (Review)*

SYNTHESIS OF SOME NEW HETEROARYLBISAZO DYES DERIVED FROM p-AMINOAZOBENZENE

Synthesis of Some Novel Arylazo Disperse Dyes Derived from 5-Amino-tetrazolo[1,5-a]pyrimidin-7-ol as Coupling Component and Investigation of Their Absorption Spectra

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