Einwirkung von Acetessigester auf Phenylhydrazin

Knorr, Ludwig

doi:10.1002/cber.188301602194

Cited by 217 publications

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“…The technique of Knorr (1883) for the preparation of 3-methyl-3-pyrazolin-5-one, referred to hereafter as MPYRAZ. The melting point [experimental 215 °, literature value 215 ° (Wiley & Wiley, 1964)], elemental analysis [calculated for C4H6N20: C, 49.98; H, 6.12; N, 28.57; O, 16.33%; found: C, 49.20; H, 6.17; N, 28.50; O (by difference), 16.13%] and infrared spectrum (Refn, 1961)all confirmed the chemical structure of the product.…”

Section: Introductionmentioning

confidence: 99%

The crystal and molecular structure of 3-methyl-3-pyrazolin-5-one

Camp¹,

Stewart²

1971

Acta Crystallogr Sect B

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The crystal structure of 3-methyl-3-pyrazolin-5-one (C4H6N20) has been determined by X-ray diffraction as a model for the pyrazolin-5-one compounds. The space group is P2a/a. Cell dimensions are a= 10.520 (3), b=6.499 (2), c= 8.052 (1)/~, fl= 114.45 (1) °, Z=4, D~= 1.299 (1) g.cm-3. Three-dimensional X-ray data were collected using Mo Ka radiation. The structure was solved using statistical methods of phase determination, and refined by the full-matrix least-squares method to R= 0.071 (unit weights). Hydrogen-bonded layers are found parallel to the ab plane. The predominant tautomer is established as 3-methyl-3-pyrazolin-5-one. A comparison of structures based on data gathered by moving-crystal moving-counter and stationary-crystal stationary-counter methods shows no significant differences in bond lengths and angles calculated from atomic parameters refined on either set of data.

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Section: Introductionmentioning

confidence: 99%

The crystal and molecular structure of 3-methyl-3-pyrazolin-5-one

Camp¹,

Stewart²

1971

Acta Crystallogr Sect B

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“…7 The term "pyrazole" was given to this class of compounds by Ludwig Knorr in 1883. 8 Although there are many ways to prepare pyrazole ring, the condensation of the 1,3-dicarbonyls with hydrazine derivatives remains the most common and facile method to assemble this ring system. Many of the reported methods for the Knorr synthesis of pyrazoles suffer from drawbacks, such as the use of organic solvent and unrecoverable catalyst, 9 harsh reaction conditions, 10 and long reaction times.…”

Section: Introductionmentioning

confidence: 99%

A Modified and Practical Synthetic Route to Indazoles and Pyrazoles Using Tungstate Sulfuric Acid

Rahmatzadeh

Karami

Khodabakhshi³

2014

J Chinese Chemical Soc

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Tungstate sulfuric acid-catalyzed Knorr reaction have been used as a simple, rapid, atom economic and green method for the synthesis of indazole and pyrazole derivatives based on the condensation of hydrazine derivatives and b-dicarbonyl compounds under solvent-free conditions. It was found that the catalyst could be recovered and reused without significant loss of its activity. The use of this method provides a novel and improved modification of Knorr synthesis in terms of clean reaction profile, use of a safe catalyst and solvent-free conditions.

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“…It has a molecular formula of C 3 H 4 N 2 O.The chemistry of pyrazolone began in 1883 when Knorr reported the first pyrazolone derivative. The reaction of phenyl hydrazine and ethylacetoacetate resulted in novel structure identified in 1887 as 1-phenyl-3-methyl-5-pyrazolone [8]. The Knorr pyrazole synthesis is the reaction of hydrazines with 1,3 dicarbonyl compounds to provide the pyrazole or pyrazolone ring system.…”

Section: Introductionmentioning

confidence: 99%

“…Several 4,4-dimethyl derivatives, as well as Pyrazole Blue and tartrazine are derived from formula II whereas from structure III several pyrazolone dyes have been derived. When pyrazolones were discovered, they were only known as non-steroidal anti-inflammatory agents (or drugs) -NSAID, but in recent times, they are known to exhibit antioxidant, anticancer, antibacterial and several other pharmacological actions [8,10]. Pyrazolones are very important class of heterocycles due to their wide applications in pharmacological and biological activities [3,6].…”

Section: Introductionmentioning

confidence: 99%

“…It is also well known that they exhibit varied biological activities like anti-inflammatory, antibacterial, antifungal, analgesic, antipyretic, antioxidant, anticonvulsant, antidepressant, antihyperglycemic, antitumor, radioprotectivity, antiviral activities, etc. [8,10,15]. 4-acyl pyrazolones form metal chelates that are highly soluble in most organic solvents.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, Complexation and Characterization of 1-Phenyl-3-Methyl-4- (p-nitrobenzoyl) Pyrazolone-5(HNPz) and its complexes of Barium(II), Strontium(II) and Zinc(II)

Ekekwe¹,

Arinze²,

Nnanna³

et al. 2012

CHEMISTRY

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Complexes of Ba(II), Sr(II) and Zn(II) with 1-phenyl-3-methyl-4-(p-nitrobenzoyl) pyrazolone-5(HNPz) have been synthesized and characterized. The HNPz was prepared from high grade p-nitrobenzoyl chloride and 1-phenyl-3-methyl-5-pyrazolone. The process involved benzoylation of 17.60 g (0.10 M) 1-phenyl-3-methyl-5-pyrazolone (HPMP) with 14.55 g (0.103 M) nitrobenzoylchloride. The complexes of Ba (II), Sr (II) and Zn (II) were prepared by dissolving 5 mmol of BaCl 2 .2H 2 O,SrCl 2 .6H 2 O and ZnSO 4 .7H 2 O respectively in 10 mmol of HNPz. The complexing agent and the metal complexes were characterized by elemental analysis, UV-visible and infrared spectroscopies. The results show the complexes to be dihydrated bischelates conforming to a general molecular formula, MLn.2H 2 O, where L is the 4-acylpyrazolonato ion and n is the ligand number or oxidation state of metal,M (Ba, Sr, Zn). The study also indicates the formation of octahedral complexes which are presumed to have been formed through the enolic and carbonyl oxygen atoms of the coordination reagent; in which water molecules complete the expected coordination numbers of Ba(II), Sr(II) and Zn(II).

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Einwirkung von Acetessigester auf Phenylhydrazin

Cited by 217 publications

References 0 publications

The crystal and molecular structure of 3-methyl-3-pyrazolin-5-one

The crystal and molecular structure of 3-methyl-3-pyrazolin-5-one

A Modified and Practical Synthetic Route to Indazoles and Pyrazoles Using Tungstate Sulfuric Acid

Synthesis, Complexation and Characterization of 1-Phenyl-3-Methyl-4- (p-nitrobenzoyl) Pyrazolone-5(HNPz) and its complexes of Barium(II), Strontium(II) and Zinc(II)

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