Synthesis of Pyrazolone Derivatives:

ABSTRACT: Heterocyclic compounds are acquiring more importance in recent years because of their pharmacological activities. Pyrazolones have a particular value due to their broad spectrum of biological activity and their wide ranging utility as synthetic tools in the design of various bioactive molecules. Pyrazolone is a five membered lactum ring, containing two nitrogen and one ketonic group in its structure. In addition, pyrazolones possess antimicrobial, antifungal, antimycobacterial, antibacterial, anti-inflammatory, antitumor, gastric secretion stimulatory, antidepressant and antifilarial activities. They also serve as precursors for dyes, pigments, pesticides and chelating agents, besides finding applications in the extraction and separation of various metal ions. The high therapeutic properties of the pyrazolone releted drugs have encouraged the medicinal chemists to synthesized a large number of novel chemotherapeutic agents. Numerous methods for the synthesis of pyrazolone and also their various structure reactions offer enormous scope in the field of medicinal chemistry. This articles aims to review the work reported, their chemistry and biological activities of pyrazolone during past years.

SCHEME 8: SYNTHESIS OF HYDROXYALKENOYL-3-METHYL-1H-PYRAZOL-5(4H)-ONES

SCHEME 5:  SYNTHESIS OF 2-ARYL-5-METHYL-2, 3-DIHYDRO-1H-3-PYRAZOLONES IN PRESENCE OF p-TSA

SCHEME11: SYNTHESIS OF BISINDOLYLPYRAZOLONE DERIVATIVES

The process comprises the following steps: firstly, the pH of methanol solution of phenylhydrazine is adjusted to be between 5.0 and 6.5 with hydrochloric acid, acetoacetic ester is added drop by drop when the solution is mixed, the temperature is controlled between 40 DEG C and 90 DEG C, and the reflux reaction lasts for 1 to 6 hours secondly, the methanol in the reaction solution is distilled, the pH is adjusted to be neutral, the reaction solution is stirred, and the reflux reaction lasts for 1 to 3 hours at the temperature between 60 DEG C and 80 DEG C thirdly, the reaction solution is cooled after the reaction is completed, the crystal is separated, and the crude product is acquired through filtration fourthly, the crude product is dissolved in a solvent with methanol under the hot condition and recrystallized, and the finished product of white crystal 1-benzyl-3-methyl-5-pyrazole alkone can be prepared.

SCHEME15: SYNTHESIS OF UNSUBSTITUTED PYRAZOLONE DERIVATIVES

In this laboratory experiment, students synthesize 3-methyl-4-(4-methylbenzoyl)-1-phenyl-pyrazol-5-one by selective C-acylation of 3-methyl-1-phenyl-1-pyrazol-5-one. Calcium hydroxide is used to push the tautomeric equilibrium toward the enol form, to protect the hydroxyl functionality as a complex, to trap the liberated hydrogen chloride, and to keep the reaction media basic. The product is obtained in excellent yield and recrystallized from various solvents and solvent systems. The chromatographic and physical parameters are determined and the results are analyzed. The signals in the NMR spectra of acyl pyrazolone are assigned and then compared with those of three previously synthesized acyl pyrazolones and two corresponding O-acylated products.

Search results for 1-phenyl-3-methyl-5-pyrazolone at Sigma-Aldrich

Developer 1; AURORA KA-3365; 2,4-Dihydro-5-Methyl-2-Phenyl-3h-Pyrazol-
Molecular Formula: C10H10N2O
Molecular Weight: 174.2
CAS Number: 89-25-8
EINECS Number: 201-891-0
Merck: 14,6713
BRN: 609575


Traits: White Crystals Or Powder
Melting Point: 126-128 ° C
Boiling Point: 287 ℃
Density: 1,12 G / Cm3
Flash Point: 191 ° C
Water Solubility: 3 G / L (20 ° C)
Solubility: Soluble In Water, Slightly Soluble In Alcohol And Benzene, Insoluble In Ether, Petroleum Ether And Cold Water.


1, Mainly For The Synthesis Of Pyrazolone Antipyretic Analgesics Such As Analgin, Antipyrine, Aminopyrine;
2, Also Pyrazolone Acid Dyes Such As Acid Media Zaohong BN, Permanent Yellow G And Color Film Dyes, Pesticides And Some Other Fine Chemicals Intermediates;
3, For The Determination Of Cobalt, Copper, Iron, Nickel, Silver And Vitamin B12 Reagents, But Also For Dye Synthesis.

25KG / Woven Bags.

Synthesis of Some Pyrazolone Derivatives and Evaluation …

In the recent years much attention has been focused on the synthesis of heterocycles containing nitrogen atom because of their biological and medicinal importance including ontological research. They are widely distributed in nature and are essential for life. Pyrazolones is a five member heterocyclic compound containing one ketonic group and two nitrogen atoms adjacent to each other. In 1883, Knorr et al 1 gave the generic name pyrazole to above class of the compounds, which is a five member unsaturated ring compound with two adjacent nitrogen atoms. Antipyrine was the first pyrazolone derivative for clinical use and was synthesized in 1883 2. It was used as the first agent to reduce fever and also for arthritis. There are three possible heteropyrazolines [1, 2, 3] in which carbonyl group is adjacent to nitrogen.

General Procedure for synthesis of 3-Methyl-1-Phenyl-Pyrazolone ..

The carbonyl at position five leads to 5-hydroxyl pyrazoles [4], since the 5-hydroxy compound exhibits pronounced enol character, tautomeric forms shown below for the 1-phenylderivative are the fundamental structures involved in the pyrazolone reactions.