4-Bromopyrazole
[CAS# 2075-45-8]

Identification

• Classification: Pharmaceutical intermediate >> API intermediate
• Name: 4-Bromopyrazole
• Synonyms: 4-Bromo-1H-pyrazole
• Molecular Formula: C₃H₃BrN₂
• Molecular Weight: 146.97
• CAS Registry Number: 2075-45-8
• EC Number: 629-057-5
• SMILES: C1=C(C=NN1)Br

Properties

• Density: 1.9±0.1 g/cm³, Calc.^*
• Melting point: 93-96 ºC (expl.)
• Index of Refraction: 1.602, Calc.^*
• Boiling Point: 255.0±0.0 ºC (760 mmHg), Calc.^*, 250-260 ºC (expl.)
• Flash Point: 108.0±19.8 ºC, Calc.^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H315-H319-H335
• Precautionary Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2	H319
Eye irritation	Eye Irrit.	2A	H319
Flammable solids	Flam. Sol.	2	H228

Discovory and Applicatios

4-Bromopyrazole is a halogenated pyrazole compound that has garnered interest in various fields of chemistry due to its versatile reactivity and potential applications in drug discovery, agrochemical development, and materials science. Pyrazole derivatives, including 4-bromopyrazole, are characterized by their five-membered heterocyclic ring, which consists of three carbon atoms and two nitrogen atoms. The bromine atom attached at the 4-position of the pyrazole ring imparts unique properties to the compound, making it valuable for a range of synthetic and industrial applications.

The discovery of 4-bromopyrazole is part of a broader interest in halogenated pyrazole derivatives, which are known for their biological activity and chemical reactivity. The bromine atom plays a crucial role in modulating the compound's reactivity, making it a useful building block for the synthesis of other bioactive molecules and functional materials. The introduction of bromine into the pyrazole ring increases its lipophilicity, which can enhance its ability to penetrate biological membranes, a key property for pharmaceutical applications.

In medicinal chemistry, 4-bromopyrazole and its derivatives have been investigated for their potential to interact with various biological targets, including enzymes, receptors, and ion channels. One of the key areas of research is the development of 4-bromopyrazole-based compounds as kinase inhibitors. Kinases are enzymes that regulate many cellular processes, and their dysregulation is implicated in a variety of diseases, including cancer and neurological disorders. 4-Bromopyrazole derivatives have been shown to inhibit certain kinases, making them promising candidates for the development of targeted therapies.

Additionally, 4-bromopyrazole has demonstrated antimicrobial and antifungal activity, further expanding its potential applications in the pharmaceutical and agrochemical industries. By modifying the 4-bromopyrazole structure, researchers can develop more potent and selective compounds for the treatment of infections caused by bacteria, fungi, and other pathogens.

In the field of agrochemicals, 4-bromopyrazole derivatives are being explored for use in the development of pesticides and herbicides. The bromine atom enhances the stability and reactivity of the pyrazole ring, which can improve the efficacy and selectivity of agrochemicals. For example, 4-bromopyrazole derivatives have been studied for their ability to interact with specific enzymes involved in the metabolism of plants or pests, providing a means to selectively target undesirable organisms while minimizing environmental impact.

Beyond its biological and industrial applications, 4-bromopyrazole is also used in materials science, particularly in the development of organic electronic materials. Pyrazole-based compounds, including 4-bromopyrazole, can be incorporated into organic semiconductors and photovoltaic devices. The halogenated pyrazole ring structure provides desirable electronic properties, such as improved charge transport and stability, making it suitable for use in organic light-emitting diodes (OLEDs), organic solar cells, and other electronic devices.

The synthesis of 4-bromopyrazole typically involves bromination of pyrazole under controlled conditions, which allows for the selective introduction of the bromine atom at the 4-position. This process can be optimized to yield high purity and yield of 4-bromopyrazole, which is essential for subsequent applications in chemical synthesis and industrial processes.

In conclusion, 4-bromopyrazole is a versatile chemical compound with significant applications in medicinal chemistry, agrochemicals, and materials science. Its ability to interact with biological targets, coupled with its stability and reactivity, makes it an attractive candidate for the development of new therapeutic agents, agrochemical formulations, and electronic materials. Further research into its synthesis, reactivity, and biological activity will likely continue to expand its utility in both academic and industrial settings.

References

2024. A comprehensive review on synthetic strategy and MOA of marketed drugs having therapeutically potential chemical entity pyrazole. Journal of the Iranian Chemical Society, 21(9).
DOI: 10.1007/s13738-024-03095-7

2016. Recent Advances in Bromination of Aromatic and Heteroaromatic Compounds. Synthesis, 48(04).
DOI: 10.1055/s-0035-1561503

2012. Metalation of Pyrazoles and Indazoles. Metalation of Azoles and Related Five-Membered Ring Heterocycles.
DOI: 10.1007/7081_2012_82