4-(4-Bromophenyl)-1-methyl-1h-pyrazole
[CAS# 1191616-45-1]

Identification

• Classification: Organic raw materials >> Aryl compounds
• Name: 4-(4-Bromophenyl)-1-methyl-1h-pyrazole
• Molecular Formula: C₁₀H₉BrN₂
• Molecular Weight: 237.1
• CAS Registry Number: 1191616-45-1
• SMILES: CN1C=C(C=N1)C2=CC=C(C=C2)Br

Properties

• Density: 1.4±0.1 g/cm³ Calc.^*
• Boiling point: 345.3±25.0 ºC 760 mmHg (Calc.)^*
• Flash point: 162.6±23.2 ºC (Calc.)^*
• Index of refraction: 1.626 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H302-H317
• Precautionary Statements: P280

Discovory and Applicatios

4-(4-Bromophenyl)-1-methyl-1H-pyrazole is a member of the aryl-substituted pyrazole family, a group of heterocyclic compounds that have been extensively documented in the chemical literature due to their versatility in synthetic chemistry and their presence in numerous bioactive molecules. The structure consists of a pyrazole ring bearing a para-bromophenyl substituent at the 4-position and a methyl group attached to the ring nitrogen. This substitution pattern places the compound among derivatives that were historically explored as intermediates in heterocycle construction, ligand frameworks, and precursors for metal-catalyzed cross-coupling reactions.

The discovery of pyrazole derivatives dates back to early heterocyclic chemistry, where condensation reactions between hydrazines and 1,3-dicarbonyl compounds provided reliable routes to substituted pyrazoles. Subsequent developments in cycloaddition chemistry further expanded the synthetic repertoire, particularly through the 1,3-dipolar cycloaddition of diazo compounds with alkynes, a transformation that has been treated comprehensively in later literature. These methods established the foundation for the preparation of aryl-substituted pyrazoles such as 4-(4-bromophenyl)-1-methyl-1H-pyrazole, which can be accessed through condensation, cycloaddition, or transition-metal-catalyzed transformations depending on the substitution sequence required.

The presence of a bromine atom on the phenyl ring makes the compound particularly suitable for synthetic applications involving carbon–carbon and carbon–heteroatom bond formation. Brominated arylpyrazoles have been widely used in cross-coupling reactions, including Suzuki–Miyaura, Buchwald–Hartwig, and Stille processes, as documented in studies on pyrazole functionalization. These reactions allow access to a broad array of derivatives by replacing the bromine with alkyl, aryl, amino, or heteroaryl substituents, and they have been key in the preparation of compounds for medicinal chemistry, materials development, and agrochemical research. The predictable reactivity of aryl bromides under palladium catalysis is one of the characteristics that led to the use of compounds of this type as modular intermediates.

Pyrazole derivatives have been recognized for decades as a central heterocycle class in the development of biologically active molecules, including anti-inflammatory agents, enzyme inhibitors, and agricultural products. Reviews on pyrazole chemistry have outlined how the ring system’s electronic distribution, hydrogen-bonding capacity, and stability contribute to its widespread use. While 4-(4-bromophenyl)-1-methyl-1H-pyrazole itself is primarily known as a synthetic precursor, related arylpyrazoles have appeared in patent and research literature dealing with pharmaceutical leads, ligand design, and small-molecule probes. This background provides context for the compound’s relevance in applied research settings.

The systematic study of pyrazole chemistry also includes detailed analyses of structural effects associated with substituents on both the pyrazole ring and appended aromatic groups. Comprehensive heterocyclic references describe how substitutions at the 4-position influence reactivity, tautomer preference, and metal-binding properties. Although individual derivatives may differ in their specific roles, the broader literature establishes the chemical behavior that also governs compounds like the 4-bromophenyl analogue. These foundational insights are essential to understanding how such a molecule participates in reactions and why it serves as a valuable intermediate in multistep synthesis.

Overall, the significance of 4-(4-bromophenyl)-1-methyl-1H-pyrazole is rooted in the established chemistry of pyrazole derivatives, their documented preparation methods, and their long-standing use as intermediates in synthetic design. The literature record reflects both the historical development of pyrazole synthesis and the modern impact of arylpyrazoles in organic chemistry, where compounds with activating substituents such as bromine occupy an important role in cross-coupling methodology and derivative construction.

References

2024. CDK inhibitors. CN Patent, 118546154.

2023. Fused heterocyclic compounds as pi3kalpha inhibitors. WO Patent, 2023104111.

2022. Kdm1a inhibitors for the treatment of disease. WO Patent, 2023069884.