Chemical Identity and Structure

5-Chloro-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid is a substituted pyrazole derivative bearing three distinct functional groups: a chloro substituent at the 5-position, a difluoromethyl (–CHF₂) group at the 3-position, and a carboxylic acid (–COOH) at the 4-position, with an N-methyl group on the pyrazole nitrogen. This combination of electron-withdrawing groups renders the molecule highly polar and moderately acidic.

The pyrazole ring is a five-membered aromatic heterocycle containing two adjacent nitrogen atoms, widely exploited as a pharmacophore and agrochemical building block due to its metabolic stability and capacity for hydrogen bonding. The presence of the difluoromethyl group imparts lipophilicity modulation and resistance to oxidative metabolism, while the carboxylic acid moiety provides a handle for amide coupling or ester formation in downstream synthesis.

Physicochemical Properties and Handling

As a carboxylic acid with multiple halogen substituents, this compound is expected to be a solid at room temperature with limited solubility in water but improved solubility in polar aprotic solvents such as DMF, DMSO, and acetonitrile. The difluoromethyl and chloro groups increase molecular weight and contribute to the compound's overall crystallinity.

When handling this reagent, standard laboratory precautions apply. Researchers should wear appropriate personal protective equipment (PPE) including nitrile gloves, safety glasses, and a lab coat. Work should be performed in a well-ventilated fume hood, as halogenated organic compounds may generate irritating vapors. The compound should be stored in a tightly sealed container at cool, dry conditions, away from moisture and light, to prevent hydrolysis of the acid functionality or decomposition of the difluoromethyl group.

Consult the Safety Data Sheet (SDS) provided by Aladdin Scientific prior to use for specific hazard classifications, first-aid measures, and disposal guidance in accordance with local regulations.

Applications in Agrochemical and Synthetic Chemistry

The primary utility of 5-Chloro-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid lies in its role as a key building block for the synthesis of succinate dehydrogenase inhibitor (SDHI) fungicides. SDHI fungicides act by inhibiting complex II of the mitochondrial respiratory chain in fungal pathogens, making them effective broad-spectrum crop protection agents. The difluoromethylpyrazole motif is a recognizable pharmacophoric fragment found in several commercial fungicide active ingredients relevant to wheat and other cereal crop protection.

The carboxylic acid group is particularly amenable to amide bond formation via coupling reagents (e.g., HATU, EDC/NHS) or via conversion to the acyl chloride, enabling the attachment of amine-containing partner molecules to produce the final amide-linked active ingredient scaffolds. The chloro substituent at the 5-position may also participate in nucleophilic aromatic substitution under appropriate conditions, further extending the compound's synthetic versatility.

Beyond fungicides, this compound class finds relevance in medicinal chemistry research where fluorinated heterocycles are valued for their metabolic stability, lipophilicity, and ability to engage in dipole interactions with biological targets.

Reagent Specifications and Quality

Aladdin Scientific supplies 5-Chloro-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid under SKU C729624. Researchers and procurement teams are encouraged to request the current Certificate of Analysis (CoA) for lot-specific purity data, including HPLC purity, melting point, NMR characterization, and residual solvent content where applicable.

For synthetic applications requiring high-fidelity coupling reactions, it is advisable to verify carboxylic acid content by titration or quantitative NMR prior to use. Ensure the product is fully dried if moisture-sensitive downstream reactions (e.g., acyl chloride formation) are planned.

Multiple quantities may be available depending on application scale, from milligram quantities for feasibility studies to gram-scale supply for process chemistry. Contact Aladdin Scientific for availability, bulk pricing, and custom packaging options.