1-(4-Chlorophenyl)-1H-pyrazol-3-ol: Handling & Use Protocol

1-(4-Chlorophenyl)-1H-pyrazol-3-ol is a chlorophenyl-substituted pyrazolol building block widely employed in medicinal chemistry and organic synthesis as a versatile scaffold for the preparation of bioactive heterocyclic derivatives.

Product Name

1-(4-Chlorophenyl)-1H-pyrazol-3-ol

SKU

C194946

Molecular Formula

C9H7ClN2O

Molecular Weight

194.62 g/mol

CAS Number

Needs review — not confirmed in source material

Appearance

Solid (typical for pyrazolol derivatives; verify CoA)

Recommended Storage

Store in a cool, dry, well-ventilated area away from light and moisture; verify exact conditions on product CoA

Materials and Safety Precautions

Before beginning any work with 1-(4-Chlorophenyl)-1H-pyrazol-3-ol (SKU: C194946), consult the Safety Data Sheet (SDS) supplied by Aladdin Scientific. As a halogenated heterocyclic compound, it should be handled with appropriate personal protective equipment (PPE), including nitrile gloves, safety goggles, and a laboratory coat. All manipulations should be performed in a well-ventilated fume hood.

Required materials:

• 1-(4-Chlorophenyl)-1H-pyrazol-3-ol (C194946), Aladdin Scientific
• Analytical balance (0.1 mg resolution or better)
• Amber glass vials or screw-cap microcentrifuge tubes
• Appropriate solvents (see Dissolution section)
• Nitrile gloves, lab coat, safety goggles
• Fume hood

Note: Always verify current handling requirements against the SDS and Certificate of Analysis (CoA) provided with each lot.

Stock Solution Preparation and Dissolution

1-(4-Chlorophenyl)-1H-pyrazol-3-ol contains both a pyrazolol (hydroxypyrazole) moiety and a para-chlorophenyl substituent, which together influence its solubility profile. The compound is expected to dissolve in polar aprotic solvents such as dimethyl sulfoxide (DMSO) and dimethylformamide (DMF), and may show limited solubility in aqueous buffers at neutral pH. Solubility in ethanol or methanol may be moderate.

Recommended procedure for stock solution preparation:

1. Allow the sealed container to equilibrate to room temperature before opening, to prevent condensation on the compound.
2. Accurately weigh the required amount of compound using an analytical balance in the fume hood.
3. Transfer to an appropriate vessel and add DMSO (preferred) or another suitable solvent in small increments, mixing gently (vortex or sonicate briefly) until fully dissolved.
4. Prepare stock solutions at a concentration appropriate for downstream dilution (e.g., 10–100 mM in DMSO; verify solubility experimentally).
5. Aliquot into single-use volumes to avoid repeated freeze-thaw cycles.
6. Label each vial with compound name, SKU, lot number, concentration, solvent, and preparation date.

Important: Actual solubility values have not been confirmed in the provided source material. Researchers should experimentally verify solubility in their chosen solvent system prior to preparing large-scale stocks.

Storage and Stability

Proper storage is essential to maintain the integrity of 1-(4-Chlorophenyl)-1H-pyrazol-3-ol over time. As a general guideline for solid pyrazolol derivatives:

• Solid form: Store in a tightly sealed container in a cool, dry, well-ventilated area, away from direct light, heat sources, and moisture. Refer to the product CoA for lot-specific storage temperature recommendations.
• Stock solutions in DMSO: Aliquots are typically stored at –20 °C. Avoid repeated freeze-thaw cycles, which can promote degradation or precipitation.
• Stability: The hydroxypyrazole tautomeric system may be sensitive to prolonged exposure to strong acids, bases, or oxidizing agents. Specific stability data should be verified from the product CoA or established literature.

Disclaimer: Exact stability data are not confirmed in the provided source material. Review lot-specific CoA and consult SDS for confirmed storage conditions.

Application Notes and Typical Research Uses

1-(4-Chlorophenyl)-1H-pyrazol-3-ol serves as a valuable building block and intermediate in synthetic and medicinal chemistry. Key application areas include:

• Heterocyclic synthesis: The reactive 3-hydroxy (or 3-oxo tautomer) group and the N1-aryl substituent make this compound a versatile precursor for the preparation of pyrazole-based pharmacophores, including pyrazolone and pyrazolyl ether derivatives.
• Medicinal chemistry: Pyrazolol scaffolds are well-established in drug discovery programmes targeting a range of biological activities. Researchers use such building blocks to elaborate structure-activity relationships (SAR).
• Material science and agrochemical research: Chlorophenyl-substituted pyrazoles have been investigated as intermediates in the synthesis of agrochemicals and functional materials.

Note: Specific biological activity data for this exact compound (C194946) are not confirmed in the source material. Any reported activities should be independently verified by the researcher.

Quality Control and Documentation

Aladdin Scientific provides a Certificate of Analysis (CoA) for each lot of 1-(4-Chlorophenyl)-1H-pyrazol-3-ol (C194946). Researchers should review the CoA prior to use to confirm:

• Identity (e.g., NMR, MS, or HPLC confirmation)
• Purity (e.g., HPLC purity ≥95% or as stated on CoA)
• Appearance and physical form
• Lot number and expiry/retest date

For critical applications, in-house analytical verification (e.g., LC-MS, ¹H NMR) is recommended to confirm compound identity and purity before use. Record all lot-specific information in your laboratory notebook or electronic laboratory notebook (ELN) for traceability.

Contact Aladdin Scientific technical support if any discrepancy is observed between the CoA specifications and observed properties of the received material.

Frequently asked questions

What solvents are recommended for dissolving 1-(4-Chlorophenyl)-1H-pyrazol-3-ol?

DMSO and DMF are generally recommended as primary solvents for pyrazolol derivatives of this type due to their high solvating power. Moderate solubility may be achievable in ethanol or methanol. Aqueous solubility at neutral pH is expected to be limited. Researchers should verify solubility experimentally in their chosen solvent before preparing large-scale stock solutions.

How should 1-(4-Chlorophenyl)-1H-pyrazol-3-ol be stored to ensure long-term stability?

The solid compound should be stored in a tightly sealed container in a cool, dry, well-ventilated location away from light and moisture. For stock solutions prepared in DMSO, storage at –20 °C in single-use aliquots is advisable to prevent degradation from repeated freeze-thaw cycles. Always refer to the lot-specific CoA and SDS for confirmed storage conditions.

What is the tautomeric behavior of 1-(4-Chlorophenyl)-1H-pyrazol-3-ol and why does it matter?

3-Hydroxypyrazoles are well known to exist as an equilibrium mixture of the 3-hydroxy (enol) and 3-oxo (pyrazol-3(2H)-one) tautomers in solution; the predominant form depends on solvent polarity, concentration, and temperature. This tautomerism can influence the compound's reactivity in synthesis and its interactions in biological assays. Researchers should account for this equilibrium when designing reactions or interpreting assay data.

Where can I find the Certificate of Analysis (CoA) for lot C194946?

The Certificate of Analysis for 1-(4-Chlorophenyl)-1H-pyrazol-3-ol (C194946) is available on the Aladdin Scientific website by entering the product SKU and lot number. It can also be requested directly from Aladdin Scientific customer service. The CoA contains purity, identity, and storage information specific to your received lot.

References

1. Aladdin Scientific. Product page and Certificate of Analysis for 1-(4-Chlorophenyl)-1H-pyrazol-3-ol, SKU C194946. Aladdin Scientific.
2. Elguero, J. Pyrazoles. In Comprehensive Heterocyclic Chemistry; Katritzky, A. R., Rees, C. W., Eds.; Pergamon: Oxford, 1984. (General reference on pyrazole chemistry and tautomerism.)
3. Claramunt, R. M.; Lopez, C.; Elguero, J. The tautomerism of hydroxypyrazoles revisited. ARKIVOC 2006, (iv), 5–11. (General reference; specific applicability to C194946 not confirmed.)

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.