Compound Overview and Physicochemical Properties

2-((4-Chloro-2-nitrophenyl)amino)benzoic acid (Aladdin SKU A726441) is an aromatic secondary amine bearing a carboxylic acid group on one phenyl ring and both a nitro group and a chloro substituent on the other. This combination of electron-withdrawing groups (–NO₂, –Cl, –COOH) and the bridging amine makes the molecule a useful building block in heterocyclic chemistry, dye synthesis, and medicinal chemistry programmes.

The compound belongs to the broader family of diphenylamine carboxylic acids, structurally related to fenamate-class non-steroidal anti-inflammatory drug (NSAID) scaffolds, though its specific biological activity profile requires confirmation by primary literature. Key physicochemical attributes include a molecular formula of C₁₃H₉ClN₂O₄, a molecular weight of approximately 292.67 g/mol, and the presence of an intramolecular hydrogen-bonding capacity between the amine proton and the ortho-nitro group, which influences conformation and reactivity.

Note: Researchers should consult the Aladdin Scientific Certificate of Analysis (CoA) supplied with each lot for confirmed purity, melting point, and spectroscopic data, as batch-specific values supersede generic literature estimates.

Materials, Safety, and Pre-Experiment Preparation

Personal Protective Equipment (PPE): Always wear appropriate PPE when handling this compound: nitrile gloves, laboratory coat, and safety glasses at minimum. Because the molecule contains a nitro group and an aromatic amine moiety, potential sensitisation and toxicity risks apply. Work in a fume hood whenever weighing or preparing solutions.

Materials required:

• 2-((4-Chloro-2-nitrophenyl)amino)benzoic acid (A726441, Aladdin Scientific)
• Analytical balance (±0.1 mg resolution)
• Appropriate solvent (see Solubilisation section below)
• Amber glass vials or light-resistant containers
• pH meter or indicator paper (if aqueous buffers are used)
• Nitrogen or argon purge line (for moisture-sensitive preparations)

Regulatory and waste disposal: Dispose of all waste containing this compound in accordance with local regulations for aromatic amines and nitro-aromatic compounds. Do not pour down the drain. Consult your institution's Environmental Health and Safety (EHS) office for approved disposal routes.

Step-by-Step Protocol: Solubilisation and Stock Solution Preparation

The carboxylic acid and the electron-poor aromatic ring affect aqueous solubility. The compound is expected to have limited solubility in pure water at neutral pH. The following general protocol is recommended:

1. Select solvent: Dimethyl sulfoxide (DMSO) or dimethylformamide (DMF) are preferred for preparing concentrated stock solutions. Ethanol or acetone may be used for less concentrated preparations. Confirm compatibility with your downstream assay.
2. Determine target concentration: For a 10 mM stock, calculate the required mass: mass (mg) = 10 mM × 0.29267 g/mmol × volume (mL). For example, for 1 mL of 10 mM in DMSO, weigh approximately 2.93 mg.
3. Weigh accurately: Using a calibrated analytical balance, weigh the required amount of compound into a tared amber vial inside a fume hood.
4. Add solvent: Add approximately 80% of the target solvent volume, cap, and vortex or sonicate (30–60 s, ambient temperature) until fully dissolved. Add the remaining solvent to reach the final volume.
5. Verify dissolution: Inspect visually for complete dissolution. If turbidity persists, gentle warming (40–50 °C, water bath) may assist; avoid prolonged heating to prevent decomposition.
6. Aliquot and store: Divide the stock solution into single-use aliquots in capped vials. Store at –20 °C protected from light. Avoid repeated freeze–thaw cycles.
7. Record keeping: Label each vial with compound name, SKU (A726441), concentration, solvent, date, and preparer's initials.

Aqueous dilution: If aqueous working solutions are needed, add the DMSO stock dropwise to the aqueous buffer with continuous mixing to minimise precipitation. Keep the final DMSO content ≤1% v/v where possible to limit co-solvent interference in biological assays.

Typical Research Applications

2-((4-Chloro-2-nitrophenyl)amino)benzoic acid is primarily used as a synthetic intermediate and reference standard. Representative application areas include:

• Heterocyclic synthesis: The ortho-amino carboxylic acid motif is a classic precursor for constructing benzoxazinone, benzoxazole, and related ring systems. The nitro group can be reduced to an amine, opening further cyclisation pathways.
• Dye and pigment chemistry: Diarylamine carboxylic acids serve as key intermediates in azo and anthraquinone dye synthesis.
• Medicinal chemistry: Structural analogy to fenamate NSAIDs means the scaffold may be explored in SAR studies targeting prostaglandin pathways or ion channels; however, specific biological data for this compound should be sourced from peer-reviewed literature.
• Reference standard use: High-purity lots (consult CoA) are suitable for use as analytical reference standards in HPLC method development and impurity profiling.

Disclaimer: Researchers should independently validate the suitability of this compound for their specific application and consult primary literature for biological activity data not confirmed in the Aladdin Scientific product description.

Troubleshooting and Quality Control

Common issues and solutions:

Quality control checks before use:

• Confirm lot purity against the CoA supplied by Aladdin Scientific.
• Run an identity check by ¹H NMR or LC-MS if the compound is used in a critical synthesis step.
• Record the appearance (expected: solid powder; colour may vary by lot — consult CoA for details).