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Chemical product profile

HONGKUN / PRODUCT DIRECTORY

2-Chloronicotinic acid | CAS 2942-59-8

A pyridine-3-carboxylic acid bearing chlorine at C2, connecting nicotinamide agrochemical chemistry with substituted anilinonicotinic-acid routes. Purchasing criteria differ between a synthesis intermediate and an analytical related-substance material.

CAS2942-59-8
Molecular formulaC6H4ClNO2
Molecular weight157.55 g/mol

Product overview

The neighbouring chlorine and carboxyl groups make 2-chloronicotinic acid useful in two different reaction families. Its carboxyl group supplies the acyl fragment for amide construction, while substitution at C2 can introduce a nitrogen- or oxygen-linked partner. This arrangement places it in supply chains involving boscalid, diflufenican and substituted nicotinic-acid pharmaceuticals. The same chemical identity also occurs in analytical catalogues as flunixin related compound A and niflumic acid impurity A. A purchasing enquiry should therefore state whether the material is intended for synthesis or quantitative analysis. Identity, HPLC profile and acid assay should be assessed with methods appropriate to that purpose.

Chemical identity

Chemical name
2-Chloronicotinic acid
CAS number
2942-59-8
Molecular formula
C6H4ClNO2
Molecular weight
157.55 g/mol

Application context

Agrochemical applications include the chloronicotinoyl chemistry associated with boscalid and the substituted nicotinamide framework of diflufenican. Pharmaceutical intermediate applications include flunixin and niflumic acid, where substitution of the chloropyridine contributes to the required molecular framework.

In analytical work, 2-chloronicotinic acid can be encountered as a named related substance of these nicotinic-acid derivatives. Quantitative use requires an assigned value, its calculation basis and suitable traceability. For preparative chemistry, the priority is a qualified reagent specification covering acid content, related compounds and water where relevant to acyl activation. The intended use should accompany the CAS and structural name so that the appropriate documentation can be reviewed.

Chemistry and synthetic role

The C2 chlorine and C3 carboxyl group provide separate synthetic handles on an electron-deficient pyridine. Amidation uses the acid function; aromatic substitution modifies the C2 position.

Quality review

Confirm the 2,3 arrangement

Use structural identification that separates chloronicotinic-acid positional isomers.

Compare acid content with HPLC

Acid-base titration measures acidity, while chromatography assesses related organic components; agree both reporting bases if required.

Define analytical-reference requirements

For quantitative impurity analysis, request assigned content, uncertainty or traceability information appropriate to the method.

Preparing a specification

Identify the free acid, intended synthesis or analytical use, HPLC related-substance limits and acid-assay basis. For acylation specify water requirements; for reference use specify assigned-content documentation.

Packaging and storage

Packaging, closure and net weight are agreed for the selected grade, order quantity and destination. Confirm storage and transport requirements against the actual supplier SDS.

Documentation

Request a batch COA, specification, identity data and SDS. Confirm the availability of the analytical methods and any application-specific impurity results with the proposed supplier.

Procurement questions

Why does this CAS appear under pharmaceutical impurity names?

The same molecule is identified as flunixin related compound A and niflumic acid impurity A in analytical catalogues.

Does an acid titration replace chromatography?

No. Acidity and the distribution of related organic compounds are different measurements.

Which group forms the amide bond?

The carboxyl group at pyridine C3 provides the acyl fragment; C2 retains a separate substitution site.

Technical sources
  1. 2-Chloronicotinic acid CID 76258PubChem
  2. 2-Chloronicotinic Acid C1108TCI
  3. Fine Chemicals and Crop ProtectionJubilant Ingrevia
  4. CAS 2942-59-8 reference productsSigma-Aldrich