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Chemical product profile

HONGKUN / PRODUCT DIRECTORY

4-Bromopyridine hydrochloride | CAS 19524-06-2

The hydrochloride salt of a C4-brominated pyridine, combining a reactive heteroaromatic framework with an explicit acid equivalent. Qualification should address salt composition as well as the organic impurity profile.

CAS19524-06-2
Molecular formulaC5H5BrClN
Molecular weight194.46 g/mol

Product overview

This material contains a protonated pyridine nitrogen and a chloride counterion; the bromine remains covalently attached at C4. These two halogens therefore have different chemical roles. Specifying only bromopyridine can leave the free base and its hydrochloride unresolved, with consequences for formula weight, assay calculation and base demand in a reaction. Published research uses the hydrochloride in activated-pyridine addition chemistry. For purchasing, confirm the salt identity, the basis of the organic-component assay and any required acid or chloride measurement. Water should also be considered when calculating the amount of pyridine substrate introduced into a moisture-sensitive or stoichiometrically controlled process.

Chemical identity

Chemical name
4-Bromopyridine hydrochloride
CAS number
19524-06-2
Molecular formula
C5H5BrClN
Molecular weight
194.46 g/mol

Application context

In published copper-catalyzed ynamide chemistry, 4-bromopyridine hydrochloride is used to prepare an activated pyridine substrate and form a substituted dihydropyridine. The bromine at C4 is retained in that reported transformation, illustrating a route in which the nitrogen-containing ring is elaborated without consuming the aryl bromide.

The hydrochloride form matters when defining reaction inputs. A qualification specification can separate organic purity from acid content, chloride identity and water. State whether results should be calculated on the hydrochloride or free-base equivalent so that quotations, sample testing and reaction charges use the same basis.

Chemistry and synthetic role

Protonation occurs at the pyridine nitrogen. Chloride is the counterion, whereas C4–Br is a covalent bond on the aromatic skeleton.

Quality review

Confirm hydrochloride stoichiometry

Review the salt composition and the acid-equivalent basis required by the process.

Separate counterion and ring halogen

Use chloride/acid tests for the salt and structural data for the C4 bromide.

Report water with assay basis

Define whether the content is as received, dry basis or free-base equivalent.

Preparing a specification

Request CAS 19524-06-2 as the hydrochloride, with a defined salt-basis assay, C4 identity, water and acid/chloride criteria. State any free-base-equivalent reporting requirement.

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

Is the chlorine attached to the pyridine ring?

No. Chloride is the counterion; bromine is covalently attached at C4.

Can a free-base purity figure be used unchanged?

The reporting basis must be converted or defined for the hydrochloride and its water content.

Does every use consume the C–Br bond?

No. Published activated-pyridine addition chemistry retains the C4 bromide while modifying the ring.

Technical sources
  1. 4-Bromopyridine Hydrochloride B0653TCI
  2. 4-Bromopyridine Hydrochloride safety data sheetTCI
  3. Copper(I)-Catalyzed Nucleophilic Addition of Ynamides to Acyl Chlorides and Activated N-HeterocyclesJournal of Organic Chemistry