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HONGKUN / PRODUCT DIRECTORY

4-Chlorophenylboronic acid | CAS 1679-18-1

A para-chlorinated arylboronic acid used to introduce a 4-chlorophenyl group in coupling chemistry, with boronic-acid content and positional identity central to selecting material for a defined reaction.

CAS1679-18-1
Molecular formulaC6H6BClO2

Product overview

The boronic acid group and chlorine occupy opposite positions on the benzene ring of 4-chlorophenylboronic acid. Its carbon–boron bond supplies the aryl fragment in suitable coupling reactions, while the chlorine provides a distinct substituent on that fragment. This is the free boronic acid, rather than a pinacol boronate ester. The required chemical form should therefore be explicit in procurement documents. For reaction development, comparing only a quoted chromatographic purity can leave differences in active content unresolved. Confirm the assay basis, the method used to establish the para substitution pattern and any water or anhydride contribution relevant to the chosen material and dosing calculation.

Chemical identity

Chemical name
4-Chlorophenylboronic acid
CAS number
1679-18-1
Molecular formula
C6H6BClO2

Application context

4-Chlorophenylboronic acid is used in Suzuki–Miyaura coupling chemistry to construct substituted aromatic products. Its role is to supply the 4-chlorophenyl component to the selected reaction partner. Published applications also include other catalytic arylation and cyclization systems, where the same arylboron unit is used in a different reaction design. These transformations require their own catalyst and substrate evaluation; the aryl chloride is an additional site whose behaviour must be considered when designing a selective process. For purchasing, the practical distinction is between obtaining the correct free boronic acid and assuming that any organoboron derivative will behave identically. A useful qualification package connects identity, assay and impurity profile to the specific coupling under evaluation, allowing different proposed grades to be assessed on a comparable basis.

Chemistry and synthetic role

The molecule contains B(OH)2 bonded directly to an aromatic carbon, with chlorine para to that bond. A boronate ester changes the boron-bound oxygen groups and is a different procurement item.

Quality review

Confirm the para isomer

Require identity data that distinguish the 4-chloro structure from the 2- and 3-chloro isomers.

Define boronic-acid content

Agree the assay basis and whether any anhydride contribution is measured or included. Use this basis for molar charging.

Review coupling-relevant contaminants

Select water, solvent and related aromatic-compound limits for the intended process. Add metal limits only where the downstream specification requires them.

Preparing a specification

Name the free acid and CAS 1679-18-1, with assay method, reporting basis and positional-isomer requirements. Clarify treatment of water and any anhydride content before comparing quotations or calculating charges.

Packaging and storage

Agree packaging and net quantity for the proposed grade. Obtain the selected supplier’s SDS and storage instructions before setting warehouse or transport conditions.

Documentation

Request the specification, lot COA and identity test; confirm whether supporting assay data distinguish free boronic acid from other boron-containing forms. Request chromatograms or metal results when required by the coupling qualification.

Procurement questions

Can a pinacol ester replace this material directly?

It is a different chemical form; equivalence must be established in the intended reaction rather than assumed from the aryl group.

Why specify the para position?

The chloro position is carried into the aryl fragment and determines the structure of the intended product.

Should trace-metal limits always be included?

Set them where catalyst sensitivity, downstream use or an agreed impurity specification makes them relevant.

Technical sources
  1. PubChem CAS-resolved identity, CID 74299NCBI / National Library of Medicine
  2. 4-Chlorophenylboronic acid 417548Sigma-Aldrich
  3. 4-Chlorophenylboronic acid C1473Tokyo Chemical Industry