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HONGKUN / PRODUCT DIRECTORY

2-Chlorothiophene | CAS 96-43-5

A sulfur heterocycle bearing chlorine next to the ring sulfur, used as a starting point in published substituted-thiophene research, where positional identity and route-compatible impurity controls are more informative than a general heterocycle grade.

CAS96-43-5
Molecular formulaC4H3ClS

Product overview

The chlorine in 2-chlorothiophene occupies the position next to sulfur in the five-membered aromatic ring. This positional identity distinguishes CAS 96-43-5 from 3-chlorothiophene and defines the starting scaffold for subsequent ring functionalisation. The compound has been used in research routes to substituted diarylthiophenes, including DuP 697 and related structures. Qualification should combine identification of the starting isomer with a chromatographic profile suited to relevant impurities. Water requirements depend on the reagents and transformations selected for the downstream sequence.

Chemical identity

Chemical name
2-Chlorothiophene
CAS number
96-43-5
Molecular formula
C4H3ClS

Application context

Research routes use 2-chlorothiophene as the starting ring for staged functionalisation, followed by borylation and Suzuki coupling to diversify diarylthiophenes. DuP 697 and analogues are examples prepared within this synthetic-method context. The sequence uses several sites of the thiophene framework, making the identity of the initial chloro isomer a key purchasing criterion. Agree the positional-isomer profile before evaluating the material in the selected route. Where moisture-sensitive reagents are involved, specify water separately; include trace-metal controls when required by the process or final application.

Chemistry and synthetic role

The ring provides both a C–Cl bond and unsubstituted carbon positions. Published route design uses this combination for staged functionalisation; which position reacts depends on the transformation, so the starting identity cannot be replaced by an unspecified chlorothiophene mixture.

Quality review

Discriminate the positional isomer

Agree an identity test or chromatographic comparison capable of separating 2- from 3-chlorothiophene.

Review volatile related substances

A GC profile is a useful external grade benchmark. Define the impurities and reporting thresholds relevant to the receiving process.

Set moisture to the actual reaction

Request a separate water result if the selected functionalisation sequence requires it; GC area alone does not quantify water.

Preparing a specification

Specify 2-chlorothiophene, CAS 96-43-5, identity testing, GC purity or assay and agreed related-thiophene limits. Add water or trace-metal criteria only when justified by the intended route.

Packaging and storage

Reference handling information in the Sigma-Aldrich SDS calls for a tightly closed container in a cool, well-ventilated location. Confirm packaging, net weight, storage and transport against the actual selected supplier SDS.

Documentation

Request the proposed specification, COA and batch-relevant SDS. Confirm whether a representative GC chromatogram and positional-isomer identity evidence are available; add a water report when required by route qualification.

Procurement questions

Is 3-chlorothiophene an equivalent substitute?

No. The chlorine position changes the starting scaffold and must match the selected route.

When should water be specified separately?

Include a water method and limit when the receiving sequence uses moisture-sensitive reagents or has a defined water tolerance.

Should every order include trace-metal limits?

Specify trace-metal limits when required by the downstream process or end use, including the analytical method and reporting limit.

Technical sources
  1. PubChem CID 7299NCBI / PubChem
  2. 2-Chlorothiophene C0807Tokyo Chemical Industry
  3. Divergent synthesis of 2,3,5-substituted thiophenes by C–H activation/borylation/Suzuki couplingKallepalli et al., Heterocycles 80 (2010); Michigan State University
  4. 2-Chlorothiophene SDS 155667Sigma-Aldrich