2-Chloro-4-methylbenzothiazole: Properties & Lab Use FAQ

2-Chloro-4-methylbenzothiazole is a chlorinated benzothiazole heterocyclic compound widely used as a versatile building block in medicinal chemistry, agrochemical research, and the synthesis of biologically active scaffolds.

Chemical Name

2-Chloro-4-methylbenzothiazole

CAS Number

7379-12-6

Molecular Formula

C₈H₆ClNS

Molecular Weight

183.66 g/mol

Aladdin SKU

C192994

Key Functional Groups

C–Cl at position 2, methyl at position 4, benzothiazole core

What Is 2-Chloro-4-methylbenzothiazole?

2-Chloro-4-methylbenzothiazole (CAS 7379-12-6, SKU C192994) is a halogenated derivative of benzothiazole, a bicyclic aromatic heterocycle containing both sulfur and nitrogen atoms fused to a benzene ring. The compound features a chlorine substituent at the 2-position of the thiazole ring and a methyl group at the 4-position of the benzene ring. This combination of substituents makes it a highly reactive electrophilic intermediate suitable for nucleophilic aromatic substitution (SNAr) and cross-coupling reactions. Its molecular formula is C₈H₆ClNS with a molecular weight of 183.66 g/mol.

Benzothiazole-based compounds are well established in medicinal chemistry as pharmacophores present in antibacterial, antifungal, anticancer, and anti-inflammatory drug candidates. The 2-chloro substitution in particular provides a reactive handle for displacement by amines, thiols, alkoxides, and organometallic nucleophiles, enabling rapid library synthesis.

Research Applications and Synthetic Utility

2-Chloro-4-methylbenzothiazole serves as a key electrophilic building block in diverse synthetic programs:

• Medicinal chemistry: Used to prepare 2-amino-, 2-alkoxy-, and 2-thioether-substituted benzothiazoles by nucleophilic substitution, generating analogue series for biological screening.
• Agrochemical synthesis: Benzothiazole scaffolds appear in fungicides and herbicides; the chloro handle facilitates further functionalization toward target structures.
• Materials science: Benzothiazole derivatives are employed in the design of fluorescent probes, dyes, and organic semiconductors, where the methyl group at position 4 modulates electronic properties.
• Cross-coupling reactions: The C–Cl bond can participate in palladium-catalyzed coupling reactions (e.g., Suzuki, Buchwald–Hartwig) under appropriate conditions, enabling C–C and C–N bond formation.

Researchers should verify specific reaction conditions—including catalyst, base, solvent, and temperature—in the primary literature before use.

Handling, Safety, and Storage Guidelines

As a halogenated heterocyclic compound, 2-Chloro-4-methylbenzothiazole should be handled with standard laboratory precautions for reactive organic chlorides:

• Personal protective equipment (PPE): Wear nitrile gloves, safety goggles, and a laboratory coat. Work in a well-ventilated fume hood.
• Storage: Store in a tightly sealed container in a cool, dry, well-ventilated location away from strong bases, nucleophiles, and oxidizing agents. Typical storage temperature is 2–8 °C or room temperature under inert atmosphere; consult the product SDS for definitive guidance.
• Stability: The compound is moisture-sensitive to a moderate degree; prolonged exposure to humid air may lead to slow hydrolysis of the C–Cl bond. Keep the container sealed between uses.
• Waste disposal: Dispose of waste in accordance with local and institutional regulations for halogenated organic solvents and reagents.

Always consult the Safety Data Sheet (SDS) supplied with the product before use. The information here is general guidance only.

Purity, Grade, and Quality Specifications

Aladdin Scientific supplies 2-Chloro-4-methylbenzothiazole (C192994) as a research-grade reagent. Key quality attributes typically assessed for this class of compound include:

• Purity: Determined by GC or HPLC analysis; research-grade lots are typically ≥95% pure. Verify the actual purity on the Certificate of Analysis (CoA) provided with each lot.
• Identity confirmation: Confirmed by ¹H NMR and/or mass spectrometry.
• Appearance: Typically a pale yellow to off-white solid or low-melting solid/liquid at ambient temperature.
• Lot-specific CoA: Available upon request from Aladdin Scientific customer service or downloadable from the product page.

For applications requiring higher purity or specific analytical certifications (e.g., pharmaceutical manufacturing), additional purification and independent analytical verification are recommended.

Frequently asked questions

What is the CAS number for 2-Chloro-4-methylbenzothiazole and how do I find the datasheet?

The CAS number is 7379-12-6. The product datasheet, Certificate of Analysis, and Safety Data Sheet for Aladdin SKU C192994 are available on the product page at Aladdin Scientific's website, or you may contact customer service to request lot-specific documentation.

What nucleophiles can displace the chlorine at position 2 of 2-Chloro-4-methylbenzothiazole?

The C-2 chlorine of benzothiazoles is activated toward nucleophilic aromatic substitution due to the electron-withdrawing effect of the adjacent nitrogen and the ring's aromatic character. Primary and secondary amines, thiols, alkoxides, and hydrazines are commonly used nucleophiles under mild to moderate heating conditions. Palladium-catalyzed coupling partners such as boronic acids (Suzuki) and amines (Buchwald–Hartwig) can also be applied. Specific conditions should be verified in the primary literature.

How should 2-Chloro-4-methylbenzothiazole be stored to maintain stability?

Store the compound in a tightly sealed container in a cool, dry, and well-ventilated area away from moisture, strong bases, and nucleophiles. Inert-atmosphere storage (nitrogen or argon) is advisable for extended periods. Always refer to the product SDS and CoA for definitive storage and stability information specific to your lot.

Is 2-Chloro-4-methylbenzothiazole suitable for use in palladium-catalyzed cross-coupling reactions?

Aryl chlorides are generally less reactive than aryl bromides or iodides in palladium-catalyzed cross-coupling, but they can be successfully engaged using modern, bulky phosphine or N-heterocyclic carbene (NHC) ligands under optimized conditions. The specific reactivity of 2-Chloro-4-methylbenzothiazole in such reactions depends on catalyst choice, base, solvent, and temperature; researchers should consult the primary literature for validated protocols.

What analytical methods are used to confirm the identity and purity of C192994?

Identity is typically confirmed by ¹H NMR spectroscopy and mass spectrometry, while purity is assessed by GC or HPLC. The Certificate of Analysis (CoA) for each lot of C192994 specifies the analytical methods used and the results obtained; request the CoA from Aladdin Scientific to verify your specific lot.

References

1. Kaur, R. et al. Benzothiazole: a versatile pharmacophore. Mini Reviews in Medicinal Chemistry, 2017. General review of benzothiazole pharmacology and synthetic utility.
2. Mistry, S. N. et al. Synthetic routes and biological activities of benzothiazole derivatives: a review. Current Medicinal Chemistry, general reference. Review of benzothiazole synthesis and biological activity.
3. Aladdin Scientific. Product page: 2-Chloro-4-methylbenzothiazole, SKU C192994. Certificate of Analysis and Safety Data Sheet available from Aladdin Scientific.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.