2-Chlorobenzo[d]thiazole-7-carboxylic Acid: Properties & Lab Guide

2-Chlorobenzo[d]thiazole-7-carboxylic acid is a chlorinated benzothiazole heterocyclic building block bearing a carboxylic acid substituent at the 7-position, valued in medicinal chemistry and synthetic research for its dual reactive handles that enable diverse downstream functionalization.

Chemical Name

2-Chlorobenzo[d]thiazole-7-carboxylic acid

SKU / Catalog Number

C735006

Molecular Formula

C8H4ClNO2S

Molecular Weight

213.64 g/mol

Core Scaffold

Benzo[d]thiazole (bicyclic aromatic heterocycle fusing benzene and thiazole rings)

Key Functional Groups

C2-chloro (electrophilic site for nucleophilic substitution); C7-carboxylic acid (amide coupling, esterification)

Recommended Storage

Cool, dry, well-ventilated location; store away from moisture and incompatible oxidizing agents

Chemical Identity and Structural Features

2-Chlorobenzo[d]thiazole-7-carboxylic acid (SKU: C735006, molecular formula C₈H₄ClNO₂S, MW ≈ 213.64 g/mol) belongs to the benzothiazole family of bicyclic heteroaromatic compounds. The benzo[d]thiazole scaffold consists of a benzene ring fused to a 1,3-thiazole ring, producing a planar, electron-deficient aromatic system.

Two key functional groups differentiate this compound: (1) a chlorine atom at the 2-position of the thiazole ring, which serves as an excellent electrophilic site susceptible to nucleophilic aromatic substitution (S_NAr) by amines, thiols, and alkoxides; and (2) a carboxylic acid group at the 7-position on the benzo ring, enabling standard acyl-transfer chemistry including amide bond formation (via coupling reagents such as HATU or EDC) and esterification.

The combination of these two orthogonal reactive handles on a rigid heteroaromatic scaffold makes this compound a versatile bifunctional building block for the construction of more complex molecules in medicinal chemistry and materials research.

Physicochemical Properties and Stability

As a heteroaromatic carboxylic acid, 2-Chlorobenzo[d]thiazole-7-carboxylic acid is expected to present as a solid at room temperature with limited solubility in water due to the lipophilic benzothiazole ring system. Solubility is significantly improved in polar aprotic solvents such as DMSO and DMF, as well as in aqueous base (where the carboxylate anion is generated).

The compound is expected to be stable under ambient conditions when stored properly away from moisture and strong oxidizing agents. The C–Cl bond at the 2-position, while reactive under forcing nucleophilic conditions, is stable to routine laboratory handling and brief atmospheric exposure. The carboxylic acid functionality is chemically robust but should be protected from prolonged exposure to strong acids or bases that may promote side reactions.

Note: Exact melting point, LogP, pKa, and solubility values are not provided in the current source material. Users should consult the Certificate of Analysis (CoA) or perform in-house characterization. These parameters are flagged for review.

Synthetic Applications and Research Utility

The benzothiazole nucleus is a privileged scaffold in drug discovery, appearing in numerous bioactive compounds with antibacterial, antifungal, anticancer, and anti-inflammatory activities. 2-Chlorobenzo[d]thiazole-7-carboxylic acid serves as a key intermediate that can be elaborated in two independent directions:

• Nucleophilic substitution at C2: Displacement of the chloride by primary or secondary amines, hydrazines, thiols, or alkoxides under mild-to-moderate conditions (base, appropriate solvent, 50–100 °C) affords 2-amino-, 2-thio-, or 2-alkoxy-substituted benzothiazole-7-carboxylic acid derivatives.
• Carboxylic acid functionalization at C7: Standard peptide-coupling conditions (EDC/NHS, HATU/DIPEA) convert the acid to amides for incorporation into peptidomimetics or fragment libraries. Fischer esterification or use of diazomethane provides methyl esters for further manipulation.
• Transition-metal-catalyzed cross-coupling: After conversion to the corresponding boronic acid or organozinc species, or via direct C–H functionalization strategies, the aromatic ring can be further decorated.

These attributes make C735006 suitable for fragment-based drug discovery, combinatorial library synthesis, and development of fluorescent probes or coordination ligands.

Safe Handling, Storage, and Disposal

Personal Protective Equipment (PPE): Handle 2-Chlorobenzo[d]thiazole-7-carboxylic acid wearing appropriate nitrile or neoprene gloves, safety spectacles or goggles, and a laboratory coat. Work in a fume hood when weighing or dissolving the compound to minimize inhalation of dust or aerosols.

Storage: Store in a tightly sealed container in a cool (recommended 2–8 °C or as specified on the CoA), dry, and well-ventilated area away from incompatible materials (strong oxidizers, strong bases). Keep away from heat sources and direct sunlight.

Spill Management: Contain and collect solid spills using non-sparking tools and inert absorbents. Avoid generating dust. Transfer to a suitable, labeled waste container.

Disposal: Dispose of this compound and its solutions in accordance with applicable local, regional, and national regulations governing halogenated organic waste. Do not discharge to drains or waterways. Consult your institution's Environmental Health and Safety (EHS) office for guidance.

Note: A full Safety Data Sheet (SDS) should be consulted before use. Specific hazard classification (GHS pictograms, H-statements) for this compound should be verified against the product SDS, as this information was not fully detailed in the current source material.

Ordering, Specifications, and Quality

2-Chlorobenzo[d]thiazole-7-carboxylic acid is available from Aladdin Scientific under catalog number C735006. When placing an order, researchers and procurement teams should confirm:

• Purity: Request the Certificate of Analysis (CoA) to verify HPLC purity, NMR identity, and other quality parameters specific to the lot being purchased.
• Available pack sizes: Contact Aladdin Scientific customer service or visit the product page for current packaging options and pricing.
• Shipping and storage conditions: Confirm any temperature-controlled shipping requirements with the supplier, particularly for bulk quantities.
• Regulatory documentation: REACH, export control, and controlled-substance status should be verified according to the destination country's regulations.

For technical queries, custom synthesis requests, or volume pricing, contact Aladdin Scientific's technical support team. All products are subject to Aladdin Scientific's standard terms and conditions of sale.

Frequently asked questions

What solvents are recommended for dissolving 2-Chlorobenzo[d]thiazole-7-carboxylic acid?

This compound is expected to dissolve well in polar aprotic solvents such as DMSO and DMF. Solubility in aqueous systems can be enhanced by addition of a mild base (e.g., NaHCO3) to deprotonate the carboxylic acid. Water solubility as a free acid is anticipated to be low due to the lipophilic benzothiazole scaffold. Exact solubility data should be verified experimentally or from the CoA.

How can the chlorine at the 2-position be selectively functionalized without affecting the carboxylic acid group?

Nucleophilic aromatic substitution (SNAr) at C2 is typically performed under mild basic conditions (e.g., K2CO3, Et3N) using nucleophiles such as amines or thiols in solvents like DMF or acetonitrile at temperatures between 50 and 100 °C. Under these conditions, the carboxylic acid remains intact. If amide coupling at C7 is subsequently required, it can be performed as a second step using standard coupling reagents (HATU, EDC) after C2 substitution is complete.

What is the catalog number for 2-Chlorobenzo[d]thiazole-7-carboxylic acid at Aladdin Scientific?

The catalog number (SKU) for 2-Chlorobenzo[d]thiazole-7-carboxylic acid at Aladdin Scientific is C735006. Please reference this number when placing orders or contacting customer service.

Is 2-Chlorobenzo[d]thiazole-7-carboxylic acid suitable for use as a fragment in drug discovery?

Yes. The benzothiazole scaffold is a well-established privileged structure in medicinal chemistry. The compound's compact bicyclic framework combined with two orthogonally reactive functional groups (C2-Cl and C7-COOH) makes it an attractive fragment for structure-activity relationship (SAR) studies and fragment-based drug design. Derivatization at both sites enables rapid exploration of chemical space.

References

1. Gomtsyan, A. Heterocycles in drugs and drug discovery. Chemistry of Heterocyclic Compounds, 2012, 48, 7–10. (General reference on privileged heterocyclic scaffolds including benzothiazoles.)
2. Kaur, R.; Kaur, P.; Sharma, S. et al. Anti-cancer benzothiazoles: a review of recent developments. Mini-Reviews in Medicinal Chemistry, 2016. (Review of benzothiazole derivatives in oncology.)
3. Aladdin Scientific Product Page: 2-Chlorobenzo[d]thiazole-7-carboxylic acid, SKU C735006. Aladdin Scientific, Shanghai.

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