Chemical Identity and Structure

2-Aminobenzene-1-sulfonyl chloride hydrochloride (CAS-registered compound, SKU A190877) is the hydrochloride salt of 2-aminobenzenesulfonyl chloride, also known as 2-chlorosulfonylaniline hydrochloride. The molecule features an ortho-substituted benzene ring carrying two orthogonal reactive handles: a sulfonyl chloride group (–SO₂Cl) at the 1-position and a primary aromatic amine (–NH₂) at the 2-position, protonated as –NH₃⁺Cl⁻ in the salt form.

The hydrochloride salt formulation significantly improves bench stability relative to the free base, by suppressing the intramolecular cyclisation between the amine and the sulfonyl chloride that would otherwise generate the cyclic sultam (1,2-benzisothiazol-3(2H)-one 1,1-dioxide) under neutral or basic conditions. As a result, the hydrochloride form can be weighed and handled in air for short periods, provided moisture is excluded.

The compound is typically a white-to-off-white crystalline solid. Solutions should be prepared freshly in anhydrous aprotic solvents such as dichloromethane, THF, or acetonitrile immediately prior to use.

Synthesis Applications

Sulfonamide formation: The sulfonyl chloride group reacts readily with primary and secondary amines in the presence of a base (e.g., triethylamine or pyridine) to furnish ortho-aminophenylsulfonamides. The free amine, liberated by deprotonation of the hydrochloride, can subsequently serve as a handle for further diversification — acylation, reductive amination, or condensation — enabling rapid construction of complex pharmacophores in a single pot or stepwise sequence.

Sultam and heterocycle synthesis: Under mildly basic conditions the ortho-amino and sulfonyl chloride groups undergo spontaneous intramolecular cyclisation to afford saccharin precursors and 1,2-benzisothiazoline-based scaffolds. This reactivity is deliberately exploited in multi-step routes to saccharin analogues, benzothiadiazine dioxides, and related fused ring systems of interest in drug discovery.

Cross-coupling and further functionalisation: The aromatic amine can be diazotised under standard Sandmeyer conditions to introduce halogens, cyano groups, or other substituents, expanding the scope of downstream chemistry. Alternatively, the amine can be converted to isocyanates or carbamates for use in combinatorial library synthesis.

Overall, the orthogonal reactivity of the two functional groups makes this building block particularly attractive for diversity-oriented synthesis and fragment-based drug discovery campaigns.

Handling, Safety, and Storage

Reactivity hazards: As an arylsulfonyl chloride, this compound reacts vigorously with water, alcohols, and amines, releasing hydrochloric acid. Contact with moisture generates HCl gas; reactions with nucleophilic solvents can be exothermic. Always handle under anhydrous conditions and in a well-ventilated fume hood.

Personal protective equipment: Wear appropriate chemical-resistant gloves (nitrile or neoprene), safety goggles, and a lab coat. In the event of skin or eye contact, flush immediately with copious water and seek medical attention as required. Consult the full Safety Data Sheet (SDS) for this product before use.

Storage: Store in a tightly sealed container in a cool, dry location away from moisture, heat sources, and incompatible materials (bases, nucleophiles, oxidisers). The hydrochloride salt formulation confers improved ambient stability compared with the free base; however, long-term storage under inert atmosphere (nitrogen or argon) at low temperature is recommended to maintain purity.

Disposal: Dispose of waste in accordance with local, national, and institutional regulations for halogenated organic compounds and corrosive materials.

Ordering and Specifications

2-Aminobenzene-1-sulfonyl chloride hydrochloride is available from Aladdin Scientific under SKU A190877. Researchers are encouraged to confirm the current lot-specific certificate of analysis (CoA), including purity (typically assessed by HPLC or NMR), appearance, and water content, before use in critical applications.

For bulk quantities, custom packaging, or special purity grades, please contact Aladdin Scientific's sales or technical support team. Volume pricing may be available for institutional or industrial customers.

When ordering, ensure that adequate cold-chain or desiccant packaging options are selected to maintain product integrity during transit. Aladdin Scientific ships reagents in compliance with applicable transport regulations for corrosive and reactive chemical substances.