4-Bromobenzenesulfonyl Chloride (CAS No. 98-58-8)

4-Bromobenzenesulfonyl chloride, often abbreviated as 4-BrBsCl, is a key organosulfur compound serving as a versatile sulfonylating agent in organic synthesis. With the chemical formula C₆H₄BrClO₂S, it presents as a white to off-white crystalline powder that is highly reactive toward nucleophiles and moisture-sensitive. This reagent is indispensable in the manufacture of sulfonamides, agrochemicals, pharmaceuticals, and advanced materials, providing efficient introduction of the sulfonyl bromide moiety for further derivatization and functionalization.

CAS Number: 98-58-8 Molecular Weight: 255.52 g/mol Synonyms: p-Bromobenzenesulfonyl chloride, 4-Bromophenylsulfonyl chloride, Bromobenzenesulfonyl chloride (para)

Key Properties

4-Bromobenzenesulfonyl chloride features robust physical and chemical properties that facilitate its use in precise synthetic protocols. The following table details core specifications:

Property Value/Description
Appearance White to off-white crystalline powder
Purity ≥98.0% (GC)
Melting Point 68-70°C
Boiling Point ~320°C (decomposes)
Density 1.84 g/cm³ (estimated)
Refractive Index 1.600 (estimated)
Flash Point >100°C
Solubility in Water Insoluble (decomposes)
Moisture Sensitivity High (hydrolyzes readily)

These traits underscore its thermal stability and reactivity, ideal for reactions conducted under anhydrous conditions.

4-Bromo benzenesulfonyl chloride Applications and Uses

The bromo-substituted structure of 4-bromobenzenesulfonyl chloride enables broad applicability in chemical and material sciences:

  • Pharmaceutical Synthesis: Utilized as an intermediate for sulfonamide antibiotics, anti-inflammatory agents, and protease inhibitors through selective sulfonylation of amines.
  • Agrochemical Production: Key building block in herbicides, insecticides, and fungicides, enhancing bioactivity via sulfonyl group incorporation.
  • Dyes and Pigments: Employed in the synthesis of reactive dyes for textiles and optical brighteners, leveraging the halogen for cross-coupling reactions.
  • Materials Chemistry: Serves in polymer modification and as a reagent for functionalizing surfaces in electronics and coatings.
  • Research and Development: Valuable in organic methodology for Heck, Suzuki, or Sonogashira couplings after sulfonyl activation.

Its compatibility with palladium catalysis positions it as a cornerstone for modern cross-coupling strategies in drug discovery and fine chemicals.

Safety and Handling

4-Bromobenzenesulfonyl chloride is corrosive and lachrymatory, requiring meticulous handling to mitigate risks of severe irritation or burns. It liberates HCl upon hydrolysis, posing inhalation hazards. Recommended practices include:

  • Storage: Keep in a dry, cool environment (<25°C) in sealed amber glass under nitrogen; incompatible with water, bases, or metals.
  • Handling: Use PPE such as nitrile gloves, safety goggles, lab coat, and fume hood. Quench spills with sodium bicarbonate; avoid direct water contact.
  • Environmental Considerations: Harmful to aquatic organisms; manage waste through neutralization and incineration per hazardous regulations.
  • Regulatory Compliance: UN 3261 (Class 8, PG II); compliant with REACH, TSCA, and GHS for irritants and corrosives.

Obtain the complete Safety Data Sheet (SDS) for protocol specifics.

4-Bromo benzenesulfonyl chloride Frequently Asked Questions (FAQs)

What is the main use of 4-Bromobenzenesulfonyl chloride?

It is primarily employed as a sulfonylating agent in the synthesis of sulfonamides for pharmaceuticals and agrochemicals, enabling the formation of amide bonds with high efficiency.

Is 4-Bromobenzenesulfonyl chloride suitable for sensitive reactions?

Yes, its moderate reactivity allows use in multi-step syntheses, though anhydrous conditions are essential to prevent decomposition and side reactions.

What is the stability and shelf life of 4-Bromobenzenesulfonyl chloride?

Under inert, dry storage below 25°C, it maintains integrity for 12-18 months; monitor for discoloration indicating moisture exposure.

Can 4-Bromobenzenesulfonyl chloride be exported internationally?

Certainly, it is shipped globally under UN 3261 guidelines, in moisture-proof packaging like polyethylene-lined drums or bottles for lab to industrial scales.

How does 4-Bromobenzenesulfonyl chloride differ from chlorobenzenesulfonyl chloride?

The bromine substituent enhances electron-withdrawing effects and facilitates halogen exchange or coupling reactions, offering greater versatility in synthetic routes compared to the chloro analog.

Does 4-Bromobenzenesulfonyl chloride react with water?

It hydrolyzes exothermically with water, generating HCl gas and sulfonic acid; always handle in desiccated environments to preserve activity.

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