2,6-Dimethoxybenzenesulfonyl chloride
[CAS# 145980-89-8]

Identification

• Classification: Chemical reagent >> Organic reagent >> Sulfonyl halide
• Name: 2,6-Dimethoxybenzenesulfonyl chloride
• Molecular Formula: C₈H₉ClO₄S
• Molecular Weight: 236.67
• CAS Registry Number: 145980-89-8
• EC Number: 885-526-6
• SMILES: COC1=C(C(=CC=C1)OC)S(=O)(=O)Cl

Safety Data

• Hazard Symbols: GHS05 Danger
• Risk Statements: H335-H314
• Safety Statements: P260-P264-P271-P280-P301+P330+P331-P303+P361+P353-P304+P340-P305+P351+P338-P310-P363-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Acute toxicity	Acute Tox.	4	H302
Specific target organ toxicity - single exposure	STOT SE	3	H335

• Transport Information: UN 3261

Discovery and Applications

2,6-Dimethoxybenzenesulfonyl chloride is an aromatic sulfonyl chloride derivative characterized by a benzene ring substituted with methoxy groups at the 2- and 6-positions and a sulfonyl chloride functional group at the 1-position. The methoxy substituents are electron-donating, which affects the electronic density of the aromatic ring and can influence the reactivity of the sulfonyl chloride group. The sulfonyl chloride functional group is highly reactive, allowing the compound to serve as an intermediate for the synthesis of sulfonamides, sulfonate esters, and other sulfonyl-containing derivatives.

This compound typically exists as a colorless to pale yellow crystalline solid or liquid, depending on the purity and preparation method. It is reactive toward nucleophiles, particularly amines and alcohols, forming sulfonamide and sulfonate ester linkages, respectively. The electron-donating methoxy groups can slightly reduce the electrophilicity of the sulfonyl chloride compared to unsubstituted benzenesulfonyl chloride, which may influence reaction rates in nucleophilic substitution reactions.

In organic synthesis, 2,6-dimethoxybenzenesulfonyl chloride is widely used as a protecting group reagent for amines or alcohols and as a sulfonylating agent in the preparation of pharmaceuticals, agrochemicals, and specialty chemicals. The steric hindrance provided by the 2,6-methoxy substituents can enhance selectivity in reactions, making it suitable for situations where selective sulfonylation is desired.

The compound's aromatic ring and sulfonyl chloride group can also participate in electrophilic aromatic substitution reactions, although such reactions are typically directed by the substituents on the ring. The methoxy groups strongly activate the ortho and para positions relative to themselves, but in this case, steric hindrance limits substitution predominantly to positions not blocked by the methoxy groups.

2,6-Dimethoxybenzenesulfonyl chloride is generally stable under dry conditions but reacts readily with moisture to hydrolyze to the corresponding sulfonic acid. It should therefore be handled under anhydrous conditions using inert atmospheres when stored or during chemical reactions. Solvents such as dichloromethane or chloroform are commonly used for reactions involving this compound, providing suitable solubility and minimizing side reactions.

Due to its reactivity and structural features, this compound is valuable in medicinal chemistry for the synthesis of bioactive sulfonamide derivatives. It is also used in materials chemistry for modifying polymers or creating functionalized surfaces, leveraging the sulfonyl group’s ability to form covalent bonds with nucleophilic moieties.

Overall, 2,6-dimethoxybenzenesulfonyl chloride is a versatile and important intermediate in both laboratory and industrial chemistry. Its combination of electronic activation, steric properties, and high reactivity of the sulfonyl chloride group allows for a range of synthetic transformations, making it a widely used building block for the preparation of functionalized aromatic compounds.