Methanesulfonyl chloride
[CAS# 124-63-0]

Identification

• Classification: Chemical reagent >> Organic reagent >> Sulfonate / sulfinate
• Name: Methanesulfonyl chloride
• Synonyms: Mesyl chloride;Methylsulfonyl chloride;Methanesulfonic acid chloride;Methanesulfonyl chloride; Methanesulphonyl chloride
• Molecular Formula: CH₃ClO₂S
• Molecular Weight: 114.54
• CAS Registry Number: 124-63-0
• EC Number: 204-706-1
• SMILES: CS(=O)(=O)Cl

Properties

• Density: 1.5±0.1 g/cm³, Calc.^*, 1.48 g/mL (Expl.)
• Melting point: -33 ºC (Expl.)
• Index of Refraction: 1.438, Calc.^*, 1.452 (Expl.)
• Boiling Point: 160.7 ºC (760 mmHg), Calc.^*, 173.8 ºC (Expl.)
• Flash Point: 42.2±18.7 ºC, Calc.^*, 113 ºC (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS05;GHS06;GHS07 Danger
• Hazard Statements: H290-H300-H301+H311-H301-H302-H311-H312--H314-H317-H318-H330-H335-H412
• Precautionary Statements: P234-P260-P261-P262-P264-P264+P265-P270-P271-P272-P273-P280-P284-P301+P316-P301+P317-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P319-P320-P321-P330-P333+P317-P361+P364-P362+P364-P363-P390-P403+P233-P405-P406-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	1	H330
Skin corrosion	Skin Corr.	1B	H314
Acute toxicity	Acute Tox.	3	H311
Serious eye damage	Eye Dam.	1	H318
Acute toxicity	Acute Tox.	3	H301
Specific target organ toxicity - single exposure	STOT SE	3	H335
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Skin sensitization	Skin Sens.	1	H317
Acute toxicity	Acute Tox.	2	H300
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	4	H302
Skin corrosion	Skin Corr.	1C	H314
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Acute toxicity	Acute Tox.	2	H330
Acute toxicity	Acute Tox.	3	H330
Acute toxicity	Acute Tox.	2	H310
Specific target organ toxicity - single exposure	STOT SE	3	H371

• Transport Information: UN 3246

Discovory and Applicatios

Methanesulfonyl chloride (also known as mesyl chloride) is a chemical compound with the molecular formula CH₃SO₂Cl. It is a colorless to light yellow liquid that is highly reactive and commonly used in organic synthesis. Methanesulfonyl chloride is primarily known for its role as a sulfonating agent, and it is widely used in the preparation of sulfonate esters, which are valuable intermediates in various chemical processes.

Methanesulfonyl chloride was first synthesized in the early 20th century as part of research on sulfonating reagents. It is derived from methanesulfonic acid (CH₃SO₃H), which is produced by the sulfonation of methane, typically using sulfur trioxide (SO₃). The reaction of methanesulfonic acid with chlorinating agents like thionyl chloride (SOCl₂) leads to the formation of methanesulfonyl chloride.

The main application of methanesulfonyl chloride is in the synthesis of mesylates, which are esters formed by reacting methanesulfonyl chloride with alcohols. Mesylates are commonly used as leaving groups in nucleophilic substitution reactions, particularly in the synthesis of complex organic molecules. The presence of the mesylate group improves the reactivity of alcohols and other nucleophiles, making them more susceptible to substitution by various nucleophiles, including halides and amines.

Methanesulfonyl chloride is also utilized in the preparation of other sulfonated derivatives, such as sulfonamides and sulfonic acid derivatives, which are important in the development of pharmaceuticals, agrochemicals, and other specialized chemicals. The high electrophilicity of the mesyl group makes it particularly useful for the functionalization of a wide range of organic substrates.

In addition to its use in organic synthesis, methanesulfonyl chloride has applications in the field of polymer chemistry. It is used to introduce mesylate groups into polymer chains, which can then be further modified or cross-linked to improve the properties of the resulting materials. This is useful in the production of polymers with enhanced stability, mechanical strength, and other desirable characteristics.

Methanesulfonyl chloride is also employed in the pharmaceutical industry as a reagent in the synthesis of certain active pharmaceutical ingredients (APIs). By introducing the mesyl group into various intermediates, it is possible to optimize the reactivity and selectivity of subsequent reactions. The compound’s ability to act as a sulfonating agent makes it valuable in the synthesis of both small molecules and larger bioactive compounds.

Handling methanesulfonyl chloride requires caution due to its highly reactive nature. It is corrosive and can cause severe irritation to the skin, eyes, and respiratory system. Proper personal protective equipment (PPE), including gloves, goggles, and a lab coat, should be worn when working with this substance. Additionally, methanesulfonyl chloride should be used in a well-ventilated area, and storage should be in tightly sealed containers, away from moisture, as the compound reacts with water to produce methanesulfonic acid and hydrochloric acid, which can cause damage to equipment and materials.

In conclusion, methanesulfonyl chloride is a versatile and widely used reagent in organic chemistry, particularly for the preparation of mesylates, which are valuable intermediates in the synthesis of complex organic compounds. Its applications extend across various industries, including pharmaceuticals, polymers, and agrochemicals. Despite its utility, it is a highly reactive and hazardous substance that requires careful handling to ensure safe use in laboratory and industrial settings.

References

2024. Synthesis and characterization of a novel nitrogen-rich PEG-based hydrogel through click chemistry. Polymer Bulletin, 81(10).
DOI: 10.1007/s00289-024-05548-8

2024. Available strategies for the synthesis of indenes for metal complex catalysis. Russian Chemical Bulletin, 73(10).
DOI: 10.1007/s11172-024-4395-3

2024. Quinazolinone-based subchemotypes for targeting HIV-1 capsid protein: design and synthesis. Medicinal Chemistry Research, 33(9).
DOI: 10.1007/s00044-024-03305-0