Methyl o-Toluenesulfonate
Methyl toluenesulfonate (CAS 28804-47-9), also called methyl o/p-toluenesulfonate or OPTSM, is supplied as a mixture of the ortho and para isomers, a colourless to slightly yellow liquid with a density of about 1.41 grams per cubic centimetre and a strong aromatic odour. It is the methyl ester of toluenesulfonic acid and a potent methylating agent: the sulfonate ester is an excellent leaving group, so the methyl group is transferred readily to nucleophiles including amines, thiols, phenoxides, carboxylates and stabilised carbanions. Because methyl sulfonate esters are mutagenic and genotoxic, this material is classified as a potential genotoxic impurity, is handled under tight control and specifications, and is frequently supplied as a certified reference standard for method development and impurity control in pharmaceutical analysis.
1. Methylating agent: used to introduce methyl groups onto oxygen, nitrogen and sulfur nucleophiles in pharmaceutical, agrochemical and fine chemical synthesis where a mild, selective and easily handled electrophile is preferred over methyl iodide or dimethyl sulfate.
2. Genotoxic impurity reference standard: supplied as a reference material for the detection, quantification and control of methyl toluenesulfonate and related sulfonate esters in drug substances, intermediates and finished products.
3. Process chemistry and safety: used to study the formation, purge and clearance of genotoxic impurities during active pharmaceutical ingredient manufacture, supporting toxicological risk assessment, control strategies and specification setting.
4. Handling and storage: toxic and potentially mutagenic; keep in a tightly closed container in a cool, dry, well-ventilated place away from water, bases and amines, use impermeable gloves, eye protection and containment, avoid inhalation of vapour and treat residues as hazardous waste.
Product Name: Methyl o-Toluenesulfonate
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