This compound arises as a process-related impurity when the carboxylic acid intermediate (modafinil acid) undergoes incomplete or side-reaction esterification during synthesis, or from residual esterified intermediates carried through the manufacturing route. Structurally, it retains the sulfinyl (sulfoxide) oxidation state characteristic of the active modafinil pharmacophore, but bears a methyl ester rather than the primary amide present in modafinil itself --- making it chemically distinct from, but closely monitored alongside, the parent API.
Methyl 2-benzhydrylsulfinylacetate, officially designated as Modafinil EP Impurity C, is the methyl ester analog of modafinil acid within the modafinil synthetic and impurity family. It is used exclusively as a pharmacopeial reference standard for European Pharmacopoeia (EP)-compliant quality control testing of modafinil and armodafinil drug substances.
| Chemical Name | Methyl [(RS)-(Diphenylmethyl)sulfinyl]acetate (Modafinil EP Impurity C) |
| CAS Number | 63547-25-1 |
| IUPAC Name | Methyl 2-benzhydrylsulfinylacetate |
| Molecular Formula | C16H16O3S |
| Molecular Weight | 288.36 g/mol g/mol |
Designated EP Impurity C for European Pharmacopoeia-compliant drug substance quality control.
Used for HPLC method development and validation (AMV) in ANDA and commercial modafinil manufacturing quality programs.
Tracked during API process chemistry to control esterification-related side products in modafinil synthesis routes.
Supplied with characterization data to support ANDA and EP/USP compendial filing requirements.
Ph. Eur. monograph reference
J. Pharm. Biomed. Anal.
Org. Process Res. Dev.
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