2-Pentanone,4-methyl-4-(methylthio)- , its CAS NO. is 23550-40-5, the synonyms are 4-(Methylthio)-4-methyl-2-pentanone ; 4-Methyl-4-(methylthio)-2-pentanone ; 4-Methylmercapto-4-methylpentan-2-one ; FEMA No. 3376 .