Methanesulfonyl chloride (0.78 g, 0.52 ml, 6.6 mmole) is added dropwise with stirring to a cooled solution of N-cycloheptyl-5-[benzyl(2-hydroxyethyl)amino]pentanamide (2.14 g, 6 mmole) in dichloromethane (20 ml) in the presence of triethylamine (0.69 g, 0.94 ml, 6.6 mmole). Agitation is maintained for 18 hours at 20° C. The reaction mixture is filtered with iced water (25 ml) then dried over magnesium sulfate. Filtration and evaporation of the solvent under reduced pressure give 2.2 g (98%) of the desired compound in the form of an oil.
