0.7 g (2.53 mmole) (3RS)-1-(N-benzyloxycarbonylamidino)-3-hydroxymethyl pyrrolidine and 0.70 ml (5.05 mmole) triethylamine was dissolved in 15 ml diethyl ether/CH2Cl2 1/1 and the mixture was cooled to 0° C. 0.25 ml (3.29 mmole) methanesulphonyl chloride in 3 ml diethyl ether was slowly added and the reaction mixture was stirred at 0° C for three hours. The solvent was evaporated and the residue was dissolved in ethyl acetate and extracted with a 0.3M KHSO4 -solution. The water layer was washed once with CH2Cl2. The water layer was made neutral with 10M NaOH-solution and extracted twice with CH2Cl2. The combined organic layer was dried (Na2 SO4), filtered and evaporated to yield 0.450 g (50%) of the title compound.
