A)a) 3.7 g of tetrabutylammonium hydrogen sulphate and 100 ml of 1N sodium hydroxide solution are added to a solution of 10.0 g of t-butyl (S)-3-aminomethyl-1-piperidinecarboxylate (Example 6d) in 400 ml of hexane and 100 ml of water. 9.3 ml of benzyl chloroformate are added dropwise to this mixture and the mixture obtained is stirred at room temperature for 3 hours. Subsequently, the organic phase is separated, washed with water, 10% citric acid, water and saturated sodium bicarbonate solution, dried and evaporated. t-Butyl (S)-3-[(1-(benzyloxy)formamido]-methyl]-1-piperidinecarboxylate is obtained.
