A 1.50 g (6.14 mmol) portion of 1-benzyl-4-(1-aminocyclobutyl)-2-pyrrolidone (fr. 2) was dissolved in 200.0 ml of tetrahydrofuran to which, with cooling in an ice bath, was subsequently added 932 mg (24.56 mmol) of lithium aluminum hydride in small portions. After 12 hours of stirring with heating under reflux, the reaction solution was cooled in an ice bath and mixed with 932 μl of water in small portions, 932 μl of 15% sodium hydroxide aqueous solution and 932 μl of water in that order. After 30 minutes of stirring at room temperature, insoluble material was removed by filtration and the solvent was evaporated. To the thus obtained syrup were added 70.0 ml of acetonitrile and then 1.69 ml (7.37 mmol) of di-tert-butylcarbonate at room temperature, followed by overnight stirring. After evaporation of the solvent, the resulting residue was purified by a silica gel column chromatography (230-400 mesh silica gel 150 ml, 5% methanol-chloroform) to yield 525 mg (26%) of the title compound.
