Piperidine → 3-Amino-oxetane-3-carboxylic acid {(S)-5-[5-chloro-3-fluoro-2-(5-methyl-[1,2,4]oxadiazol-3-yl)-phenyl]-indan-1-yl}-amide

To a solution of (3-{(S)-5-[5-chloro-3-fluoro-2-(5-methyl-[1,2,4]oxadiazol-3-yl)-phenyl]-indan-1-ylcarbamoyl}-oxetan-3-yl)-carbamic acid 9H-fluoren-9-ylmethyl ester (intermediate A-12) (2.94 g, 4.42 mmol) in MeCl2 (50.0 ml) was added piperidine (4.38 ml) and the mixture was stirred at room temperature for 15 h. The colorless solution was concentrated to dryness under high vacuum at RT. The remaining residue was purified by chromatography (silica gel; MeCl2/MeOH 100:0-95:5) and the title compound was obtained as light brown oil (1.09 g, 56%). MS: 443.1 (MH+, 1Cl).