336191-17-4

929301-98-4

336191-17-4

Preparation of Compound 6: Compound 5 (2,8-diazaspiro[4.5]decane-2,8-dicarboxylic acid, 2-(1,1-dimethylethyl)8-(phenylmethyl) ester, 30 g, 0.08 mol) was dissolved in methanol (100 mL), and hydrogenation reaction was carried out by adding 20% Pd(OH)2/C catalyst (5 g) at room temperature and under hydrogen pressure of 76 cmHg. until the reaction was complete. After completion of the reaction, the catalyst was removed by filtration and the filtrate was concentrated. The resulting residue was purified by column chromatography to afford the target product compound 6 (tert-butyl 2,8-diazaspiro[4.5]deca-2-carboxylate, 11 g, 57% yield).1H NMR (DMSO, HCl salt) δ: 8.88 (broad peak, 2H), 3.28-3.23 (multiple peaks, 2H), 3.10 (double peaks, 2H), 2.99 (triple peaks, 2H) , 1.68-1.61 (multiple peaks, 2H), 1.63-1.59 (multiple peaks, 4H), 1.36 (single peak, 9H).