(2′-Amino-4′-methyl-4,5′-bi-1,3-thiazol-2-yl)acetonitrile, prepared in Step I, described above (236.3 mg; 1 mmol; 1 eq.), is suspended in DCM (5 ml). N,N-Diisopropylethylamine (377 μl; 2.20 mmol; 2.20 eq.) is added, followed by a solution of ethyl 3-isocyanatopropionate (143.1 mg; 1 mmol; 1 eq.) in DCM (3 ml). The reaction mixture is heated at 50° C. overnight. As the reaction is not complete, a second batch of ethyl 3-isocyanatopropionate (Aldrich) (143.1 mg; 1 mmol; 1 eq.) is added. After 36 hours the reaction is complete. The solvents are evaporated. EtOAc is added and the mixture is washed with brine, dried over MgSO4 and evaporated. The resulting crude product is purified by preparative HPLC, affording Compound (50) as white-off solid (76.6 mg; 20%). 1H NMR (DMSO-d6, 300 MHz) δ 1.21 (t, J=7.5 Hz, 3H), 2.44 (s, 3H), 2.58 (m, 2H), 3.39 (q, J=6 Hz, 2H), 4.10 (q, J=7.5 Hz, 2H), 4.62 (s, 2H), 6.72 (t, J=6 Hz, 1H), 7.64 (s, 1H), 10.49 (br s, 1H). M− (ESI): 378.17; M+ (ESI): 380.10. HPLC (method A), Rt: 2.60 min (purity: 100%).
