[C:1]([O:5][C:6]([N:8]1[CH2:12][CH2:11][CH:10]([C:13]2[S:14][CH:15]=[C:16]([CH2:18]Cl)[N:17]=2)[CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].[N:20]1([C:25]2[CH:30]=[CH:29][C:28]([OH:31])=[CH:27][CH:26]=2)[CH:24]=[N:23][N:22]=[N:21]1>C(#N)C>[C:1]([O:5][C:6]([N:8]1[CH2:12][CH2:11][CH:10]([C:13]2[S:14][CH:15]=[C:16]([CH2:18][O:31][C:28]3[CH:29]=[CH:30][C:25]([N:20]4[CH:24]=[N:23][N:22]=[N:21]4)=[CH:26][CH:27]=3)[N:17]=2)[CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2]A mixture of 3-(4-Chloromethyl-thiazol-2-yl)-pyrrolidine-1-carboxylic acid tert-butyl ester (From Step 1) (775 mg, 2.56 mmol), 4-tetrazol-1-yl-phenol (415 mg, 2.56 mmol), CsCO3 (1.25 mg, 3.84 mmol) and KI (44 mg, 0.26 mmol) in acetonitrile (20 mL) was heated under reflux overnight. After cooling, the solid was filtered through a pad of celite. The filtrate was concentrated in vacuo. The residue was purified on silica gel (EtOAc-hexanes, 1:1) to afford the desired product. 1H NMR (CDCl3): δ 8.92 (1H, s), 7.63 (2H, d), 7.27 (1H, s), 7.17 (2H, d), 5.24 (2H, s), 3.87 (1H, m), 3.79 (1H, m), 3.65 (2H, m), 3.45 (1H, m), 2.40 (1H, m), 2.23 (1H, m), 1.47 (9H, s).
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