[Br:1][C:2]1[S:6][C:5]([NH:7][C:8](=[O:14])[O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[N:4][CH:3]=1.[CH:15](O)([CH3:17])[CH3:16].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.N(C(OCC)=O)=NC(OCC)=O>C1COCC1>[Br:1][C:2]1[S:6][C:5]([N:7]([CH:15]([CH3:17])[CH3:16])[C:8](=[O:14])[O:9][C:10]([CH3:11])([CH3:13])[CH3:12])=[N:4][CH:3]=1Step 2 A solution of tert-butyl 5-bromothiazol-2-ylcarbamate (3 g, 10.7 mmol), isopropanol (6.40 g, 107.4 mmol) and triphenylphosphine (5.63 g, 21.5 mmol) in THF (30 mL) was treated with diethyl azodicarboxylate (3.74 g, 21.5 mmol) dropwise at 0° C. and was stirred overnight while warming slowly to rt. The mixture was concentrated and the residue was dissolved in DCM (20 mL), filtered to remove undissolved solid and concentrated. The residue was purified by column chromatography (eluting with hexane) to give tert-butyl 5-bromothiazol-2-yl(isopropyl)carbamate as a light yellow oil (3.10 g, 90%). 1H NMR (400 MHz, chloroform-d) δ 7.34 (s, 1H) 5.29 (m, 1H) 1.59 (s, 9H) 1.45 (d, 6.8 Hz, 6H). Mass spectrum m/z 265, 267 (M+H—C4H9)+.
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