[CH2:1]([O:3][C:4]([C:6]1[N:7]=[C:8]([NH:21]C(OC(C)(C)C)=O)[S:9][C:10]=1[CH:11](O)[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][C:13]=1[O:18][CH3:19])=[O:5])[CH3:2].C([SiH](CC)CC)C.FC(F)(F)C(O)=O>ClCCl>[CH2:1]([O:3][C:4]([C:6]1[N:7]=[C:8]([NH2:21])[S:9][C:10]=1[CH2:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][C:13]=1[O:18][CH3:19])=[O:5])[CH3:2]A mixture of 2-tert-butoxycarbonylamino-5-[hydroxy-(2-methoxy-phenyl)-methyl]-thiazole-4-carboxylic acid ethyl ester (12 g, 29 mmol), triethylsilane (52 g, 45 mmol), and trifluoroacetic acid (100. g, 89.6 mmol) was stirred for 15 hours in dichloromethane (150 mL). The mixture was evaporated to dryness and then diluted with water. The precipitated solid was filtered and washed with water, diethyl ether, and petroleum ether to give the pure target molecule as a trifluoroacetic acid salt (7.6 g, 19 mmol, 64%). ESI-MS m/z calc. 292.09. found; 292.25 (M+1)+ 1H NMR (CDCl3) δ 7.7 (br, 2H), 7.24 (t, 1H), 7.17 (d, 1H), 6.99 (d, 1H), 6.88 (t, 1H), 4.22-4.25 (m, 4H), 3.78 (s, 3H), 1.26 (t, 3H).
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