4-(Hydroxymethyl)-2-Isopropylthiazole → N-((2-Isopropyl-4-thiazolyl)methoxycarbonyl)valine Methyl Ester

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A solution of 2.18 g (15 mmol) of 4-(hydroxymethyl)-2-isopropylthiazole, 15.8 mmol of α-isocyanato-valine methyl ester and 1.5 mmol of 4-dimethylaminopyridine in 75 ml of dichloromethane was heated at reflux for 5 h. The resulting solution was washed successively with 10% citric acid, aqueous NaHCO3 and brine, dried over Na2SO4, and concentrated in vacuo. Silica gel chromatography of the residue using 5% ethyl acetate in chloroform provided 2.67 g (57%) of the pure desired compound, Rf 0.46 (4% methanol in chloroform). NMR 1H NMR (DMSO-d6) δ1.26 (d, J=8 Hz, 3H), 1.32 (d, J=7 Hz, 6H), 3.27 (heptet, J=7 Hz, 1H), 3.63 (s, 3H), 4.10 (pentet, J=8 Hz, 1H), 5.02 (s, 2H), 7.47 (s, 1H), 7.81 (d, J=8 Hz, 1H). Mass spectrum: (M+H)+ =287.

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