Carbamic acid, (3-methyl-5-isoxazolyl)-, 1,1-dimethylethyl ester (9CI) synthesis

Yield:-

Reaction Conditions:

with dmap in dichloromethane at 20; for 48 h;

Steps:

20 5-(t-Butoxycarbonylamino)-3-methylisoxazole

5-Amino-3-methylisoxazole (4.91 g, 0.05 M) was dissolved in dry dichloromethane (80 ml), and 4-dimethylaminopyridine (100 mg) and di-t-butyl dicarbonate (21.85 g, 0.1 M) added. The mixture was stirred at ambient temperature for 48 hours, then evaporated to dryness. The residue was purified by chromatography on a 90 g Biotage silica column, eluding with a gradient increasing in polarity from 0 to 5% diethyl ether in dichloromethane. Relevant fractions were combined and evaporated to give the desired product (0.67 g). NMR (DMSO-d₆) δ: 1.46 (s, 9H); 2.12 (s, 3H); 5.81 (s, 1H); 10.85 (br, 1H). MS (ESP): 199 (MH⁺) for C₉H₁₄N₂O₃

References:

US2003/207899,2003,A1 Location in patent:Page/Page column 36