With azodicarboxylic acid bis(2-methoxyethyl) ester; triphenylphosphine In tetrahydrofuran at 20℃; for 3 h; Cooling with ice
A mixture of 2.16 g of azodicarboxylic acid bis(2- methoxyethyl)ester and 10 ml of THF was added dropwise to a mixture of 1.2 g of methyl 2-[(2-hydroxyphenyl)amino]-2- oxo-acetate, 2.42 g oftriphenylphosphine, and 25 ml of THF under ice cooling, followed by stirring for 3 hours at room temperature. The reaction mixture was concentrated under reduced pressure, and the residues were subjected to silica gel column chromatography, thereby obtaining 0.72 g of methyl benzoxazole-2-carboxylate (hereinafier, described as a “compound 16 of the present invention”).Compound 16 of the Present Invention11219] ‘H-NMR (CDC13) ö: 7.92-7.89 (m, 1H), 7.70-7.66 (m, 1H), 7.57-7.52 (m, 1H), 7.50-7.45 (m, 1H), 4.10 (s, 3H)
With azodicarboxylic acid bis(2-methoxyethyl) ester; triphenylphosphine; In tetrahydrofuran; at 20℃; for 3h;Cooling with ice;
A mixture of 2.16 g of azodicarboxylic acid bis(2- methoxyethyl)ester and 10 ml of THF was added dropwise to a mixture of 1.2 g of methyl 2-[(2-hydroxyphenyl)amino]-2- oxo-acetate, 2.42 g oftriphenylphosphine, and 25 ml of THF under ice cooling, followed by stirring for 3 hours at room temperature. The reaction mixture was concentrated under reduced pressure, and the residues were subjected to silica gel column chromatography, thereby obtaining 0.72 g of methyl benzoxazole-2-carboxylate (hereinafier, described as a ?compound 16 of the present invention?).Compound 16 of the Present Invention11219] ?H-NMR (CDC13) oe: 7.92-7.89 (m, 1H), 7.70-7.66 (m, 1H), 7.57-7.52 (m, 1H), 7.50-7.45 (m, 1H), 4.10 (s, 3H)