Reaction Steps
N-(Mesityl)-oxanilic acid (2.15 g, 10.4 mmol, 1.0 eq), prepared according to the synthesis method described in Example 5, and 1-hydroxybenzotriazole (2.39 g, 15.6 mmol, 1.5 eq) were added to an oven dried, two-necked flask, forming a solution. THF (100 ml) was then added and the solution was cooled to 0° C. 1,3-dicyclohexylcarbodiimide (1 M in CH2Cl2) (12.5 ml, 12.5 mmol, 1.2 eq) was then added to the solution. The solution was then allowed to stir at 0° for one hour. During this time, a white precipitate formed. 2-amino-4-methyl-6-tert-butylphenol (1.863 g, 10.4 mmol, 1.0 eq), prepared according to the synthesis method described in Example 6, was then added to the suspension. The suspension was then allowed to stir overnight. The next day, the solvent was removed under reduced pressure, and ethyl acetate was added. The resulting suspension was then filtered to remove the solid. The filtrate was washed with 10% citric acid solution (2×50 ml), 5% NaHCO3 (2×50 ml) and brine (50 ml). It was dried over MgSO4, and the solvent was removed under reduced pressure, leaving a solid which was recrystallized from hexane to give the product as a white solid (2.92 g, 7.9 mmol, 76% yield). 1H NMR (300 MHz, CDCl3) δ 9.55 (s, 1H), 8.77 (s, 1H), 7.84 (s, 1H), 7.05 (d, J=1.8 Hz, 1H), 6.92 (m, 3H), 2.30 (s, 3H), 2.28 (s, 3H), 2.22 (s, 6H), 1.45 (s, 9H); 13C NMR (75 MHz, CDCl3) δ 158.5, 157.4, 146.2, 140.6, 138.1, 134.9, 129.9, 129.6, 129.4, 126.9, 124.9, 121.4, 35.3, 30.0, 21.2, 21.0, 18.5. Anal. Calcd for C22H28N2O3: C, 71.71; H, 7.66; N, 7.60. Found: C, 72.01; H, 8.03; N, 7.36.
