[OH:1][C:2]1[C:3]([CH3:18])=[C:4]2[C:9](=[C:10]([CH3:13])[C:11]=1[CH3:12])[O:8][C:7]([CH3:17])([C:14]([OH:16])=O)[CH2:6][CH2:5]2.C1N=CN(C(N2C=NC=C2)=O)C=1.Cl.[CH3:32][NH:33][O:34][CH3:35].C(N(CC)C(C)C)(C)C>C1COCC1.C(Cl)Cl>[OH:1][C:2]1[C:3]([CH3:18])=[C:4]2[C:9](=[C:10]([CH3:13])[C:11]=1[CH3:12])[O:8][C:7]([CH3:17])([C:14]([N:33]([O:34][CH3:35])[CH3:32])=[O:16])[CH2:6][CH2:5]2To a solution of 5.47 g 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (21.9 mmol) in 170 mL THF was added 3.92 g CDI (24.2 mmol) and stirred for 1.25 h at room temperature. To this was added a solution of 2.14 g N,O-dimethylhydroxylamine hydrochloride (21.97 mmol) and 8.2 g N,N-diisopropylethylamine in 50 mL CH2Cl2 dropwise over 1 h. The reaction was stirred overnight, concentrated, 250 mL CH2Cl2 added and washed sequentially with 100 mL 0.625 M HCl, 100 mL 1.0 M NaHCO3 and 100 mL saturated NaCl. The organics were dried over Na2SO4, concentrated and purified by flash chromatography yielding 4.43 g of 6-hydroxy-N-methoxy-N,2,5,7,8-pentamethylchroman-2-carboxamide as an off-white crystalline solid.
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