N[C:2]1[CH:3]=[CH:4][C:5]([O:9][CH3:10])=[C:6]([OH:8])[CH:7]=1.[CH2:11]=O.[C:13]([BH3-])#[N:14].[Na+].[H-]>C(O)C.C(O)(=O)C>[CH3:11][N:14]([CH3:13])[C:2]1[CH:3]=[CH:4][C:5]([O:9][CH3:10])=[C:6]([OH:8])[CH:7]=1
To a stirred solution of 5-amino-2-methoxyphenol (5.0 g, 36 mmol) in ethanol (250 mL), was added 33% formaldehyde (4×1.5 mL at times 0, 60 min, 140 min and 185 min) and sodium cyanoborohydride (4×0.8 g, at times 30 min, 120 min, 165 min and 210 min). After each addition of the hydride, pH was adjusted to ˜6 using acetic acid. The mixture was stirred for an additional 2 h and then concentrated in vacuo. The residue was partitioned between brine/diethyl ether and the organic phase was dried and concentrated. The residue was purified by column chromatography on silica gel using hexane/EtOAc (7:3) as eluent to give 1.17 g (20%) of the title compound. MS m/z 168 (M+H)+.
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