[CH:1](=[O:13])[C:2]1[CH:12]=[C:9]([O:10][CH3:11])[C:7]([OH:8])=[C:4]([O:5][CH3:6])[CH:3]=1.CCN(C(C)C)C(C)C.Br[CH2:24][C:25]([O:27][CH3:28])=[O:26].O>C(Cl)Cl>[CH:1]([C:2]1[CH:12]=[C:9]([O:10][CH3:11])[C:7]([O:8][CH2:24][C:25]([O:27][CH3:28])=[O:26])=[C:4]([O:5][CH3:6])[CH:3]=1)=[O:13]To a solution of syringaldehyde (3.0 g, 16.5 mmol) in methylene chloride (33 mL, 0.5 M) was added Hunig's base (5.7 mL, 32.7 mmol) and methyl bromoacetate (1.87 mL, 19.8 mmol), and the mixture was stirred for 15 hours at room temperature, followed by addition of H2O. The reaction mixture was then extracted with chloroform, washed with saturated saline, next dried over magnesium sulfate, and evaporated under diminished pressure. The residue was subjected to silica gel chromatography, and a white solid product (3.895 g, 92.9%) was obtained from an ethyl acetate/hexane eluent (1:1.5 v/v). Recrystallization of a portion of the white solid product from ethyl acetate gave a colorless needle-like crystal (m.p. 100 to 102° C.).
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