[C:1](N1C=CN=C1)(N1C=CN=C1)=[O:2].[OH:13][C:14]1[CH:19]=[CH:18][C:17]([CH2:20][CH2:21][OH:22])=[CH:16][CH:15]=1.[C:23]([O:27][C:28]([CH3:31])([CH3:30])[CH3:29])(=[O:26])[NH:24][NH2:25].O>O1CCCC1.C(OCC)(=O)C>[NH:24]([C:23]([O:27][C:28]([CH3:31])([CH3:30])[CH3:29])=[O:26])[NH:25][C:1]([O:22][CH2:21][CH2:20][C:17]1[CH:18]=[CH:19][C:14]([OH:13])=[CH:15][CH:16]=1)=[O:2]
To a suspension of 1,1′-carbonyldiimidazole (1.620 g, 9.989 mmol) in anhydrous tetrahydrofuran (20 ml) was added 2-(4-hydroxyphenyl)ethanol (1.383 g, 10.01 mmol), and the mixture was stirred at room temperature for 3 hr. tert-Butyl carbazate (1.323 g, 10.01 mmol) was added, and the mixture was stirred at room temperature for 1.5 hr. Water (100 ml) and ethyl acetate (100 ml) were added to the reaction mixture, and the mixture was stirred, stood still and then partitioned. The aqueous layer was extracted with ethyl acetate, and the combined organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (FUJI SILYSIA CHEMICAL LTD. BW-300SP 40 g, ethyl acetate:hexane=4:6→5:5). The fractions containing the object product were concentrated under reduced pressure, and the obtained solid was suspended in diisopropyl ether (50 ml) and filtered. The filtered product was washed 3 times with diisopropyl ether and dried under reduced pressure to give tert-butyl 2-(4-hydroxyphenyl)ethyl hydrazine-1,2-dicarboxylate (616.7 mg, 2.08 mmol, yield 20.8%) as a white solid.
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