反应详情

Hydrazine hydrate (containing 55% hydrazine, 1.5 mL, 26.25 mmol, 1.05 equiv.) was added dropwise over 1 minute to a mixture containing benzyl 4-nitrobenzoate (Brewster, J. H.; Ciotti, C. J., Jr. J. Am. Chem. Soc. 1955, 77, 6214; 6.43 g, 25 mmole, 1 equiv.), 5% rhodium on carbon (wet, 625 mg), and tetrahydrofuran (50 ml) at 0° C. under argon. When the addition was complete, the mixture was warmed to room temperature, stirred for 4 hours, and then was filtered through Celite®. Concentration of the filtrate gave crude benzyl 4-(hydroxyamino)benzoate as a yellow oil which was used without further purification. Pure benzyl 4-(hydroxyamino)benzoate, obtained from a separate preparation by silica gel chromatography (30% ethyl acetate/toluene) was used for characterization purposes: TLC(30% ethyl acetate/toluene) Rf 0.52; 1H NMR (250 MHz, CDCl3) δ 7.99 (d, J=8.6 Hz, 2 H), 7.26-7.55 (m, 5 H), 6.97 (d, J=8.6 Hz, 2H), 5.33 (s, 2H); IR (CHCl3) 3550, 3315, 1703, 1606, 1273, 1169, 1101, 693 cm-1 ; MS(DC/NH3) 261.2 (M+NH4)+, 245.2 (M+MH4 -16)+, 228.1 (M+H-16)+.

1. additionWhen the addition
2. filtrationwas filtered through Celite®
3. customConcentration of the filtrate gave crude benzyl 4-(hydroxyamino)benzoate as a yellow oil which
4. customwas used without further purification