反应详情

Acetone (0.377 g; 0.477 ml; 6.50 mmol) was added to a solution of carbobenzyloxyhydrazine (1.00 g; 6.02 mmol) in absolute ethanol (6 ml). After one hour, the solution was concentrated to dryness and then ethanol (5 ml) and sodium cyanoborohydride (0.19 g; 3.0 mmol) were added. The mixture was stirred for 18 hours and then evaporated to a thick syrup. Hydrochloric acid (0.50 N; 5 ml) and ether (50 ml) were added and the two-phase mixture was stirred for one hour. The aqueous layer was neutralized by addition of solid NaHCO3 and extracted with ether (2×25 ml). The combined ether portions were washed with water and brine and dried (MgSO4) Removal of solvent gave a solid which was recrystallized from hexanes - ether, giving pure hydrazide 4 (1.09 g; 5.25 mmol; 87%), mp 61°-62°. TLC (silica gel; CH2Cl2 --CH3OH; 20:1) Rf=0.5. MS m/e 208 (M+). Analysis: Calculated for C11H16N2O2 : (C, 63.44; H, 7.44; N, 13.45). Found: C, 63.22; H, 7.67; N, 13.71; NMR (CDCl3);δ0.97 (6H,d,J=6); 3.15 (1H, septet, J=6); 3.8-4.6(1H, broad); 5.13(2H,S); 6.2-7.0(1H, broad); 7.33 (5H,S); IR(CHCl3) 3500, 1720 cm-1.

1. concentrationthe solution was concentrated to dryness
2. customevaporated to a thick syrup
3. additionHydrochloric acid (0.50 N; 5 ml) and ether (50 ml) were added
4. stirringthe two-phase mixture was stirred for one hour
5. additionThe aqueous layer was neutralized by addition of solid NaHCO3
6. extractionextracted with ether (2×25 ml)
7. washThe combined ether portions were washed with water and brine
8. customdried
9. custom(MgSO4) Removal of solvent
10. customgave a solid which
11. customwas recrystallized from hexanes - ether