Hydrazine hydrate (1:1) → (S)-4-benzyloxy-3-hydroxybutanohydrazide

Temperature

5 °C

In a 100 ml flask were put 4.15 g (17.4 mmol) of ethyl (S)-4-benzyloxy-3-hydroxybutyrate (optical purity: 89%e.e.) prepared in Reference Example 2, 20 ml of ethanol, and 2.62 g (52.2 mmol) of hydrazine monohydrate in a nitrogen stream, and the mixture was heated under reflux for 20 hours. The reaction mixture was cooled to room temperature (22 to 24° C.), and ethanol was removed by evaporation under reduced pressure. To the residue was added 40 ml of diethyl ether, followed by heating under reflux to dissolve the crude crystals. The solution was cooled to 5° C., followed by stirring for 1 hour. The crystals thus precipitated were collected by filtration and washed with 10 ml of diethyl ether to give 2.90 g (74%) of the title compound. Melting point: 96.9° C. Optical purity: >99.9%e.e.

1. customIn a 100 ml flask were put
2. temperaturethe mixture was heated
3. temperatureunder reflux for 20 hours
4. customwas removed by evaporation under reduced pressure
5. additionTo the residue was added 40 ml of diethyl ether
6. temperatureby heating
7. temperatureunder reflux
8. dissolutionto dissolve the crude crystals
9. customThe crystals thus precipitated
10. filtrationwere collected by filtration
11. washwashed with 10 ml of diethyl ether

ORD record

ord-91bf0004919c40f0b1647304f7844eda

Source dataset

uspto-grants-2002_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06403804B1