Hydrazine hydrate (1:1) → 2-Fluorobenzhydrazide

Methyl 2-fluorobenzoate (27) (25 g, 160 mmol) was dissolved in ethanol (200 mL) and hydrazine monohydrate (11.8 mL, 240 mmol) was added. The mixture was heated to reflux for 4 hr then allowed to cool to room temperature overnight. The reaction was incomplete. After heating for a further 2 hr, starting material still remained. Additional hydrazine monohydrate (4 mL) was added. After heating for 2-3 hr the reaction was nearly complete. The mixture was cooled and concentrated under reduced pressure. Water (50 mL) was added to the residue and the aqueous layer was saturated with solid NaCl. The product was extracted with EtOAc (3×100 mL). The combined organic solution was dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was triturated with heptane (100 mL), filtered, and dried to provide 23.8 g (95%) of 13 as a pinkish solid.

1. temperatureThe mixture was heated
2. temperatureto reflux for 4 hr
3. temperatureAfter heating for a further 2 hr
4. temperatureAfter heating for 2-3 hr the reaction
5. temperatureThe mixture was cooled
6. concentrationconcentrated under reduced pressure
7. additionWater (50 mL) was added to the residue
8. extractionThe product was extracted with EtOAc (3×100 mL)
9. dry with materialThe combined organic solution was dried over Na2SO4
10. filtrationfiltered
11. concentrationconcentrated under reduced pressure
12. customThe residue was triturated with heptane (100 mL)
13. filtrationfiltered
14. customdried

ORD-Eintrag

ord-c4dea629fed449ceb1d2d131f63cf95e

Quelldatensatz

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08993570B2