Methylhydrazine → N-ethyl(tert-butoxy)carbohydrazide

Methylhydrazine (1.415 mL, 26.9 mmol) was added to a solution of tert-butyl 1,3-dioxoisoindolin-2-yl(ethyl)carbamate (example 74A, 5.2 g, 17.91 mmol) in THF (40 mL) at 0° C. and the reaction mixture was stirred at room temperature overnight. A white precipitate formed and was filtered off through a pad of Celite, The filtrate was concentrated in vacuo. The residue was dissolved in ethyl acetate (50 ml) and extracted with 1N HCl (3×30 ml), the acid layer was washed with ethyl acetate (50 ml) and basified to pH 10 by addition of 20% NaOH. The basic solution was then extracted with ethyl acetate (3×50 ml) and the combined organic layers were washed with brine, dried over magnesium sulfate, filtered and concentrated in vacuo to give tert-butyl 1-ethylhydrazinecarboxylate (2.5 g, 87% yield) as colorless oil.

1. customA white precipitate formed
2. filtrationwas filtered off through a pad of Celite
3. concentrationThe filtrate was concentrated in vacuo
4. dissolutionThe residue was dissolved in ethyl acetate (50 ml)
5. extractionextracted with 1N HCl (3×30 ml)
6. washthe acid layer was washed with ethyl acetate (50 ml)
7. additionbasified to pH 10 by addition of 20% NaOH
8. extractionThe basic solution was then extracted with ethyl acetate (3×50 ml)
9. washthe combined organic layers were washed with brine
10. dry with materialdried over magnesium sulfate
11. filtrationfiltered
12. concentrationconcentrated in vacuo

ORD record

ord-370332bc3522440f9fe00a30fbb0713f

Source dataset

uspto-grants-2012_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08202881B2