Water → tert-Butyl 1-cyclopropylhydrazinecarboxylate

Temperature

50 °C

Water (24 mL) was added over 1 min to a mixture of N-nitroso-N-cyclopropyl-carbamic acid tert-butyl ester (2.01 g, 10.8 mmol), zinc powder (7.2 g, 110 mmol) and ammonium chloride (8.8 g, 165 mmol) in methanol (48 mL). An exotherm and gas evolution were noted. The mixture was stirred at room temperature for 2.25 h and at 50° C. for 2 h. The mixture was allowed to cool. It was filtered through Celite, and the Celite was washed well with methanol. The colvents were evaporated and dichloromethane (250 mL) was added. Salts were filtered off and the solution was dried (magnesium sulfate), filtered, and evaporated. The residue was passed through a cotton plug with a small amount of dichloromethane, the solvent was evaporated to give a clear oil. This was purified by chromatography using an ISCO 120 g column, eluting with 10-60% ethyl acetate/hexanes to give N-cyclopropyl-hydrazinecarboxylic acid tert-butyl ester (207 mg, 11%) as a pale yellow oil, along with a 36% yield of over-reduced cyclopropyl-carbamic acid tert-butyl ester.

1. temperatureto cool
2. filtrationIt was filtered through Celite
3. washthe Celite was washed well with methanol
4. customThe colvents were evaporated
5. additiondichloromethane (250 mL) was added
6. filtrationSalts were filtered off
7. dry with materialthe solution was dried (magnesium sulfate)
8. filtrationfiltered
9. customevaporated
10. customthe solvent was evaporated
11. customto give a clear oil
12. customThis was purified by chromatography
13. washeluting with 10-60% ethyl acetate/hexanes

ORD record

ord-ece8f9f6a0d94c3c88bdc3fdc4fa4e14

Source dataset

uspto-grants-2009_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07622492B2