tert-butyl 2-(cyclopropanecarbonyl)hydrazinecarboxylate synthesis

Yield:851295-78-8 47%

Reaction Conditions:

with triethylamine in dichloromethane at 0; for 1 h;

Steps:

15.A Step A:
tert-butyl 2-(cyclopropanecarbonyl)hydrazinecarboxylate

To a mixture of tert-butyl hydrazinecarboxylate (3.00 g, 22.7 mmol), TEA (6.33 mL, 45.4 mmol) in DCM (51 mL) was added a solution of cyclopropanecarbonyl chloride (3.10 mL, 34.0 mmol) in DCM (10 mL) at 0° C.
The reaction mixture was stirred at 0° C. for 1 hour and quenched with water.
The mixture was extracted with DCM, washed with 1 N aq. HCl and brine, dried over Na₂SO₄, filtered and concentrated in vacuo.
The residue was purified by column chromatography on SiO₂ (Hex:EtOAc=2:1 to 1:1) to afford tert-butyl 2-(cyclopropanecarbonyl)hydrazinecarboxylate (2.16 g, 47%) as a white solid. ¹H-NMR (CDCl₃, Varian, 400 MHz): δ 0.81-0.84 (2H, m), 1.02-1.04 (2H, m), 1.45-1.52 (10H, m), 6.65 (1H, br. s), 7.95 (1H, br. s).

References:

US2016/168156,2016,A1 Location in patent:Paragraph 0288; 0289