Hydrazine hydrate (1:1) → HCID 178469276, compound

HRID 1846246Notes

Reaction equation

[C:1](/[C:3](=[C:9](\OCC)/[CH3:10])/[C:4]([O:6][CH2:7][CH3:8])=O)#[N:2].[OH2:14].[NH2:15][NH2:16]>C(O)(=O)C>[NH2:2][C:1]1[NH:16][N:15]=[C:9]([CH3:10])[C:3]=1[C:4]([O:6][CH2:7][CH3:8])=[O:14]

Participants

Conditions

Temperature: 110 °C

Procedure

A mixture of (E)-ethyl 2-cyano-3-ethoxybut-2-enoate (4.4 g, 24.02 mmol, 1.00 equiv) and hydrazine hydrate (3 mL) in acetic acid (40 mL) was stirred at 110° C. for 2 h. The resulting mixture was cooled to room temperature and concentrated under vacuum. Water (20 mL) was added to the residue and the resulting solution extracted with 2×20 mL of dichloromethane. The combined organic layers was washed with 2×40 mL of brine, dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified on a silica gel column eluted with 0-50% of ethyl acetate in petroleum ether to give 2.1 g (52%) of ethyl 5-amino-3-methyl-1H-pyrazole-4-carboxylate as a yellow oil. 1H-NMR (300 MHz, CDCl3): δ 6.76 (br s, 2H), 4.30 (q, J=7.2 Hz, 2H), 2.41 (s, 3H), 1.35 (t, J=7.2 Hz, 3H) ppm. LCMS (method D, ESI): RT=0.98 min, m/z=170.0 [M+H]+.

Workup

temperatureThe resulting mixture was cooled to room temperature
concentrationconcentrated under vacuum
additionWater (20 mL) was added to the residue
extractionthe resulting solution extracted with 2×20 mL of dichloromethane
washThe combined organic layers was washed with 2×40 mL of brine
dry with materialdried over anhydrous sodium sulfate
concentrationconcentrated under vacuum
customThe residue was purified on a silica gel column
washeluted with 0-50% of ethyl acetate in petroleum ether

Sources & evidence

ORD record: ord-4c818a661bdf4a9ca36c8a16d36044b9
Source dataset: uspto-grants-2015_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08952026B2

Reaction notes

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