Yield:175137-46-9 57%

Reaction Conditions:

with hydrazine hydrate in ethanol at 0 - 70; for 3 h;

Steps:

int-2: 5-cyclopropyl-1H-pyrazol-3-amine
To a solution of 3-cyclopropyl-3-oxopropanenitrile (10 g, 91.7 mmol)) in ethanol (200 mL) was dropwise added hydrazine monohydrate (7.74 mL, 160 mmol) at 0 . The resulting mixture was heated under reflux for 3 hours. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. The residue was partitioned with ethyl acetate and water. The organic layer was dried over sodium sulfate, filtered and concentrated. The crude was purified using MPLC to provide 6.43 g (57%) of 5-cyclopropyl-1H-pyrazol-3-amine as a solid: ¹H NMR (CDCl₃, 500 MHz): δ 5.32 (s, 1 H), 1.80-1.75 (m, 1 H), 0.94-0.91 (m, 2 H), 0.70-0.67 (m, 2 H).

References:

Ali, Imran;Park, Sangjun;Jung, Myoung Eun;Lee, Nari;Bibi, Maimoona;Chae, Chong Hak;Yang, Kyung-Min;Kim, Seong-Jin;Choi, Gildon;Lee, Kwangho [Bulletin of the Korean Chemical Society,2020,vol. 41,# 5,p. 567 - 569] Location in patent:supporting information

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