1,3-Dimethyl-1H-pyrazol-5-amine

Chemical Properties

white to light yellow crystal powde

Uses

5-Amino-1,3-dimethylpyrazole may be used in the preparation of:

• 5-benzamido-1,3-dimethylpyrazole
• diethyl 2-{[(1,3-dimethyl-1H-pyrazol-5-yl)amino]methylene}malonate
• 5-amino-1,3-dimethyl-4-phthalidylpyrazole
• (E)-N-(3,7-dimethylocta-2,6-dienyl)-1,3-dimethyl-1H-pyrazol-5-amine analog(LQFM002)
• 4-isopropyl-1,3-dimethyl-1H-pyrazolo[3,4-b]pyridin-6-ol

General Description

5-Amino-1,3-dimethylpyrazole undergoes cyclocondensation with ethyl acetoacetate to form the corresponding tetrahydropyrazolopyridine derivatives.

Synthesis

To a solution of 3-aminobut-2-enenenitrile (16.5 g, 0.2 mol) in n-pentanol (40 mL) was slowly added methylhydrazine (12.9 g, 0.28 mol). The reaction mixture was heated to reflux and kept for 3 hours. Upon completion of the reaction, n-pentanol and excess methylhydrazine were removed by distillation under reduced pressure. The resulting beige precipitate was dissolved in heptane (150 mL) and filtered through a sintered funnel. The filtrate was dried under vacuum at 40 °C to afford 5-amino-1,3-dimethylpyrazole as a beige solid (13.5 g, 60.4% yield).

References

[1] Patent: WO2012/92880, 2012, A1. Location in patent: Page/Page column 59
[2] Journal of the American Chemical Society, 1959, vol. 81, p. 2452,2455
[3] Patent: US6338741, 2002, B1. Location in patent: Page column 15
[4] Journal of Combinatorial Chemistry, 2010, vol. 12, # 4, p. 510 - 517