Chemical Properties
White to orange solid
Uses
3-Methyl-5-(trifluoromethyl)pyrazole is a reagent used in the preparation of (fluoromethyl)pyrazole via microwave-assisted Stille coupling.
Definition
ChEBI: 3-Methyl-5-(trifluoromethyl)-1H-pyrazole is a member of pyrazoles.
General Description
3-Methyl-5-(trifluoromethyl)pyrazole is a pyrazole derivative. It has been reported to be synthesized from 3-methyl-5-trifluoromethyl-1
H-pyrazole.
Synthesis
Example 127: Preparation of 5-methyl-3-trifluoromethyl-1H-pyrazole
Hydrazine hydrate (945 μl, 30 mmol) was slowly added to a solution of 1,1,1-trifluoro-2,4-pentanedione (4.62 g, 30 mmol) in methanol (20 ml) at 0 °C. The reaction mixture was gradually warmed up to room temperature and stirred at that temperature for 16 hours. After completion of the reaction, the solvent was removed by concentration under reduced pressure to give 5-methyl-3-trifluoromethyl-1H-pyrazole as a yellow solid (4.5 g, 95% yield).
1H-NMR (400 MHz, CDCl3): δ 2.35 (s, 3H, CH3), 6.32 (s, 1H, CH), 9.88 (bs, 1H, NH) ppm.
References
[1] Patent: WO2007/71900, 2007, A1. Location in patent: Page/Page column 88-89
[2] Tetrahedron Letters, 2016, vol. 57, # 14, p. 1555 - 1559
[3] Tetrahedron Letters, 2014, vol. 55, # 52, p. 7198 - 7202
[4] Patent: WO2013/6792, 2013, A1. Location in patent: Paragraph 0149
[5] Journal of the American Chemical Society, 1998, vol. 120, # 44, p. 11408 - 11418
