Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 5744-80-9, name is 3-Bromo-1,5-dimethyl-1H-pyrazole, A new synthetic method of this compound is introduced below., Formula: C5H7BrN2
General procedure: A mixture of 19d (0.20 g, 0.81 mmol), bis(pinacolato)-diboron(0.44 g, 1.72 mmol), Pd(Ph3P)4 (0.050 g, 0.043 mmol), and KOAc (0.17 g, 1.72 mmol) in 1,4-dioxane/H2O (30 mL, v/v, 5/1) was stirred at 100 C for 4 h under argon. It was cooled to room temperature. 10a(0.20 g, 0.54 mmol), Pd(Ph3P)4 (0.030 g, 0.029 mmol), and K2CO3(0.16 g, 1.14 mmol) were added to the reaction mixture at room temperature,and the mixture was stirred at 100 C for 12 h under argon. It was cooled to room temperature, and H2O was added to the mixture.The mixture was extracted with EtOAc. The organic layer was washed with brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silicagel column chromatography (eluting with 0-10% MeOH in DCM) to afford 10c as a pale yellow solid (0.13 g, 52%). 1H NMR (300 MHz,DMSO-d6) delta 8.27 (s, 1H), 7.78-7.75 (m, 1H), 7.54 (s, 1H), 7.18-7.15(m, 1H), 6.88-6.87 (m, 1H), 6.15 (s, 1H), 6.02-5.93 (m, 1H), 5.82-5.76(m, 1H), 5.32-5.27 (m, 1H), 5.03 (s, 2H), 3.93 (s, 3H), 3.64 (m, 4H),3.33 (m, 4H); 13C NMR (75 MHz, DMSO-d6) delta 161.85, 158.29, 156.01,153.75, 152.72, 142.91, 140.24, 139.17, 138.42, 137.18, 131.81,128.07, 126.97, 126.44, 124.53, 119.49, 116.23, 97.23, 65.97, 60.28,51.65, 41.76; MS (ESI) m/z:460.3 [M+H]+.
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.
Reference:
Article; Yin, Yuan; Chen, Cheng-Juan; Yu, Ru-Nan; Shu, Lei; Zhang, Tian-Tai; Zhang, Da-Yong; Bioorganic and Medicinal Chemistry; vol. 27; 8; (2019); p. 1562 – 1576;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics