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. 16034-46-1, name is 1-Methyl-1H-pyrazole-5-carboxylic acid, A new synthetic method of this compound is introduced below., HPLC of Formula: C5H6N2O2
To a solution of i-methyl-I H-pyrazole-5-carboxylic acid (5.28 g, 41.9 mmol) in dichloromethane (55 ml) was added oxalyl chloride (9.14 ml, 104.8 mmol) followed by 3 drops of dimethylformamide. The reaction was stirred at room temperature for 18 hours before concentration in vacuo. The residue was dissolved in acetonitrile (42 ml) and added dropwise to a cooled solution of 3- (2-chloro-5-methoxyphenyl)pyridine-2,6-diamine (preparation 1 , 9.5 g, 38 mmol) and lutidine (6.6 ml, 57.1 mmol) in acetonitrile (650 ml). The reaction was allowed to warm to room temperature and stirred under nitrogen for 2 hours. The reaction was quenched by the addition of water (300 ml) and concentrated to low volume in vacuo. The aqueous residue was washed with dichloromethane (2×300 ml), dried (MgSO4) and concentrated in vacuo. The residue was purified by silica gel column chromatography eluting with ethylacetate: heptane 1 :4 to furnish a solid. This was recrystallised from toluene (100 ml) to afford 6.7 g of the title product. LCMS Rt=1.88 min MS m/z 358 [MH]+1HNMR (alphafe-DMSO): 3.75 (s, 3H), 4.05 (s, 3H), 5.3 (br s, 2H), 6.9 (m, 1 H), 6.95 (m, 1 H), 7.2 (m, 1 H), 7.3 (m, 1 H), 7.35 (m, 1 H), 7.45 (m, 1 H), 7.5 (m, 1 H), 10.3 (br s, 1 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:
Patent; PFIZER LIMITED; WO2008/135826; (2008); A2;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics