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. 28466-26-4, name is 4-Aminopyrazole, A new synthetic method of this compound is introduced below., Quality Control of 4-Aminopyrazole
1/-/-Pyrazol-4-amine (for a preparation see intermediate 1 ; 0.54 g, 6.5 mmol) was dissolved in acetonitrile (25 ml) with triethylamine (1.81 ml, 13.0 mmol) to give a red- purple suspension which was cooled in an ice-water bath. To the suspension was added a solution of 2,6-difluorobenzoyl chloride (Aldrich; 0.817 ml, 6.5 mmol) in acetonitrile (25 ml) dropwise over 15 min. The mixture was stirred cold under nitrogen. The reaction was stirred and allowed to warm slowly towards room temperature over 2 h, then at room temperature for 30 min. The reaction mixture was partitioned between EtOAc and water (-100 ml each). The aqueous phase was extracted with further EtOAc (2 x 50 ml). The combined organic extracts were dried (MgS04) and concentrated in vacuo. The residue (1.41 g) was purified on silica (50 g) using 0-100% EtOAc-cyclohexane then 0-20% methanol- EtOAc. Relevant fractions were concentrated in vacuo to give some pure product (0.925 g) and some less pure material (0.50 g). The latter material was re-purified on silica (20 g) using EtOAc to give further pure product (0.366 g). The two batches of pure product were combined to give the title compound (1.28 g) as a pale cream solid; LCMS (System 1): MH+= 224, tRET = 2.08 min.
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; GLAXO GROUP LIMITED; COOPER, Anthony, William, James; GORE, Paul, Martin; HOUSE, David; WO2012/52459; (2012); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics