Synthetic Route of 89510-90-7, 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. 89510-90-7, name is 2-Chloro-5-fluoro-4-pyridinamine. A new synthetic method of this compound is introduced below.
4-Amino-2-chloro-5-fluoropyridine (0.77 g, 4.7 mmol) was carefully added to 7.5 niL of concentrated sulfuric acid at 0-5 C (ice-bath) with stirring to give a solution. Potassium nitrate (1.1 g, 10 mmol) was gradually added to the solution during a period of 10 min while the internal temperature was maintained below 5 C. The reaction mixture was further stirred at 0-5 C for 1 hr and at room temperature for 10 min when TLC showed that all starting material had disappeared and a new product was formed. The mixture was carefully poured onto 30 g of crushed ice. The resulting solution was extracted with methylene chloride (2 x 20 mL). Combined organics were dried, filtered, and concentrated to give the crude product (0.56 g, yield: 61 %), which was directly carried to the next step without purification. LCMS(ESI) m/z: 192.6 [M+H+].Step 5 : 2-Chloro-5-fluoro-4-nitroaminopyridine (560 mg, 2.9 mmol) was carefully added to4.5 mL of concentrated sulfuric acid. The mixture was stirred at room temperature for 12 hrs when TLC showed that the starting material had disappeared and a new product had formed. The mixture was then poured onto 11 g of crushed ice with stirring. The resulting solution was mixed with 20 mL of methylene chloride and neutralized by dropwise addition of 28% ammonium hydroxide with stirring while the internal temperature was maintained below 5 C in a salted ice bath. The organic layer was separated and the aqueous layer was extracted with methylene chloride (2 x 20 mL). The combined organic extracts were dried over MgS04, filtered, evaporated in vacuo to give the crude product (450 mg, yield: 80%), which was carried to the next step without purification. LCMS(ESI) m/z: 192.6 [M+H+].
At the same time, in my other blogs, there are other synthetic methods of this type of compound,89510-90-7, 2-Chloro-5-fluoro-4-pyridinamine, and friends who are interested can also refer to it.
Reference:
Patent; F. HOFFMANN-LA ROCHE AG; LAI, Yingjie; LIANG, Jun; MAGNUSON, Steven R.; TSUI, Vickie H.; ZHANG, Birong; ROBARGE, Kirk; WO2011/113802; (2011); A2;,
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem