Adding a certain compound to certain chemical reactions, such as: 909717-95-9, Ethyl 4-methoxypyrazolo[1,5-a]pyridine-3-carboxylate, can increase the reaction rate and produce products with better performance than those obtained under traditional synthetic methods. Here is a downstream synthesis route of the compound, category: pyridine-derivatives, blongs to pyridine-derivatives compound. category: pyridine-derivatives
Example 47 4-hydroxypyrazolo[1,5-a]pyridine The compound of Example 23 (4.30 g) was dissolved in dichloromethane (50 mL) in an argon atmosphere. While the solution was kept at 0 C., boron tribromide (1.0 mol/L dichloromethane solution, 23.4 mL) was added and the mixture was stirred for 1 hour. Additional boron tribromide (23.4 mL) was then added and the mixture was stirred at room temperature for another 3 hours. Subsequently, water was added and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine and dried over sodium sulfate. The solvent was evaporated under reduced pressure to give a yellow powder (4.80 g). To this product, 47% hydrobromic acid (100 mL) was added and the mixture was stirred for 5 hours under reflux. Subsequently, the mixture was made basic by adding sodium hydroxide and then made acidic again by adding hydrochloric acid. The mixture was extracted three times with ethyl acetate and the organic layer was washed with saturated brine and dried over sodium sulfate. Evaporating the solvent under reduced pressure afforded the title compound as a yellow powder (2.10 g) (Process C). 1H-NMR (CDCl3, 400 MHz) delta 5.76 (1H, brs), 6.47 (1H, d, J=7.3 Hz), 6.62-6.65 (2H, m), 7.92 (1H, d, J=2.4 Hz), 8.17 (1H, d, J=6.7 Hz).
At the same time, in my other blogs, there are other synthetic methods of this type of compound,909717-95-9, Ethyl 4-methoxypyrazolo[1,5-a]pyridine-3-carboxylate, and friends who are interested can also refer to it.
Reference:
Patent; Kohno, Yasushi; Adams, David Roger; Ando, Naoki; US2008/207902; (2008); A1;,
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem