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. 5521-61-9, name is 6-Methylpyrazine-2-carboxylic acid, A new synthetic method of this compound is introduced below., category: Pyrazines
General procedure: Under argon, a stirred solution of appropriate carboxylic acid (0.37 mmol, 1.0 eq.) and Et3N (0.48 mmol, 1.3 eq.) in dry THF (7 mL) was cooled to -10 °C. Ethyl chloroformate (0.55 mmol, 1.5 eq.) was dropwise added and the resulting mixture was stirred for 2 h. Afterward, a solution of sodium azide (0.63 mmol, 1.7 eq.) in water (2 mL) was added in one portion. After 1 h at -10 °C, the reaction was found to be complete (TLC) and was quenched into iced water (5 mL). The mixture was extracted with EtOAc (3 * 10 mL) and the combined organic layers were successively dried over MgSO4, filtered and evaporated under reduced pressure. The crude acyl azide was placed in dry toluene (20 mL) and the mixture heated at reflux for 1 h to give the corresponding crude isocyanate. The latter was dissolved in dry dioxane (7 mL) prior to adding the amine 4 (0.37 mmol, 1.0 eq.). The solution was heated at reflux for 24 h. The reaction mixture was cooled to room temperature and the volatiles were removed to dryness in vacuum at 40 °C. The dark residue was purified by silica gel chromatography column (CH2Cl2/MeOH 99/1) to afford the desired valmerins.
The synthetic route of 5521-61-9 has been constantly updated, and we look forward to future research findings.