1904-31-0, name is 1-Methyl-1H-pyrazol-3-amine, belongs to pyrazoles-derivatives compound, is considered to be a conventional heterocyclic compound, which is widely used in drug synthesis. The chemical synthesis route is as follows. COA of Formula: C4H7N3
Synthesis Example 4 Synthesis of ethyl 3-chloro-1-methyl-5-pyrazolecarboxylate (Compound No. 4.3 (a) of the invention) 6.5 g of 3-amino-1-methylpyrazole was dissolved in 55 ml of conc. hydrochloric acid. To this solution was added dropwise a solution of 6.22 g of sodium nitrite in 12.5 ml of water while maintaining the temperature of from 0° to 5° C. through cooling with ice. After the completion of the dropwise addition, the stirring was continued at this temperature for 1 hour. The above-mentioned diazonium solution was added dropwise to a suspension of 7 g of cuprous chloride in 55 ml of chloroform. 2 g of cuprous chloride were twice added thereto during that time. After the completion of the dropwise addition, the mixture was reacted at 50° C. for 5 hours, and was then stirred at room temperature for 15 hours. This solution was filtered using a Celite, and was then neutralized with a sodium carbonate aqueous solution. The chloroform layer was extracted, and the aqueous layer was further extracted twice with 50 ml of chloroform. The combined chloroform solution was washed with a saturated aqueous solution of sodium chloride, and was dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to obtain 7 g of a crude product. This crude product was purified through silica-gel column chromatography to obtain 5.2 g of 3-chloro-1-methylpyrazole as a yellow oil.
The synthetic route of 1904-31-0 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; Nissan Chemical Industries, Ltd.; US5817829; (1998); A;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics