Electric Literature of 930-36-9, As we all know, there are many different methods for the synthesis of a compound, and people can choose the synthesis method that suits their own laboratory according to the actual situation. 930-36-9 name is 1-Methylpyrazole, This compound is widely used in many fields, so it is necessary to find a new synthetic route. The downstream synthesis method of this compound is introduced below.
Step 1) Method A: Phosphorus oxychloride (6.92 g, 45.1 mmol, 1.5 eq.) was cooled to 0C and then added drop- wise to anhydrous DMF (3.50 mL, 45.2 mmol, 1.5 eq.) at 0C. The colorless DMF solution soon becomes orange. The mixture was stirred for 1 hour at room temperature and then heated to 80C. 1 -Methyl- IH-pyrazole (2.5 mL, 30.2 mmol) is then added drop-wise to the reaction, and the resulting mixture was stirred 3 hours at 95C. The reaction was then quenched by slow addition to ice (40 g) via Pasteur pipette. The pH of the resulting solution was 2, and it was raised to 5 by slowly adding 12N aqueous sodium hydroxide solution (11.2 mL total). The resulting aqueous solution was extracted with dichloromethane (3 x 40 mL). At this point, the pH of the aqueous layer had dropped to 3, therefore additional 12 N NaOH solution (1 mL) was added to bring the pH to 6. The aqueous layer was then extracted further with ether (4 x 40 mL). The combined extracts were then dried over sodium sulfate, filtered and concentrated (at about 40-50C). After drying for 30 minutes under vacuum, a brown oil was recovered (3.79 g) which NMR indicated consisted of a mixture of product, starting material and DMF (52 wt %, 22 wt %, and 26 wt %, respectively). The calculated yield of was 59% and the calculated yield for recovery of unreacted starting material, was 34%. This crude material may be used without further purification in the next step.
At the same time, in my other blogs, there are other synthetic methods of this type of compound, 1-Methylpyrazole, and friends who are interested can also refer to it.
Reference:
Patent; MERCK SHARP & DOHME CORP.; SHUMWAY, Stuart Denham; TONIATTI, Carlo; ROBERTS, Brian Scott; MARTIN, Melissa M.; WO2013/39854; (2013); A1;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics