402-61-9, 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. 402-61-9 name is 5-Methyl-1H-pyrazole-3-carboxylic acid, 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.
502 mg (2.62 mmol) of EDC, 401 mg (2.62 mmol) of HOBt and 500 mg (2.38 mmol) of the compound from Example 6A/Step 3 were added successively at RT to a solution of 300 mg (2.38 mmol) of 5-methyl-1H-pyrazole-3-carboxylic acid in 10 ml of anhydrous DMF. The mixture was stirred first at RT for 16 h and then at 140 C. for 45 min. After cooling, the solvent was removed on a rotary evaporator. 120 ml of water were added to the remaining residue, which was extracted three times with approx. 100 ml each time of diethyl ether. The combined organic extracts were washed with saturated sodium chloride solution, dried over anhydrous magnesium sulphate, filtered and finally concentrated on a rotary evaporator. The crude product was stirred with 5 ml of ethanol at RT for 1 h. After filtering and drying the undissolved solid under high vacuum, a first fraction of 204 mg of the title compound was obtained. The mother liquor was concentrated to dryness. Subsequently, a further fraction of 29 mg of the title compound was isolated from the residue by means of preparative HPLC (method 13). In total, 233 mg (33% of theory) of the title compound were thus obtained.1H NMR (400 MHz, CDCl3, delta/ppm): 8.27 (d, 2H), 7.72 (d, 2H), 6.81 (s, 1H), 5.05 (dd, 2H), 5.01 (dd, 2H), 2.47 (s, 3H).LC/MS (method 2, ESIpos): Rt=1.93 min, m/z=301 [M+H]+.
At the same time, in my other blogs, there are other synthetic methods of this type of compound, 5-Methyl-1H-pyrazole-3-carboxylic acid, and friends who are interested can also refer to it.