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.
EXAMPLE 13 beta-{4-[2-(5-Methylpyrazole-3-carboxamido)-ethyl]-phenyl}-propionic acid 1.27 ml. triethylamine and 0.85 ml. ethyl chloroformate are added at -10 C. to a solution of 1.12 g. of 5-methylpyrazole-3-carboxylic acid in 25 ml. anhydrous tetrahydrofuran. After 15 minutes, a further 1.27 ml. triethylamine is added and then 2.57 g. ethyl beta-[4-(2-aminoethyl)-phenyl]-propionate hydrochloride. The reaction mixture is stirred for 1 hour at +20 C., filtered with suction and the filtrate is evaporated and the residue taken up in methylene chloride. After extraction with 2N hydrochloric acid, 2N aqueous sodium hydroxide solution and neutralization, the solution is dried and evaporated. The crude ester thus obtained is heated under reflux for 1 hour with 0.6 g. sodium hydroxide in 30 ml. ethanol. After cooling, the precipitated sodium salt is filtered off with suction, dissolved in water and carefully acidified. The precipitate obtained is filtered off and recrystallized from 20% ethanol. There is obtained beta-{4-[2-(5-methylpyrazole- 3-carboxamido)-ethyl]-phenyl}-propionic acid in a yield of 22% of theory; m.p. 202-205 C.
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.