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. 141573-95-7, name is Ethyl 3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylate, A new synthetic method of this compound is introduced below., Formula: C8H10F2N2O2
ethyl 5-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylate containing 0.2 area%, Purity 96.6 area% of ethyl 3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylate 10.0 g (0.05 mol), toluene 94 g, water 15.2 g, 25 wt% sodium hydroxide aqueous solution 1.8 g (0.07 mol) were added to the 200ml round-bottomed flask, while stirring it was heated in an oil bath and reacted under reflux for 23 hours. After cooling to room temperature, 15 mass% hydrochloric acid 21.0 g (0.09 mol) was dropped from the dropping funnel. After dropping, after cooling for 1 hour in an ice-water bath, using a 5C filter paper, suction filtered through a Kiriyama funnel, the filtrate was washed with 2 volumes of cold water. The obtained filtrate was dried under reduced pressure at 80 C. for 4 hours and got 8.60 g of crystals. When this crystal was analyzed by HPLC, it was 3- (difluoromethyl) -1-methyl -1H- pyrazole-4-carboxylic acid : 99.2 area %, 5- (difluoromethyl) -1-methyl-1 H-pyrazole-4-carboxylic acid : 0.1 area %. The toluene layer obtained by separating the filtrate into two layers, after concentrated in an evaporator, dried under reduced pressure at 80 C for 4 hours, got 0.02 g of crystals. When this crystal analyzed by HPLC, it was 3- (difluoromethyl) -1-methyl -1H- pyrazole-4-carboxylic acid : 27.2 area %, 5- (difluoromethyl) -1-methyl-1 H-pyrazole-4- carboxylic acid: 15.0 area %.
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.
Reference:
Patent; CENTRAL GLASS COMPANY LIMITED; IMURA, HIDEAKI; TAKADA, NAOTO; (11 pag.)JP5830957; (2015); B2;,
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics