These common heterocyclic compound, 231285-86-2, name is Ethyl 1-methyl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route. Formula: C8H9F3N2O2
ethyl 5- (trifluoromethyl) -1-methyl -1H- pyrazole-4- carboxylate and 5.5 mol% and ethyl 3-(trifluoromethyl) -1-methyl -1H- pyrazole-4-carboxylate 94 .5 mol% containing crude crystals 5.08g (0.02mol), water 7.58 g, 25 mass% sodium hydroxide aqueous solution 5.56 g (0.01 mol) were added to the 100ml round-bottomed flask, while stirring it was heated in an oil bath and reacted under reflux for 3 hours. After cooling to room temperature, 15 mass% hydrochloric acid 10.0 g (0.04 mol) was dropped from the dropping funnel and then toluene 50.0g was added. 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 3.94 g of crystals. When 19F-NMR analyzed this crystal, it was 3-(trifluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid: 99.9 mol%, 5-(trifluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid: 0.1 mol%. 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 0.28 g of crystals. When this crystal analyzed by NMR equally, it was 3-(trifluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid: 18.8 mole %, 5-(trifluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid 81.2 mol%.
The synthetic route of Ethyl 1-methyl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate has been constantly updated, and we look forward to future research findings.