Preparation method of 2-amino-5-trifluoromethyl thiazole
A technology of trifluoromethylthiazole and aminothiazole, which is applied in the direction of organic chemistry, can solve the problems of 2-amino-5-trifluoromethylthiazole, such as high cost, harsh reaction conditions, and cumbersome preparation of raw materials, and achieve simple and easy reagent preparation. obtained, the reaction conditions are mild, and the post-treatment is simple
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Embodiment 1
[0017] Add 40g 2-aminothiazole, 160g hydrosulfite, 100g disodium hydrogen phosphate, 1.2 liters of acetonitrile, 400 milliliters of water into a 2L autoclave, seal and equip a mechanical stirring device, freeze the autoclave to -78°C, and evacuate to Bromotrifluoromethane replaces the air three times, vacuumizes, presses in 180g bromotrifluoromethane, after returning to room temperature, heats to 90°C and reacts for 6 hours, stops stirring, cools to room temperature, spins off most of the acetonitrile in vacuum, adjusts with saturated aqueous solution of sodium hydroxide The pH value of the aqueous phase was 8-10, extracted with ether, dried over anhydrous magnesium sulfate, concentrated and then column chromatographed (n-hexane:ethyl acetate=4:1), the pure product was light yellow viscous liquid with a yield of 75% .
Embodiment 2
[0019] Add 20g of 2-aminothiazole, 52.5g of hydrosulfite, 56.3g of sodium bicarbonate, 500ml of acetonitrile, and 200ml of water into a 1L autoclave, seal it and equip it with a mechanical stirring device, freeze the autoclave to -78°C, and evacuate it. Press into 100g of bromotrifluoromethane, after returning to room temperature, heat to 40°C to react for 6 hours, stop stirring, cool to room temperature, spin off most of the acetonitrile under vacuum, adjust the pH value of the water phase to 8-10 with a saturated aqueous solution of sodium hydroxide, diethyl ether Extraction, drying over anhydrous magnesium sulfate, concentration and column chromatography (n-hexane: ethyl acetate = 4:1), the pure product was obtained as light yellow viscous liquid with a yield of 60%.
Embodiment 3
[0021] Add 3g of 2-aminothiazole, 1.9g of sodium bicarbonate into a 250ml Schlenk tube, pump and vent three times, under the protection of Ar, add 50ml of acetonitrile, 50ml of dimethylformamide, 20ml of water, stir to dissolve the solid. Then, the reaction solution was put into an ice-water bath, cooled to 3°C, and a solution of 4 g of trifluoroiodomethane in 10 ml of acetonitrile was added and stirred for two minutes. Add 3.58g of sodium hydrosulfite in batches within half an hour, stir for 2 hours, and track the reaction by thin chromatography. After completion, spin off acetonitrile under reduced pressure, add an appropriate amount of deionized water, adjust the solution to be alkaline with sodium carbonate, and extract three times with 300 ml of ether. It was dried over anhydrous magnesium sulfate and concentrated to obtain a viscous orange-yellow liquid. Column chromatography (n-hexane:ethyl acetate=4:1) gave the pure product light yellow viscous liquid with a yield of 85...
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