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Example 81Preparation of Derivative 81 According to the Present InventionDerivative 81 having the following formula was prepared as follows. Sodium hydride (343.2 mg, 8.58 mmol, 60% dispersed oil) was slowly added to cyclohexaneethanol (1 g, 7.8 mmol) dissolved in 30 ml of dried dimethylformamide under nitrogen at room temperature while stirring. The mixture was further stirred at room temperature for 30 minutes. Then, <strong>[90176-80-0]4-fluoro-2-(trifluoromethyl)benzaldehyde</strong> (1.2 g, 7.8 mmol) dissolved in dried dimethylformamide was added thereto over 10 minutes and stirred at room temperature for 18 hours until the initial product disappeared. Subsequently, ice water was added thereto, and the resulting mixture was extracted with ethyl acetate and water. The organic layer was washed with water several times, dried with anhydrous magnesium sulfate, filtered and solvent-evaporated. The residual oil was chromatographed on the silica gel column (hexane:ethyl acetate-20:1) to afford the intermediate, 4-(2-cyclohexylethoxy)-2-(trifluoromethyl)benzaldehyde (1.77 g, yield: 75.6%).
2-cyclohexylethyl thiazole-4-carboxylate[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
38.9%
With dmap; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; In dichloromethane; at 0 - 20℃; for 5h;
General procedure: 2.5mmol thiazole-4-carboxyli acid and 2.0mmol alcohol were dissolved in 25mL dichloromethane (DCM) in a dry flask with continuous stirring, followed by the addition of 2.5mmol 3-(3-dimethylaminopropyl) -1-ethylcarbodiimide hydrochloride. When the temperature of the reaction system cooled to 0°C, 0.2mmol 4-dimethylaminopyridine was added dropwise and reacted for 1hat 0°C. Then the temperature was elevated to room temperature for another 4h reaction. The reaction was stopped by adding 25mL saturated NaHCO3 solution and extracted twice with 20mL dichloromethane (2×20mL). The extracted organic layers were first dried by anhydrous Na2SO4, and then filtered and concentrated under vacuum distillation, obtaining the crude products. Finally, the crude products were further purified using column chromatography (ethy lacetate:petroleum ether, 1:5).