反应详情

NaOH aqueous solution was added to ethyl-2-(4-butyloxyphenyl)-5-pyrimidinecarboxylate (VI), followed by heating the mixture, adding hydrochloric acid, filtering off the resulting precipitates, and drying to obtain 2-(4-butyloxyphenyl)-5-pyrimidinecarboxylic acid (VII). This compound (VII) (1.0 g, 3.7 mmols), 4-dimethylaminopyridine (0.2 g), N,N'-dicyclohexylcarbodiimide (1.7 g) and 3-chloro-4-fluorophenol (0.7 g) were dissolved in dichloromethane (30 ml), followed by agitating the solution for 5 minutes, further agitating at room temperature overnight, filtering off the resulting precipitates, washing the dichloromethane phase with 2N-hydrochloric acid, then with 2N-NaOH aqueous solution and further with water till the washing water became pH 7, drying over magnesium sulfate, concentrating under reduced pressure, and recrystallizing the residual white solids from methanol to obtain the objective 3-chloro-4-fluorophenyl-2-(4-butyloxyphenyl)-5-pyrimidinecarboxylate (0.5 g). This compound had a crystalline-smectic point (C-S point) of 152.3° C. and a smectic-clearing point (S-I point) of 165.4° C. The elemental analysis values of this compound were as follows: C: 62.9%, H: 4.5%, N: 7.0% (calculated values in terms of C21H18ClFN2O3 --C: 62.92%, H: 4.53%, N: 6.99%.

1. temperatureby heating the mixture
2. filtrationfiltering off the resulting
3. customprecipitates
4. customdrying