反应详情

To a solution of 3.7 g of the compound of Example 43 in 20 ml of chloroform is added 1.5 g of triethylamine, and to the mixture with stirring at -10°--2° C. is added 1.4 g of ethyl chlorocarbonate dropwise. After completion of the addition, the whole mixture is stirred at 0° C. for 3 hours, and then at room temperature for 2 hours. The reaction solution is washed with water, dried and concentrated, and then the resulting residue is recrystallized from isopropyl ether to give 3.8 g of 3-(3,5-di-tertiary butyl-4-hydroxyphenyl)-1-(2-ethoxycarbonyloxyethyl)-1H-pyrazolo[3,4-b]-pyridine as white crystals, melting at 103°-105° C.

1. additionAfter completion of the addition
2. stirringthe whole mixture is stirred at 0° C. for 3 hours
3. washThe reaction solution is washed with water
4. customdried
5. concentrationconcentrated
6. customthe resulting residue is recrystallized from isopropyl ether