反应详情

Methyl[(2,2-dimethylpropyl)benzoxazol-5-yl]acetate [from step 6] (5.00 g, 0.0185 mole) was dissolved in methanol (5 ml) and then a solution of sodium hydroxide (0.81 g, 0.0204 mole) in water (5 ml) was added slowly over 20 minutes, maintaining the temperature below 25° C. by external cooling. Once the addition was complete, the mixture was allowed to stir at room temperature for 1 hour. The reaction mixture was poured slowly into water (50 ml) and concentrated hydrochloride acid was added until the pH of the mixture was below pH6. The mixture was stirred for 1 hour then filtered and the solid was washed thoroughly with water and dried. Trituration with hexane gave [(2,2-dimethylpropyl)benzoxazol-5yl]acetic acid (4.51 g) as a white solid, m.p. 108-109° C.

1. temperaturemaintaining the temperature below 25° C. by external cooling
2. additionOnce the addition
3. additionwas added until the pH of the mixture
4. stirringThe mixture was stirred for 1 hour
5. filtrationthen filtered
6. washthe solid was washed thoroughly with water
7. customdried