反应详情

温度

150 °C

A mixture of 60 g of Intermediate A and 44 g ethyl p-toluenesulfonate was heated in a round bottom flask at 150° C. for 5 minutes. Upon cooling to room temperature, the crude brown mass was almost solidified. The product was dissolved in 25 ml methanol and poured into 300 ml diethyl ether with rapid stirring for 1 hour. The solid precipitate was chilled at 2° C. overnight, and then filtered. The tan powder was thoroughly washed with ether and recrystallized from 200 ml hot isopropyl alcohol to yield 23.4 g of 3-ethyl-5-hexylsulfonamido-2-methylbenzoxazolium p-toluenesulfonate (Intermediate B).

1. temperatureUpon cooling to room temperature
2. temperatureThe solid precipitate was chilled at 2° C. overnight
3. filtrationfiltered
4. washThe tan powder was thoroughly washed with ether
5. customrecrystallized from 200 ml hot isopropyl alcohol