反应详情

温度

150 °C

Anhydrous aluminum chloride (550 g, 4.135 mol, 4 eq) and sodium chloride (105 g, 1.795 mol, 2.7 eq) were mixed and heated to 150° C. Dihydrocoumarin (75) (100 g, 675.7 mol, 1 eq) was added slowly maintaining the internal temperature between 150-160° C. After the addition, the temperature was increased to 200° C. and the reaction mixture stirred for 1.5 h, and while hot, poured into a porcelain dish to cool. The solidified mass was broken and added to a vigorously stirred mixture of ice and water (4 L) containing 400 mL conc. HCl. The resulting suspension was stirred for 1 h, filtered, washed with water and dried to give 85 g (85%) of crude 4-hydroxy-1-indanone (76) as a grey solid. It was sufficiently pure to be used in the next step.

1. temperaturemaintaining the internal temperature between 150-160° C
2. additionAfter the addition
3. temperaturethe temperature was increased to 200° C.
4. additionwhile hot, poured into a porcelain dish
5. temperatureto cool
6. stirringThe resulting suspension was stirred for 1 h
7. filtrationfiltered
8. washwashed with water
9. customdried