反应详情

温度

75 °C

A solution of 28 g of potassium hydroxide in 0.2 l of water was added to 44.8 g of 2-formyl-3-hydroxy-5-methoxy-6-methylbenzoic acid methyl ester. The mixture was warmed to 75° C. within 30 min and subsequently cooled to 5° C. Upon addition of 50 ml of 10N hydrochloric acid, a precipitate was formed immediately. The mixture was stirred at 0° C. for 30 min and then filtered. The solid material was washed with water and dried in vacuo. The crude product was triturated with 160 ml of hot ethyl acetate. The mixture was cooled and 0.9 l of hexane were added. The solid was isolated by filtration to yield 41.2 g of (RS)-3,4-dihydroxy-6-methoxy-7-methyl-1,3-dihydro-iso-benzofuran-1-one, m.p. >255° C. (dec.).

1. temperaturesubsequently cooled to 5° C
2. customa precipitate was formed immediately
3. filtrationfiltered
4. washThe solid material was washed with water
5. customdried in vacuo
6. customThe crude product was triturated with 160 ml of hot ethyl acetate
7. temperatureThe mixture was cooled
8. addition0.9 l of hexane were added
9. customThe solid was isolated by filtration