反应详情

A mixture of intermediate (2) (0.138 mol) in a 2N NaOH solution (500 ml) was stirred and refluxed for 1 hour, then cooled and washed with DCM. The mixture was separated into its layers. The aqueous layer was acidified with a concentrated HCl solution until pH=2. The solid was filtered off, washed with water and dried in vacuo. A part (2.5 g) of this fraction was crystallized from methanol. The precipitate was filtered off and dried, yielding 0.88 g of 7-chloro-2,3-dihydro-8-methoxy-1,4-benzodioxin-5-carboxylic acid (intermediate 3, mp. 172° C.).

1. temperaturerefluxed for 1 hour
2. temperaturecooled
3. washwashed with DCM
4. customThe mixture was separated into its layers
5. filtrationThe solid was filtered off
6. washwashed with water
7. customdried in vacuo
8. customA part (2.5 g) of this fraction was crystallized from methanol
9. filtrationThe precipitate was filtered off
10. customdried