Methyl 7-chloro-2,3-dihydro-8-methoxy-1,4-benzodioxin-5-carboxylate → 7-Chloro-2,3-dihydro-8-methoxy-1,4-benzodioxin-5-carboxylic acid
反応式
[Cl:1][C:2]1[CH:3]=[C:4]([C:14]([O:16]C)=[O:15])[C:5]2[O:10][CH2:9][CH2:8][O:7][C:6]=2[C:11]=1[O:12][CH3:13]>[OH-].[Na+]>[Cl:1][C:2]1[CH:3]=[C:4]([C:14]([OH:16])=[O:15])[C:5]2[O:10][CH2:9][CH2:8][O:7][C:6]=2[C:11]=1[O:12][CH3:13]参加物
3
実験手順
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.).