反应详情

Sulfuric acid (18 ml) was added dropwise to cooled methanol (90 ml). 4-Amino-5-chloro-2,3-dihydro-7-benzofurancarboxylic acid (20 g) was added to the mixture which was subsequently stirred and refluxed for 3 hours. The reaction mixture was cooled and alkalized with CH3OH/NH3. The solvent was evaporated and the residue stirred in water. The precipitate was filtered off and washed with water and DIPE. The remaining solid was dried, yielding 17.2 g (81%) of methyl 4-amino-5-chloro-2,3-di-hydro-7-benzofurancarboxylate (intermediate 1; mp. 135.4° C.).

1. temperaturerefluxed for 3 hours
2. temperatureThe reaction mixture was cooled
3. customThe solvent was evaporated
4. stirringthe residue stirred in water
5. filtrationThe precipitate was filtered off
6. washwashed with water and DIPE
7. customThe remaining solid was dried