反应详情

A mixture of 2,3-dihydroxy-4-methoxy benzoic acid methyl ester (0.45 mol), 1,3-dibromopropane (0.72 mol), K2CO3 (155 g) and CuO (3.6 g) in DMF (2500 ml) was stirred at 120° C. to 130° C. for 7 hours, cooled and filtered. The solvent was evaporated. HCl (aqueous solution of 0.5 N, 1000 ml)) was added. The mixture was extracted twice with DCM (750 ml). The organic layer was separated, dried, filtered and the solvent was evaporated. The residue was purified by column chromatography over silica gel (eluent: hexane/ethyl acetate/DCM 70/30/15). The pure fractions were collected and the solvent was evaporated. The residue was crystallized from DIPE, yielding methyl 3,4-dihydro-9-methoxy-2H-1,5-benzodioxepin-6-carboxylate (intermediate 7).

1. temperaturecooled
2. filtrationfiltered
3. customThe solvent was evaporated
4. additionHCl (aqueous solution of 0.5 N, 1000 ml)) was added
5. extractionThe mixture was extracted twice with DCM (750 ml)
6. customThe organic layer was separated
7. customdried
8. filtrationfiltered
9. customthe solvent was evaporated
10. customThe residue was purified by column chromatography over silica gel (eluent: hexane/ethyl acetate/DCM 70/30/15)
11. customThe pure fractions were collected
12. customthe solvent was evaporated
13. customThe residue was crystallized from DIPE