Reacción #43297

Ecuación de reacción

2,3-dihydroxy-4-methoxy benzoic acid methyl ester

1,3-dibromopropane

K2CO3

→

intermediate 7

methyl 3,4-dihydro-9-methoxy-2H-1,5-benzodioxepin-6-carboxylate

Disolventes

DMF

Condiciones de reacción

Tratamiento posterior

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

Procedimiento

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).

Fuente