反应详情

A mixture of methyl 6-amino-1,3-benzodioxole-5-carboxylate (6.3 g, 32 mmol), concentrated sulfuric acid (7 mL) and water (35 mL) was cooled in an ice-bath and then a mixture of sodium nitrite (2.3 g, 33 mmol) and water (15 mL) was added. The mixture was diluted with 50 mL of water and added to a boiling solution of cupric sulfate pentahydrate (35 g, 140 mmol) and water (75 mL). The mixture was heated 10 minutes at boiling and then cooled in an ice-bath and extracted with diethyl ether (3×). The combined extracts were washed with water (4×) and brine (1×), dried. (K2CO3) and concentrated. The residue was purified by column chromatography eluting with hexane/ethyl acetate (98:2-97:3) to give methyl 6-hydroxy-1,3-benzodioxole-5-carboxylate (2.7 g, 14 mmol), m.p. 100°-101° C.

1. temperaturewas cooled in an ice-bath
2. additionwas added
3. temperatureThe mixture was heated 10 minutes
4. temperaturecooled in an ice-bath
5. extractionextracted with diethyl ether (3×)
6. washThe combined extracts were washed with water (4×) and brine (1×)
7. customdried
8. concentration(K2CO3) and concentrated
9. customThe residue was purified by column chromatography
10. washeluting with hexane/ethyl acetate (98:2-97:3)