反应详情

A mixture of 5.40g (0.020 mole) of ethyl 4,5-dihydro-5-methyl-4-oxopyrano [3,2-b]indole-2-carboxylate in 80ml of 1% aqueous sodium hydroxide was stirred at room temperature for 30 min. The nearly one-phase mixture was extracted twice with 50ml CH2Cl2 and the aqueous layer was cooled in ice and acidified with 4N HCl. The gelatinous yellow crude product was filtered, digested for a few minutes on a steam bath with 100ml hot water and then re-filtered. Recrystallization from ab. EtOH gave yellow needles of mpt. 280°-dec.

1. extractionThe nearly one-phase mixture was extracted twice with 50ml CH2Cl2
2. temperaturethe aqueous layer was cooled in ice
3. filtrationThe gelatinous yellow crude product was filtered
4. waitdigested for a few minutes on a steam bath with 100ml hot water
5. filtrationre-filtered
6. customRecrystallization from ab
7. customEtOH gave yellow needles of mpt
8. custom280°-dec