HCID 12620579, compound → 5-Methyl-4-oxo-4,5-dihydropyrano[3,2-b]indole-2-carboxylic acid
Reaction equation
[CH3:1][N:2]1[C:10]2[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=2[C:4]2[O:11][C:12]([C:16]([O:18]CC)=[O:17])=[CH:13][C:14](=[O:15])[C:3]1=2>[OH-].[Na+]>[CH3:1][N:2]1[C:10]2[CH:9]=[CH:8][CH:7]=[CH:6][C:5]=2[C:4]2[O:11][C:12]([C:16]([OH:18])=[O:17])=[CH:13][C:14](=[O:15])[C:3]1=2Participants
3
Reactant 1
Product 1
Reagents, catalysts & solvents 1
Procedure
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.