ethyl 5-fluoro-1H-indole-2-carboxylate → HCID 21914152, compound

Participants

Reaction Steps

To a suspension of 5-fluoro-1H-indole-2-carboxylic acid, ethyl ester (0.121 mole) in methanol (600 ml) was added Mg (0.36 mole). The mixture was in a 3-neck round bottom flask under argon at room temperature. The temperature of the reaction was monitored closely. After about 10 minutes, the mixture began to bubble, slowly at first and then more vigorously. The reaction temperature was maintained between 15 and 25° C. with intermittent applications of an ice bath. After 30 minutes, the bubbling had slowed. The mixture was allowed to stir at room temperature for three days. The mixture was partitioned between 600 ml of chloroform and 500 ml of saturated NH4Cl solution. The organic layer was dried over MgSO4 and concentrated to a brown oil. The oil was dissolved in ether and extracted with 3N HCl. The aqueous layer was washed with ether, basified with 3N NaOH, and extracted with chloroform. The extract was dried over MgSO4 and concentrated, yielding 13.91 g of methyl 5-fluoro-2,3-dihydro-1H-indole-2-carboxylate (intermediate 16).

Provenance & Evidence