Cesium carbonate → spiro[cyclopent-3-ene-1,3'-pyrrolo[2,3-b]pyridin]-2'(1'H)-one

Participants

Reaction Conditions

Reaction Steps

To a solution of cis-1,4-dichloro-2-butene (1.98 g, 15.8 mmol) and 1-{[2-(trimethylsilyl)ethoxy]methyl}-1,3-dihydro-2H-pyrrolo[2,3-b]pyridin-2-one (3.49 g, 13.2 mmol) in DMF (175 mL) was added cesium carbonate (10.7 g, 32.9 mmol). After 24 h the reaction mixture was partitioned between Et2O (200 mL) and H2O (200 mL). The aqueous layer was extracted further with Et2O (2×200 mL). The combined organic layers were washed with H2O (2×100 mL), then brine (100 mL), dried over MgSO4, filtered, and concentrated under reduced pressure. To a solution of this material in dichloromethane (150 mL) was added trifluoroacetic acid (150 mL). After 1 h, the reaction was concentrated, dissolved in EtOH (150 mL) and 2N HCl (150 mL) was added. This mixture was heated at 45° C. for 48 h. The mixture was concentrated, diluted with saturated aqueous NaHCO3, and extracted with dichloromethane (2×). The combined organic layers were dried and concentrated. The crude product was purified by silica gel chromatography, eluting with a gradient of 0 to 5% methanol:dichloromethane to give the title compound (0.62 g). MS: m/z=187.1 (M+1).

Provenance & Evidence