Ethanol → HCID 86665250, compound

Participants

Reaction Steps

To a solution of (6S)-5′-bromo-2′-oxo-1′,2′,5,7-tetrahydrospiro[cyclopenta[b]pyridine-6,3′-pyrrolo[2,3-b]pyridine]-3-carboxylic acid (described in Intermediate 3) (6.00 g, 16.7 mmol) in EtOH (250 mL) was added concentrated sulfuric acid (2.22 mL, 41.6 mmol) and the resulting mixture was heated at reflux for 18 h. The reaction mixture was cooled to ambient temperature and the volume was reduced to about 80 mL under reduced pressure. The residual mixture was poured into saturated aqueous sodium bicarbonate (100 mL) and the mixture was extracted with EtOAc (2×150 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated to dryness in vacuo. The crude product was purified by silica gel chromatography, eluting with a gradient of CH2Cl2:MeOH—100:0 to 90:10, to give the title compound. MS: m/z=389.9 (M+1).

Provenance & Evidence