Hydrochloric Acid → 2'-Oxo-1',2',5,7-tetrahydrospiro[cyclopenta[b]pyridine-6,3'-pyrrolo[2,3-b]pyridine]-3-carboxylic acid

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Reaction Conditions

Reaction Steps

A solution of methyl 2′-oxo-1′-{[2-(trimethylsilyl)ethoxy]methyl}-1′,2′,5,7-tetrahydrospiro[cyclopenta[b]pyridine-6,3′-pyrrolo[2,3-b]pyridine]-3-carboxylate (30.9 g, 73 mmol) in MeOH (400 mL) was saturated with HCl gas, allowing the internal temperature to increase to 55° C. The reaction mixture was cooled to ambient temperature, stirred for 20 h, then concentrated in vacuo. Aqueous 10 N sodium hydroxide (50 mL, 500 mmol) was added to a solution of the residue in MeOH (400 mL), and the resulting mixture was heated at reflux for 2 h. The solution was cooled to ambient temperature and the pH was adjusted to 3 with concentrated HCl. The resulting solid was filtered, washed with water then heptane, and dried to give the title compound. MS: m/z=282.2 (M+1).

Provenance & Evidence