Hydrochloric Acid → (S)-2'-oxo-1',2',5,7-tetrahydrospiro(cyclopenta(b)pyridine-6,3'-pyrrolo(2,3-b)-bipyridine)-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A solution of methyl (6S)-2′-oxo-1′-{[2-(trimethylsilyl)ethoxy]methyl}-1′,2′,5,7-tetrahydrospiro[cyclopenta[b]pyridine-6,3′-pyrrolo[2,3-b]pyridine]-3-carboxylate (238 g, 559 mmol) in methanol (2 L) was saturated with HCl gas, allowing temperature to increase to 55° C. The reaction mixture was cooled to 23° C., stirred for 20 h, then concentrated. Aqueous 10 N sodium hydroxide (400 mL, 4 mol) was added to a solution of the residue in methanol (2 L), and the resulting mixture was heated at reflux for 2 h. The solution was cooled to 23° C. 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