Hydrochloric Acid → (R)-2'-Oxo-1,1',2',3-tetrahydrospiro[indene-2,3'-pyrrolo[2,3-b]pyridine]-5-carboxylic acid

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Reaction Conditions

Reaction Steps

A solution of (R)-methyl 1′-tert-butyl-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxylate (53 g, 151 mmol) in methanesulfonic acid (196 mL) was heated at 90° C. for 1 h. Water (100 mL) was added and the solution was stirred for an additional 3 h at 90° C. The acidic mixture was cooled to 0° C., diluted with water (1 L), and basified to pH 14 with 50% aqueous NaOH solution. The basic mixture was then acidified to pH 3 by careful addition of concentrated aqueous HCl solution. The solids were collected by filtration and dried under nitrogen atmosphere to give the title compound which was used without further purification. MS: m/z=281.1 (M+1).

Provenance & Evidence