Hydrochloric Acid → 5-amino-1,3-dihydrospiro[indene-2,3'-pyrrolo[2,3-b]pyridin]-2'(1'H)-one

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Reaction Steps

A solution of (−)-5-amino-1′-{[2-(trimethylsilyl)ethoxy]methyl}-1,3-dihydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridin]-2′(1′H)-one from Step B (13.7 g, 35.9 mmol) in methanol (300 mL) was saturated with HCl (g). The mixture was resaturated with HCl (g) every 30 min until the starting material was consumed, and then concentrated in vacuo. The residue was dissolved in MeOH (150 mL) and treated with ethylenediamine (2.4 mL, 35.9 mmol) and 10 N sodium hydroxide (7.2 mL, 72 mmol) to adjust the mixture to pH 10. After 30 min, the mixture was diluted with H2O (400 mL) and extracted with CHCl3 (2×1 L). The combined organic layers were dried over Na2SO4, filtered, and concentrated in vacuo. The crude material was triturated with MeOH (50 mL) to give the title compound. MS: m/z=252 (M+1).

Provenance & Evidence