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

Participants

Reaction Steps

A solution of sodium nitrite (275 mg, 3.98 mmol) in water (1.6 mL) was slowly added to a cooled mixture of (R)-5-amino-1,3-dihydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridin]-2′(1′H)-one (1 g, 3.98 mmol, described in Intermediate 3) in of 10% aqueous H2SO4 (8 mL) at 0° C. The ice bath was removed and the reaction allowed to stir at ambient temperature. The reaction mixture was then placed into a 70° C. oil bath and the bath was heated to 100° C. Bubbling was observed and heating was continued until LCMS indicated that the reaction was complete. The reaction was slowly neutralized by addition of 30% NH4OH (ca. 2 mL) and the precipitate was collected by filtration and washed with water. The solid was then air dried and chromatographed by first mixing with silica and dry loading on a silica gel column. The product was eluted. with (10% MeOH/CH2Cl2). Concentration of the product containing fractions gave the title compound. MS: m/z=253 (M+1).

Provenance & Evidence