Hydrogen Bromide → (2R)-5-bromo-1,3-dihydrospiro[indene-2,3'-pyrrolo[2,3-b]pyridin]-2'(1'H)-one

Participants

Reaction Conditions

Reaction Steps

To a solution of (R)-5-amino-1,3-dihydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridin]-2′(1′H)-one (500 mg, 1.99 mmol, described in Intermediate 3) in 48% HBr (4 mL) at 0° C. was added slowly over 10 min a solution of sodium nitrite (137 mg, 1.99 mmol) in water (0.8 mL). After 5 minutes CuBr (285 mg, 1.99 mmol) was added and the reaction mixture was placed into a 100° C. oil bath and heated at 100° C. for 20 min. The reaction mixture was then diluted with water followed by 2.5 mL of 30% NH4OH (2.5 mL) and the resulting solid was collected by filtration and washed with water. The solid was 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. to 740 mg and ˜2 g of silica gel was added. The mixture was dry-loaded on to a silica gel column and the product was eluted with a gradient of EtOAc:hexanes:CH2Cl2—10:80:10 to 70:20:10. The product containing fractions were combined and concentrated at reduced pressure to give the title compound. MS: m/z=315 (M+1).

Provenance & Evidence