tert-Butanol → Ammonium Hydroxide

Participants

Reaction Steps

To a suspension of (±)-2′-oxo-1′,2′,5,7-tetrahydrospiro[cyclopenta[b]pyridine-6,3′-pyrrolo[2,3-b]pyridine]-2-carboxylic acid from Step E (224 mg, 0.796 mmol) and triethylamine (0.333 mL, 2.39 mmol) in tert-butanol (5 mL) was added diphenylphosphoryl azide (0.258 mL, 1.20 mmol) and the mixture was heated at reflux for 1 h. The reaction mixture was concentrated in vacuo and then partitioned between CH2Cl2 (20 mL) and saturated NaHCO3 (20 mL). The organic layer was separated and the aqueous layer was further extracted with CH2Cl2 (2×20 mL). The combined organic layers were dried over Na2SO4, filtered, and concentrated in vacuo. The crude product was purified by silica gel chromatography, eluting with a gradient of CH2Cl2:MeOH:NH4OH—100:0:0 to 95:5:1, to give the title compound. MS: m/z=353 (M+1).

Provenance & Evidence