tert-Butanol → Ammonium Hydroxide

Participants

Reaction Steps

To a suspension of (±)-sodium 2′-oxo-1′,2′,5,7-tetrahydrospiro[cyclopenta[c]pyridine-6,3′-pyrrolo[2,3-b]pyridine]-3-carboxylate from Step D (1.64 g, 5.83 mmol) and triethylamine (1.62 mL, 11.7 mmol) in tert-butanol (50 mL) was added diphenylphosphoryl azide (1.89 mL, 8.75 mmol) and the mixture was heated at reflux for 72 h. Additional diphenylphosphoryl azide (1.89 mL, 8.75 mmol) was added at 24 and 56 h. The reaction mixture was concentrated in vacuo and then partitioned between CH2Cl2 (75 mL) and saturated NaHCO3 (100 mL). The organic layer was separated and the aqueous layer was further extracted with CH2Cl2 (2×50 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