tert-Butanol → 6-(((Tert-butoxy)carbonyl)amino)pyridine-2-carboxylic acid

Participants

Reaction Steps

To a suspension of 2,6-pyridinedicarboxylic acid (8.35 g, 50 mmol) and triethylamine (5.05 g, 50 mmol) in tert-butyl alcohol (ca. 60 mL) was dropwise added diphenylphosphoryl azide (13.8 g, 50 mmol), and the mixture was stirred at room temperature until the reaction mixture became a clear solution. The solution was then slowly heated and refluxed for 2.5 hour. After cooling, the mixture was partitioned between ethyl acetate/hexane (1:1, v/v) and 1% aqueous sodium hydroxide. The organic layer was washed again with 1% aqueous sodium hydroxide. All the aqueous solutions were combined and neutralized to pH=5 with concentrated hydrochloric acid in the presence of ethyl acetate. The ethyl acetate layer was washed with brine, dried over sodium sulfate and concentrated to obtain 5.0 g of 6-tert-butoxycarbonylamino-2-pyridinecarboxylic acid.

Provenance & Evidence