General procedure for the synthesis of ethyl (6-aminopyridin-2-yl)acetate from ethyl [6-[(tert-butoxycarbonyl)amino]-2-pyridinyl]acetate: to a solution of ethyl [6-[(tert-butoxycarbonyl)amino]-2-pyridinyl]acetate (1.38 g, 4.92 mmol) in methylene chloride (20 ml), was added a solution of dioxane in 4 M HCl (4 equiv. 19.7 mmol) and the reaction mixture was stirred at room temperature for 4 hours. Subsequently, 4 equivalents of dioxane solution of 4M HCl was added additionally and stirring was continued for 16 hours. Upon completion of the reaction, the mixture was concentrated in vacuum to afford the crude product ethyl (6-aminopyridin-2-yl)acetate (1.20 g, yield >100%, containing about 14% of the feedstock). Analysis by LC/MS showed a product purity of about 75% (MH+, m/z 181, retention time Rt=0.68 min). The resulting product does not require further purification and can be used directly in subsequent reactions.
