General procedure for the synthesis of 4-((tert-butoxycarbonyl)amino)nicotinic acid from methyl 4-((tert-butoxycarbonyl)amino)nicotinate: 4-((tert-butoxycarbonyl)amino)nicotinic acid methyl ester (6.02 g, 23.86 mmol) was dissolved in dioxane (100 mL), and an aqueous sodium hydroxide solution (0.970 N, 28.05 mL, 27.20 mmol ). The reaction mixture was heated to 60°C and held for 1 hr and subsequently cooled to room temperature. To the cooled mixture was added aqueous hydrochloric acid (1.03 M, 26.99 mL, 27.20 mmol) and then extracted with chloroform (5 x 100 mL). The organic phases were combined, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give 4-((tert-butoxycarbonyl)amino)nicotinic acid as a creamy solid (4.70 g, 83% yield).
