First Synthesis of Methyl 2-Amino-6-Methoxynicotinate Using a Combination of Microwave and Flow Reaction Technologies

The synthesis of methyl 2-amino-6-methoxynicotinate, a valuable building block for the preparation of fused 2-pyridones, is reported. The optimized synthesis includes sequential microwave-induced regioselective 6-methoxylation, esterification, followed by microwave-induced reaction with p-methoxybenzylamine, and final deprotection under flow reaction hydrogenation conditions. Two key steps in the reported synthesis are a microwave-induced methoxylation and a microfluidic hydrogenation that afford improved regioselectivity and purity profile of the reaction products.