METHOD OF OBTAINING DICARBOXYLATE DERIVATIVES OF PYRIDINE

摘要

Single vessel preparation of pyridine dicarboxylate comprises sequential condensation of alkyl vinyl ether and Vilsmeier reagent, oxalacetate and ammonia. Preparation of substituted pyridine derivatives of formula (I) comprises: (a) reacting an alkyl vinyl ether derivative of formula (II) with at least one molar equivalent of Vilsmeier reagent optionally in the presence of a first solvent to form a first intermediate; (b) reacting with at least one molar equivalent oxalacetate derivative of formula (III) in the presence of at least two molar equivalents of an organic amine base to form a second intermediate; and (c) reacting with an ammonia source optionally in the presence of a second solvent to form (I). [Image] R 1H or 1-4C alkyl (optionally substituted by 1-4C alkoxy or halo); R 2, R 31-6C alkyl; and R : 1-4C alkyl.