A new method for the synthesis of encainide has been reported: The acylation of methyl anthranilate (I) with 4-anisoyl chloride (II) by means of NaOH in methylene chloride gives methyl N-(p-anisoyl)anthranilate (III), which is condensed with 2-picoline (IV) by means of n-butyllithium in THF yielding 2-(2-pyridylacetyl)-p-anisanilide (V). Finally, this compound is reduced with H2 over Pt/C then with Pd/C, treated with formaldehyde and reduced again with H2 over Pt/C.
The condensation of 2-methylpyridine (I) with 2-nitrobenzaldehyde (II) in acetic anhydride gives 2-(2-nitrostyryl)pyridine (III), which is quaternized with methyl iodide in refluxing acetone yielding 2-(2-nitrostyryl)-1-methylpyridinium iodide (IV) . The reduction of (IV) with H2 over PtO2 in ethanol affords 2-(2-aminophenethyl)-1-methylpiperidine (V), which is then acylated with 4-methoxybenzoyl chloride (A) in pyridine.