Abstract
N-Acylmethylpyridinium salts (Ia-c) were applied to some pyridine and quinoline N-oxides in the presence of acetic anhydride. 4-Methoxyquinoline 1-oxide (IV) readily reacted with Ia-c to give N-(α-acyl-4-methoxy-2-quinolylmethyl) pyridinium compounds (Va-c) in good yields. Whereas N-oxides of lepidine (VIII), pyridine (XII) and 4-picoline (XV) reacted similarly with N-acetonylpyridinium chloride (Ia). Quinaldine and 2-pi-coline N-oxides did not react even with Ia.
The pyridinium salts thus obtained afforded smoothly the corresponding quinaldyl (XVIIIa, b; XIX) or α-picolyl ketones (XXI, XXII) upon treatment zinc powder and acetic acid.
The tautomeric structures of the quinaldyl ketones (XVIIIa, b; XIX) were discussed.
