An improved preparation of tetrahydropyridines from 1-alkyl-3-acylpyridinium salts

The hydrogenation of 1-alkyl-3-acylpyridinium salts in methanol in the presence of 10% palladium-charcoal/disodium hydrogen phosphate-sodium dihydrogenphosphate suspension leads to the corresponding tetrahydropyridines. This represents an improvement over the Wenkert method.