Synthesis and Properties of 4,5-trans-2-Alkylthio-3-cyano-6-hydroxy-6-methyl-4-phenyl-5-pyridinio-1,4,5,6-tetrahydropyridine Iodides

Alkylation of 4,5-trans-4-aryl-3-cyano-6-hydroxy-6-methyl-5-pyridinio-1,4,5,6-tetrahydropyridine-2-thiolates 1, 2 was carried out. The presence of 5-pyridinio cation in thiolates 1, 2 as a strong electron-withdrawing group leads to a pronounced enhancement of their stability to dehydration but decreases their reactivity with electrophilic reagents. Steric structures of 2-alkylthio-6-hydroxytetrahydropyridines 3-5 are discussed in the light of ¹H NMR spectra and crystal X-ray diffraction data.