OXIDATIVE COUPLING AND UNUSUAL HYDROXYMETHYLATION OF 1-METHYL-4-PHENYL-1,2,3,6-TETRAHYDROPYRIDINE IN THE PRESENCE OF DICYANOMETHANE

Potassium permanganate oxidizes a mixture of 1-methyl-4-phenyl-1,2,3,6 -tetrahydropyridine (THP) 1 and dicyanomethane to 2-dicyanomethylidene tetrahydropyridine 2, but using manganese dioxide leads to the unusual oxidative hydroxymethylation of 1; subsequent treatment of the 3-hydr oxymethyltetrahydropyridine 4 formed with aqueous potassium permangana te results in lactamination, accompanied by aromatization or oxodihydr oxylation.