4,4′,4″-Trimethyl-2,2′:6′,2″-terpyridine by Oxidative Coupling of 4-Picoline

[Image: see text] Alkylated terpyridine ligands are an increasingly important component of catalysis and dyes but are costly because their synthesis is challenging and often low-yielding. We report an improved method for the Pd/C-catalyzed dehydrogenative coupling of 4-picoline to form the bi- and terpyridine. The addition of MnO(2) improves the yield of the reaction, making the reaction useful on a large scale (up to 200 mmol). The use of Pd(OAc)(2) or Pd/C/pivalic acid leads to the selective formation of bipyridine.