4,4',4"-trimethyl-2,2':6',2"-terpyridine by oxidative coupling of 4-picoline

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 MnO2 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.