Pd-catalyzed amidation of 2-chloro- and 2,7-dichloro-1,8-naphthyridines

reactions: see text] The catalytic amidation between 2-chloro- and 2,7-dichloro-1,8-naphthyridines and primary amides bearing functional groups is reported. When Pd(OAc)2, xantphos, and K2CO3 are used, it is possible to obtain symmetric as well as nonsymmetric 2,7-diamido-1,8-naphthyridines in 50-90% yield with good functional-group tolerance. Monoamidation of 2,7-dichloro-1,8-naphthyridine using 0.9 equiv of the amide proceeded with good selectivity compared to the formation of the diamide, but as a result of the difficult isolation of the product, isolated yields were poor to moderate (22-42%).