Among 13 kinds of metal oxides, ceria (CeO 2) shows the highest catalytic activity for one-pot selective synthesis of the secondary amide from 2-cyanopyridine and n-octylamine as a test reaction. CeO 2 acts as a reusable heterogeneous catalyst, and it is effective for the secondary amide formation from various nitriles and amines in high yields (73% to >99%). Pharmacologically important products such as heteroaromatic N-alky amides and morpholine amide are effectively synthesized, indicating that CeO 2 can be a practically useful catalyst. A proposed mechanism includes (1) hydration of nitrile to the primary amide and (2) transamidation of the primary amide with amine as the rate-limiting step. This reaction mechanism provides a reason why the present catalytic system gives high selectivity.
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