Environmentally friendly synthesis of secondary amines via one-pot reductive amination over a heterogeneous Co-Nx catalyst

The application of earth-abundant transition metal catalysts in the mild and selective synthesis of secondary amines via the reductive amination method is very challenging. In this regard, we have developed a new method for the reductive amination of carbonyl compounds with nitro compounds over a heterogeneous Co-nitrogen (Co-N-x) catalyst under mild conditions (110 degrees C and 10 bar H-2). This method afforded the corresponding secondary amines with the yields of 43.7-100% at 110 degrees C and under 10 bar H2 pressure. Kinetic studies revealed that the hydrogenation of imines was the rate-determining step with much higher activation energy than the first step of the hydrogenation of nitro compounds. To the best of our knowledge, no such non-noble heterogeneous catalyst that shows very high catalytic activity under mild conditions (110 degrees C and 10 bar H-2) has been reported to date. This promising cheap heterogeneous catalyst allows an efficient domino reductive amination of carbonyl compounds with nitro compounds.