Study on the Synthesis of 2,6-di(pyridin-2-yl)pyridin- 4(1H)-one

In this paper, 2,6-di(pyridin-2-yl)pyridin-4(1H)-one was synthesized from ethyl picolinate and acetone via Kröhnke-type reaction. Initially, optimization of the reaction conditions for the synthesis of 1,5-bis(2′-bipyridyl)pentane-1,3,5-trione 2, such as the molar ratio of ethyl picolinate: acetone: sodium hydride and the reaction temperature, were researched. In the ring-forming step, the different nitrogen sources were also researched. At the end, the optimal reaction conditions obtained: the best reaction temperature of first step is 10°C, the molar ratio of ethyl picolinate: acetone is 2:1.1, and ethyl picolinate: sodium hydride is 2: 3, and the optimum nitrogen source is ammonium formate. Under the optimal reaction conditions, the total yield is obtained up to 66% (the yield is only 37% refer to the literatures).