A Protocol for the Direct Conversion of Lactones to Lactams Mediated by 1,5,7-Triazabicyclo[4.4.0]dec-5-ene: Synthesis of Pyridopyrazine-1,6-diones.

We present an operationally simple lactone-to-lactam transformation utilizing diverse amine nucleophiles. The key steps of amidation, alcohol activation, and cyclization are all mediated by one reagent (TBD) in a single vessel at room temperature. We illustrate the convenience of this protocol by synthesizing a wide range of N-alkyl, N-aryl, and N-hetereoaryl pyridopyrazine-1,6-diones, an important class of medicinally significant lactams. Furthermore, the reported methodology can be applied to the synthesis of milligram to hundred gram quantities of pyridopyrazine-1,6-diones without the use of specialized equipment.