Synthesis of a new functionalized pyridoxine derivatives based on 2-halopyridine-3,4-dicarbonitriles

Two new approaches to the synthesis of functionalized pyridoxine derivatives with hydroxymethyl groups at positions 3 and 4 of the pyridine ring have been implemented based on the transformations of 2-halopyridine-3,4-dicarbonitriles. The first path involves obtaining target compounds with a halogen atom in the 2-position of pyridine by reduction of intermediate pyridine-3,4-dicarboxylates with sodium borohydride. The second approach is based on the reduction of annelated furo[3,4-c]pyridin-3(1H)-ones and allows obtaining both 2-halogen- and 2-alkylamino-substituted pyridoxine derivatives.