An Convenient Synthesis of Ricinine and Its Analogues

Ricinine is an alkaloid of Ricinus communis that displays numerous biological properties. Ricinine (4-methoxy-1-methyl-2-oxo-dihydropyridine-3-carbonitrile)) and new N-analogues of Ricinine were obtained by the reaction of ethyl α-ethoxyethylidenecyanoacetate with various amines. Earlier, ethyl α-ethoxyethylidenecyanoacetate was easily prepared from ethyl cyanoacetate. Biologically, amines such as tryptamine and histamine were used in order to introduce a second pharmacophore on the target molecule.