The ketol (II'), obtained by ozonolysis of dimethyl agathenedicarboxylate, was converted to the pyridine derivative (III), which was reduced with sodium and ethanol to several stereoisomeric imino-esters (IVa) and imino-alcohols (Va). One of the imino-esters was obtained directly by catalytic reduction of the ketol (II') in methanolic ammonia.
