Isonicotinamide (pyridine-4-carboxamide) is a chemical based on the nicotinamide structure, but in which the amide is in the 4-position and not the 3-position.
Isonicotinamide (pyridine-4-carboxamide) is the amide form of isonicotinic acid. The amide group of isonicotinamide is in the 4-position while the amide group for nicotinamide is in the 3-position.