4-(dimethylamino)-1-(2-formylethyl)pyridinium cation

3-(4-(dimethylamino)pyridinium)butanal

4-(dimethylamino)-1-(3-oxobutyl)pyridin-1-ium

4-(dimethylamino)-1-(2-(1-methylpyridin-1-ium-4-yl)ethyl)pyridin-1-ium

4-苯氧基吡啶