(7-methyl-5-oxofuro[3,4-b]pyridin-7-yl) acetate

6-羟基烟酸

2-羟基烟酸

(7-methyl-1-oxido-5-oxofuro[3,4-b]pyridin-1-ium-7-yl) acetate

6-氨基烟酸