2,2′,5,5′-Tetrahydroxy-3,3′-bipyridine-6,6′(1H,1′H)-dione

2,2′,5,5′-Tetrahydroxy-3,3′-bipyridin-6,6′(1H,1′H)-dion

2,2′,5,5′-Tetrahydroxy-3,3′-bipyridine-6,6′(1H,1′H)-dione

2,2′,5,5′-Tétrahydroxy-3,3′-bipyridine-6,6′(1H,1′H)-dione

[3,3′-Bipyridine]-2,2′,5,5′,6,6′-hexol

5-(2,5,6-trihydroxy-6H-pyridin-3-ylidene)-2H-pyridine-2,3,6-triol

nicotine blue leuco form