phenyl 4-[[5-cyano-1,6-dihydro-2-hydroxy-1-(3-methoxypropyl)-4-methyl-6-oxo-3-pyridyl]azo]benzenesulphonate

4-[[[5-Cyano-1,6-dihydro-2-hydroxy-1-(3-methoxypropyl)-4-methyl-6-oxopyridin]-3-yl]azo]benzenesulfonic acid phenyl ester