p-[4-[(3-ethyl-3H-benzoxazol-2-ylidene)ethylidene]-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonic acid

4-[[4-[2-(3-Ethylbenzoxazol-2(3H)-ylidene)ethylidene]-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol]-1-yl]benzenesulfonic acid