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

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