1980-93-4 Color Precursor No. 21 Yellow Color precursor X-4405 NSC328474 Phenol, 4-[2-(3,3-dimethyl-3H-indol-2-yl)ethenyl]- Phenol, p-[2-(3,3-dimethyl-3H-indol-2-yl)vinyl]- p-[2-(3,3-Dimethyl-3H-indol-2-yl)vinyl]phenol