Main Reaction: 4-aminoantipyrine + Phenol >> Red quinone dye

Reference: PubMed ID: 7017049
Authors: Gurantz D, Laker MF, Hofmann AF
Title: Enzymatic measurement of choline-containing phospholipids in bile.
Published: 1981 Feb

4-aminoantipyrine + Phenol --> Red quinone dye