Reaction of 1-methyl-2-phenylindole with nitrogen dioxide or with nitrous acid (NaNO2-CH3COOH) in benzene has been studied. 1-Methyl-2-phenylindole is reported to react with malondialdehyde (MDA) and 4-hydroxyalkenals to afford a stable chromophore with intense maximal absorbance at 586nm. Application Reactant for preparation of: Cyano indoles Difluorohydroxy indoles Reactant for: Carboxylation of indoles Allylation of indoles Formylation of indoles Nitrosylation of indoles 1-Methyl-2-phenylindole may be used in the following studies: The estimation of lipid peroxidation in third instar larvae of transgenic Drosophila melanogaster (hsp70-lacZ)Bg. As chromogenic agent for the determination of estimation of malondialdehyde (MDA) production. Colorimetric assay of lipid peroxidation. Synthesis of 1-methyl-2-phenyl-3-(1,3,4-thiadiazol-2-yldiazenyl)-1H-indole. Synthesis of 3-(5-ethyl-1,3,4-thiadiazol-2-yldiazenyl)-1-methyl-2-phenyl-1H-indole.