Synthesis of 3-Iodoindoles and Their Glucose Electrooxidation Performance as an Anode Catalyst

Herein, indole derivatives namely 3-iodo- 1-methyl-2-phenyl-1H-indole (4A), 3-iodo-1-methyl-2-(p-tolyl)-1H- indole (4B), and 2-(2,5-dimethylphenyl)-3-iodo-1-methyl-1H-indole (4C) prepared by Sonogashira coupling and electrophilic cyclization reactions with yield of 70%, 68%, and 67%, respectively. Organic catalysts were characterized by using Liquid Chromatography with tandem mass spectrometry (LC-MS-MS), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spektrofotometre (FT-IR), and Nuclear Magnetic Resonance (NMR). Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA) were utilized to observe the electrocatalytic behavior of 4A, 4B, and 4C. Specific activity for glucose electrooxidation of 4A was determined as 3.26 mA/cm2. Compound 4A exhibits long-term stability toward glucose electrooxidation. As a metal-free catalyst, Compound 4A may be a good candidate as an electrocatalyst for glucose electrooxidation.