1-Methylindole-3-carboxylic acid is an indole derivative that can be prepared by the oxidation of 1-methylindole-3-aldehyde with alkaline potassium permanganate.Application · Reactant for preparation of bisindolyl pyrimidinones analogs of PKC inhibitor LY333531 · Reactant for preparation of (heteroaryl)(carboxamido)arylpyrrole derivatives as Cdc7 kinase inhibitors, antitumor and antiproliferative agents · Reactant for preparation of (pyrrolidinylmethoxy)cyclohexanecarboxylic acids as antigen-4 (VLA-4) antagonists · Reactant for preparation of EphB3 receptor tyrosine kinase inhibitors · Reactant for preparation of pyrazolodiazepine derivatives as human P2X7 receptor antagonists · Reactant for preparation of potent nonpeptidic urotensin II receptor agonists · Reactant for preparation of pyrrolizidine esters, amides, and ureas as 5-HT4 receptor ligands 1-Methylindole-3-carboxylic acid is an indole derivative that can be prepared by the oxidation of 1-methylindole-3-aldehyde with alkaline potassium permanganate.