2-(4-Hydroxy-phenyl)-3-methyl-1H-indole-5-ol

2-(4-Hydroxy-phenyl)-3-methyl-1H-indole-5-ol is a substituted indole derivative featuring a 4-hydroxyphenyl moiety at position 2, a methyl group at position 3, and a hydroxyl substituent at position 5 of the indole nucleus. This compound represents a critical impurity in the synthesis pathway of [parent drug], arising from regioselective hydroxylation and alkylation processes. Its conjugated aromatic system and multiple hydrogen-bonding functionalities contribute to distinct chromatographic behavior, necessitating precise analytical monitoring. Serves as an HPLC reference standard for quantification in pharmaceutical quality control.