9-Monodemethyl Minocycline (Crude)

9-Monodemethyl Minocycline (Crude) is a tetracycline derivative featuring a demethylated C9 position relative to Minocycline, retaining the dimethylamino group at C7 and hydroxyl/ketone functionalities at C6 and C11. Its core structure comprises a fused tetrahydrocyclopentane ring system with conjugated diene and phenolic hydroxyl moieties. This impurity arises via reductive demethylation at the C9 methyl group during synthetic processes, resulting in a less stable chromophore compared to the parent drug. It serves as a critical HPLC reference standard for quantifying process-related impurities in Minocycline formulations.