Isosorbide-5-mononitrate1,2,3,4,5,6

Isosorbide-5-mononitrate1,2,3,4,5,6 is a cyclic nitrate ester derived from the 1,3-dioxane ring of isosorbide, featuring a nitrate group at the 5-position and a residual hydroxyl group at the 2-position. Its structure retains the six-membered ring framework of the parent compound but introduces an electron-withdrawing nitrate moiety, altering regioselectivity during synthetic pathways. This impurity arises via partial nitration of isosorbide, diverging from the fully nitrated isosorbide dinitrate. It serves as a critical HPLC reference standard for quantifying nitration byproducts in API synthesis.