N,O-Iminoboronates: Reversible Iminoboronates with Improved Stability for Cancer Cells Targeted Delivery

Abstract

Herein a new class of iminoboronates obtained from 2-acetylbenzene boronic acids and aminophenols is presented. The N,O-ligand topology enabled the formation of an additional B-O bond that locks the boron center in a tetrahedral geometry. This molecular arrangement decisively contributes to improve the construct's stability in biocompatible conditions and retaining the iminoboronate reversibility in more acidic environments. 2-Acetylbenzene boronic acid was reacted with a fluorescent amino-coumarin to yield a stable and non-fluorescent N,O-iminoboronate. This mechanism was further used to assemble a folate receptor targeting conjugate that selectively delivered the fluorescent amino-coumarin to MDA-MB-231 human breast cancer cells.

Keywords: boronic acids; drug delivery; iminoboronate; reversibility; small-molecule-drug conjugates.