Acidobasic properties of nitro precursors of inubosin determined by spectroscopic methods.

Inubosin precursors are important building blocks for the preparation of neurodegenerative medicines. Their scaffold is also widely used in antibiotics, blood-pressure regulators, antithrombotics, and other drugs. Physicochemical properties of inubosin precursors are thus important for optimization of reaction yields and choosing the synthetic strategy. We focused on several inubosin B precursors, where acidobasic constants may also affect biological activity. The precursors contain a free or protected nitrophenol group and thus mimic products of oxidative stress in organisms. The constants were determined using UV-Vis spectroscopy. The structure-spectra relationship, including solvatochromic effects, was interpreted on the basis of time dependent density functional theory (TDDFT) modeling. The methodology provides reliable values of acidobasic constants, and understanding of the solvent effects is important for chemical and biological inubosin applications.