boron and 2-aminoethoxydiphenyl-borate

NLRP3 is a receptor important for host responses to infection, yet is also known to contribute to devastating diseases such as Alzheimer's disease, diabetes, atherosclerosis, and others, making inhibitors for NLRP3 sought after. One of the inhibitors currently in use is 2-aminoethoxy diphenylborinate (2APB). Unfortunately, in addition to inhibiting NLRP3, 2APB also displays non-selective effects on cellular Ca

Topics: Animals; Bone Marrow Cells; Boron; Boron Compounds; Calcium; Cells, Cultured; Crystallography, X-Ray; Humans; Inflammasomes; Inhibitory Concentration 50; Interleukin-1beta; Lipopolysaccharides; Macrophages; Mice; Molecular Conformation; NLR Family, Pyrin Domain-Containing 3 Protein; Structure-Activity Relationship

Aminoethoxydiphenyl borate (2-APB), 1, is a potent inhibitor of store-operated calcium entry channels (SOCCs). Other SOCC inhibitors are being investigated as promising pharmacological agents for a variety of conditions. Though toxic, 2-APB could be useful in the development of additional inhibitors, but its preferred binding structure must first be determined. Thus, we performed ab initio calculations to study the conformers and the strength of the dative bond of 2-APB. As a first step, we performed a series of computations at various levels of theory. We obtained vastly different dissociation energies for the dative bond depending on whether we used MP2 or B3LYP (7-10 kcal/mol different). This discrepancy has previously been observed for other B-N dative bonds by Gilbert, who found that the MP2 values were in much better agreement with experimental values (Gilbert, T. M. J. Phys. Chem. A 2004, 108, 2550-2554). Since we lacked experimental data for comparison, we performed CCSD(T) calculations and found them to have similar results to those from MP2. Thus, we conclude that MP2 is more accurate for 2-APB. The dissociation free energy at the MP2 level is 7 kcal/mol and indicates that the dative bond conformer will be the predominant structure in the gas phase. The dissociation energy is comparatively low due to the electron donation from the oxygen atom to the boron atom and due to the ring strain in the dative bond conformer.

Topics: Borates; Boron; Boron Compounds; Models, Chemical; Molecular Structure; Nitrogen; Thermodynamics