Extracting kinetics from affinity capillary electrophoresis (ACE) data: a new blade for the old tool.

We describe a mathematical approach that enables extraction of kinetic rate constants from thousands of studies conducted over the past two decades with affinity capillary electrophoresis (ACE). Previously, ACE has been used almost exclusively for obtaining equilibrium constants of intermolecular interactions. In this article, we prove that there exists an analytical solution of partial differential equations describing mass transfer in ACE. By using an in silico study, we demonstrate that the solution is applicable to experimental conditions that are typically used in ACE and found in most historical ACE experiments. The solution was validated by extracting rate constants from previously published ACE data and closely matching independently obtained results. Lastly, it was used to obtain previously unknown rate constants from historical ACE data. The new mathematical approach expands the applicability of ACE to a wider range of biomolecular interactions and enables both prospective and retrospective data analysis. The obtained kinetic information will be of significant practical value to the fields of pharmacology and molecular biology.

Using glucaminium-based ionic liquids for improving the separation of 2-aminopyrimidine-5-ylboronic acid and its pinacol ester by high performance liquid chromatography.

A reversed-phase high performance liquid chromatography (HPLC) method is described for the determination of boronic acids that are commonly present as impurities in pinacolboronate ester reagents. Boronic acids and their pinacolboronate esters are key reagents in the Suzuki-Miyaura coupling reaction. The retention of hydrophilic boronic acids in reversed-phase chromatography is often a challenge, especially in very high pH mobile phases, which are needed to mitigate the on-column degradation of pinacolboronate esters. In this study, a hydrophilic boronic acid, 2-aminopyrimidine-5-ylboronic acid, was complexed with specifically functionalized glucaminium-based ionic liquids that were added to the diluent. The two glucaminium-based ILs possess cis-diol moieties that are capable of forming complexes with boronic acids. In addition, aromatic functional groups within the glucaminium cation allow strong π-π interactions with the polymeric stationary phase. Using this approach, the limit of detection for 2-aminopyrimidine-5-ylboronic acid was found to be 3-4µM. The quantification of 2-aminopyrimidine-5-ylboronic acid within a 2-aminopyrimidine-5-pinacolboronate ester sample was successfully achieved using this method.

Streamlined approach to high-quality purification and identification of compound series using high-resolution MS and NMR.

Automated medicinal chemistry (parallel chemistry) has become an integral part of the drug-discovery process in almost every large pharmaceutical company. Parallel array synthesis of individual organic compounds has been used extensively to generate diverse structural libraries to support different phases of the drug-discovery process, such as hit-to-lead, lead finding, or lead optimization. In order to guarantee effective project support, efficiency in the production of compound libraries has been maximized. As a consequence, also throughput in chromatographic purification and analysis has been adapted. As a recent trend, more laboratories are preparing smaller, yet more focused libraries with even increasing demands towards quality, i.e. optimal purity and unambiguous confirmation of identity. This paper presents an automated approach how to combine effective purification and structural conformation of a lead optimization library created by microwave-assisted organic synthesis. The results of complementary analytical techniques such as UHPLC-HRMS and NMR are not only regarded but even merged for fast and easy decision making, providing optimal quality of compound stock. In comparison with the previous procedures, throughput times are at least four times faster, while compound consumption could be decreased more than threefold.

Discovery of a novel proteasome inhibitor selective for cancer cells over non-transformed cells.

Numerous proteins controlling cell cycle progression, apoptosis and angiogenesis are degraded by the ubiquitin/proteasome system, which has become the subject for intense investigations for cancer therapeutics. Therefore, we used in silico and experimental approaches to screen compounds from the NCI chemical libraries for inhibitors against the chymotrypsin-like (CT-L) activity of the proteasome and discovered PI-083. Molecular docking indicates that PI-083 interacts with the Thr21, Gly47 and Ala49 residues of the beta5 subunit and Asp114 of the beta6 subunit of the proteasome. PI-083 inhibits CT-L activity and cell proliferation and induces apoptosis selectively in cancer cells (ovarian T80-Hras, pancreatic C7-Kras and breast MCF-7) as compared to their normal/immortalized counterparts (T80, C7 and MCF-10A, respectively). In contrast, Bortezomib, the only proteasome inhibitor approved by the Food and Drug Administration (FDA), did not exhibit this selectivity for cancer over non-transformed cells. In addition, in all cancer cells tested, including Multiple Myeloma (MM), breast, pancreatic, ovarian, lung, prostate cancer cell lines as well as fresh MM cells from patients, PI-083 required less time than Bortezomib to induce its antitumor effects. Furthermore, in nude mouse xenografts in vivo, PI-083, but not Bortezomib, suppressed the growth of human breast and lung tumors. Finally, following in vivo treatment of mice, PI-083 inhibited tumor, but not hepatic liver CT-L activity, whereas Bortezomib inhibited both tumor and liver CT-L activities. These results suggest that PI-083 is more selective for cancer cells and may have broader antitumor activity and therefore warrants further advanced preclinical studies.

Efficient synthesis of chiral 1,1'-binaphthalenes by the asymmetric suzuki-miyaura reaction: dramatic synthetic improvement by simple purification of naphthylboronic acids.

Naphthylboronic acids prepared as reported in the literature are contaminated with HCl. A very simple purification prior to their use in Suzuki-Miyaura couplings has been found to be crucial, rendering efficient some reactions that had been reported in the literature either to fail or to give extremely poor yields. With this improvement, parent boronic acids can be used instead of esters at moderate temperatures, and bromo derivatives can be used instead of iodo derivatives. Convenient access to chiral sterically hindered binaphthalene derivatives has been achieved through the use of boronic acids, bromonaphthalenes, and ferrocenylphosphane ligands. The products were obtained in good yields (95-55 %) and with good enantioselectivities (90-50 %). Bulkier ligands are less efficient in the coupling of hindered partners.