Effects of Boron-Containing Compounds on Liposoluble Hormone Functions

Boron-containing compounds (BCC), particularly boronic acids and derivatives, are being increasingly tested as diagnostic and therapeutic agents. Some effects of BCC involve phenomena linked to the action of steroid or thyroid hormones; among these, are the effects on muscle mass or basal metabolism. Additionally, some toxicology reports on mammals, including humans, sound an alert concerning damage to several systems, among which are the negative effects on the induction of male infertility. Systemic and local mechanisms to explain changes in metabolism and impaired fertility were collected and presented. Then, we presented the putative pharmacodynamic and pharmacokinetic mechanisms involved and demonstrated in these events. In addition, it is proposed that there are adducts of some oxygenated BCC with cis-diols in fructose, an essential source of energy for sperm–cell motility, an uncoupling of sex hormone-binding globulin (SHBG) and its ligands, and the modulation of the DNA synthetic rate. These effects share the reactivity of boron-containing compounds on the cis-diols of key molecules. Moreover, data reporting no DNA damage after BCC administration are included. Further studies are required to support the clear role of BCC through these events to disrupt metabolism or fertility in mammals. If such phenomena are confirmed and elucidated, an advance could be useful to design strategies for avoiding BCC toxicity after BCC administration, and possibly for designing metabolism regulators and contraceptive drugs, among other purposes. Boronic derivatives and carboranes have been proposed and studied in this field.

Structural Biology Inspired Development of a Series of Human Peroxisome Proliferator-Activated Receptor Gamma (PPARγ) Ligands: From Agonist to Antagonist

Recent progress in the structural and molecular pharmacological understanding of the nuclear receptor, peroxisome proliferator-activated receptor gamma (hPPARγ)-a transcription factor with pleiotropic effects on biological responses-has enabled the investigation of various graded hPPARγ ligands (full agonist, partial agonist, and antagonist). Such ligands are useful tools to investigate the functions of hPPARγ in detail and are also candidate drugs for the treatment of hPPARγ-mediated diseases, such as metabolic syndrome and cancer. This review summarizes our medicinal chemistry research on the design, synthesis, and pharmacological evaluation of a covalent-binding and non-covalent-binding hPPARγ antagonist, both of which have been created based on our working hypothesis of the helix 12 (H12) holding induction/inhibition concept. X-ray crystallographic analyses of our representative antagonists complexed with an hPPARγ ligand binding domain (LBD) indicated the unique binding modes of hPPARγ LBD, which are quite different from the binding modes observed for hPPARγ agonists and partial agonists.

Advanced Tool for Chiral Separations of Anionic and Zwitterionic (Metalla)carboranes: Supercritical Fluid Chromatography

The continuous expansion of research in the field of stable carboranes and their wide potential in the drug design require carrying out fundamental studies regarding their chiral separations. Although supercritical fluid chromatography (SFC) is a viable technique for fast enantioseparations, no investigation concerning boron cluster compounds has been done yet. We aimed at the development of a straightforward method enabling chiral separations of racemic mixtures of anionic cluster carboranes and metallacarboranes that represent an analytical challenge. The fast gradient screening testing nine polysaccharide-based columns was used. The key parameters affecting the selectivity were the type of chiral selector, the type of alcohol, and the base in cosolvent. Moreover, the addition of acetonitrile or water to the cosolvent was identified as an effective tool for decreasing the analysis time while preserving the resolution. After the optimization, the chiral separations of 19 out of 20 selected compounds were achieved in less than 10 min. These results demonstrate the clear advantage of SFC over chiral separations using HPLC in terms of both analysis time and structural variety of successfully separated compounds.

EGFR-Targeted Cellular Delivery of Therapeutic Nucleic Acids Mediated by Boron Clusters

New boron carriers with high boron content and targeted cancer-cell delivery are considered the first choice for boron neutron capture therapy (BNCT) for cancer treatment. Previously, we have shown that composites of antisense oligonucleotide and boron clusters are functional nanoparticles for the downregulation of expression of epidermal growth factor receptor (EGFR) and can be loaded into EGFR-overexpressing cancer cells without a transfection factor. In this study, we hypothesize that free cellular uptake is mediated by binding and activation of the EGFR by boron clusters. Proteomic analysis of proteins pulled-down from various EGFR-overexpressing cancer cells using short oligonucleotide probes, conjugated to 1,2-dicarba-closo-dodecaborane (1,2-DCDDB, [C₂B₁₀H₁₂]) and [(3,3'-Iron-1,2,1',2'-dicarbollide)^-] (FESAN, [Fe(C₂B₉H₁₁)₂]^-), evidenced that boron cage binds to EGFR subdomains. Moreover, inductively coupled plasma mass spectrometry (ICP MS) and fluorescence microscopy analyses confirmed that FESANs-highly decorated B-ASOs were efficiently delivered and internalized by EGFR-overexpressing cells. Antisense reduction of EGFR in A431 and U87-MG cells resulted in decreased boron accumulation compared to control cells, indicating that cellular uptake of B-ASOs is related to EGFR-dependent internalization. The data obtained suggest that EGFR-mediated cellular uptake of B-ASO represents a novel strategy for cellular delivery of therapeutic nucleic acids (and possibly other medicines) conjugated to boron clusters.

Recent Advances in the Synthesis and Medicinal Chemistry of SF5 and SF4Cl Compounds

This short review covers the most important advances published in the literature during the last five years, concerning the synthesis, chemical modifications, and applications of SF5 and SF4Cl compounds in medicinal/bioorganic chemistry and materials science.

1 Introduction

2 Methods for Incorporation/Manipulation of SF4Cl/SF5 Groups

2.1 Nonaromatic SF5 Compounds via Direct Pentafluorosulfanylation of Alkenes and Alkynes

2.2 SF4Cl- and SF5-Aryl/Heteroaryl Derivatives

3 Synthesis of SF5/SF4Cl/SF4-Substituted Small Molecules

3.1 Heterocycles

3.2 Amines and Amino Acids

3.3 α-SF5 ketones

3.4 Miscellaneous Alkyl-, Alkenyl-, and Aryl-SF5 Compounds

4 Medicinal/Biological Applications

4.1 Anticancer Compounds

4.2 Antibacterial and Antiparasitic Compounds

4.3 Central Nervous System

4.4 Miscellaneous Biological Activity

5 Materials Science Applications

6 Conclusion

The Boron Advantage: The Evolution and Diversification of Boron’s Applications in Medicinal Chemistry

In this review, the history of boron’s early use in drugs, and the history of the use of boron functional groups in medicinal chemistry applications are discussed. This includes diazaborines, boronic acids, benzoxaboroles, boron clusters, and carboranes. Furthermore, critical developments from these functional groups are highlighted along with recent developments, which exemplify potential prospects. Lastly, the application of boron in the form of a prodrug, softdrug, and as a nanocarrier are discussed to showcase boron’s emergence into new and exciting fields. Overall, we emphasize the evolution of organoboron therapeutic agents as privileged structures in medicinal chemistry and outline the impact that boron has had on drug discovery and development.

Boron clusters as breast cancer therapeutics

Since the foundation of small molecule-based therapeutics over 100 years ago, their design has been dominated by organic based components. This has also been apparent in anti-cancer therapeutics in a broad range of strategies; from the older DNA chelating drugs, to the more recent molecular-targeted therapies. The main challenges facing current treatments; multidrug resistance and low therapeutic index, can potentially be alleviated by the incorporation of boron clusters. While retaining the versatility of their organic counterparts, these compounds offer a unique set of molecular interactions, which are a useful tool in targeted therapies and can improve many organic formulations with their incorporation. This review will discuss the potential of boron clusters in medicine while focusing on their activity in the breast cancer setting.

Amine-borane complex-initiated SF5Cl radical addition on alkenes and alkynes

The SF5Cl radical addition on unsaturated compounds was performed using an air-stable amine-borane complex as the radical initiator. This method showed to be complementary to the classic Et3B-mediated SF5Cl addition on alkenes and alkynes. A total of seven alkene and three alkyne derivatives were tested in the reaction, with yields ranging from 3% to 85%.