Synthesis of 13β- and 13α-epimers of 3-hydroxy-17-hydroxymethylestra-1,3,5(10)-triene and considerations on their hormonal and antiproliferative potency.

Starting from 3-methoxyestra-1,3,5(10),16-tetraene-17-carbaldehydes of natural (13β) and epimeric (13α) series, a series of isomeric 3-hydroxy-17-hydroxymethylestra-1,3,5(10)-trienes, including those containing 16α,17α-annulated cyclopropane and cyclohexane ring D', were prepared using the Corey-Chaykovsky and Diels-Alder reactions followed by reduction-demethylation with diisobutylaluminum hydride and hydrogenation. Target compounds showed antiproliferative effects on MCF-7 breast cancer cells to varying degrees superior to that on MCF-10A cells, in low micromolar concentrations. The ERα-mediated luciferase reporter gene assay demonstrated that obtained steroids without an additional carbocycle or with a cyclopropane 16α,17α-annulated carbocycle are effective ERα activators.

Evaluation and Modeling of Polylactide Photodegradation under Ultraviolet Irradiation: Bio-Based Polyester Photolysis Mechanism.

In our study, we investigated the accelerated aging process of PLA under 253.7 nm UV-C irradiation with the use of the GPC, NMR, FTIR, and DSC methods and formal kinetic analysis. The results of GPC and DSC indicated a significant degree of destructive changes in the PLA macromolecules, while spectroscopic methods NMR and FTIR showed maintenance of the PLA main structural elements even after a long time of UV exposure.

Phenoxaphosphonium Mixed Ylides in Ring Expansion Reaction.

Treatment of mixed phosphonium-iodonium ylides featuring a six-membered phenoxaphosphonium fragment with aqueous tetrafluoroboronic acid induces a rearrangement, resulting in expansion of the phosphacycle and oxidation of the phosphorus atom. The target difficult-to-access dibenzo[,][1,4]oxaphosphepine oxides (3 examples) were isolated in excellent yields (up to 95%) as mixtures of stereoisomers. Hydrolysis of a five-membered mixed ylide, a dibenzophosphole derivative, predominantly preserves the phosphole system with cycle expansion occurring as a side process.

Effects of Progesterone and Selective Ligands of Membrane Progesterone Receptors in HepG2 Cells of Human Hepatocellular Carcinoma.

Progesterone exerts multiple effects in different tissues through nuclear receptors (nPRs) and through membrane receptors (mPRs) of adiponectin and progestin receptor families. The effect of progesterone on the cells through different types of receptors can vary significantly. At the same time, it affects the processes of proliferation and apoptosis in normal and tumor tissues in a dual way, stimulating proliferation and carcinogenesis in some tissues, suppressing them and stimulating cell death in others.

Solvent Swelling-Induced Halogenation of Butyl Rubber Using Polychlorinated N-Alkanes: Structure and Properties.

Traditional butyl rubber halogenation technology involves the halogenation of IIR using molecular chlorine or bromine in a solution. However, this method is technologically complex. This study investigated a novel method for the halogenation of butyl rubber to enhance its stability and resistance to thermal oxidation and aggressive media.