Expanding the Repertoire of ceDAF-12 Ligands for Modulation of the Steroid Endocrine System in C. Elegans.

Steroid hormones are essential for the biological processes of eukaryotic organisms. The steroid endocrine system of C. elegans, which includes dafachronic acids (DA) and the nuclear receptor ceDAF-12, provides a simple model for exploring the role of steroid hormone signaling pathways in animals.

Light-Driven Two-Step Preparation of 4-Chromanone Fused to Estrone Derivatives.

A protocol involving the irradiation of some 3-(2-alkenyl)estrone and 3-(2-alkenyl)-17-estrone derivatives under a nitrogen atmosphere in organic solvents (both hexane and MeOH) followed by base-mediated intramolecular -Michael cyclization reaction was investigated under steady-state conditions. The solvent effect and nature of the acyl group on the preparative photoreaction were studied and the multiplicity of the excited state was also demonstrated. The -regioisomers were obtained in modest to good yields.

Direct Cysteine Desulfurase Activity Determination by NMR and the Study of the Functional Role of Key Structural Elements of Human NFS1.

The mitochondrial cysteine desulfurase NFS1 is an essential PLP-dependent enzyme involved in iron-sulfur cluster assembly. The enzyme catalyzes the desulfurization of the l-Cys substrate, producing a persulfide and l-Ala as products. In this study, we set the measurement of the product l-Ala by NMR in vitro by means of H NMR spectra acquisition.

Induced selectivity in the photochemistry of estrone derivatives in sustainable and micellar environment: preparative and mechanistic studies.

In this study, we carried out preparative and mechanistic studies on the photochemical reaction of a series of 3-acylestrone derivatives in confined and sustainable micellar environment under steady-state conditions and the results were compared with those obtained in cyclohexane solution. The aim of this work is mainly focused to show whether the nature of the surfactant (cationic, neutral and anionic) leads to noticeable selectivity in the photoproduct formation. The 3-acylestrone derivatives underwent the photo-Fries rearrangement, with concomitant homolytic fragmentation of the ester group and [1;3]-acyl migration.

Photochemical Behavior of Some Estrone Aryl and Methyl Sulfonates in Solution: Preparative and Mechanistic Studies.

Direct irradiation of estrone aryl and methyl sulfonates in different organic solvents under nitrogen atmosphere was investigated under steady-state conditions. The estrone derivatives reacted efficiently through the photo-Fries rearrangement reaction involving [1;3]-sulfonyl migration providing the ortho-sulfonyl estrone derivatives and estrone as the photoproducts. In addition, estrone and 2-arylsulfonyl estrone derivatives were epimerized involving a Norrish Type-I reaction.

Photo-Fries Rearrangement of Some 3-Acylestrones in Homogeneous Media: Preparative and Mechanistic Studies.

Irradiation of a series of 3-acylestrones under a nitrogen atmosphere in cyclohexane, acetonitrile (MeCN), and methanol (MeOH) was investigated under steady-state conditions. The molecules underwent the photo-Fries rearrangement, with concomitant homolytic fragmentation of the ester group and [1;3]-acyl migration. This pathway afforded the ortho-acyl estrone derivatives, the main photoproducts, together with estrone.

One-step synthesis of N,N'-substituted 4-imidazolidinones by an isocyanide-based pseudo-five-multicomponent reaction.

A pseudo-five-multicomponent reaction involving an isocyanide, a primary amine, two molecules of formaldehyde and water is reported, which gives N,N'-substituted 4-imidazolidinones when trifluoroethanol is used as the solvent. The reaction proceeds with good yields and with a wide variety of amines and isocyanides, providing an efficient new entry to these heterocycles. A preliminary study of the reaction mechanism suggests that trifluoroethanol, although acting as the solvent, is directly involved as a reagent in the reaction pathway.

A Minimalist Approach to the Design of Complexity-Enriched Bioactive Small Molecules: Discovery of Phenanthrenoid Mimics as Antiproliferative Agents.

Over the last decades, much effort has been devoted to the design of the "ideal" library for screening, the most promising strategies being those which draw inspiration from biogenic compounds, as the aim is to add biological relevance to such libraries. On the other hand, there is a growing understanding of the role that molecular complexity plays in the discovery of new bioactive small molecules. Nevertheless, the introduction of molecular complexity must be balanced with synthetic accessibility.