Potent and Selective Agonists of Sphingosine 1-Phosphate 1 (S1P1): Discovery and SAR of a Novel Isoxazole Based Series

Synthesis of (4-Trifluoromethyl)isoxazoles through a Tandem Trifluoromethyloximation/Cyclization/Elimination Reaction of α,β-Unsaturated Carbonyls

We disclose a metal-free, cascade regio- and stereoselective trifluormethyloximation, cyclization, and elimination strategy with readily available α,β-unsaturated carbonyl compounds to access a wide variety of pharmaceutically potential heteroaromatics, i.e., 4-(trifluoromethyl)isoxazoles including a trifluoromethyl analogue of an anticancer agent. The transformation requires only a couple of commercially available and cheap reagents i.e., CF₃SO₂Na as the trifluoromethyl source, and ^tBuONO as an oxidant as well as a source of N and O. Notably, 5-alkenyl-4-(trifluoromethyl)isoxazoles were further synthetically diversified to a new class of biheteroaryls, i.e., 5-(3-pyrrolyl)-4-(trifluoromethyl)isoxazoles. Mechanistic studies revealed a radical pathway for the reaction.

Scalable Approach to Fluorinated Heterocycles with Sulfur Tetrafluoride (SF4)

A general approach to fluorinated (hetero)aromatic derivatives is elaborated. The key reaction is a deoxofluorination of substituted acetophenones with sulfur tetrafluoride (SF₄). In contrast to previous deoxofluorination methods, this transformation is fast, scalable (up to 70 g), and high-yielding. More than 100 novel or previously hardly accessible fluorinated heterocycles, interesting for medicinal chemistry and agrochemistry, were synthesized.

Structure-Based Design of MptpB Inhibitors That Reduce Multidrug-Resistant Mycobacterium tuberculosis Survival and Infection Burden in Vivo

Mycobacterium tuberculosis protein-tyrosine-phosphatase B (MptpB) is a secreted virulence factor that subverts antimicrobial activity in the host. We report here the structure-based design of selective MptpB inhibitors that reduce survival of multidrug-resistant tuberculosis strains in macrophages and enhance killing efficacy by first-line antibiotics. Monotherapy with an orally bioavailable MptpB inhibitor reduces infection burden in acute and chronic guinea pig models and improves the overall pathology. Our findings provide a new paradigm for tuberculosis treatment.

The synthetic and therapeutic expedition of isoxazole and its analogs

Isoxazole, constituting an important family of five-membered heterocycles with one oxygen atom and one nitrogen atom at adjacent positions is of immense importance because of its wide spectrum of biological activities and therapeutic potential. It is, therefore, of prime importance that the development of new synthetic strategies and designing of new isoxazole derivatives should be based on the most recent knowledge emerging from the latest research. This review is an endeavor to highlight the progress in the chemistry and biological activity of isoxazole derivatives which could provide a low-height flying bird's eye view of isoxazole derivatives to the medicinal chemists for the development of clinically viable drugs using this information.

Isoxazole ring as a useful scaffold in a search for new therapeutic agents

Due to its relatively easy synthesis, isoxazole ring has been as an object of interest for chemists and pharmacologists from research groups all over the world. Its chemical modifications include both connection of isoxazole with other aromatic, heteroaromatic or non aromatic rings and substitution with different alkyl groups. Thanks to their usually low cytotoxicity, isoxazole derivatives are still popular scaffolds for the development of new agents with variable biological activities, such as antimicrobial, antiviral, anticancer, anti-inflammatory, immunomodulatory, anticonvulsant or anti-diabetic properties. This review discusses the chemical structure of recently developed isoxazole derivatives with regards to their activity and potential therapeutic use.

Modulators of Sphingosine-1-phosphate Pathway Biology: Recent Advances of Sphingosine-1-phosphate Receptor 1 (S1P1) Agonists and Future Perspectives

The sphingoid base derived class of lipids (sphingolipids) is a family of interconverting molecules that play key roles in numerous structural and signaling processes. The biosynthetic pathway of the sphingolipids affords many opportunities for therapeutic intervention: targeting the ligands directly, targeting the various proteins involved in the interconversion of the ligands, or targeting the receptors that respond to the ligands. The focus of this article is on the most advanced of the sphingosine-related therapeutics, agonists of sphingosine-1-phosphate receptor 1 (S1P₁). The diverse structural classes of S1P₁ agonists will be discussed and the status of compounds of clinical relevance will be detailed. An examination of how potential safety concerns are being navigated with compounds currently under clinical evaluation is followed by a discussion of the novel methods being explored to identify next-generation S1P₁ agonists with improved safety profiles. Finally, therapeutic opportunities for sphingosine-related targets outside of S1P₁ are touched upon.