Stereoselective Electrochemical Synthesis of E-Tetrasubstituted Haloalkenyl Chalcogenides.

Herein, we describe an electrochemical method for the synthesis of haloalkenyl chalcogenides from internal alkynes using hydrobromic and hydrochloric acids as halogenating agents, with the sole byproduct being hydrogen gas. This e-halochalcogenation protocol generates electrophilic chalcogenium species under mild conditions in a simple, undivided cell setup, enabling the synthesis of 25 examples of chloro- and bromovinyl selenides and sulfides with yields ranging from 10 % to 94 %, predominantly as the E-isomer. The synthetic utility of the halovinyl chalcogenides was demonstrated through various transformations, yielding densely functionalized tetra-substituted olefins.

Gold Meets Selenium: Dual Activation of Selenium-Containing Propargyl Alcohols Towards the Synthesis of 2H-Chromenes and Mechanistic Insights.

Herein, we report the synthesis of seleno-substituted chromenes from selenoalkynes and phenols. In this cascade reaction, the applied gold catalyst not only functions as a π-acid, but also as a Lewis acid, enabling the propargylic substitution in the first step to connect the oxygen carbon bond. Under the optimal reaction condition a total of 26 chromenes were accessible by this modular access.

PyrAtes: Modular Organic Salts with Large Stokes Shifts for Fluo-rescence Microscopy.

The deployment of small-molecule fluorescent agents plays an ever-growing role in medicine and drug development. Herein, we complement the portfolio of powerful fluorophores, reporting the serendipitous discovery and development of a novel class with an imidazo[1,2-a]pyridinium triflate core, which we term PyrAtes. These fluorophores are synthesized in a single step from readily available materials (>60 examples) and display Stokes shifts as large as 240 nm, while also reaching NIR-I emissions at λ as long as 720 nm.

Synthesis and structural properties of -diselenopyrazines.

Recently, dithienopyrazines have emerged as promising building blocks in the field of materials science, showcasing their potential as hole-transport materials in organic electronic devices. Herein, we report the synthesis of its heavier analogues, the diselenopyrazines, along with an analysis of their optoelectronic and structural properties. In the acquired crystal structures, interesting molecular packing motifs suitable for potential device fabrication were observed.

Chalcogenium-AZT Derivatives: A Plausible Strategy To Tackle The RT-Inhibitors-Related Oxidative Stress While Maintaining Their Anti- HIV Properties.

Background: This study presents the synthesis and multi-target behavior of the new 5'-hydroxy-3-(chalcogenyl-triazoyl)-thymidine and the biological evaluation of these compounds as antioxidant and anti-HIV agents.

Objective: Antiretroviral therapy induces oxidative stress. Based on this, this manuscript's main objective is to prepare compounds that combine anti-HIV and antioxidant activities.

Synthesis of 4-Arylselanyl-1-1,2,3-triazoles from Selenium-Containing Carbinols.

In this work, we present a simple way to achieve 4-arylselanyl-1-1,2,3-triazoles from selenium-containing carbinols in a one-pot strategy. The selenium-containing carbinols were used as starting materials to produce a range of selanyl-triazoles in moderate to good yields, including a quinoline and Zidovudine derivatives. One-pot protocols are crucial to the current concerns about waste production and solvent consumption, avoiding the isolation and purification steps of the reactive terminal selanylalkynes.

Synthesis of Isoxazolines by the Electrophilic Chalcogenation of β,γ-Unsaturated Oximes: Fishing Novel Anti-Inflammatory Agents.

Herein, we describe a new strategy to prepare chalcogen-functionalized isoxazolines. The strategy involves the reaction of β,γ-unsaturated oximes with electrophilic selenium and tellurium species, affording 19 new selenium- and tellurium-containing isoxazolines in good yields after 1 h at room temperature. The method was efficiently extended to the synthesis of 5 new (bis)isoxazoline ditellurides.

α-Keto Acids: Acylating Agents in Organic Synthesis.

A significant number of important acyl-transfer reactions, such as direct acylation, acylation, heteroatom acylation, and a diversity of cyclization reactions using the title compound as a key starting material, have been described in recent years. Just like a sleeping beauty, α-oxocarboxylic acids were awakened from a 17-year sleep to become important reagents in classical and new acylation reactions. The greener characteristic of the coproduct formed in reactions using α-keto acid (only CO), together with its versatility as a building block in catalytic organic synthesis, accredit it as a candidate to green acylating agent, an alternative to acyl chloride, and other acyl-transfer reagents.

Synthesis of Terminal Ethynyl Aryl Selenides and Sulfides Based on the Retro-Favorskii Reaction of Hydroxypropargyl Precursors.

The retro-Favorskii reaction is an excellent way to achieve terminal alkynes. Methodologies that connect the synthesis of terminal alkynes and organochalcogen motifs are important for the construction of novel compounds. Fourteen new terminal alkynes containing either C -S or C -Se bonds were selectively prepared through the retro-Favorskii reaction from the respective carbinol precursors.