A significant number of important acyl-transfer reactions, such as direct acylation, ortho 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 2 ), 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. This review presents the impressive breakthroughs achieved mainly in the past decade in the development of new catalytic reactions for the formation of C−C, C−N, and C−S bonds using α-keto acids. CONTENTS 1. Introduction 7113 2. Classical Methods and Recent Advances in the Synthesis of α-Keto Acids 7115 2.1. Physical Properties of α-Keto Acids 7119 3. α-Keto Acids in Acylation Reactions 7119 3.1.

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. It was discovered that terminal chalcogen alkynes were stable for weeks if stored as a solution in hexanes.

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, the main objective of this manuscript is the preparation of compounds that combine anti-HIV and antioxidant activities. Methods: The compounds were prepared from commercially available AZT, through a copper-catalyzed Huisgen 1,3-dipolar cycloadditions exploiting the AZT azide group and chalcogenyl alkynes. Results: The chalcogenium-AZT derivatives were obtained in good yields via click chemistry. The compounds evaluated showed antioxidant and anti-HIV activity. Additionally, in vivo toxicity of this class of compounds was also evaluated and the representative nucleoside did not change the survival, behavior, biochemical hepatic, and renal markers compared to the control mice. Conclusion: Data suggest the feasibility of modifying the AZT nucleus with simple organochalcogen fragments, exploring the reactivity of the azide group via 1,3-dipolar Huisgen cycloaddition reaction. The design of these new compounds showed the initially desired biological activities.

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Sanitary conditions are essential for the production of meals and control of the presence of pathogensis important to guarantee the health of customers. The aim of this study was to evaluate the sanitary quality of food services by checking the presence of thermotolerant coliforms, Staphylococcus sp. and evaluate the toxigenic potential from the latter. The analysis was performed on water, surfaces, equipment, ready-to-eat foods, hands and nasal cavity of handlers in seven food services. The water used in food services proved to be suitable for the production of meals. Most food, equipment and surfaces showed poor sanitary conditions due to the presence of thermotolerant coliforms (60.6%). Twenty-six Staphylococcus species were identified from the 121 Staphylococcus isolates tested. Staphylococci coagulase-negative species were predominant in the foods, equipment and surfaces. In food handlers and foods, the predominant species was Staphylococcus epidermidis. Twelve different genotypes were found after PCR for the classical enterotoxin genes. The seb gene (19.8%) was the most prevalent among all Staphylococcus sp. Both coagulase-positive and coagulase-negative Staphylococci showed some of the genes of the enterotoxins tested. We conclude that there are hygienic and sanitary deficiencies in the food services analyzed. Although coagulase-positive Staphylococci have not been present in foods there is a wide dispersion of enterotoxigenic coagulase-negative Staphylococci in the environment and in the foods analyzed, indicating a risk to consumer health.

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. One of the prepared compounds, 3-phenyl-5-((phenylselanyl)­methyl)-isoxazoline, demonstrated better anti-inflammatory and antiedematogenic effects than the reference drug Celecoxib.

We described here an alternative method for the selective synthesis of mono‐ or bis‐selanyl alkenes. This method involves reactions of terminal alkynes with organylselenols, generated in situ by the reaction of diorganyl diselenides with H3PO2. These reactions proceeded efficiently at 90 °C under N2 atmosphere and are suitable to a range of diorganyl diselenides and terminal alkynes, both containing electron‐withdrawing and electron‐donating groups, affording the corresponding mono‐ or bis‐selanyl alkenes in good yields and selectively. When the reactions were performed using 5.0 equiv. of H3PO2 (0.5 mL; 50 wt% in H2O), mono‐selanyl alkenes were formed in good yields, whereas reactions carried out with additional H2O as the solvent (3.0 mL/mmol) provided bis‐selanyl alkenes in high yields. Additionally, the solvent/reducing agent system (H2O/H3PO2) could be recovered and directly reused for further reactions to synthesize bis‐selanyl alkenes.

A eficiência de remoção de coliformes em uma estação de tratamento de água convencional The efficiency of coliform removal in a conventional water treatment plant