A Novel and Efficient Synthesis of Tocopheryl Quinones by Homogeneous and Heterogeneous Methyltrioxorhenium/Hydrogen Peroxide Catalytic Systems

Abstract

A convenient and efficient application of heterogeneous poly(4-vinylpyridine), poly(4-vinylpyridine N-oxide), and polystyrene/methylrhenium trioxide systems for the selective oxidation of tocopherols and tocopherol derivatives to the corresponding ortho-and para-tocopherylquinones is described. Environment friendly, easily available, and low-cost hydrogen peroxide (H 2 O 2 ) was used as the oxygen atom donor. The antiviral activity of the newly synthesized tocopherylquinones and their parent tocopherols against influenza A virus is also reported. On the basis of the biological assay, the activity of tocopherols against influenza virus is higher than that showed by the corresponding tocopherylquinones, thus suggesting, for the first time, a drawback effect of the oxidative metabolism on the antiviral activity of these compounds.

Synthesis of 2′‐Deoxy‐1′‐homo‐N‐nucleosides with Anti‐Influenza Activity by Catalytic Methyltrioxorhenium (MTO)/H2O2 Oxyfunctionalization

“…In particular, whereas 11 was synthesized in highest yield with catalysts I and II , compound 12 became the major product with III and IV (Table 2, entries 2 and 3 vs. 4 and 5). These results are in accordance with our previous data on the oxidation of δ ‐tocopherylquinone, in which case a different ratio between isomeric δ ‐tocopherylquinones was obtained depending on the nature of the PVP resin 22. Microencapsulated catalyst V showed a performance similar to that of homogeneous MTO (Table 2, entry 6).…”

“…When the reaction was repeated under similar experimental conditions but in a different solvent, such as CH 3 COOH (1.0 mL), that is, a medium able to increase the reactivity of MTO,22 a greater conversion was observed (87 %) with formation of compound 9 as the main reaction product (55 % yield) as well as a small amount of 3′,5′‐di‐ O ‐benzyl‐2′‐deoxy‐1′‐homo‐7 H ‐8‐oxoadenine N (1)‐oxide 10 , derived from a further oxidation of 9 at the C(8) position of the purine ring (Table 1, entry 2).…”

“…On entering the cell, the compound is initially converted to its monophosphate by phosphoribosyl transferase, then to its triphosphate by cellular kinases and, in this form, it inhibits the RdRp 47. Finally, a rising trend of different approaches can be observed that focus on cellular factors or pathways that are essential for viral replication,48 and that can be inhibited by natural or synthetic compounds 22. 49…”

Efficacy of Dietary Antioxidants on Broiler Oxidative Stress, Performance and Meat Quality: Science and Market

“…α-Tocopherol, a form of vitamin E, is one of the major lipid-soluble antioxidant of the tocopherol family and it cannot be synthesised by animal cells (Saladino et al, 2008). Dietary vitamin E supplementation has been shown to protect cells from oxidative stress mediated by oxidised oil and improve the oxidative stability of meat Lin et al, 1989;Wang et al, 1997;Asghar et al, 1999).…”

Lipophilic Compounds from the Femoral Gland Secretions of Male Hungarian Green Lizards, Lacerta viridis

“…To our knowledge this compound has not been described as a natural product, although it can be synthesized in the laboratory, for example by treating α-tocopherol with diazomethane (Saladino et al, 2008). However, the simple analytical procedures that we used and the recurrent appearance of this compound in all samples of several lizard species, and in different years, made very unlikely that this compound was an artifact of our analyses.…”