Synthesis of Selenoesters via Aldol Condensation and/or Conjugate Reduction and Their Antiviral Activities

Abstract

A variety of unsaturated selenoesters (including phenolic ones) were produced in good to high yields and with high E/Z ratios using TiCl4-promoted aldol condensation between Se-phenyl selenoacetate and their respective aldehydes without aqueous workup. A representative phenolic unsaturated selenoester was applied to acylation of tyrosine methyl ester without protection of the phenolic hydroxy groups to furnish the corresponding amino acid conjugate. The conjugate reduction of the unsaturated selenoesters including phenolic ones and selenocoumarin with HSiEt3 was catalyzed by B(C6F5)3 to afford the corresponding saturated selenoesters in good to high yields. This method was also applicable to the reduction of a saturated selenoester to the corresponding O-silyl hemiselenoacetal in a high yield. Moreover, most acyclic unsaturated selenoesters were found to show good multiple antiviral activities against HIV-1, HBV, and SARS-CoV-2.

Neutralization against Omicron sublineages (BA.2/BA.5/BQ.1.1/XBB/XBB.1.5) in bivalent BNT162b2-vaccinated HCWs with or without risk factors, or following BT infection with Omicron

“…The neutralizing activity of sera from vaccinated individuals was determined by quantifying the serum-mediated viral suppression in SARS-CoV-2-infected VeroE6 TMPRSS2 cells as previously described with minor modifications 14 , 21 . In brief, each serum was serially diluted in culture medium.…”

Selenium compounds as promising antiviral agents

“…131 Unsaturated selenoesters (27,28), obtained by TiCl 4 promoted aldol condensation of Se-phenylselenoacetate (PhSeC(O)Me) with an appropriate aldehyde, have been evaluated for their antiviral activities against HIV-1, SARS-CoV-2 and hepatitis B virus (HBV) using MTT, WST and PCR assays, respectively. 132 All these compounds showed antiviral activities against these viruses with EC 50 values ranging from 1.6 to 32.2 mM. Compounds of series 27 have better activity than those of 28.…”

“…130 A number of selenoesters (26-28) exhibit antiviral activities against different viruses. 131,132 The antiviral activity of 26 was evaluated in HSV-2 infected Vero cells using real-time polymerase chain reaction. 131 Among these compounds, 26f emerged as the most potent anti-HSV-2 inhibitor as it could inhibit replication of HSV-2 at 1.25 mM concentration whereas under similar conditions acyclovir could not inhibit the replication of the virus completely in the concentration range of 1.25 to 2500 mM.…”

“…This compound also showed comparable activity against Alpha and Delta variants of SARS-CoV-2, but exhibited lower activity against other variants of concern (such as Beta, Gamma and Omicron). 132 6. Antiviral activity of selenium nanoparticles (SeNPs)…”