Expanding the Antiviral Spectrum of 3-Fluoro-2-(phosphonomethoxy)propyl Acyclic Nucleoside Phosphonates: Diamyl Aspartate Amidate Prodrugs

Abstract

Acyclic nucleosides containing a 3-fluoro-2-(phosphonomethoxy)propyl (FPMP) side chain are known to be moderately potent antihuman immunodeficiency virus (HIV) agents, while being completely devoid of antiviral activity against a wide range of DNA viruses. The derivatization of the phosphonic acid functionality of FPMPs with a diamyl aspartate phenoxyamidate group led to a novel generation of compounds that not only demonstrate drastically improved antiretroviral potency but also are characterized by an expanded spectrum of activity that also covers hepatitis B and herpes viruses. The best compound, the (S)-FPMPA amidate prodrug, exerts anti-HIV-1 activity in TZM-bl and peripheral blood mononuclear cells at low nanomolar concentrations and displays excellent potency against hepatitis B virus (HBV) and varicella-zoster virus (VZV). This prodrug is stable in acid and human plasma media, but it is efficiently processed in human liver microsomes with a half-life of 2 min. The (R) isomeric guanine derivative emerged as a selectively active anti-HIV and anti-HBV inhibitor, while being nontoxic to human hepatoblastoma cells. Notably, the pyrimidine containing prodrug (S)-Asp-FPMPC is the only congener within this series to demonstrate micromolar antihuman cytomegalovirus (HCMV) potency.

Discovery of HIV entry inhibitors via a hybrid CXCR4 and CCR5 receptor pharmacophore‐based virtual screening approach

“…The cellular toxicity of the compounds was also evaluated in TZM-bl cells. The anti-HIV replication assays in TZM-bl cells have been described previously ( Luo et al., 2017 ).…”

Expression of novel fusion antiviral proteins Ricin A Chain-Pokeweed Antiviral Proteins (RTA-PAPs) in Escherichia coli and their inhibition of protein synthesis and of hepatitis B virus in vitro

“…The anti-HBV assay was performed as previously described (Min et al, 2017) with modifications to use HepAD38 cells. ImQuest BioSciences developed a multi-marker screening assay utilizing the HepAD38 cells to detect proteins, RNA, and DNA intermediates characteristic of HBV replication.…”

Synthesis and Anti‐HIV Activity of Guanine Modified Fluorinated Acyclic Nucleoside Phosphonate Derivatives

“…[15] Therefore, the amyl aspartate phosphonoamidate and phosphonobisamidate prodrugs 23 and 24 were prepared from the parent 7deazaguanine derived FPMP nucleoside (R)-11a in moderate yields using a common procedure, which utilizes 2,2'-dithiodipyridine and triphenylphosphine as activating agents (Scheme 4). [15] Therefore, the amyl aspartate phosphonoamidate and phosphonobisamidate prodrugs 23 and 24 were prepared from the parent 7deazaguanine derived FPMP nucleoside (R)-11a in moderate yields using a common procedure, which utilizes 2,2'-dithiodipyridine and triphenylphosphine as activating agents (Scheme 4).…”

“…Recently, we and others have employed phosphonate esters of fluorohydrin precursors 2a/b (Scheme 1) as convenient chiral starting materials in the synthesis of enantiomerically pure FPMPs bearing natural nucleobases. [15,16] Likewise, 6-chloropurine (1) was reacted under Mitsunobu conditions (Ph 3 P, DIAD) with precursors 2a/b to provide compounds 3a/b along with the concomitant formation of the corresponding triphenylphosphine adducts. However, by refluxing the crude reaction mixtures for 24 h in water, the undesired adducts were successfully hydrolyzed leading to the isolation of compounds 3a/b in excellent yields over two steps.…”

“…Recently, we disclosed that the prodrug derivatization of the phosphonic acid functionality of FPMPs with a diamyl aspartate phenoxyamidate group not only produced a dramatic improvement in antiretroviral potency but also led to compounds endowed with an unprecedented spectrum of activity against DNA viruses. [15] Therefore, the amyl aspartate phosphonoamidate and phosphonobisamidate prodrugs 23 and 24 were prepared from the parent 7deazaguanine derived FPMP nucleoside (R)-11a in moderate yields using a common procedure, which utilizes 2,2'-dithiodipyridine and triphenylphosphine as activating agents (Scheme 4). Compound 23 was isolated as a diastereoisomeric mixture (ratio 1 : 1.4), which was biologically tested as such.…”