Antiviral Activity of N1,N3-Disubstituted Uracil Derivatives against SARS-CoV-2 Variants of Concern.

Despite the widespread use of the COVID-19 vaccines, the search for effective antiviral drugs for the treatment of patients infected with SARS-CoV-2 is still relevant. Genetic variability leads to the continued circulation of new variants of concern (VOC). There is a significant decrease in the effectiveness of antibody-based therapy, which raises concerns about the development of new antiviral drugs with a high spectrum of activity against VOCs. We synthesized new analogs of uracil derivatives where uracil was substituted at the N1 and N3 positions. Antiviral activity was studied in Vero E6 cells against VOC, including currently widely circulating SARS-CoV-2 Omicron. All synthesized compounds of the panel showed a wide antiviral effect. In addition, we determined that these compounds inhibit the activity of recombinant SARS-CoV-2 RdRp. Our study suggests that these non-nucleoside uracil-based analogs may be of future use as a treatment for patients infected with circulating SARS-CoV-2 variants.

Dual-targeted anti-CMV/anti-HIV-1 heterodimers.

Despite the development of efficient anti-human immunodeficiency virus-1 (HIV-1) therapy, HIV-1 associated pathogens remain a major clinical problem. Human cytomegalovirus (CMV) is among the most common HIV-1 copathogens and one of the main causes of persistent immune activation associated with dysregulation of the immune system, cerebrovascular and cardiovascular pathologies, and premature aging. Here, we report on the development of dual-targeted drugs with activity against both HIV-1 and CMV. We synthesized seven compounds that constitute conjugates of molecules that suppress both pathogens. We showed that all seven compounds exhibit low cytotoxicity and efficiently inhibited both viruses in cell lines. Furthermore, we chose a representative compound and demonstrated that it efficiently suppressed replication of HIV-1 and CMV in human lymphoid tissue ex vivo coinfected with both viruses. Further development of such compounds may lead to the development of dual-targeted anti-CMV/HIV-1 drugs.

Scaffold hopping: exploration of acetanilide-containing uracil analogues as potential NNRTIs.

In order to identify novel nonnucleoside inhibitors of HIV-1 reverse transcriptase two series of amide-containing uracil derivatives were designed as hybrids of two scaffolds of previously reported inhibitors. Subsequent biological evaluation confirmed acetamide uracil derivatives 15a-k as selective micromolar NNRTIs with a first generation-like resistance profile. Molecular modeling of the most active compounds 15c and 15i was employed to provide insight on their inhibitory properties and direct future design efforts.

Synthesis and anti-HCMV activity of 1-[ω-(phenoxy)alkyl]uracil derivatives and analogues thereof.

HCMV infection represents a life-threatening condition for immunocompromised patients and newborn infants and novel anti-HCMV agents are clearly needed. In this regard, a series of 1-[ω-(phenoxy)alkyl]uracil derivatives were synthesized and examined for antiviral properties. Compounds 17, 20, 24 and 28 were found to exhibit highly specific and promising inhibitory activity against HCMV replication in HEL cell cultures with EC50 values within 5.5-12µM range. Further studies should be undertaken to elucidate the mechanism of action of these compounds and the structure-activity relationship for the linker region.

N1,N3-disubstituted uracils as nonnucleoside inhibitors of HIV-1 reverse transcriptase.

A series of phenyloxyethyl and cinnamyl derivatives of substituted uracils were synthesized and found to exhibit potent activity against HIV-RT and HIV replication in cell culture. In general, the cinnamyl derivatives proved superior to the phenyloxyethyl derivatives, however 1-[2-(4-methylphenoxy)ethyl]-3-(3,5-dimethylbenzyl)uracil (19) exhibited the highest activity (EC(50)=0.27 µM) thus confirming that the 3-benzyluracil fragment in the NNRTI structure can be regarded as a functional analogue of the benzophenone pharmacophore typically found in NNRTIs.

A highly facile approach to the synthesis of novel 2-(3-benzyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl)-N-phenylacetamides.

A series of heterocyclic compounds were designed as potential nonnucleoside HIV reverse transcriptase inhibitors. Although the compounds ultimately proved inactive against HIV, during the course of the synthesis, a new and highly facile method to realize N-phenylacetamides was developed. Notably, the new route avoids the intractable workups and byproducts previously reported procedures have been associated with, thereby making this approach highly attractive to adaptation with other heterocyclics.