5-Alkyl-2-(alkylthio)-6-(2,6-dihalophenylmethyl)-3, 4-dihydropyrimidin-4(3H)-ones: novel potent and selective dihydro-alkoxy-benzyl-oxopyrimidine derivatives

N-Heterocycles as Promising Antiviral Agents: A Comprehensive Overview

Viruses are a real threat to every organism at any stage of life leading to extensive infections and casualties. N-heterocycles can affect the viral life cycle at many points, including viral entrance into host cells, viral genome replication, and the production of novel viral species. Certain N-heterocycles can also stimulate the host's immune system, producing antiviral cytokines and chemokines that can stop the reproduction of viruses. This review focused on recent five- or six-membered synthetic N-heterocyclic molecules showing antiviral activity through SAR analyses. The review will assist in identifying robust scaffolds that might be utilized to create effective antiviral drugs with either no or few side effects.

Development of novel S-N3-DABO derivatives as potent non-nucleoside reverse transcriptase inhibitors with improved potency and selectivity

Following on our initial discovery of S-CN-DABOs as non-nucleoside reverse transcriptase inhibitors (NNRTIs), a series of novel S-N₃-DABO derivatives F1-F31 were developed by substituting the cyano group of S-CN-DABOs with azide group. Some of these compounds were conferred significantly increased potency against wild-type HIV-1 and clinically observed mutant strains. Remarkably, the best compound F10 exerted a 7-fold improvement in potency (EC₅₀ = 0.053 μM) and 12.5-fold higher selectivity (SI = 6818) in MT-4 cells infected with wild-type HIV-1, compared to that of the parent compound B1 (EC₅₀ = 370 nM, SI = 547). The anti-HIV-1 activity of F10 against the tested mutant strains was prominently enhanced. For wild-type reverse transcriptase, it was approximately 19-fold more potent (IC₅₀ = 0.080 μM) than B1 (IC₅₀ = 1.51 μM). It was not found that this analog had significant inhibition of hERG, CYP, and acute toxicity after a single dose of F10 (1.0 g/kg).

An Epigenetic LINE-1-Based Mechanism in Cancer

In the last fifty years, large efforts have been deployed in basic research, clinical oncology, and clinical trials, yielding an enormous amount of information regarding the molecular mechanisms of cancer and the design of effective therapies. The knowledge that has accumulated underpins the complexity, multifactoriality, and heterogeneity of cancer, disclosing novel landscapes in cancer biology with a key role of genome plasticity. Here, we propose that cancer onset and progression are determined by a stress-responsive epigenetic mechanism, resulting from the convergence of upregulation of LINE-1 (long interspersed nuclear element 1), the largest family of human retrotransposons, genome damage, nuclear lamina fragmentation, chromatin remodeling, genome reprogramming, and autophagy activation. The upregulated expression of LINE-1 retrotransposons and their protein products plays a key role in these processes, yielding an increased plasticity of the nuclear architecture with the ensuing reprogramming of global gene expression, including the reactivation of embryonic transcription profiles. Cancer phenotypes would thus emerge as a consequence of the unscheduled reactivation of embryonic gene expression patterns in an inappropriate context, triggering de-differentiation and aberrant proliferation in differentiated cells. Depending on the intensity of the stressing stimuli and the level of LINE-1 response, diverse degrees of malignity would be generated.

Development of non-nucleoside reverse transcriptase inhibitors (NNRTIs): our past twenty years

Human immunodeficiency virus (HIV) is the primary infectious agent of acquired immunodeficiency syndrome (AIDS), and non-nucleoside reverse transcriptase inhibitors (NNRTIs) are the cornerstone of HIV treatment. In the last 20 years, our medicinal chemistry group has made great strides in developing several distinct novel NNRTIs, including 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT), thio-dihydro-alkoxy-benzyl-oxopyrimidine (S-DABO), diaryltriazine (DATA), diarylpyrimidine (DAPY) analogues, and their hybrid derivatives. Application of integrated modern medicinal strategies, including structure-based drug design, fragment-based optimization, scaffold/fragment hopping, molecular/fragment hybridization, and bioisosterism, led to the development of several highly potent analogues for further evaluations. In this paper, we review the development of NNRTIs in the last two decades using the above optimization strategies, including their structure–activity relationships, molecular modeling, and their binding modes with HIV-1 reverse transcriptase (RT). Future directions and perspectives on the design and associated challenges are also discussed.

Synthesis and biological evaluation of a series of 2-(((5-akly/aryl-1H-pyrazol-3-yl)methyl)thio)-5-alkyl-6-(cyclohexylmethyl)-pyrimidin-4(3H)-ones as potential HIV-1 inhibitors

A series of 2-(((5-akly/aryl-1H-pyrazol-3-yl)methyl)thio)-5-alkyl-6-(cyclohexylmethyl)-pyrimidin-4(3H)-ones were synthesized and their anti-HIV-1 activities were evaluated. Most of these compounds were highly active against wild-type (WT) HIV-1 strain (IIIB) with EC₅₀ values in the range of 0.0038–0.4759 μmol/L. Among those compounds, I-11 had an EC₅₀ value of 3.8 nmol/L and SI (selectivity index) of up to 25,468 indicating excellent activity against WT HIV-1. In vitro anti-HIV-1 activity and resistance profile studies suggested that compounds I-11 and I-12 displayed potential anti-HIV-1 activity against laboratory adapted strains and primary isolated strains including different subtypes and tropism strains (EC₅₀s range from 4.3 to 63.6 nmol/L and 18.9–219.3 nmol/L, respectively). On the other hand, it was observed that those two compounds were less effective with EC₅₀ values of 2.77 and 4.87 μmol/L for HIV-1A₁₇ (K103N + Y181C). The activity against reverse transcriptase (RT) was also evaluated for those compounds. Both I-11 and I-12 obtained sub-micromolar IC₅₀ values showing their potential in RT inhibition. The pharmacokinetics examination in rats indicated that compound I-11 has acceptable pharmacokinetic properties and bioavailability. Preliminary structure–activity relationships and molecular modeling studies were also discussed.

Reverse transcriptase inhibitors promote the remodelling of nuclear architecture and induce autophagy in prostate cancer cells

Emerging data indicate that the reverse transcriptase (RT) protein encoded by LINE-1 transposable elements is a promising cancer target. Nonnucleoside RT inhibitors, e.g. efavirenz (EFV) and SPV122.2, reduce proliferation and promote differentiation of cancer cells, concomitant with a global reprogramming of the transcription profile. Both inhibitors have therapeutic anticancer efficacy in animal models. Here we have sought to clarify the mechanisms of RT inhibitors in cancer cells. We report that exposure of PC3 metastatic prostate carcinoma cells to both RT inhibitors results in decreased proliferation, and concomitantly induces genome damage. This is associated with rearrangements of the nuclear architecture, particularly at peripheral chromatin, disruption of the nuclear lamina, and budding of micronuclei. These changes are reversible upon discontinuation of the RT-inhibitory treatment, with reconsititution of the lamina and resumption of the cancer cell original features. The use of pharmacological autophagy inhibitors proves that autophagy is largely responsible for the antiproliferative effect of RT inhibitors. These alterations are not induced in non-cancer cell lines exposed to RT inhibitors. These data provide novel insight in the molecular pathways targeted by RT inhibitors in cancer cells.

Synthesis of Novel Uracil Non-Nucleosides Analogues of 3,4-Dihydro-2-Alkylthio-6-benzyl-4-oxopyrimidines and 6-benzyl-1-ethoxymethyl-5-isopropyluracil

A series of new uracil non-nucleosides analogues of S-DABO's was synthesised by reaction of 5-alkyl-6-( p-chlorobenzyl)-2-thiouracils with chloroethyl dialkylamine hydrochloride, N-(2-chloroethyl)-pyrrolidine hydrochloride, N-(2-chloroethyl)-piperidine hydrochloride or appropriate haloethers. Novel emivirine analogues were synthesised by silylation of 5-alkyl-6-( p-chlorobenzyl)uracils and treatment with bromomethyl methyl ether, chloromethyl ethyl ether or benzyl chloromethyl ether. Compounds 6-( p-chlorobenzyl)-5-ethyl-1-ethyloxymethyluracil (9e) and 1-benzyloxymethyl-6-(4-chlorobenzyl)-5-ethyluracil (9f) showed activity against wild-type HIV-1 strain III B in MT-4 cells.

Eurotiumins A⁻E, Five New Alkaloids from the Marine-Derived Fungus Eurotium sp. SCSIO F452

Three new prenylated indole 2,5-diketopiperazine alkaloids (1–3) with nine known ones (5–13), one new indole alkaloid (4), and one new bis-benzyl pyrimidine derivative (14) were isolated and characterized from the marine-derived fungus Eurotium sp. SCSIO F452. 1 and 2, occurring as a pair of diastereomers, both presented a hexahydropyrrolo[2,3-b]indole skeleton. Their chemical structures, including absolute configurations, were elucidated by 1D and 2D NMR, HRESIMS, quantum chemical calculations of electronic circular dichroism, and single crystal X-ray diffraction experiments. Most isolated compounds were screened for antioxidative potency. Compounds 3, 5, 6, 7, 9, 10, and 12 showed significant radical scavenging activities against DPPH with IC₅₀ values of 13, 19, 4, 3, 24, 13, and 18 µM, respectively. Five new compounds were evaluated for cytotoxic activities.

Novel HIV-1 Non-nucleoside Reverse Transcriptase Inhibitors: A Combinatorial Approach

Highly active antiretroviral therapy (HAART) is one of the most effective means for fighting against HIV-infection. HAART primarily targets HIV-1 reverse transcriptase (RT), and 14 of 28 compounds approved by the FDA as anti-HIV drugs act on this enzyme. HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) hold a special place among HIV RT inhibitors owing to their high specificity and unique mode of action. Nonetheless, these drugs show a tendency to decrease their efficacy due to high HIV-1 variability and formation of resistant virus strains tolerant to clinically applied HIV NNRTIs. A combinatorial approach based on varying substituents within various fragments of the parent molecule that results in development of highly potent compounds is one of the approaches aimed at designing novel HIV NNRTIs. Generation of HIV NNRTIs based on pyrimidine derivatives explicitly exemplifies this approach, which is discussed in this review.

3D-QSAR analysis of a series of S-DABO derivatives as anti-HIV agents by CoMFA and CoMSIA

In this study, we retrieved a series of 59 dihydroalkylthio-benzyloxopyrimidine (S-DABO) derivatives, which is a class of highly potent HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) reported from published articles, and analysed them with comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). Statistically significant three-dimensional quantitative structure-activity relationship (3D-QSAR) models by CoMFA and CoMSIA were derived from a training set of 46 compounds on the basis of the rigid body alignment. Further, the predictive ability of the QSAR models was validated by a test set of 13 compounds. Based on the information derived from CoMFA and CoMSIA contour maps, we have identified some steric and electrostatic features for improving the activities of these inhibitors, and we validated the 3D-QSAR results by a molecular docking method. On the basis of the obtained results, we designed a new series of S-DABO derivatives with high activities. Therefore, this study could be utilized to design more potent S-DABO analogues as anti-HIV agents.

Synthesis and Antiviral Activity of 1,3-Disubstituted Uracils against HIV-1 and HCMV

The development of new non-nucleoside reverse transcriptase inhibitors (NNRTIs) is an efficient strategy for finding new therapeutic agents against human immunodeficiency virus (HIV). A large number of 6-substituted uracil derivatives have been prepared in order to explore new NNRTIs. However, there are few approaches to anti-HIV agents from 1,3-disubstituted uracil derivatives. Therefore, we tried to prepare several 1,3-disubstituted uracils, which were easily obtainable from uracil by preparation under alkali and Mitsunobu conditions, and examined their antiviral activity against HIV-1 and human cytomegalovirus (HCMV). We found that 1-benzyl-3-(3,5-dimethylbenzyl)uracil and 1-cyanomethyl-3-(3,5-dimethylbenzyl)-4-thiouracil showed powerful inhibition against HCMV and HIV-1, respectively.

Synthesis and biological evaluation of 2-thioxopyrimidin-4(1H)-one derivatives as potential non-nucleoside HIV-1 reverse transcriptase inhibitors

A series of new 5-allyl-6-benzylpyrimidin-4(3H)-ones bearing different substituents at the C-2 position of the pyrimidine core have been synthesized and evaluated for their in vitro activities against human immunodeficiency virus type 1 (HIV-1) in the human T-lymphotropic type (MT-4 cell cultures). The majority of the title compounds showed moderate to good activities against HIV-1. Amongst them, 5-allyl-6-benzyl-2-(3-hydroxypropylthio)pyrimidin-4(3H)-one analogue 11c exhibited the most potent anti-HIV-1 activity (IC₅₀ 0.32 µM). The biological testing results clearly indicated that the substitution at C-2 position of the pyrimidine ring could increase the anti-HIV-1 reverse transcriptase (RT) activity.

Significance and biological importance of pyrimidine in the microbial world

Microbes are unique creatures that adapt to varying lifestyles and environment resistance in extreme or adverse conditions. The genetic architecture of microbe may bear a significant signature not only in the sequences position, but also in the lifestyle to which it is adapted. It becomes a challenge for the society to find new chemical entities which can treat microbial infections. The present review aims to focus on account of important chemical moiety, that is, pyrimidine and its various derivatives as antimicrobial agents. In the current studies we represent more than 200 pyrimidines as antimicrobial agents with different mono-, di-, tri-, and tetrasubstituted classes along with in vitro antimicrobial activities of pyrimidines derivatives which can facilitate the development of more potent and effective antimicrobial agents.

DB-02, a C-6-cyclohexylmethyl substituted pyrimidinone HIV-1 reverse transcriptase inhibitor with nanomolar activity, displays an improved sensitivity against K103N or Y181C than S-DABOs

6-(cyclohexylmethyl)-5-ethyl-2-((2-oxo-2-phenylethyl)thio)pyrimidin-4(3H)-one (DB-02) is a member of the newly reported synthetic anti-HIV-1 compounds dihydro-aryl/alkylsulfanyl-cyclohexylmethyl-oxopyrimidines, S-DACOs. In vitro anti-HIV-1 activity and resistance profile studies have suggested that DB-02 has very low cytotoxicity (CC₅₀>1mM) to cell lines and peripheral blood mononuclear cells (PBMCs). It displays potent anti-HIV-1 activity against laboratory adapted strains and primary isolated strains including different subtypes and tropism strains (EC₅₀s range from 2.40 to 41.8 nM). Studies on site-directed mutagenesis, genotypic resistance profiles revealed that V106A was the major resistance contributor for the compound. Molecular docking analysis showed that DB-02 located in the hydrophobic pocket with interactions of Lys101, Val106, Leu234, His235. DB-02 also showed non-antagonistic effects to four approved antiretroviral drugs. All studies indicated that DB-02 would be a potential NNRTI with low cytotoxicity and improved activity.

Towards new C6-rigid S-DABO HIV-1 reverse transcriptase inhibitors: synthesis, biological investigation and molecular modeling studies

A series of C6-rigid S-DABO analogs characterized by a substituted benzoyl group at C6 position of the pyrimidine ring has been synthesized and biological evaluation as NNRTIs against wild-type HIV-1 strain IIIB, double RT mutant (K103N+Y181C) strain RES056 as well as HIV-2 strain ROD in MT-4 cell cultures. Most of the compounds exhibited moderate antiviral activities. Among them, compound 7q displayed the highest anti-HIV-1 activity with an EC50 value of 0.26μM and a selectivity index (SI) of 541. The preliminary structure-activity relationship (SAR) of these new S-DABOs was investigated, the target RT was confirmed and docking study was performed.

Residue-ligand interaction energy (ReLIE) on a receptor-dependent 3D-QSAR analysis of S- and NH-DABOs as non-nucleoside reverse transcriptase inhibitors

A series of 74 dihydroalkoxybenzyloxopyrimidines (DABOs), a class of highly potent non-nucleoside reverse transcriptase inhibitors (NNRTIs), was retrieved from the literature and studied by receptor-dependent (RD) three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis to derive RD-3D-QSAR models. The descriptors in this new method are the steric and electrostatic interaction energies of the protein-ligand complexes (per residue) simulated by molecular dynamics, an approach named Residue-Ligand Interaction Energy (ReLIE). This study was performed using a training set of 59 compounds and the MKC-442/RT complex structure as reference. The ReLIE-3D-QSAR models were constructed and evaluated by genetic algorithm (GA) and partial least squares (PLS). In the best equations, at least one term is related to one of the amino acid residues of the p51 subunit: Asn136, Asn137, Glu138, and Thr139. This fact implies the importance of interchain interaction (p66-p51) in the equations that best describe the structure-activity relationship for this class of compounds. The best equation shows q² = 0.660, SE(cv) = 0.500, r² = 0.930, and SEE = 0.226. The external predictive ability of this best model was evaluated using a test set of 15 compounds. In order to design more potent DABO analogues as anti-HIV/AIDS agents, substituents capable of interactions with residues like Ile94, Lys101, Tyr181, and Tyr188 should be selected. Also, given the importance of the conserved Asn136, this residue could become an attractive target for the design of novel NNRTIs with improved potency and increased ability to avoid the development of drug-resistant viruses.

Design, synthesis, and biological evaluation of 1-[(2-benzyloxyl/alkoxyl)methyl]-5-halo-6-aryluracils as potent HIV-1 non-nucleoside reverse transcriptase inhibitors with an improved drug resistance profile

Because the emergence of drug-resistant mutants has limited the efficacy of non-nucleoside reverse transcriptase inhibitors (NNRTIs), it is essential to develop new antivirals with better drug resistance and pharmacokinetic profiles. Here we designed and synthesized a series of 1-[(2-benzyloxyl/alkoxyl)methyl]-5-halo-6-aryluracils, the HEPT analogues, and evaluated their biological activity using nevirapine and 18 (TNK-651) as reference compounds. Most of these compounds, especially 6b, 7b, 9b, 11b, and 7c, exhibited highly potent anti-HIV-1 activity against both wild-type and NNRTI-resistant HIV-1 strains. Compound 7b, which had the highest selectivity index (SI = 38 215), is more potent than nevirapine and 18. These results suggest that the introduction of a halogen at the C-5 position may contribute to the effectiveness of these compounds against RTI-resistant variants. In addition, meta substituents on the C-6 aromatic moiety could significantly enhance activity against NNRTI-resistant HIV-1 strains. These compounds can be further developed as next-generation NNRTIs with an improved antiviral efficacy and drug-resistance profile.

Discovery of dihydro-alkyloxy-benzyl-oxopyrimidines as promising anti-influenza virus agents

A series of novel dihydro-alkyloxy-benzyl-oxopyrimidine derivatives were synthesized and evaluated for their activity against influenza virus in Madin-Darby canine kidney cells. Four dihydro-alkyloxy-benzyl-oxopyrimidine derivatives (4a1, 4a2, 4a3, and 4d1) showed potent activity against influenza virus. Among them, compound 4a3 was the most promising lead with broad activity against influenza A (antiviral EC(50) values of 9 and 18 μm for the A/H1N1 and A/H3N2 subtype, respectively) and influenza B viruses (EC(50) : 33 μm). The antiviral mechanism of action of these dihydro-alkyloxy-benzyl-oxopyrimidine derivatives must be quite different from that of the currently approved anti-influenza virus drugs that target the viral M2 or neuraminidase proteins. The dihydro-alkyloxy-benzyl-oxopyrimidine derivatives represent a new avenue for further optimization and development of novel anti-influenza virus agents.

Synthesis and structure-activity relationship of novel diarylpyrimidines with hydromethyl linker (CH(OH)-DAPYs) as HIV-1 NNRTIs

A series of 26 diarylpyrimidines, characterized by the hydroxymethyl linker between the left wing benzene ring and the central pyrimidine, were synthesized and evaluated for in vitro anti-HIV activity. Most of the compounds exhibited moderate to excellent activities against wild-type HIV-1. Among them, compound 10i, bearing a chlorine atom at the C-2 position of left benzene ring, was the best congener and showed potent activity against wild-type HIV-1 with an EC(50) value of 0.009 μM, along with moderate activities against the double RT mutant (K103N+Y181C) HIV-1(III(B)) and HIV-2(ROD) with an EC(50) value of 6.2 and 6.0 μM, respectively. The preliminary structure-activity relationship (SAR) of this new series of compounds was also investigated.

Diarylpyrimidine-dihydrobenzyloxopyrimidine hybrids: new, wide-spectrum anti-HIV-1 agents active at (sub)-nanomolar level

Here, we describe a novel small series of non-nucleoside reverse transcriptase inhibitors (NNRTIs) that combine peculiar structural features of diarylpyrimidines (DAPYs) and dihydro-alkoxy-benzyl-oxopyrimidines (DABOs). These DAPY-DABO hybrids (1-4) showed a characteristic SAR profile and a nanomolar anti-HIV-1 activity at both enzymatic and cellular level. In particular, the two compounds 4d and 2d, with a (sub)nanomolar activity against wild-type and clinically relevant HIV-1 mutant strains, were selected as lead compounds for next optimization studies.

Synthesis and biological evaluation of novel dihydro-aryl/alkylsulfanyl-cyclohexylmethyl-oxopyrimidines (S-DACOs) as high active anti-HIV agents

A novel dihydro-aryl/alkylsulfanyl-cyclohexylmethyl-oxopyrimidines (S-DACOs) combinatory library was synthesized and evaluated with C8166 cells infected by the HIV-1(IIIB) in vitro, using Nevirapine (NVP) and Zidovudine (AZT) as positive control. The anti-HIV screening results revealed that C-6-cyclohexylmethyl substituted pyrimidinones possessed higher selective index than its 6-arylmethyl counterparts. Compounds 1g, 1c, 1e and 1b showed potent anti-HIV activities with EC(50) values of 0.012, 0.025, 0.088 and 0.162nM, respectively.

Looking for an active conformation of the future HIV type-1 non-nucleoside reverse transcriptase inhibitors

HIV type-1 (HIV-1) non-nucleoside reverse transcriptase inhibitors (NNRTIs) are key drugs of highly active antiretroviral therapy (HAART) in the clinical management of AIDS/HIV infection. NNRTI-based HAART regimes effectively suppress viral reproduction, are not cytotoxic and show favourable pharmacokinetic properties. First-generation NNRTIs suffer the rapid selection of viral variants, hampering the binding of inhibitors into the reverse transcriptase (RT) non-nucleoside binding site (NNBS). Efforts to improve these first inhibitors led to the discovery of second-generation NNRTIs that proved to be effective against the drug-resistant mutant HIV-1 strains. The success of such agents launched a new season of NNRTI design and synthesis. This paper reviews the characteristics of second-generation NNRTIs, including etravirine, rilpivirine, RDEA-806, UK-453061, BIRL 355 BS, IDX 899, MK-4965 and HBY 097. In particular, the binding modes of these inhibitors into the NNBS of the HIV-1 RT and the most clinically relevant mutant RTs are analysed and discussed.

Synthesis, antimicrobial, and anti-inflammatory activities of novel 5-(1-adamantyl)-4-arylideneamino-3-mercapto-1,2,4-triazoles and related derivatives

The reaction of 5-(1-adamantyl)-4-amino-3-mercapto-1,2,4-triazole (5) with various aromatic aldehydes in ethanol or acetic acid yielded the corresponding 4-arylideneamino derivatives 6a–v. Treatment of the 4-(2,6-difluoro- and dichlorobenzylideneamino) derivatives 6o and 6q with 1-substituted piperazines, and formaldehyde solution in ethanol afforded good yields of the corresponding 5-(1-adamantyl)-4-(2,6-dihalobenzylideneamino-2-(4-substituted-1-piperazinylmethyl)-1,2,4-triazoline-3-thiones 7a–p. 5-(1-Adamantyl)-4-arylideneamino-2-(4-ethoxycarbonyl-1-piperidylmethyl)-1,2,4-triazoline-3-thiones 8a–n, were similarly prepared via the reaction of the corresponding arylideneamino derivative with ethyl 4-piperidinecarboxylate and formaldehyde solution in ethanol. Compounds 6a–v, 7a–p and 8a–n were tested for in vitro activities against a panel of Gram-positive and Gram-negative bacteria and the yeast-like pathogenic fungus Candida albicans. Several derivatives showed good or moderate activities, particularly against the tested Gram-positive bacteria. In addition, the in vivo anti-inflammatory activity of 21 compounds was determined using the carrageenan-induced paw oedema method in rats. Compounds 7d, 7g, 7i, 7j, 7l, 8c, 8e and 8l showed good or moderate dose-dependent activity in this area.

Synthesis and biological evaluation of novel C5 halogen-functionalized S-DABO as potent HIV-1 non-nucleoside reverse transcriptase inhibitors

A series of novel S-DABO analogues (4a1-5a12) have been synthesized by an efficient method and evaluated as inhibitors of human immunodeficiency virus type-1 (HIV-1). The biological testing results clearly indicated that the substitution of halogen at the C5 position of pyrimidine ring could increase the anti-HIV-1 RT activity. The most active compounds showed activity in the low micromole range with IC(50) values (IC(50) 0.18-3.03 microM) comparable to nevirapine (IC(50) 4.12 microM). The docking showed that a new halogen bond was formed between halogen and carbonyl of TYR188 in the HIV-I RT.

Characterization of sirtuin inhibitors in nematodes expressing a muscular dystrophy protein reveals muscle cell and behavioral protection by specific sirtinol analogues

In oculopharyngeal muscular dystrophy (OPMD), a disease caused by polyalanine expansion in the nuclear protein PABPN1, the genetic inhibition of sirtuins and treatment with sirtuin inhibitors protect from mutant PABPN1 toxicity in transgenic nematodes. Here, we tested the SIRT1/2 inhibitors 1-12, bearing different degrees of inhibition, for protection against mutant PABPN1 toxicity in Caenorhabditis elegans. Compounds 2, 4, and 11 were the most efficient, revealing a potential therapeutic application for muscle cell protection in OPMD.

Microwave-assisted synthesis of substituted 2-(benzylthio)imidazo[1,2a]pyrimidin-5-ones

A microwave-assisted solid-phase synthesis of 2-(benzylthio)imidazo[1,2a]pyrimidin-5-ones has been developed. Using microwave irradiation, the reaction time was significantly reduced from a few days to 80 min. A representative set of 10 2-(benzylthio)-6,7-substituted-imidazo[1,2a]pyrimidin-5-ones was prepared. These compounds were subsequently N-alkylated and formylated in good yields.