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

Synthesis of 1-[ω-(Bromophenoxy)alkyl]-3-naphthalenylmethyl Derivatives of Uracil and Their Analogues As Probable Inhibitors of Human Cytomegalovirus Replication

The synthesis of a new series of 1-[ω-(bromophenoxy)alkyl]-uracil derivatives containing in position 3 naphthalen-1-yl-, naphthalen-2-yl-, 1-bromonaphthalen-2-ylmethyl, benzyl, and anthracene 9-methyl fragment was carried out. The antiviral properties of the synthesized compounds were studied against human cytomegalovirus. It was found that the compound that contained a bridge of five methylene groups has a high anti-cytomegalovirus activity in vitro.

Design, Synthesis, Anti-Varicella-Zoster and Antimicrobial Activity of (Isoxazolidin-3-yl)Phosphonate Conjugates of N1-Functionalised Quinazoline-2,4-Diones

Dipolar cycloaddition of the N-substituted C-(diethoxyphosphonyl)nitrones with N³-allyl-N¹-benzylquinazoline-2,4-diones produced mixtures of diastereoisomeric 3-(diethoxyphosphonyl)isoxazolidines with a N¹-benzylquinazoline-2,4-dione unit at C5. The obtained compounds were assessed for antiviral and antibacterial activities. Several compounds showed moderate inhibitory activities against VZV with EC₅₀ values in the range of 12.63-58.48 µM. A mixture of isoxazolidines cis-20c/trans-20c (6:94) was found to be the most active against B. cereus PCM 1948, showing an MIC value 0.625 mg/mL, and also was not mutagenic up to this concentration.

Analogues of Pyrimidine Nucleosides as Mycobacteria Growth Inhibitors

Tuberculosis (TB) is the oldest human infection disease. Mortality from TB significantly decreased in the 20th century, because of vaccination and the widespread use of antibiotics. However, about a third of the world’s population is currently infected with Mycobacterium tuberculosis (Mtb) and the death rate from TB is about 1.4–2 million people per year. In the second half of the 20th century, new extensively multidrug-resistant strains of Mtb were identified, which are steadily increasing among TB patients. Therefore, there is an urgent need to develop new anti-TB drugs, which remains one of the priorities of pharmacology and medicinal chemistry. The antimycobacterial activity of nucleoside derivatives and analogues was revealed not so long ago, and a lot of studies on their antibacterial properties have been published. Despite the fact that there are no clinically used drugs based on nucleoside analogues, some progress has been made in this area. This review summarizes current research in the field of the design and study of inhibitors of mycobacteria, primarily Mtb.

Synthesis of 1-[ω-(Bromophenoxy)alkyl]-3-Naphthalenylmethyl Uracil Derivatives and Their Analogues as Probable Inhibitors of Human Cytomegalovirus Replication

A new series of 1-[ω-(bromophenoxy)alkyl]-uracil derivatives containing naphthalen-1-yl, naphthalen-2-yl, 1-bromonaphthalen-2-ylmethyl, benzyl, and anthracene-9-ylmethyl fragments in position 3 of uracil residue was synthesized. The antiviral properties of the synthesized compounds against human cytomegalovirus were studied. It was found that the compound containing a bridge consisting of five methylene groups exhibits a high anti-cytomegalovirus activity in vitro.

Novel Thiazolidin-4-ones as Potential Non-nucleoside Inhibitors of HIV-1 Reverse Transcriptase

BACKGROUND

HIV is the causative agent of Acquired Immunodeficiency Syndrome (AIDS), an infectious disease with increasing incidence worldwide. Non-nucleoside reverse transcriptase inhibitors (NNRTIs) play an important role in the treatment of AIDS. Although, many compounds are already being used as anti-HIV drugs, research for the development of new inhibitors continues as the virus develops resistant strains.

METHODS

The best features of available NNRTIs were taken into account for the design of novel inhibitors. PASS (Prediction of activity spectra for substances) prediction program and molecular docking studies for the selection of designed compounds were used for the synthesis. Compounds were synthesized using conventional and microwave irradiation methods and HIV RT inhibitory action was evaluated by colorimetric photometric immunoassay.

RESULTS

The evaluation of HIV-1 RT inhibitory activity revealed that seven compounds have significantly lower ΙC50 values than nevirapine (0.3 μΜ). It was observed that the activity of compounds depends not only on the nature of substituent and it position in benzothiazole ring but also on the nature and position of substituents in benzene ring.

CONCLUSION

Twenty four of the tested compounds exhibited inhibitory action lower than 4 μΜ. Seven of them showed better activity than nevirapine, while three of the compounds exhibited IC50 values lower than 5 nM. Two compounds 9 and 10 exhibited very good inhibitory activity with IC50 1 nM.

Recent Advances in the Design and Development of Non-nucleoside Reverse Transcriptase Inhibitor Scaffolds

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) have always been an important part of the anti-HIV-1 combination therapy known as combination antiretroviral therapy (cART) since 1996. The use of NNRTIs for about 22 years has led to some mutations in the residues that compose the reverse transcriptase active site, resulting in the emergence of drug-resistant viruses. Thus, the search for new potent NNRTIs with an improved safety profile and activity against drug-resistant HIV strains is indispensable, and many hit and lead NNRTIs have been discovered in the last decade. This review provides an overview of the development in this field from 2013 to August 2018.

Novel 5'-Norcarbocyclic Pyrimidine Derivatives as Antibacterial Agents

A series of novel 5'-norcarbocyclic derivatives of 5-alkoxymethyl or 5-alkyltriazolyl-methyl uracil were synthesized and the activity of the compounds evaluated against both Gram-positive and Gram-negative bacteria. The growth of Mycobacterium smegmatis was completely inhibited by the most active compounds at a MIC99 of 67 μg/mL (mc²155) and a MIC99 of 6.7⁻67 μg/mL (VKPM Ac 1339). Several compounds also showed the ability to inhibit the growth of attenuated strains of Mycobacterium tuberculosis ATCC 25177 (MIC99 28⁻61 μg/mL) and Mycobacterium bovis ATCC 35737 (MIC99 50⁻60 μg/mL), as well as two virulent strains of M. tuberculosis; a laboratory strain H37Rv (MIC99 20⁻50 μg/mL) and a clinical strain with multiple drug resistance MS-115 (MIC99 20⁻50 μg/mL). Transmission electron microscopy (TEM) evaluation of M. tuberculosis H37Rv bacterial cells treated with one of the compounds demonstrated destruction of the bacterial cell wall, suggesting that the mechanism of action for these compounds may be related to their interactions with bacteria cell walls.

Design, Synthesis, and the Biological Evaluation of a New Series of Acyclic 1,2,3-Triazole Nucleosides

A new strategy for the synthesis of N3 -benzoylated- and N3 -benzylated N1 -propargylquinazoline-2,4-diones 30a-d and 31a-d from isatoic anhydride 41 is reported. The alkynes 30a-d and 31a-d were applied in the 1,3-dipolar cycloadditions with azides 27 and 28 to synthesize acyclic 1,2,3-triazole nucleosides. The obtained alkynes and 1,2,3-triazole were evaluated for antiviral activity against a broad range of DNA and RNA viruses. The alkyne 30d showed activity against adenovirus-2 (EC50  = 8.3 μM), while compounds 37a and 37d were also active toward herpes simplex virus-1 wild-type and thymidine kinase deficient (HSV-1 TK- ) strains (EC50 values in the range of 4.6-13.8 μM). In addition, compounds 30a, 30b, 37b, and 37c exhibited activity toward varicella-zoster virus (VZV) TK+ and TK- strains (EC50  = 2.1-9.5 μM). The compound 30b proved to be the most selective against VZV and displayed marginal activity against human cytomegalovirus (HCMV). Although the compound 30a had improved anti-HCMV activity, the increase in anti-HCMV activity was accompanied by significant toxicity. Compounds 37a and 37d showed inhibitory effects toward the human T lymphocyte (CEM) cell line (IC50  = 21 ± 7 and 22 ± 1 μM, respectively), while compound 35 exhibited cytostatic activity toward HMEC-1 cells (IC50  = 28 ± 2 μM).

Synthesis, anti-varicella-zoster virus and anti-cytomegalovirus activity of quinazoline-2,4-diones containing isoxazolidine and phosphonate substructures

Cycloadditions of N-substituted C-(diethoxyphosphoryl)nitrones to N-allylated quinazoline-2,4-diones functionalized at N3 with substituted benzoyl or benzyl groups proceeded with moderate to good diastereoselectivities (d.e. 28-68%). The synthesized isoxazolidine phosphonates were assessed for the antiviral activity against a broad range of DNA and RNA viruses. Compounds trans-13c, cis-13c/trans-13c (86:14), cis-15b/trans-15b (87:13) and trans-15d/cis-15d (95:5) exhibited the highest activity toward both TK⁺ and TK^- VZV strains (mean EC₅₀ values in the range of 3.0-8.7 μM). The EC₅₀'s for isoxazolidines trans-12a, cis-12a, cis-13a, trans-13d, cis-15a/trans-15a (50:50) ranged between 6.9 and 8.5 μM for VZV TK⁺ strain and between 10.7 and 13.2 μM for VZV TK^- strain. The isoxazolidine phosphonates cis-15/trans-15 having benzyl substituents both at N3 of the quinazoline-2,4-dione skeleton and at N2 of the isoxazolidine ring displayed some anti-cytomegalovirus potency but at the same time showed significant cytostatic activity for human embryonic lung fibroblasts (used to carry out the antiviral assays) as well as for other cell lines (i.e. CEM, L1210, HeLa and HMEC-1).

2-(2,4-Dioxy-1,2,3,4-Tetrahydropyrimidin-1-yl)-N-(4-Phenoxyphenyl)-Acetamides as a Novel Class of Cytomegalovirus Replication Inhibitors

A series of novel uracil derivatives, bearing N-(4-phenoxyphenyl)acetamide moiety at N3 of a pyrimidine ring, has been synthesized. Their antiviral activity has been evaluated. It has been found that the novel compounds possess high inhibitory activity against replication of human cytomegalovirus (AD-169 and Davis strains) in HEL cell cultures. In addition, some of the derivatives proved to be inhibitory against varicella zoster virus.

Double Variational Binding--(SMILES) Conformational Analysis by Docking Mechanisms for Anti-HIV Pyrimidine Ligands

Variational quantitative binding–conformational analysis for a series of anti-HIV pyrimidine-based ligands is advanced at the individual molecular level. This was achieved by employing ligand-receptor docking algorithms for each molecule in the 1,3-disubstituted uracil derivative series that was studied. Such computational algorithms were employed for analyzing both genuine molecular cases and their simplified molecular input line entry system (SMILES) transformations, which were created via the controlled breaking of chemical bonds, so as to generate the longest SMILES molecular chain (LoSMoC) and Branching SMILES (BraS) conformations. The study identified the most active anti-HIV molecules, and analyzed their special and relevant bonding fragments (chemical alerts), and the recorded energetic and geometric docking results (i.e., binding and affinity energies, and the surface area and volume of bonding, respectively). Clear computational evidence was also produced concerning the ligand-receptor pocket binding efficacies of the LoSMoc and BraS conformation types, thus confirming their earlier presence (as suggested by variational quantitative structure-activity relationship, variational-QSAR) as active intermediates for the molecule-to-cell transduction process.

5-Arylaminouracil Derivatives as Potential Dual-Action Agents

Several 5-aminouracil derivatives that have previously been shown to inhibit Mycobacterium tuberculosis growth at concentrations of 5-40 μg/mL are demonstrated to act also as noncompetitive non-nucleoside inhibitors of HIV-1 reverse transcriptase without causing toxicity in vitro (MT-4 cells) and ex vivo (human tonsillar tissue).

Chemometrics approach for the prediction of structure-activity relationship for membrane transporter bilitranslocase

Membrane transport proteins are essential for cellular uptake of numerous salts, nutrients and drugs. Bilitranslocase is a transporter, specific for water-soluble organic anions, and is the only known carrier of nucleotides and nucleotide-like compounds. Experimental data of bilitranslocase ligand specificity for 120 compounds were used to construct classification models using counter-propagation artificial neural networks (CP-ANNs) and support vector machines (SVMs). A subset of active compounds with experimentally determined transport rates was used to build predictive QSAR models for estimation of transport rates of unknown compounds. Several modelling methods and techniques were applied, i.e. CP-ANN, genetic algorithm, self-organizing mapping and multiple linear regression method. The best predictions were achieved using CP-ANN coupled with a genetic algorithm, with the external validation parameter QV(2) of 0.96. The applicability domains of the models were defined to determine the chemical space in which reliable predictions can be obtained. The models were applied for the estimation of bilitranslocase transport activity for two sets of pharmaceutically interesting compounds, antioxidants and antiprions. We found that the relative planarity and a high potential for hydrogen bond formation are the common structural features of anticipated substrates of bilitranslocase. These features may serve as guidelines in the design of new pharmaceuticals transported by bilitranslocase.

Synthesis, Single Crystal X-Ray Structure, and Antimicrobial Activity of 6-(1,3-Benzodioxol-5-ylmethyl)-5-ethyl-2-{[2-(morpholin-4-yl)ethyl]sulfanyl}pyrimidin-4(3H)-one

Synthesis, X-ray structure and antimicrobial activity of 6-(1,3-benzodioxol-5-ylmethyl)-5-ethyl-2-{[2-(morpholin-4-yl)ethyl]sulfanyl}pyrimidin-4(3H)-one (8) are reported. Compound8exhibited activity towardsS. aureuswith MIC value of 0.0619 μmol/mL while it showed activity towardsB. subtilis,B. cereus,C. albicans, andA. nigerwith MIC = 0.1859 μmol/mL. Single crystal X-ray structure of the title compound8confirmed itsS-alkylation. The title compound crystallizes in the triclinic,P-1,a=11.1220(5) Å,b=12.2241(5) Å,c=21.5246(9) Å,α=88.958(2)°,β=79.836(2)°,γ=79.384(2)°,V=2830.9(2) Å3,Z=6,R(F)=0.046,wR(F2)=0.110,T=100 K. The crystal structure is stabilized by weak intermolecular C–H⋯O and N–H⋯O hydrogen interactions.

Synthesis of novel 2-(substituted amino)alkylthiopyrimidin-4(3H)-ones as potential antimicrobial agents

5-Alkyl-6-(substituted benzyl)-2-thiouracils 3a,c were reacted with (2-chloroethyl) diethylamine hydrochloride to afford the corresponding 2-(2-diethylamino)ethylthiopyrimidin- 4(3H)-ones 4a,b. Reaction of 3a-c with N-(2-chloroethyl)pyrrolidine hydrochloride and/or N-(2-chloroethyl)piperidine hydrochloride gave the corresponding 2-[2-(pyrrolidin-1-yl)ethyl]-thiopyrimidin-4(3H)-ones 5a-c and 2-[2-(piperidin-1-yl)ethyl]thiopyrimidin-4(3H)-ones 6a,b, respectively. Treatment of 3a-d with N-(2-chloroethyl)morpholine hydrochloride under the same reaction conditions formed the corresponding 2-[2-(morpholin-4-yl)ethyl]thiopyrimidines 6c-f. On the other hand, 3a,b were reacted with N-(2-bromoethyl)phthalimide and/or N-(3-bromopropyl)phthalimide to furnish the corresponding 2-[2-(N-phthalimido)ethyl]-pyrimidines 7a,b and 2-[3-(N-phthalimido)-propyl]pyrimidines 7c,d, respectively. Compounds 3a-d, 4a,b, 5a-c, 6a-f and 7a-d were screened against Gram-positive bacteria (Staphylococcus aureus ATCC 29213, Bacillus subtilis NRRL 4219 and Bacillus cereus), yeast-like pathogenic fungus (Candida albicans ATCC 10231) and a fungus (Aspergillusniger NRRL 599). The best antibacterial activity was displayed by compounds 3a, 3b, 4a, 5a, 5b, 6d, 6f, 7b and 7d, whereas compounds 4b, 5b, 5c, 6a, 6b and 6f exhibited the best antifungal activity.

Synthesis of some new benzisothiazolone and benzenesulfonamide derivatives of biological interest starting from saccharin sodium

Two new series of benzenesulfonamide (4a-f, 5a-b, 6, 7) and 1,2-benzisothiazol-3(2H)-one-1,1-dioxide (9a-c, 10, 12a-d) derivatives were prepared starting from saccharin sodium. The novel compounds were characterized using elemental analyses and different spectroscopic methods. Assessment of the antiviral activities of these novel compounds against a broad panel of viruses in different cell cultures revealed that only the thiazole derivatives belonging to the benzisothiazol-3(2H)-one-1,1-dioxide series are the active ones. All thiazole derivatives 12a-d showed activity against both varicella-zoster virus, especially TK(-) VZV strain 07-1, and the cytomegalovirus strains AD-169 and Davis in human embryonic lung (HEL) cell culture.

Design, synthesis and biological evaluation of 3-benzyloxy-linked pyrimidinylphenylamine derivatives as potent HIV-1 NNRTIs

A novel series of 3-benzyloxy-linked pyrimidinylphenylamine derivatives (8a-8s) was designed, synthesized and evaluated for their in vitro anti-HIV activity in MT-4 cell cultures. Most of the compounds inhibited wild-type (wt) HIV-1 replication in the lower micromolar concentration range (EC(50)=0.05-35 μM) with high selectivity index (SI) values (ranged from 10 to >4870). In particular, 8h and 8g displayed excellent antiretroviral activity against wt HIV-1 with low cytotoxicity (EC(50)=0.07 μM, CC(50) >347 μM, SI >4870; EC50=0.05 μM, CC(50)=42 μM, SI=777, respectively), comparable to that of the marked drug nevirapine (EC(50)=0.113 μM, CC(50) >15 μM, SI >133). In order to confirm the binding target, 8h was selected to perform the anti-HIV-1 RT assay. Additionally, preliminary structure activity relationship (SAR) analysis and molecular docking studies of newly synthesized compounds were also discussed, as well as the predicted physicochemical properties.