Compounds 5r Research Articles

Design, synthesis, and bioassay of novel 1‐(3‐chloropyridin‐2‐yl)‐5‐amino‐4‐pyrazole derivatives containing a 1,3,4‐thiadiazole thioether or sulfone moiety

AbstractA series of novel 1‐(3‐chloropyridin‐2‐yl)‐5‐amino‐4‐pyrazole derivatives containing a 1,3,4‐thiadiazole thioether or sulfone moiety were designed and synthesized. All the title compounds were confirmed by 1H NMR, 13C NMR, and MS, and the intermediate 2 and title compound 5e were confirmed by single crystal X‐ray diffraction analysis. Bioassay evaluation revealed that compound 5a (54.2 ± 2.0%) and 5r (75.2 ± 3.9%) exhibited good curative and protection activity against TMV, respectively, which was slightly lower than that of ningnanmycin (57.1 ± 2.2% and 73.8 ± 3.4%). Compound 5b (64.7 ± 8.5% and 67.7 ± 2.1%) exhibited good curative and protective activity against CMV, which was better than that of ningnanmycin (55.8 ± 1.4% and 64.2 ± 5.8%). The lethality rates of 5a, 5c, 5d, 5h, 5j, 5n, 5o, 5p, 5q, 5r, 5t, 6a, and 6e against C. pipiens were 100% at a concentration of 10 μg/ml, as well as chlorantraniliprole (100%). These results may provide enough support to justify further molecular design and derivation.

Synthesis and antibacterial activity studies in vitro of indirubin-3'-monoximes.

Multi-drug-resistant microbial pathogens are a serious global health problem. New compounds with antibacterial activity serve as good candidates for developing novel antibacterial drugs which is very urgent and important. In this work, based on the unique scaffold of indirubin, an active ingredient of traditional Chinese medicine formulation Danggui Luhui Wan, we synthesized 29 indirubin-3′-monoximes and preliminarily evaluated their antibacterial activities. The antibacterial activity results demonstrated that the synthesized indirubin-3′-monoximes 5a–5z and 5aa–5ad displayed good potency against S. aureus ATCC25923 (MIC = 0.4–25.6 μg mL−1). Among them, we found that the 5-F, 5-Cl and 7-CF3 substituted indirubin-3′-monoximes 5r, 5s and 5aa also showed better antibacterial efficiency for S. aureus (MICs up to 0.4 μg mL−1) than the prototype natural product indirubin (MIC = 32 μg mL−1). More importantly, indirubin-3′-monoxime 5aa has certain synergistic effect with levofloxacin against clinic multidrug-resistant S. aureus (fractional inhibitory concentration index: 0.375). In addition, relevant experiments including electron microscopy observations, PI staining and the leakage of extracellular potassium ions and nucleic acid (260 nm) have been performed after treating S. aureus with indirubin-3′-monoxime 5aa, and the results revealed that indirubin-3′-monoximes could increase the cell membrane permeability of S. aureus. Although indirubin-3′-monoxime 5aa showed some cytotoxicity toward SH-SY5Y cells relative to compounds 5r and 5s, the skin irritation test of male mice after shaving showed that compound 5aa at a concentration of 12.8 μg mL−1 had no toxicity to mouse skin, and it could be used as a leading compound for skin antibacterial drugs.

Design, synthesis and evaluation of heteroaryldihydropyrimidine analogues bearing spiro ring as hepatitis B virus capsid protein inhibitors.

GLS4, a potent antiviral drug candidate, has been widely studied and entered into phase II clinical trials. Nevertheless, the therapeutic application of GLS4 is limited due to poor water solubility, short half-life, and low bioavailability. In order to improve the hydrophilicity and pharmacokinetic (PK) properties of GLS4, herein, we retained the dominant fragments, and used a scaffold hopping strategy to replace the easily metabolized morpholine ring of GLS4 with diverse sizes of spiro rings consisting of hydrogen bond donor and acceptor substituents. Potent invitroanti-HBV activity and low cytotoxicity were observed for compound 4r (EC50=0.20±0.00μM, CC50>87.03μM), which was more potent than the positive control lamivudine (EC50=0.37±0.04μM, CC50>100.00μM) in this assay and was about a quarter as effective as GLS4 (EC50=0.045±0.01μM, CC50>99.20μM). Preliminary structure-activity relationship (SAR) analysis and molecular docking studies were carried out to explore potential interactions and binding mode between compounds and target protein. In terms of the physicochemical properties, 4r was predicted to be consistent with the rule-of-five, which means 4r may have favourable absorption and permeation. Finally, ADMET and PK characteristics of 4r and GLS4 were predicted to be comparable in most aspects, implying that the two compounds may have similar profiles invivo.

Structural effects of morpholine replacement in ZSTK474 on Class I PI3K isoform inhibition: Development of novel MEK/PI3K bifunctional inhibitors

Established roles for PI3K and MAPK signaling pathways in tumorigenesis has prompted extensive research towards the discovery of small-molecule inhibitors as cancer therapeutics. However, significant compensatory regulation exists between these two signaling cascades, leading to redundancy among survival pathways. Consequently, initial clinical trials aimed at either PI3K or MEK inhibition alone have proven ineffective and highlight the need for development of targeted and innovative therapeutic combination strategies. We designed a series of PI3K inhibitor derivatives wherein a single morpholine group of the PI3K inhibitor ZSTK474 was substituted with a variety of 2-aminoethyl functional groups. Analogs with pendant hydroxyl or methoxy groups maintained low nanomolar inhibition towards PI3Kα, PI3Kγ, and PI3Kδ isoforms in contrast to those with pendant amino groups which were significantly less inhibitory. Synthesis of prototype PI3K/MEK bifunctional inhibitors (6r, 6s) was guided by the structure-activity data, where a MEK-targeting inhibitor was tethered directly via a short PEG linker to the triazine core of the PI3K inhibitor analogs. These compounds (6r, 6s) displayed nanomolar inhibition towards PI3Kα, δ, and MEK (IC50 ∼105–350 nM), and low micromolar inhibition for PI3Kβ and PI3Kγ (IC50 ∼1.5–3.9 μM) in enzymatic inhibition assays. Cell viability assays demonstrated superior anti-proliferative activity for 6s over 6r in three tumor-derived cell lines (A375, D54, SET-2), which correlated with inhibition of downstream AKT and ERK1/2 phosphorylation. Compounds 6r and 6s also demonstrated in vivo tolerability with therapeutic efficacy through reduction of kinase activation and amelioration of disease phenotypes in the JAK2V617F mutant myelofibrosis mouse cancer model. Taken together, these results support further structure optimization of 6r and 6s as promising leads for combination therapy in human cancer as a new class of PI3K/MEK bifunctional inhibitors.

Synthesis, 3D-QSAR and Molecular Docking Study of Nopol-Based 1,2,4-Triazole-Thioether Compounds as Potential Antifungal Agents.

Cytochrome bc 1 complex is an important component of cellular respiratory chain, and it is also an important target enzyme to inhibit the growth of plant pathogens. Using cytochrome bc 1 complex as the target enzyme, twenty-three novel nopol-based 1,2,4-triazole-thioether compounds were designed and synthesized from natural preponderant resource β-pinene, and their structures were confirmed by FT-IR, NMR, ESI-MS and elemental analysis. The in vitro antifungal activity of the target compounds 5a-5w was preliminarily evaluated against eight plant pathogens at the concentration of 50 µg/ml. The bioassay results showed that the target compounds exhibited the best antifungal activity against Physalospora piricola, in which compounds 5b (R= o-CH3 Ph), 5e (R= o-OCH3 Ph), 5h (R= o-F Ph), 5m (R= o-Br Ph), 5o (R= m,m-OCH3 Ph), and 5r (R= p-OH Ph) had inhibition rates of 91.4, 83.3, 86.7, 83.8, 91.4 and 87.3%, respectively, much better than that of the positive control chlorothalonil. Also, compound 5a (R= Ph) had inhibition rate of 87.9% against Rhizoeotnia solani, and compound 5b (R= o-CH3 Ph) had inhibition rates of 87.6 and 89% against Bipolaris maydis and Colleterichum orbicala, respectively. In order to develop novel and promising antifungal compounds against P. piricola, the analysis of three-dimensional quantitative structure-activity relationship (3D-QSAR) was carried out using the CoMFA method on the basis of their antifungal activity data, and a reasonable and effective 3D-QSAR model (r 2 = 0.944, q 2 = 0.685) has been established. In addition, the theoretical study of molecular docking revealed that the target compounds could bind to and interact with the site of cytochrome bc 1 complex.

Investigation of NPB Analogs That Target Phosphorylation of BAD-Ser99 in Human Mammary Carcinoma Cells

The design and development of a small molecule named NPB [3-{(4(2,3-dichlorophenyl)piperazin-1-yl}{2-hydroxyphenyl)methyl}-N-cyclopentylbenzamide], which specifically inhibited the phosphorylation of BAD at Ser99 in human carcinoma cells has been previously reported. Herein, the synthesis, characterization, and effect on cancer cell viability of NPB analogs, and the single-crystal X-ray crystallographic studies of an example compound (4r), which was grown via slow-solvent evaporation technique is reported. Screening for loss of viability in mammary carcinoma cells revealed that compounds such as 2[(4(2,3-dichlorophenyl)piperazin-1-yl][naphthalen-1-yl]methyl)phenol (4e), 5[(4(2,3-dichlorophenyl)piperazin-1-yl][2-hydroxyphenyl)methyl)uran-2-carbaldehyde (4f), 3[(2-hydroxyphenyl][4(p-tolyl)piperazin-1-yl)methyl)benzaldehyde (4i), and NPB inhibited the viability of MCF-7 cells with IC50 values of 5.90, 3.11, 7.68, and 6.5 µM, respectively. The loss of cell viability was enhanced by the NPB analogs synthesized by adding newer rings such as naphthalene and furan-2-carbaldehyde in place of N-cyclopentyl-benzamide of NPB. Furthermore, these compounds decreased Ser99 phosphorylation of hBAD. Additional in silico density functional theory calculations suggested possibilities for other analogs of NPB that may be more suitable for further development.

Synthesis, Bioactivity, and QSAR Study of 3,4-Dichlorophenyl Isoxazole-Substituted Stilbene Derivatives against the Phytopathogenic Fungus Botrytis cinerea.

Gray mold, caused by Botrytis cinerea, is one of the most destructive fungal diseases in crops, responsible for significant economic losses. In search of natural product-based fungicides, we designed and synthesized a series of novel 3,4-dichlorophenyl isoxazole-substituted stilbene derivatives, and their in vivo antifungal activities against B. cinerea were evaluated. The results indicated that some of the target molecules demonstrated remarkable efficiency for the control of tomato gray mold. In particular, compound 5r displayed the highest fungicidal potency with an inhibition rate of 56.11% comparable to that of positive control boscalid (66.96%). Moreover, a hologram quantitative structure-activity relationship (HQSAR) model with good predictive capability was developed to provide in-depth insight into the activity profiles of these compounds. Preliminary mechanism studies suggested that compound 5r might exert its antifungal effect by changing hyphal morphology and increasing the membrane permeability. The present study contributes to the development of natural stilbene derivatives as alternative bioactive agents against B. cinerea.

5-Benzylidene-2,3-diarylthiazolidine-4-ones: Design, synthesis, spectroscopic characterization, in vitro biological and computational evaluation

The synthesis and antidiabetic activity of 5-Benzylidene-2,3-diarylthiazolidine-4-one derivatives (6a–w) are presented in the current work. Screening of derivatives 6a–w for their α-glucosidase inhibitory activity, showed higher inhibitory activity of twenty of the screened compounds (IC50: 105–412 µM) in comparison to acarbose (IC50: 750 µM) as a standard. Compounds 6r, 6b, and 6q exerted the best activity with the IC50 value of 105, 110, and 127 µM, respectively. Performing the kinetic studies, revealed the competitive mode of inhibition for 6r. It binds to the active site on the enzyme and competes with the substrate for binding to the active site. based on molecular docking studies, 6b, 6q, and 6r interact with HIS280, ASP307, and PRO312 residues, which show the important role of these residues inside the active site of the enzyme. Cytotoxicity studies also showed IC50 > 750 µM for 6a–w on different cell lines namely, NIH3T3, MCF-7, and HT-29.

Synthesis, characterization and antibacterial evaluation of new pyridyl-thiazole hybrids of sulfonamides

Background and Aims: Sulfonamide drugs are a very old and noted group of small molecules, and are still one of the most important antimicrobial compounds. In this study, starting from sulfonamide drugs, new original compounds containing frequent and functional rings such as thiazole and pyridine were synthesized and their antimicrobial effects were evaluated. Methods: Eighteen new compounds were synthesized by converting the 4-amino group of the sulfonamides to thiourea, and continued by thiazole ring closure. Characterization of the compounds was carried out by FT-IR, 1 H-NMR and 13C-NMR and HRMS. MIC values were obtained in antimicrobial activity studies, which were carried out by Broth Microdilution method. Results: Compounds 3p-r had an effect of 32 µg/ml against B. spizizenii. In addition, compounds 3d-f and 3p-r each showed effect against different gram-positive bacteria. Compound 3r had an MIC of 128 µg/mL against gram-negative organisms. The rest of the series did not affect gram-negative bacteria. In the study, chloramphenicol and sulfamethoxazole were used as standards. Conclusion: Sulfanilamide and sulfadiazine derivatives showed higher inhibitory effects compared to the rest of the series. 3d-f and 3p-r showed inhibitor activity against gram-positive bacteria, conversely to the standard drug sulfamethoxazole, which possibly means that the mechanism of action is not same.

Synthesis, Antimicrobial Activity, and Molecular Docking of Benzoic Hydrazide or Amide Derivatives Containing a 1,2,3‐Triazole Group as Potential SDH Inhibitors

Main observation and conclusionThe present study was carried out in an attempt to synthesize a new class of antimicrobial agents containing a 1,2,3‐triazole motif formed by classical copper catalyzed click chemistry. Antifungal bioassay results showed that five compounds 5a, 5e, 5h, 5j, and 5k possessed a remarkable growth inhibitory activity against Botryosphaeria dothidea, Rhizoctonia solani and Gibberella zeae with EC50 values within 10.0—0.306 μg/mL. The in vitro efficacy was better than those of the commercial agrochemicals Azoxystrobin, Boscalid, and Fluxapyroxad. In vivo trials showed that compound 5l was effective for the control of rice sheath blight and wheat scab with the effects of 75% and 95%, respectively. Antifungal mechanism studies suggested that target compounds were potential succinate dehydrogenase inhibitors (SDHIs), which were proposed by the agreeable molecular docking study and restrained SDH activity (IC50 = 3.95 μg/mL, 5l). Interestingly, compounds 5r and 5s displayed good antibacterial activity against phytopathogens. In vivo screening of 5r and 5s against rice bacterial blight afforded a superior control effect (up to 51%) than those of commercial agents Bismerthiazol and Thiodiazole copper. The current studies could support some title compounds to be the lead compounds for exploring highly bioactive antimicrobial substrates, particularly the potential SDHIs.

Rational Optimization of 1,2,3-Triazole-Tailored Carbazoles As Prospective Antibacterial Alternatives with Significant In Vivo Control Efficiency and Unique Mode of Action.

Plant bacterial diseases can potentially damage agricultural products around the world, and few effective bactericides can manage these infections. Herein, to sequentially explore highly effective antibacterial alternatives, 1,2,3-triazole-tailored carbazoles were rationally fabricated. These compounds could suppress the growth of three main intractable pathogens including Xanthomonas oryzae pv oryzae (Xoo), X. axonopodis pv citri (Xac), and Pseudomonas syringae pv actinidiae (Psa) with lower EC50 values of 3.36 (3p), 2.87 (3p), and 4.57 μg/mL (3r), respectively. Pot experiments revealed that compound 3p could control the rice bacterial blight with protective and curative efficiencies of 53.23% and 50.78% at 200 μg/mL, respectively. Interestingly, the addition of 0.1% auxiliaries such as organic silicon and orange oil could significantly enhance the surface wettability of compound 3p toward rice leaves, resulting in improved control effectiveness of 65.50% and 61.38%, respectively. Meanwhile, compound 3r could clearly reduce the white pyogenic exudates triggered by Psa infection and afforded excellent control efficiencies of 79.42% (protective activity) and 78.74% (curative activity) at 200 μg/mL, which were quite better than those of commercial pesticide thiodiazole copper. Additionally, a plausible apoptosis mechanism for the antibacterial behavior of target compounds was proposed by flow cytometry, reactive oxygen species detection, and defensive enzyme (e.g., catalase and superoxide dismutase) activity assays. The current work can promote the development of 1,2,3-triazole-tailored carbazoles as prospective antibacterial alternatives bearing an intriguing mode of action.

Clerodane and 5 10-Seco-Clerodane-type diterpenoids from Salvia involucrata

From the leaves of Salvia involucrata Cav., eight clerodane diterpenoids were isolated, of which 1−3 have not been previously described. Their structures were established by spectroscopic and spectrometric means and named as involucratin A (1), involucratin B (2), and involucratin C (3). The absolute configuration of compounds 1 and 3 was established using a combination of experimental and theoretical ECD data, whereas the one for compound 2 was determined by NOESY experiments together with ECD and DP4+ statistical analysis. Furthermore, the known clerodane compounds (5R,7R,8S,9R,10R,12R)-7-hydroxycleroda-1,3,13(16),14-tetraene-17,12;18,19-diolide (4), (‒)-hardwickiic acid (5), 1-deoxybacrispine (6), 7α-hydroxybacchotricuneatin A (7), and kingidiol (8), along with the flavonoid salvigenin, and a mixture of ursolic and oleanolic acids were also isolated. The antiproliferative activity of compounds 1‒3, 5, and 7, 8 was evaluated against a panel of cancer cell-lines (six strains) using the sulforhodamine B assay.

Design and synthesis of novel glycyrrhetin ureas as anti-inflammatory agents for the treatment of acute kidney injury

To develop new anti-inflammatory drugs for the prevention and treatment of acute kidney injury, a series of novel glycyrrhetic ureas were designed, synthesized and evaluated for anti-inflammatory activity using RAW264.7 cells. Compounds 5r-5u (2.04, 2.50, 3.25 and 2.48 μM, respectively) with acidic or neutral amino acid showed potent anti-inflammatory activity (IC50 = 2–3 μM for NO inhibition), amongst them, compound 5r also inhibited tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in a dose-dependent manner. In cisplatin-induced AKI mice model, compound 5r significantly reduced the level of pro-inflammatory factors, ameliorated the pathological damage of kidney tissue, and maintained the normal metabolic capacity.

Synthesis, Molecular Docking and Evaluation of Library of 3-Mercapto-1,2,4-Triazole Derivatives as Antimicrobial Agents

Due to the increasing microbial resistance to antibacterial and antifungal drugs, the development of new antimicrobial agents is an urgent priority. In search of newer antimicrobial agents, a series of 4,5-disubstituted-3-mercapto-1,2,4-triazole derivatives were synthesized from aromatic acids and substituted isothiocyanates. The in silico study was performed to study the binding interactions of the synthesized compounds with the active pocket of CYP51. Among the synthesized 3-mercapto-triazole derivatives, compounds 6r, 6s and 6u exhibited promising antimicrobial activity comparable to standard drugs. The results suggested that the structural modification to 3-mercapto-1,2,4-triazole derivatives could lead to promising antimicrobial scaffolds.

Design, Synthesis and Biological Evaluation of a Novel Series of Thiadiazole- Based Anticancer Agents as Potent Angiogenesis Inhibitors.

Thiadiazole has attracted a great deal of interest as a versatile heterocycle for the discovery and development of potent anticancer agents. Thiadiazole derivatives exert potent antitumor activity against a variety of human cancer cell lines through various mechanisms. The goal of this work was to design and synthesize thiadiazole-based anticancer agents with anti-angiogenic activity. N-aryl-2-[(5-(aryl)amino-1,3,4-thiadiazol-2-yl)thio]acetamides (4a-r) were synthesized via the reaction of 5-(aryl)amino-1,3,4-thiadiazole-2(3H)-thiones with N-(aryl)-2-chloroacetamides in the presence of potassium carbonate. The compounds were investigated for their cytotoxic effects on three cancer (A549, HepG2, SH-SY5Y), two normal (HUVEC and 3T3-L1) cell lines using MTT and WST-1 assays. In order to examine whether the compounds have anti-angiogenic effects or not, HUVECs were cultured on matrigel matrix to create a vascular-like tube formation. Compounds 4d, 4m and 4n were more effective on A549 human lung adenocarcinoma cells than cisplatin. The IC50 values of compounds 4d, 4m and 4n for A549 cell line were found to be 7.82 ± 0.4, 12.5 ± 0.22, 10.1 ± 0.52 μM, respectively when compared with cisplatin (IC50= 20 ± 0.51 μM), whilst their IC50 values for HUVEC cell line were determined as 138.7 ± 0.84, 78 ± 0.44, 177.6 ± 0.2 μM, respectively after 48 h of the treatment. The concentrations (10-20-50 μM) of compounds 4d, 4e, 4l, 4m, 4n, 4q and 4r were found to inhibit vascular like tube formation. According to their anticancer and anti-angiogenic effects, compounds 4d, 4m and 4n may be potential anticancer agents for further in vivo studies.

Synthesis of propynyloxy substituted some novel aurones as potent cathepsin B inhibitors

Abstract A two-step synthesis was designed to develop a novel series of 6-propynyloxyaurones, 2(a-r). The synthesized aurone derivatives were characterized by their IR, NMR, and mass spectrometry data. The present study proposes these aurones as anti-inflammatory and anti-Alzheimer candidates on the basis of their cathepsin B inhibitory activities. Anti-cathepsin B activity of some of the synthesized aurones was found, either equivalent to or higher than the reference drugs, aspirin and curcumin at submicromolar concentrations. Among the studied compounds, 2e, 2i, 2n, 2q, and 2r exhibited much higher activity in comparison to the standard drugs. The molecular docking study also highlighted compound 2r for its greater anti-cathepsin B activity among all the designed aurones.

Design, synthesis, and biological activity of novel 1,2,4-oxadiazole derivatives

BackgroundPlant diseases seriously threaten food security, it is urgent to discover efficient and low-risk chemical pesticides. 1,2,4-Oxadiazole derivatives exhibit broad spectrum of agricultural biological activities. For discovering novel molecules with excellent agricultural activities, novel 1,2,4-oxadiazole derivatives were synthesized and evaluated for their agricultural activities.ResultBioassays results showed that the title compounds exhibited moderate nematocidal activity against Meloidogyne incognita and anti-fungal activity to Rhizoctonia solani. It’s worth noting that compounds 5m, 5r, 5u, 5v, 5x and 5y showed strong antibacterial effects on Xanthomonas oryzae pv. oryzae (Xoo), with EC50 values of 36.25, 24.14, 28.82, 19.44, 25.37 and 28.52 μg/mL, respectively, superior to bismerthiazol (BMT, EC50 = 77.46 μg/mL) and thiodiazole copper (TDC, EC50 = 99.31 μg/mL). Compounds 5p, 5u and 5v exhibited excellent antibacterial ability against Xanthomonas oryzae pv. oryzicola (Xoc), with EC50 values of 31.40, 19.04 and 21.78 μg/mL, respectively, better than that of BMT (EC50 = 68.50 μg/mL) and TDC (EC50 = 91.05 μg/mL). In addition, compound 5v exerted moderate antibacterial effects on rice bacterial leaf blight.ConclusionsTwenty-six novel 1,2,4-oxadiazole derivatives were obtained and their biological activities were evaluated. Compound 5u and 5v exhibited excellent antibacterial activity Xoo and Xoc. These results indicated that 1,2,4-oxadiazole derivatives containing a trifluoromethyl pyridine moiety could be as potential alternative templates for discovering novel antibacterial agents.

Synthesis of methyl piperazinyl-quinolinyl α-aminophosphonates derivatives under microwave irradiation with Pd–SrTiO3 catalyst and their antibacterial and antioxidant activities

Novel methyl piperazinyl-quinolinyl α-aminophosphonates (MPQ-APs) (4a–4t) were synthesized by a one-pot reaction under microwave conditions, in the presence of a new Pd-SrTiO3 catalyst. 4a–4t were prepared from the substrates methyl piperazinyl-quinolinyl carbaldehyde, selected aniline derivatives and diethyl phosphite. MPQ-APs were characterized by FT-IR, 1H-NMR, 13C-NMR, 2D-NMR, 31P-NMR and high-resolution mass spectroscopy. The catalyst was prepared by a sequential reaction of Sr (II) nitrate, citric acid and Ti (IV) butoxide followed by reflux in the presence of Pd (II) nitrate. Pd-SrTiO3 was characterized by FT-IR, P-XRD, SEM, BET, SEM-EDX and Raman spectroscopy techniques. The MPQ-APs were screened in vitro for antibacterial activity against four strains of bacteria and three yeast cultures. Compounds 4m and 4r showed good positive results for antimicrobial activity in ciprofloxacin and compounds 4m, 4r and 4f gave positive results for antioxidant activity.

Eco-friendly and Enantiospecific Biginelli Synthesis Using (+)-Myrtenal as the Substrate - An Impeccable and Unequivocal Analysis of the Product.

We found in the literature, an excellent review of the Biginelli reaction that addresses the methodologies for obtaining enantiopure dihydropyrimidinones (DHPMs). In 1992, optically pure DHPMs were obtained by fractional crystallization of the diastereomeric ammonium salt derivative with (S)-(-) and (R)- (+)-α-methyl benzylamine and by other chiral resolution techniques, such as chiral high-performance liquid chromatography (HPLC). Asymmetric syntheses of these compounds are also explained in the literature. The main strategy is to use acid catalysts such as organophosphates, organometallic complexes, amines and diamines, nanocomposites, and chiral ionic liquids, e.g., L-prolinium sulfate (Pro2SO4). The objective was to study the Biginelli reaction with a chiral aldehyde. A mixture of ethyl acetoacetate (0.26 g, 3 mmol), urea (0.18 g, 3 mmol) and ethyl lactate (EL) (1 mL) was left under heating at 70°C and stirring for 1 h. Next, (-)-(1R)-myrtenal (0.45 g, 3 mmol) was added, and the medium was heated for 5 h more until the formation of a white solid. Ten millilitres of distilled water was added, and the product was extracted with CH2Cl2 (3 x 4 mL). The solvent was evaporated, and the product was recrystallized from ethanol-water. (+)-Myrtenal was used as a chiral substrate for a study that led to ethyl (R)-4-((1R,5S)- 6,6-dimethylbicyclo [3.1.1]hept-2-en-2-yl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate by the Biginelli synthesis using EL as a green solvent. The result is the first example of the enantiospecific Biginelli reaction. The product was exhaustively characterized by several physical analysis methods, i.e., 1H, 13C and 2D nuclear magnetic resonance (NMR) spectroscopies, infrared (IR) spectroscopy, mass spectrometry (MS), and high-resolution MS (HRMS), and its structure was unequivocally elucidated by X-ray crystallography. Compound (4R)-4-(6,6-dimethylbicyclo[3.1.1]hept-2-en-2-yl)-6-methyl-2-oxo-1,2,3,4- tetrahydropyrimidine- 5-ethyl carboxylate is the first example of the enantiospecific Biginelli reaction. In addition, the process has the advantage of using EL as a green solvent. The product was characterized by 1H, 13C, and 2D NMR and IR spectroscopy, MS, HRMS, and X-ray crystallography.

Discovery of Phthalazinone Derivatives as Novel Hepatitis B Virus Capsid Inhibitors.

HBV capsid assembly has been viewed as an attractive target for new antiviral therapies against HBV. On the basis of a lead compound 4r, we further investigated this target to identify novel active compounds with appropriate anti-HBV potencies and improved pharmacokinetic (PK) properties. Structure-activity relationship studies based on metabolic pathways of 4r led to the identification of a phthalazinone derivative 19f with appropriate anti-HBV potencies (IC50 = 0.014 ± 0.004 μM in vitro), which demonstrated high oral bioavailability and liver exposure. In the AAV-HBV/mouse model, administration of 19f resulted in a 2.67 log reduction of the HBV DNA viral load during a 4-week treatment with 150 mg/kg dosing twice daily.