Design, synthesis, and biological evaluation of prazosin-related derivatives as multipotent compounds

To combine in the same molecule alpha(1)-adrenoreceptor blocking and antioxidant properties, compounds 2-5 were designed and synthesized. All compounds were effective alpha(1)-adrenoreceptor antagonists and were tested in both functional and binding assays. In addition, compounds 2 and 5 also displayed significant capacity to inhibit intracellular oxidative stress, whereas 3-5 exerted potent antiproliferative activity in lymph node carcinoma of prostate cells.     

Design,synthesis and biological evaluation of deuterated nintedanib for improving pharmacokinetic properties

Nintedanib is a novel triple angiokinase inhibitor that inhibits three growth factors simultaneously. Deuterated derivatives of nintedanib at certain metabolically active sites were prepared and evaluated in vitro and in vivo. In particular, deuterated compound SKLB‐C2202 had significantly improved pharmacokinetic properties compared with nintedanib. These efforts lay the foundation for further investigating the druggability of SKLB‐C2202.     

Design,synthesis, and in vitro biological evaluation of novel thiazolopyrimidine derivatives as antileishmanial compounds

A series of thiazolopyrimidine derivatives was designed and synthesized as a Leishmania major pteridine reductase 1 (LmPTR1) enzyme inhibitor. Their LmPTR1 inhibitor activities were evaluated using the enzyme produced by Escherichia coli in a recombinant way. The antileishmanial activity of the selected compounds was tested in vitro against Leishmania sp. Additionally, the compounds were evaluated for cytotoxic activity against the murine macrophage cell line RAW 264.7. According to the results, four compounds displayed not only a potent in vitro antileishmanial activity against promastigote forms but also low cytotoxicity. Among them, compound L16 exhibited an antileishmanial activity for both the promastigote and amastigote forms of L. tropica, with IC₅₀ values of 7.5 and 2.69 µM, respectively. In addition, molecular docking studies and molecular dynamics simulations were also carried out in this study. In light of these findings, the compounds provide a new potential scaffold for antileishmanial drug discovery.     

C-nitroso compounds: synthesis, physicochemical properties and biological activities

Because of the chemical and physical properties of nitric oxide, its effective use and delivery for therapeutic application represents a significant challenge. Accordingly, current understanding of nitric oxide biology largely stems from the use of nitric oxide prodrugs and adducts whose biological activities are based on their ability to release nitric oxide or a redox-related species. Among the structurally diverse ensemble of nitric oxide donor compounds reported to date are the C-nitroso compounds. These compounds have only recently been investigated with respect to their potential as nitric oxide donors, although they have been known and studied for over 120 years. Here, we consider the synthesis and physico-chemical properties of the C-nitroso compounds and the available data regarding their biological activities. Synthetic methods reviewed include direct substitution of H by NO, oxidative approaches, and the addition of various oxides of nitrogen across multiple bonds. The electronic spectra of C-nitroso compounds and the mechanism and thermodynamics of monomer-dimer equilibration are described. The physico-chemical and biological properties of two related classes of compounds, the diazetine dioxides and the furoxans, are also described.     

新型喹诺酮类化合物的设计合成与生物活性研究

目的设计合成具有抗肿瘤和抗HIV活性的新型喹诺酮类化合物。方法邻苯二胺衍生物和苯甲酰乙酸乙酯衍生物经缩合关环反应得到目标产物。结果与结论共合成5个未见文献报道的喹诺酮类化合物（7～11）,目标化合物的结构经1H—NMR、ESI-MS谱确证。并利用谱学方法解析了此类化合物的互变异构现象。其中,化合物11具有明显的抗肿瘤及抗HIV活性。     

Design, synthesis, and biological evaluation of new-generation taxoids

Novel second-generation taxoids with systematic modifications at the C2, C10, and C3'N positions were synthesized and their structure-activity relationships studied. A number of these taxoids exhibited exceptionally high potency against multidrug-resistant cell lines, and several taxoids exhibited virtually no difference in potency against the drug-sensitive and drug-resistant cell lines. These exceptionally potent taxoids were termed "third-generation taxoids". 19 (SB-T-1214), 14g (SB-T-121303), and 14i (SB-T-1213031) exhibited excellent activity against paclitaxel-resistant ovarian cancer cell lines with mutations in beta-tubulin as well, wherein the drug resistance is mediated by the beta-tubulin mutation. These taxoids were found to possess exceptional activity in promoting tubulin assembly, forming numerous very short microtubules similar to those formed by discodermolide. Taxoids 19 and 14g also showed excellent cytotoxicity against four pancreatic cancer cell lines, expressing three to four multidrug-resistant genes. Moreover, taxoid 19 exhibited excellent in vivo efficacy against highly drug-resistant CFPAC-1 pancreatic as well as DLD-1 human colon tumor xenografts in mice.     

Design,synthesis, and biological evaluation of multiple targeting antimalarials

Malaria still threatens global health seriously today. While the current discoveries of antimalarials are almost totally focused on single mode-of-action inhibitors, multi-targeting inhibitors are highly desired to overcome the increasingly serious drug resistance. Here, we performed a structure-based drug design on mitochondrial respiratory chain of Plasmodium falciparum and identified an extremely potent molecule, RYL-581, which binds to multiple protein binding sites of P. falciparum simultaneously (allosteric site of type II NADH dehydrogenase, Q_o and Q_i sites of cytochrome bc₁). Antimalarials with such multiple targeting mechanism of action have never been reported before. RYL-581 kills various drug-resistant strains in vitro and shows good solubility as well as in vivo activity. This structure-based strategy for designing RYL-581 from starting compound may be helpful for other medicinal chemistry projects in the future, especially for drug discovery on membrane-associated targets.     

Design, synthesis, and biological evaluation of potent c-Met inhibitors

c-Met is a receptor tyrosine kinase that plays a key role in several cellular processes but has also been found to be overexpressed and mutated in different human cancers. Consequently, targeting this enzyme has become an area of intense research in drug discovery. Our studies began with the design and synthesis of novel pyrimidone 7, which was found to be a potent c-Met inhibitor. Subsequent SAR studies identified 22 as a more potent analog, whereas an X-ray crystal structure of 7 bound to c-Met revealed an unexpected binding conformation. This latter finding led to the development of a new series that featured compounds that were more potent both in vitro and in vivo than 22 and also exhibited different binding conformations to c-Met. Novel c-Met inhibitors have been designed, developed, and found to be potent in vitro and in vivo.     

Novel anti-RSV dianionic dendrimer-like compounds: design, synthesis and biological evaluation

Human Respiratory Syncytial Virus (RSV) is considered to be the leading cause of lower respiratory tract disease in infants and young children. RSV is also a common pathogen in immunocompromised adults and in the elderly. RSV infection can be epidemic and is evident worldwide. Ribavirin, a small molecule agent, and Synagis, a monoclonal neutralizing antibody, are the only approved drugs for treatment and prevention of RSV in high-risk patients. This review is focused on a group of novel and specific inhibitors discovered at Wyeth-Ayerst Research. Some of these inhibitors have IC50 <50 nM and are active against all the tested group A and B viruses. They also have shown good efficacy in cotton rats and primates. Mechanism of action studies indicate that the compounds inhibit the next step in infection after adsorption suggesting that fusion is the target. A strong relationship between the inhibitor structures and their anti-RSV activity was established. This relationship appears to derive from a multivalent interaction between the functional groupings of the inhibitors and the F protein, which seem to be highly complementary and directional.     

Facile synthesis and biological evaluation of heterocyclic compounds containing diazepam

Diazepamoxadiazoles 4, 5, 6, 12, 14 and 22 were prepared with the binary form system. Diazepamthiadiazoles 15, 20 and Diazepamtriazoles 7, 8, 9, 17, 18, 19 and 21 were also shapely synthesized. Some of these compounds were screened to test their antibacterial activity against E. coli and B. subtilis compounds 15 and 20 show potent activity against these bacteria.     

Design, synthesis, and biological evaluation of conformationally restricted rivastigmine analogues

Rivastigmine (1), an acetylcholinesterase (AChE) inhibitor approved in 2000 for the treatment of Alzheimer disease, bears a carbamate moiety in its structure, which is able to react covalently with the active site of the enzyme. Kinetic and structural studies on the interaction of 1 with different cholinesterases have been published, giving deeper, but not definitive, insights on the catalysis mechanism. On the basis of these findings and in connection with our previous studies on a series of benzopyrano[4,3-b]pyrrole carbamates as AChE inhibitors, we designed a series of conformationally restricted analogues of 1 by including the dimethylamino-alpha-methylbenzyl moiety in different tricyclic systems. A superimposition between the conformation of 1 and the carbon derivative 4, as obtained from Monte Carlo simulations, supported the idea that the tricyclic derivatives might act as rigid analogues of 1. The biological profile of 4-9, assessed in vitro against human AChE and BChE, validated our rational design. Compound 5, bearing a sulfur-containing system, showed the highest inhibitory activity, being 192-fold more potent than 1. In the present study, the most potent inhibitors were always methyl derivatives 3-5, endowed with a nanomolar range potency, whereas the ethyl ones were 40 times less potent. A reasonable explanation for this finding might be a steric hindrance effect between the ethyl group of 1 and His440 in the active site, as already suggested by the crystal structure of the complex AChE/1. The unfavorable influence of the carbamic N-alkyl chain on AChE inhibition is less striking when considering BChE inhibition, since BChE is characterized by a bigger acyl binding pocket than AChE. In fact, methyl carbamates 3-5 did not show AChE/BChE selectivity, whereas compounds 6-9 were significantly more potent in inhibiting BChE than AChE activity. At 100 microM, 5 was found to inhibit the AChE-induced aggregation only by 19% likely because it is not able to strongly interact with the peripheral anionic site of AChE, which plays an essential role in the Abeta aggregation mediated by the enzyme but is lacking in BChE structure.     

联苯类PD-L1抑制剂的设计合成及生物活性评价

目的设计并合成新型联苯类PD-L1小分子抑制剂。方法以BMS-1018为先导化合物,通过变换苯环上取代基的相对位置,按照生物电子等排原理,结合分子对接技术,设计了3个系列联苯类目标化合物。采用均相时间分辨荧光法评价目标化合物对PD-1/PD-L1结合的抑制活性。结果与结论合成了10个未见文献报道的联苯类目标化合物,结构经~1H-NMR、ESI-MS谱确证。生物活性评价结果表明,大多数目标化合物对PD-L1显示不同程度的抑制活性。其中4个化合物A-1、A-3、A-4和C-2的活性较为突出,值得进一步研究。     

Design,synthesis, and biological activity evaluation of BACE1 inhibitors with antioxidant activity

The proteolytic enzyme β-secretase (BACE1) plays a central role in the synthesis of the pathogenic β-amyloid peptides (Aβ) in Alzheimer's disease (AD), antioxidants could attenuate the AD syndrome and prevent the disease progression. In this study, BACE1 inhibitors ( D1 – D18 ) with free radical-scavenging activities were synthesized by molecular hybridization of 2-aminopyridine with natural antioxidants. The biological activity evaluation showed that D1 had obvious inhibitory activity against BACE1, and strong antioxidant activity in 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS^+•) assay, which could be used as a lead compound for further study.     

Design,synthesis, antileishmanial,and antifungal biological evaluation of novel 3,5-disubstituted isoxazole compounds based on 5-nitrofuran scaffolds

Nineteen 3,5-disubstituted-isoxazole analogs were synthesized based on nitrofuran scaffolds, by a [3 + 2] cycloaddition reaction between terminal acetylenes and 5-nitrofuran chloro-oxime. The compounds were obtained in moderate to very good yields (45–91%). The antileishmanial activity was assayed against the promastigote and amastigote forms of Leishmania (Leishmania) amazonensis. Alkylchlorinated compounds 14p–r were active on both the promastigote and amastigote forms, with emphasis on compound 14p , which showed strong activity against the amastigote form (IC₅₀ = 0.6 μM and selectivity index [SI] = 5.2). In the alkyl series, compound 14o stands out with an IC₅₀ = 8.5 μM and SI = 8.0 on the amastigote form. In the aromatic series, the most active compounds were those containing electron-donor groups, such as trimethoxy isoxazole 14g (IC₅₀ = 1.2 μM and SI = 20.2); compound 14h , with IC₅₀ = 7.0 μM and SI = 6.1; and compound 14j containing the 4-SCH₃ group, with IC₅₀ = 5.7 μM and SI = 10.2. In addition, the antifungal activity of 19 nitrofuran isoxazoles was evaluated against five strains of Candida (C. albicans, C. parapsilosis, C. krusei, C. tropicalis, and C. glabrata). Eleven isoxazole derivatives were active against C. parapsilosis, and compound 14o was found to be the most active (minimal inhibitory concentration [MIC] = 3.4 μM) for this strain. Compound 14p was active against all the strains tested, with an MIC = 17.5 μM for C. glabrata, lower than that of the fluconazole used as the reference drug.     

Design, synthesis, and biological evaluation of 3,4-diarylmaleimides as angiogenesis inhibitors

The new analogue 2 of combretastatin A-4 was discovered to be an inhibitor of tubulin polymerization with an IC50 of 7.6 microM and reduced angiogenesis in the in vivo chick embryo model. Interestingly, in a series of 2,3-diarylmaleimides closely related to this lead, no other compound was found to be active in the tubulin polymerization assay. However, by screening in the in vivo chick embryo assay 10 was identified as a potent angiogenesis inhibitor indicating an alternative target. Indeed, molecular modeling studies suggest a reasonable binding mode of 10 at the ATP-binding site of the model kinase CDK2. Motivated by these results, analogues of 10 were screened for inhibitory activity in a panel of 12 selected protein kinases and a high affinity of 10 to VEGF-R2 was found showing an IC50 of 2.5 nM. Structure-activity relationships (SAR) for this compound series with the isolated enzyme and equivalent antiangiogenic activity in the chick embryo assay are presented herein.     

Design, synthesis, and biological evaluation of thiazoles targeting flavivirus envelope proteins

A series of third-generation analogues of methyl 4-(dibromomethyl)-2-(4-chlorophenyl)thiazole-5-carboxylate (1), which had the most potent antiviral activity among the first- and second-generation compounds, have been synthesized and tested against yellow fever virus using a cell-based assay. The compounds were designed with the objectives of improving metabolic stability, therapeutic index, and antiviral potency. The biological effects of C4 and C5 substitution were examined. The methylthio ester and the dihydroxypropylamide analogues had the best antiviral potencies and improved therapeutic indices and metabolic stabilities relative to the parent compound 1.     

Design,synthesis, and biological evaluation of monopyrrolinone-based HIV-1 protease inhibitors

The design, synthesis, and biological evaluation of a series of HIV-1 protease inhibitors [(-)-6, (-)-7, (-)-23, (+)-24] based upon the 3,5,5-trisubstituted pyrrolin-4-one scaffold is described. Use of a monopyrrolinone scaffold leads to inhibitors with improved cellular transport properties relative to the earlier inhibitors based on bispyrrolinones and their peptide counterparts. The most potent inhibitor (-)-7 displayed 13% oral bioavailability in dogs. X-ray structure analysis of the monopyrrolinone compounds cocrystallized with the wild-type HIV-1 protease provided valuable information on the interactions between the inhibitors and the HIV-1 enzyme. In each case, the inhibitors assumed similar orientations for the P2'-P1 substituents, along with an unexpected hydrogen bond of the pyrrolinone NH with Asp225. Interactions with the S2 pocket, however, were not optimal, as illustrated by the inclusion of a water molecule in two of the three inhibitor-enzyme complexes. Efforts to increase affinity by displacing the water molecule with second and third generation inhibitors did not prove successful. Lack of success with this venture is a testament to the difficulty of accurately predicting the many variables that influence and build binding affinity. Comparison of the inhibitor positions in three complexes with that of Indinavir revealed displacements of the protease backbones in the enzyme flap region, accompanied by variations in hydrogen bonding to accommodate the monopyrrolinone ring. The binding orientation of the pyrrolinone-based inhibitors may explain their sustained efficacy against mutant strains of the HIV-1 protease enzyme as compared to Indinavir.     

Design, synthesis, and biological evaluation of Plasmodium falciparum lactate dehydrogenase inhibitors

Plasmodium falciparum lactate dehydrogenase (pfLDH) is a key enzyme for energy generation of malarial parasites and is a potential antimalarial chemotherapeutic target. It is known that the oxamate moiety, a pyruvate analog, alone shows higher inhibition against pfLDH than human LDHs, suggesting that it can be used for the development of selective inhibitors. Oxamic acid derivatives were designed and synthesized. Derivatives 5 and 7 demonstrated activities against pfLDH with IC50 values of 3.13 and 1.75 muM, respectively, and have 59- and 7-fold selectivity over mammalian LDH, respectively. They also have micromolar range activities against Plasmodium falciparum malate dehydrogenase (pfMDH), which may fill the role of pfLDH when the activity of pfLDH is reduced. Thus, certain members of these oxamic acid derivatives may have dual inhibitory activities against both pfLDH and pfMDH. It is presumed that dual LDH/MDH inhibitors would have enhanced potential as antimalarial drugs.     

Design,synthesis, and biological evaluation of lipophilically modified bisphenol Z derivatives

In the present study, a small library of bisphenol Z (BPZ) derivatives was synthesized and investigated for anti‐proliferative effects in cultured breast and glioblastoma cell lines. Synthesized BPZ derivatives varied in molecular size, polarity, and lipophilicity. Of the 8 derivatives tested, compounds 4 and 6 , both of which displayed the highest degree of lipophilicity, were most active at inducing cell death as determined by the XTT assay. Cell membranes were interrogated using trypan blue staining and were shown to remain intact during treatments with 4 and 6 . Activation of caspase enzymes (3 and/or 7) was noted to occur following treatment with compound 4 . Polar BPZ derivatives, those with a substituted amine or alcohol, were devoid of any inhibitory or proliferative effects. The remaining derivatives seem to lack sufficient lipophilicity to execute an overt toxic effect. Our results suggest that increasing the lipophilic character of BPZ enhances the cytotoxic effects.