Discovery, X-ray Crystallography, and Anti-inflammatory Activity of Bromodomain-containing Protein 4 (BRD4) BD1 Inhibitors Targeting a Distinct New Binding Site

Bromodomain-containing protein 4 (BRD4) is an emerging epigenetic drug target for intractable inflammatory disorders. The lack of highly selective inhibitors among BRD4 family members has stalled the collective understanding of this critical system and the progress toward clinical development of effective therapeutics. Here we report the discovery of a potent BRD4 bromodomain 1 (BD1)-selective inhibitor ZL0590 (52) targeting a unique, previously unreported binding site, while exhibiting significant anti-inflammatory activities in vitro and in vivo. The X-ray crystal structural analysis of ZL0590 in complex with human BRD4 BD1 and the associated mutagenesis study illustrate a first-in-class nonacetylated lysine (KAc) binding site located at the helix αB and αC interface that contains important BRD4 residues (e.g., Glu151) not commonly shared among other family members and is spatially distinct from the classic KAc recognition pocket. This new finding facilitates further elucidation of the complex biology underpinning bromodomain specificity among BRD4 and its protein-protein interaction partners.

Natural inspired ligustrazine-based SLC-0111 analogues as novel carbonic anhydrase inhibitors

Ligustrazine is the principle bioactive alkaloid in the widely-used Chinese herb Chuan Xiong rhizome. Herein, a series of novel derivatives has been designed as human carbonic anhydrases inhibitors (hCAIs) starting from the natural product Ligustrazine inserted as a tail instead of the 4-fluorophenyl tail of SLC-0111, a front-runner selective hCA IX inhibitor currently in clinical trials as antitumor/antimetastatic agent. Other derivatives were designed via incorporation of different linkers, of amide and ester type, or incorporation of different zinc anchoring groups such as secondary sulfamoyl and carboxylic acid functionalities. The newly designed molecules were prepared following different synthetic pathways, and were assessed for their inhibitory actions against four isoforms: the widespread cytosolic (hCA I and II), and the transmembrane tumor-related (hCA IX and XII). The primary sulfonamides efficiently inhibited the target hCA IX and hCA XII in the nanomolar range (K_Is: 6.2-951.5 nM and 3.3-869.3 nM, respectively). The most selective hCA IX inhibitors 6c and 18 were assessed for their potential anticancer effects, and displayed anti-proliferative activity against MCF-7 cancer cell line with IC₅₀s of 11.9 and 36.7 μM, respectively. Molecular modelling studies unveiled the relationship between structural features and inhibitory profiles against the off-target hCA II and the target, tumor-related isoforms hCA IX and XII.

Oxa Analogues of Nexturastat A Demonstrate Improved HDAC6 Selectivity and Superior Antileukaemia Activity

The acetylome is important for maintaining the homeostasis of cells. Abnormal changes can result in the pathogenesis of immunological or neurological diseases, and degeneration can promote the manifestation of cancer. In particular, pharmacological intervention in the acetylome with pan-histone deacetylase (HDAC) inhibitors is clinically validated. However, these drugs exhibit an undesirable risk-benefit profile due to severe side effects. Selective HDAC inhibitors might promote patient compliance and represent a valuable opportunity in personalised medicine. Therefore, we envisioned the development of HDAC6-selective inhibitors. During our lead structure identification, we demonstrated that an alkoxyurea-based connecting unit proves to be beneficial for HDAC6 selectivity and established the synthesis of alkoxyurea-based hydroxamic acids. Herein, we report highly potent N-alkoxyurea-based hydroxamic acids with improved HDAC6 preference compared to nexturastat A. We further validated the biological activity of these oxa analogues of nexturastat A in a broad subset of leukaemia cell lines and demonstrated their superior anti-proliferative properties compared to nexturastat A.

Co-drug delivery of regorafenib and cisplatin with amphiphilic copolymer nanoparticles: enhanced in vivo antitumor cancer therapy in nursing care

Cancers continue to be the second leading cause of death worldwide. Despite the development and improvement of surgery, chemotherapy and radiotherapy in cancer management, effective tumor ablation strategies are still in need due to high cancer patient mortality. Hence, we have established a new approach to achieve treatment-actuated modifications in a tumor microenvironment by using synergistic activity between two potential anticancer drugs. Dual drug delivery of Regorafenib (REGO) and Cisplatin (PT) exhibits a great anticancer potential, as REGO enhances the effect of PT treatment of human cells by providing stability of the microenvironment. However, encapsulation of REGO and PT fanatical by methoxypoly(ethylene glycol)-block-poly(D, L-lactic acid) (PEG-PLA in termed as NPs) is incompetent owing to unsuitability between the binary Free REGO and PT core and the polymeric system. Now, we display that PT can be prepared by hydrophobic coating of the dual drug centers with dioleoylphosphatidic acid (DOPA). The DOPA-covered PT can be co-encapsulated in PLGA NPs alongside REGO to stimulate excellent anticancer property. The occurrence of the PT suggestively enhanced the encapsulations of REGO into PLGA NPs (REGO-PT NPs). Further, the morphology of REGO NPs, PT NPs, and REGO-PT NPs and nanoparticle size was examined by transmission microscopy (TEM), respectively. Furthermore REGO-PT NPs induced significant apoptosis in human lung A549 and ovarian A2780 cancer cells by in vitro. The morphological observation and apoptosis were confirmed by the various biochemical assayes (AO-EB, Nuclear Staining and Annexin V-FITC). In a xenograft model of lung cancer, this nanotherapy shows a durable inhibition of tumor progression upon the administration of a tolerable dose. Our results suggest that a hydrophobic and highly toxic drug can be rationally converted into a pharmacologically efficient and self-deliverable nursing care of nanotherapy. Highlights Dual drug delivery of Regorafenib (REGO) and Cisplatin (PT) exhibits a great anticancer potential, as REGO enhances the effect of PT treatment of human cells by providing stability of the microenvironment. REGO-PT NPs induced significant apoptosis in human lung A549 and ovarian A2780 cancer cells by in vitro. The morphological observation and apoptosis were confirmed by the various biochemical assayes. In a xenograft model of lung cancer, this nanotherapy shows a durable inhibition of tumor progression upon the administration of a tolerable dose.

A potentiated cooperation of carbonic anhydrase IX and histone deacetylase inhibitors against cancer

The emergence of tumour recurrence and resistance limits the survival rate for most tumour-bearing patients. Only, combination therapies targeting pathways involved in the induction and in the maintenance of cancer growth and progression might potentially result in an enhanced therapeutic efficacy. Herein, we provided a prospective combination treatment that includes suberoylanilide hydroxamic acid (SAHA), a well-known inhibitor of histone deacetylases (HDACs), and SLC-0111, a novel inhibitor of carbonic anhydrase (CA) IX. We proved that HDAC inhibition with SAHA in combination with SLC-0111 affects cell viability and colony forming capability to greater extent than either treatment alone of breast, colorectal and melanoma cancer cells. At the molecular level, this therapeutic regimen resulted in a synergistically increase of histone H4 and p53 acetylation in all tested cell lines. Overall, our findings showed that SAHA and SLC-0111 can be regarded as very attractive combination providing a potential therapeutic strategy against different cancer models.

Synthesis and biological evaluation of diaryl urea derivatives designed as potential anticarcinoma agents using de novo structure-based lead optimization approach

To develop inhibitors blocking VEGFR2 and the Raf/MEK/ERK mitogen-activated protein kinase signaling pathway new compounds based on sorafenib were designed, synthesized and biologically evaluated. Using de novo design method, a library of new ligands was generated and expanded. Considering in silico binding affinity towards VEGFR2, synthetic feasibility, and drug-likeness property, some of the designed ligands were selected for synthesis and screening for their in vitro antiproliferative activities against two cancer cell lines (HT-29 and A549). Four compounds (13a, 14a, 14l and 15b) exhibited stronger antiproliferative activity (with IC₅₀ values of 13.27, 6.62, 12.74, 3.38 μM, respectively) against HT-29 cells compared to that of the positive reference drug sorafenib (IC₅₀ = 17.28 μM). Notably, compound 15b demonstrated the highest activity, and in particular, it induced HT-29 apoptosis, increased intracellular reactive oxygen species level, arrested cell cycle at G0/G1 phase, and influenced the expression of apoptosis- and cell cycle-related proteins. 15b compound can effectively block the Raf/MEK/ERK pathway and inhibit VEGFR2 phosphorylation. Molecular docking revealed that 15b can bind well to the active site of VEGFR2 receptor. Collectively, 15b may be considered as a promising compound amenable for further investigation for the development of new anticancer agents.

Ureidobenzenesulfonamides as efficient inhibitors of carbonic anhydrase II

Sulfonamides represent an important class of drugs because of their inhibitory effect on carbonic anhydrases (CAs). We therefore synthesized several ureidobenzenesulfonamides and evaluated their bCA II inhibition for their potential use as anti-glaucoma gents. Since these compounds must not show cytotoxic effects, their cytotoxic potential against several human tumor cell lines and non-malignant fibroblasts was investigated. Several fluorophenyl substituted sulfonamides were efficient inhibitors of bCA II. Only one benzylphenyl substituted sulfonamide, however, showed a remarkable selectivity for HT29 colorectal carcinoma cells while being significantly less cytotoxic to non-malignant fibroblasts.

Design, Synthesis and Biological Evaluation of a New Series of 1-Aryl-3-{4-[(pyridin-2-ylmethyl)thio]phenyl}urea Derivatives as Antiproliferative Agents

To discover new antiproliferative agents with high efficacy and selectivity, a new series of 1-aryl-3-{4-[(pyridin-2-ylmethyl)thio]phenyl}urea derivatives (7a–7t) were designed, synthesized and evaluated for their antiproliferative activity against A549, HCT-116 and PC-3 cancer cell lines in vitro. Most of the target compounds demonstrated significant antiproliferative effects on all the selective cancer cell lines. Among them, the target compound, 1-[4-chloro-3-(trifluoromethyl)phenyl]-3-{4-{{[3-methyl-4-(2,2,2-trifluoroethoxy)pyridin-2-yl]methyl}thio}phenyl}urea (7i) was identified to be the most active one against three cell lines, which was more potent than the positive control with an IC₅₀ value of 1.53 ± 0.46, 1.11 ± 0.34 and 1.98 ± 1.27 μM, respectively. Further cellular mechanism studies confirmed that compound 7i could induce the apoptosis of A549 cells in a concentration-dependent manner and elucidated compound 7i arrests cell cycle at G1 phase by flow cytometry analysis. Herein, the studies suggested that the 1-aryl-3-{4-[(pyridin-2-ylmethyl)thio]phenyl}urea skeleton might be regarded as new chemotypes for designing effective antiproliferative agents.

Semisynthesis of an Anticancer DPAGT1 Inhibitor from a Muraymycin Biosynthetic Intermediate

We have explored a method to convert a muraymycin biosynthetic intermediate 3 to an anticancer drug lead 2 for in vivo and thorough preclinical studies. Cu(OAc)2 forms a stable complex with the amide 4 and prevents electrophilic reactions at the 2-((3-aminopropyl)amino)acetamide moiety. Under the present conditions, the desired 5″-primary amine was selectively protected with (Boc)2O to yield 6. The intermediate 6 was converted to 2 in two steps with 90% yield.

Identification and optimization of soluble epoxide hydrolase inhibitors with dual potency towards fatty acid amide hydrolase

Multi-target inhibitors have become increasing popular as a means to leverage the advantages of poly-pharmacology while simplifying drug delivery. Here, we describe dual inhibitors for soluble epoxide hydrolase (sEH) and fatty acid amide hydrolase (FAAH), two targets known to synergize when treating inflammatory and neuropathic pain. The structure activity relationship (SAR) study described herein initially started with t-TUCB (trans-4-[4-(3-trifluoromethoxyphenyl-l-ureido)-cyclohexyloxy]-benzoic acid), a potent sEH inhibitor that was previously shown to weakly inhibit FAAH. Inhibitors with a 6-fold increase of FAAH potency while maintaining high sEH potency were developed by optimization. Interestingly, compared to most FAAH inhibitors that inhibit through time-dependent covalent modification, t-TUCB and related compounds appear to inhibit FAAH through a time-independent, competitive mechanism. These inhibitors are selective for FAAH over other serine hydrolases. In addition, FAAH inhibition by t-TUCB appears to be higher in human FAAH over other species; however, the new dual sEH/FAAH inhibitors have improved cross-species potency. These dual inhibitors may be useful for future studies in understanding the therapeutic application of dual sEH/FAAH inhibition.

Identification, Synthesis, and Safety Assessment of Thidiazuron [1-Phenyl-3-(1,2,3-thidiazol-5-yl)urea] and Its Metabolites in Kiwifruits

The quality of kiwifruit became worse as a result of the abuse of plant growth regulators (PGRs). The safety of the fruits treated with PGRs also worried consumers. Therefore, the present study analyzed the structure of thidiazuron [TDZ, (1-phenyl-3-(1,2,3-thidiazol-5-yl)-urea)] (1) and its metabolites of biotransformation in kiwifruits using liquid chromatography hybrid ion trap time-of-flight mass spectrometry (LC-IT-TOF-MS). Standard compounds were also synthesized and used for structural identification of those metabolites. In addition, cytotoxicity of TDZ and its metabolites was tested through sulforhodamine B assays against normal Chinese hamster ovary (CHO) cells. Four metabolites were identified. They were 4-hydroxy-thidiazuron (2), 3-hydroxy-thidiazuron (3), thidiazuron-4-O-β-d-glucoside (4), and thidiazuron-3-O-β-d-glucoside (5). Values of IC₅₀ of compounds 1, 2, and 3 to CHO cells were 18.3 ± 1.8, 37.56 ± 1.5, and 23.36 ± 1.59 μM, respectively. Compounds 4 and 5 had no effect on CHO cells.

Functional N-Formyl Peptide Receptor 2 (FPR2) Antagonists Based on the Ureidopropanamide Scaffold Have Potential To Protect Against Inflammation-Associated Oxidative Stress

Formyl peptide receptor 2 (FPR2) is a G protein coupled receptor belonging to the N-formyl peptide receptor (FPR) family that plays critical roles in peripheral and brain inflammatory responses. FPR2 has been proposed as a target for the development of drugs that could facilitate the resolution of chronic inflammatory reactions by enhancing endogenous anti-inflammation systems. Starting from lead compounds previously identified in our laboratories, we designed a new series of ureidopropanamide derivatives with the goal of converting functional activity from agonism into antagonism and to develop new FPR2 antagonists. Although none of the compounds behaved as antagonists, some of the compounds were able to induce receptor desensitization and, thus, functionally behaved as antagonists. Evaluation of these compounds in an in vitro model of neuroinflammation showed that they decreased the production of reactive oxygen species in mouse microglial N9 cells after stimulation with lipopolysaccharide. These FPR2 ligands may protect cells from damage due to inflammation-associated oxidative stress.

Identification of Highly Specific Diversity-Oriented Synthesis-Derived Inhibitors of Clostridium difficile

In 2013, the Centers for Disease Control highlighted Clostridium difficile as an urgent threat for antibiotic-resistant infections, in part due to the emergence of highly virulent fluoroquinolone-resistant strains. Limited therapeutic options currently exist, many of which result in disease relapse. We sought to identify molecules specifically targeting C. difficile in high-throughput screens of our diversity-oriented synthesis compound collection. We identified two scaffolds with apparently novel mechanisms of action that selectively target C. difficile while having little to no activity against other intestinal anaerobes; preliminary evidence suggests that compounds from one of these scaffolds target the glutamate racemase. In vivo efficacy data suggest that both compound series may provide lead optimization candidates.

Synthesis of Novel 1-(4-Substituted pyridine-3-sulfonyl)-3-phenylureas with Potential Anticancer Activity

A series of novel 4-substituted-N-(phenylcarbamoyl)-3-pyridinesulfonamides 11–27 have been synthesized by the reaction of 4-substituted pyridine-3-sulfonamides 2–10 with the appropriate aryl isocyanates in presence of potassium carbonate. The in vitro anticancer activity of compounds 11, 12, 14–21 and 24–26 was evaluated at the U.S. National Cancer Institute and in light of the results, some structure-activity relationships were discussed. The most prominent compound, N-[(4-chlorophenyl)carbamoyl]-4-[4-(3,4-dichlorophenyl)piperazin-1-yl]pyridine-3-sulfonamide (21) has exhibited a good activity profile and selectivity toward the subpanels of leukemia, colon cancer and melanoma, with average GI₅₀ values ranging from 13.6 to 14.9 µM.

Discovery of biphenyl-aryl ureas as novel VEGFR-2 inhibitors. Part 4: exploration of diverse hinge-binding fragments

VEGFR-2 plays an essential role in angiogenesis and is an important target for cancer therapy. A series of biphenyl-aryl ureas were synthesized and evaluated as novel VEGFR-2 inhibitors. The pyridine, methylamine carbonyl pyridine and pivaloyl amide pyridine were introduced as novel hinge binding fragment. The majority of title compounds displayed potent VEGFR-2 inhibition. In particular, L1, L9, W14 and W15 exhibited significant enzymatic inhibitory activity with IC50 values of 0.36nM, 0.22nM, 0.15nM and 0.14nM. Compounds L1, L9 and W15 displayed potent antiproliferative activity against A549 and SMMC-7721 cells. SAR study suggested that incorporation of 3-trifluoromethyl and methylamine carbonyl on terminal pyridine could improve VEGFR-2 inhibitory activity. Molecular docking illustrated that urea moiety formed two critical hydrogen bonds with the DFG residues of VEGFR-2. The results indicated that these biphenyl-aryl ureas could serve as promising lead compounds for further optimization.

Identification, synthesis, and safety assessment of forchlorfenuron (1-(2-chloro-4-pyridyl)-3-phenylurea) and its metabolites in kiwifruits

Identification and evaluation of safety of forchlorfenuron ((1-(2-chloro-4-pyridyl)-3-phenylurea)), 1, metabolites after biotransformation in kiwifruit is the objective of this study. To elucidate properties of these metabolites, liquid chromatography hybrid ion trap time-of-flight mass spectrometry (LC-IT-TOF-MS) was applied, with MetID Solution and Formula Predictor Software in positive mode. Cytotoxicity of forchlorfenuron and its metabolites were tested through sulforhodamine B assays against normal Chinese hamster ovary cells (CHO). As deduced from characteristic fragment ions of forchlorfenuron, then confirmed by comparison with synthetic standards, as well as characterized by NMR and mass spectrometry techniques, results indicate the presence of 4-hydroxyphenyl-forchlorfenuron, 2, 3-hydroxyphenyl-forchlorfenuron, 3, and forchlorfenuron-4-O-β-D-glucoside, 5. Forchlorfenuron (IC50 = 12.12 ± 2.14 μM) and 4-hydroxyphenyl-forchlorfenuron (IC50 = 36.15 ± 1.59 μM), exhibits significant cytotoxicity against CHO, while 3-hydroxyphenyl-forchlorfenuron and forchlorfenuron-4-O-β-D-glucoside show no cytotoxicity.

Design, synthesis and insecticidal activity of novel phenylurea derivatives

A series of novel phenylurea derivatives were designed and synthesized according to the method of active groups linkage and the principle of aromatic groups bioisosterism in this study. The structures of the novel phenylurea derivatives were confirmed based on ESI-MS, IR and ¹H-NMR spectral data. All of the compounds were evaluated for the insecticidal activity against the third instars larvae of Spodoptera exigua Hiibner, Plutella xyllostella Linnaeus, Helicoverpa armigera Hubner and Pieris rapae Linne respectively, at the concentration of 10 mg/L. The results showed that all of the derivatives displayed strong insecticidal activity. Most of the compounds presented higher insecticidal activity against S. exigua than the reference compounds tebufenozide, chlorbenzuron and metaflumizone. Among the synthesized compounds, 3b, 3d, 3f, 4b and 4g displayed broad spectrum insecticidal activity.

Intestine-targeted DGAT1 inhibition improves obesity and insulin resistance without skin aberrations in mice

Objective

Diacylglycerol O-acyltransferase 1 (DGAT1) catalyzes the final committed step in triglyceride biosynthesis. DGAT1 null mice are known to be resistant to diet-induced obesity, and more insulin sensitive relative to the wild-type; however, the mice exhibit abnormalities in the skin. This work determined whether the intestine-targeted DGAT1 inhibitor could improve obesity and insulin resistance without skin aberrations in mice.

Design and Methods

We synthesized 2 DGAT1 inhibitors: Compound A, described in the patent application from the Japan Tobacco, and Compound B (A-922500), reported by Abbott Laboratories. Both compounds were evaluated for inhibitory activities against DGAT1 enzymes and effects on the skin in mice in vivo. Compound B was further investigated for effects on obesity and insulin resistance in diet-induced-obese (DIO) mice.

Results

The 2 compounds comparably inhibited the DGAT1 enzyme activity and the cellular triglyceride synthesis in vitro, while they showed different distribution patterns in mice in vivo. Compound A, which distributed systemically, caused skin aberrations, while Compound B, which preferentially distributed to the intestine, improved obesity and insulin resistance without skin aberrations in DIO mice.

Conclusions

Our results suggest that the intestine is the key tissue in which DGAT1 plays a role in promoting obesity and insulin resistance.

A novel compound T7 (N-{4'-[(1E)-N-hydroxyethanimidoyl]-3',5,6-trimethoxybiphenyl-3-yl}-N'-[4-(3-morpholin-4-ylpropoxy)phenyl]urea) screened by tissue angiogenesis model and its activity evaluation on anti-angiogenesis

A tissue model for angiogenesis that imitated new blood vessels formation in vivo had been established in the previous study. Here, it was used to screen and evaluate a series of synthesized compounds and the results indicated that compound T7 (N-{4'-[(1E)-N-hydroxyethanimidoyl]-3',5,6-trimethoxybiphenyl-3-yl}-N'-[4-(3-morpholin-4-ylpropoxy)phenyl]urea) could effectively inhibit the blood vessels formation. Then the anti-angiogenic potential of T7 and its related molecular mechanisms against lung carcinoma in vitro and in vivo were investigated. Treatment with T7 significantly inhibited human umbilical vein endothelial cells and A549 cells proliferation and migration. T7 reduced human umbilical vein endothelial cells tube formation as well. Western blotting analysis of cell signaling molecules indicated that T7 reduced phosphorylation of KDR and its downstream signaling players AKT and ERK1/2 activation in endothelial cells and A549 cells. Moreover, T7 inhibited tumor growth in A549 xenografted model of athymic mice and reduced CD34 expression levels in tumor-bearing mice by immunohistochemistry. In sum, our findings showed that T7 was a candidate of tumor angiogenesis inhibitors, and it functioned by interrupting the autophosphorylation of KDR, AKT and ERK1/2.

Structure driven design of novel human ether-a-go-go-related-gene channel (hERG1) activators

One of the main culprits in modern drug discovery is apparent cardiotoxicity of many lead-candidates via inadvertent pharmacologic blockade of K⁺, Ca²⁺ and Na⁺ currents. Many drugs inadvertently block hERG1 leading to an acquired form of the Long QT syndrome and potentially lethal polymorphic ventricular tachycardia. An emerging strategy is to rely on interventions with a drug that may proactively activate hERG1 channels reducing cardiovascular risks. Small molecules-activators have a great potential for co-therapies where the risk of hERG-related QT prolongation is significant and rehabilitation of the drug is impractical. Although a number of hERG1 activators have been identified in the last decade, their binding sites, functional moieties responsible for channel activation and thus mechanism of action, have yet to be established. Here, we present a proof-of-principle study that combines de-novo drug design, molecular modeling, chemical synthesis with whole cell electrophysiology and Action Potential (AP) recordings in fetal mouse ventricular myocytes to establish basic chemical principles required for efficient activator of hERG1 channel. In order to minimize the likelihood that these molecules would also block the hERG1 channel they were computationally engineered to minimize interactions with known intra-cavitary drug binding sites. The combination of experimental and theoretical studies led to identification of functional elements (functional groups, flexibility) underlying efficiency of hERG1 activators targeting binding pocket located in the S4–S5 linker, as well as identified potential side-effects in this promising line of drugs, which was associated with multi-channel targeting of the developed drugs.

[Synthesis and in vitro cytotoxic activities of sorafenib derivatives]

A series of novel sorafenib analogues were designed and synthesized. The cytotoxic activities of these compounds were tested in four tumor cell lines. Some of the compounds showed potent antiproliferative activity against the tested cell lines with IC50 = 4-20 micromol x L(-1). Some compounds demonstrated competitive antiproliferative activities to sorafenib against tested cancer cell lines. Among them, compound 7c demonstrated significant inhibitory activities on ACHN, HCT116 and MDA-MB-231 cell lines with IC50 values of 9.01, 4.97, 6.61 micromol x L(-1), respectively.

Synthesis and in vitro antitumor activities of novel benzyl urea analogues of sorafenib

A novel series of benzyl urea analogues based on the structural modification of sorafenib were synthesized. Their in vitro antitumor activities against MX-1, HepG2, Ketr3 and HT-29 were evaluated using the standard MTT assay. While several target compounds showed inhibitory activity against multiple cancer cell lines, compound 9 was of particular interest, demonstrating IC50 values (5.69-13.6 micromol x L(-1)) comparable to those of sorafenib. Furthermore, compounds 20 and 23 showed more potent inhibitory activity against HT-29 and MX-1 when compared to sorafenib. In particular, compound 20 bearing the N-3-pyridyl moiety not only exhibited greater inhibitory activity against HT-29 cell line (IC50 3.82 micromol x L(-1)), but also had improved solubility at pH 7.2, is worthy of further investigation as a lead to identify novel antitumor agents.

Design, synthesis, and insecticidal evaluation of new benzoylureas containing amide and sulfonate groups based on the sulfonylurea receptor protein binding site for diflubenzuron and glibenclamide

On the basis of the sulfonylurea receptor (SUR) protein binding site for diflubenzuron and glibenclamide, 15 new benzoylphenylureas containing amide and sulfonate groups were designed and synthesized. Their structures were characterized by (1)H nuclear magnetic resonance (NMR) and elemental analysis [or high-resolution mass spectrometry (HRMS)]. The larvicidal activities of the new compounds against oriental armyworm and diamondback moth were evaluated. Compound II-3 showed nearly the same level of insecticidal activity against oriental armyworm as commercial insecticide flucycloxuron and, thus, emerged as a new lead compound for the development of new benzoylurea insecticides.

[Design, synthesis and antitumor activity of sorafenib analogues containing 2-picolinylhydrazide moiety]

A novel series of sorafenib analogs containing 2-picolinyl hydrazide moiety were designed and synthesized. In vitro, most of synthesized compounds have antiproliferation activity on MDA-MB-231, ACHN, HepG2, Mia-PaCa-2 and SW1990 cell lines tested by MTT assay. It is worth noting that the antitumor activities of compounds 2c, 2d and 2f are more potent than that of sorafenib on pancreatic cancer cells Mia-PaCa-2 and SW1990, and the activities of compounds 3f and 3g are 2-3 times than that of sorafenib on human hepatocellular carcinoma HepG2 cell line.

Synthesis, characterization and anti-microbial activity of phenylurea-formaldehyde resin (PUF) and its polymer metal complexes (PUF-Mn(II)

Phenylurea-formaldehyde polymer (PUF) was synthesized via polycondensation of phenylurea and formaldehyde in basic medium, its polymer-metal complexes [PUF-M(II)] were prepared with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) ions. PUF and PUF-M(II) were characterized with magnetic moment measurements, elemental and spectral (UV-visible, FTIR, 1H-NMR, 13C-NMR and ESR) analysis. The thermal behaviors of all the synthesized polymers were carried out using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The thermal data revealed that all of the PUF-M(II) showed higher thermal stabilities than the PUF and also ascribed that the PUF-Cu(II) showed better thermal stability than the other PUF-M(II). The kinetic parameters such as activation energy, pre-exponential factor etc., were evaluated for these polymer metal complexes using Coats-Redfern equation. In addition, the antimicrobial activity of the synthesized polymers was tested against several microorganisms using agar well diffusion methods. Among all of the PUF-M(II), the antimicrobial activity of the PUF-Cu(II) showed the highest zone of inhibition because of its higher stability constant and may be used in biomedical applications.

Design, synthesis and biological activities of sorafenib derivatives as antitumor agents

A series of novel sorafenib derivatives, 9a-w, was designed and synthesized in high yields using various substituted anilines, and their antiproliferative activities against HCT116, PC-3 and MDA-MB-231 cell lines were also evaluated and described. All compounds exhibited potent antiproliferative activity against HCT116 and PC-3 cells with IC(50)=2.8-52.0 and 2.2-45.6 μM; compounds 9p and 9q demonstrated competitive antiproliferative activities to sorafenib against all three cancer cell lines, the cytotoxicity of compound 9r is more potent than that of sorafenib. Compounds (9g, 9p, 9q and 9r) were chosen for further evaluation of the anti-angiogenesis activity, and showed the inhibition of sprout formation from aortic ring ex vivo. The structures of all the newly synthesized compounds were determined by (1)H NMR, (13)C NMR and HRMS.

[Advances in the study of structural modifications of multi-target anticancer drug sorafenib]

Sorafenib, the first oral multikinase inhibitor, can inhibit several kinases involved in tumor proliferation and angiogenesis including Raf, VEGFR, PDGFR, kit and so on. Due to the advantages of multi-mechanisms, broad-spectrum anticancer potency, and well-tolerated results in combination trials, more and more researchers have focused on the optimization of sorafenib in order to develop novel multi-targeted anticancer drugs. The present paper reviews the development of modification of sorafenib in recent years from two aspects: bio-isosterism and scaffold hopping. The structure-activity relationship (SAR) of these compounds is also summarized.

Discovery of 1-[4-(N-benzylamino)phenyl]-3-phenylurea derivatives as non-peptidic selective SUMO-sentrin specific protease (SENP)1 inhibitors

We developed 1-[4-(N-benzylamino)phenyl]-3-phenylurea derivative 4 (GN6958) as a non-peptidic selective SUMO-sentrin specific protease (SENP)1 protease inhibitor based on the hypoxia inducible factor (HIF)-1α inhibitor 1 (GN6767). The direct interaction of compound 1 with SENP1 protein in cells was observed by the pull-down experiments using the biotin-tagged compound 2 coated on the streptavidin affinity column. Among the various 1-[4-(N-benzylamino)phenyl]-3-phenylurea derivatives tested, compounds 3 and 4 suppressed HIF-1α accumulation in a concentration-dependent manner without affecting the expression level of tubulin protein in HeLa cells. Both compounds inhibited SENP1 protease activity in a concentration-dependent manner, and compound 4 exhibited more potent inhibition than compound 3. Compound 4 exhibited selective inhibition against SENP1 protease activity without inhibiting other protease enzyme activities in vitro.

Inhibitors of Dengue virus and West Nile virus proteases based on the aminobenzamide scaffold

Dengue and West Nile viruses (WNV) are mosquito-borne members of flaviviruses that cause significant morbidity and mortality. There is no approved vaccine or antiviral drugs for human use to date. In this study, a series of functionalized meta and para aminobenzamide derivatives were synthesized and subsequently screened in vitro against Dengue virus and West Nile virus proteases. Four active compounds were identified which showed comparable activity toward the two proteases and shared in common a meta or para(phenoxy)phenyl group. The inhibition constants (K(i)) for the most potent compound 7n against Dengue and West Nile virus proteases were 8.77 and 5.55 μM, respectively. The kinetics data support a competitive mode of inhibition of both proteases by compound 7n. This conclusion is further supported by molecular modeling. This study reveals a new chemical scaffold which is amenable to further optimization to yield potent inhibitors of the viral proteases via the combined utilization of iterative medicinal chemistry/structure-activity relationship studies and in vitro screening.

Design and development of novel insect growth regulators: synthesis, characterization and effect of benzoyl thymyl thioureas and ureas on total haemocyte count of Dysdercus koenigii

Insect-growth regulators (IGRs) have been receiving foremost attention as potential means of selective insect control. Benzoyl phenyl urea (BPU) is a well-known IGR having chitin synthesis inhibitor activity. Mimics of BPU have been synthesized by suitable derivatization of a naturally occurring monoterpenoid, thymol (2-isopropyl-5-methyl phenol) to form a = series of substituted benzoyl thymyl thioureas (BTTUs) [IVa-f] and benzoyl thymyl ureas (BTUs) [Va-f]. The synthesized compounds have been characterized by (1)H and (13)C NMR, LC-MS and elemental analysis. These derivatives have been screened for their effect on total haemocyte count of Dysdercus koenigii. It has been observed that the introduction of substituted benzoyl thiourea and urea linkage into a thymol ring via an amino group results in higher activity than the parent compound thymol and a comparable pattern of results with the standard insect-growth regulators, Penfluron. Urea [Va-f] compounds exhibited greater effect on Total Haemocyte Count (THC) than thiourea [IVa-f]. Fluoro substitution enhanced the effect on THC more than chloro substituted compounds, while ortho-substitution resulted in a better effect than para-substitution. The results described in this paper are promising and provide new array of synthetic chemicals that may be utilized as insect growth regulators.

[Synthesis and biological evaluation of sorafenib thiourea derivatives]

Basing on the market multi-target antitumor agent sorafenib, a series of sixteen 4-[4-(2-methyl-aminoacyl-pyridyl)]oxylphenyl aryl thiourea derivatives were designed and synthesized. Their structures were identified by the spectra of 1H NMR, MS and elemental analysis. The evaluation of antitumor bioactivities in vitro was done by MTT method. It was shown that the synthesized compounds had antitumor activities and compounds 1a, 1d, 1i and 1j showed better or equal antitumor activity on sorafenib.

Discovery, optimization, and pharmacological characterization of novel heteroaroylphenylureas antagonists of C-C chemokine ligand 2 function

Through the application of TRAP (target-related affinity profiling), we identified a novel class of heteroaroylphenylureas that inhibit human CCL2-induced chemotaxis of monocytes/macrophages both in vitro and in vivo. This inhibition was concentration-dependent and selective with regard to other chemokines. The compounds, however, did not antagonize the binding of (125)I-labeled CCL2 to the CCR2 receptor nor did they block CCR2-mediated signal transduction responses such as calcium mobilization. Optimization of early leads for potency and pharmacokinetic parameters resulted in the identification of 17, a potent inhibitor of chemotaxis (IC(50) = 80 nM) with excellent oral bioavailability in rats (F = 60%). Compound 17 reduced swelling and joint destruction in two rat models of rheumatoid arthritis and delayed disease onset and produced near complete resolution of symptoms in a mouse model of multiple sclerosis.

Design and synthesis of benzoylphenylureas with fluorinated substituents on the aniline ring as insect growth regulators

Enormous numbers of synthetic fluorine-containing compounds have been widely used in a variety of fields, especially in drug and pesticide design. To find novel insect growth regulators, a series of benzoylphenylureas with fluorinated substituents were designed and synthesized. The results of larvicidal activities of those novel fluoro-substituted benzoylphenylureas against oriental armyworm and mosquito revealed that most compounds exhibited excellent activities. It is worth mentioning that compounds 3 and 6 exhibited higher activities against oriental armyworm and mosquito than commercial Hexaflumuron. It can be further seen that the insecticidal activities would increase significantly by introducing fluorinated substituents into the structure of the designed benzoylphenylureas.

Synthesis and triplex-forming ability of oligonucleotides bearing 1-substituted 1H-1,2,3-triazole nucleobases

Using the copper(I)-catalyzed alkyne-azide 1,3-dipolar cycloaddition, a post-elongation modification of 1-ethynyl substituted nucleobases has been employed to construct 18 variations of oligonucleotides from a common oligonucleotide precursor. The triplex-forming ability of each oligonucleotide with dsDNA was evaluated by the UV melting experiment. It was found that triazole nucleobases generally tend to exhibit binding affinities in the following order: CG>TA>AT, GC base pairs. Among the triazole nucleobases examined, a 1-(4-ureidophenyl)triazole provided the best result with regard to affinity and selectivity for the CG base pair.

Discovery of N-benzyl-N'-(4-pipyridinyl)urea CCR5 antagonists as anti-HIV-1 agents (I): optimization of the amine portion

Several series of carbamate, urea and carboxamide-based CCR5 antagonists have been discovered via optimizations at the amine portion of lead compound 2. All compounds were evaluated for their antiviral activities. Lead urea 29 showed good pharmacokinetic properties, justifying further development of this series.

Switch control pocket inhibitors of p38-MAP kinase. Durable type II inhibitors that do not require binding into the canonical ATP hinge region

Switch control pocket inhibitors of p38-alpha kinase are described. Durable type II inhibitors were designed which bind to arginines (Arg67 or Arg70) that function as key residues for mediating phospho-threonine 180 dependant conformational fluxing of p38-alpha from an inactive type II state to an active type I state. Binding to Arg70 in particular led to potent inhibitors, exemplified by DP-802, which also exhibited high kinase selectivity. Binding to Arg70 obviated the requirement for binding into the ATP Hinge region. X-ray crystallography revealed that DP-802 and analogs induce an enhanced type II conformation upon binding to either the unphosphorylated or the doubly phosphorylated form of p38-alpha kinase.

Synthesis and bioactivity of N-benzoyl-N'-[5-(2'-substituted phenyl)-2-furoyl] semicarbazide derivatives

In order to find novel chitin synthesis inhibitors (CSIs) with good activity, benzoylphenylurea, a typical kind of CSIs, was chosen as the lead compound and 15 novel derivatives containing furan moieties were designed by converting the urea linkage of benzoylphenylureas into a semicarbazide and changing the aniline part into furoyl groups. The title compounds were synthesized by the reaction of substituted benzoyl isocyanates with 5-(substituted phenyl)-2-furoyl hydrazine, and the structures were confirmed by IR, (1)H-NMR, elemental analysis and single crystal X-ray diffraction analyses (compound E2). The bioassay results indicated that the title compounds exhibit good insecticidal activity, especially towards Plutella xylostella L., but had lower fungicidal activity. Inspiringly, the title compounds possessed obvious anticancer activity against human promyelocytic leukemic cell line (HL-60), and some of the title compounds also had activity against human hepatocellular carcinoma cell line (Bel-7402), human gastric carcinoma cell line (BGC-823), and human nasopharyngeal carcinoma cell line (KB). The results indicated that the linkage in the lead compounds was important to the bioactivity and spectra. The modification on the urea linkage is an effective strategy to discover new pesticide and drug candidates.

Synthesis and insecticidal activity of heptafluoroisopropyl-containing benzoylphenylurea structures

Fourteen novel heptafluoroisopropyl-containing benzoylphenylureas were designed and synthesized. Their insecticidal activities against armyworm ( Pseudaletia separata Walker) were examined and compared with the commercial product diflubenzuron. Three compounds (IIi, IIj, and IIk) showed excellent insecticidal effect, and their activity resembled that of diflubenzuron. Compound IIi also showed nearly the same insecticidal activity as novaluron on African cotton leafworm ( Spodoptera littoralis ). Furthermore, results from a field trial indicated that 5% EC IIi exhibited similar efficacy in comparison with chlorfluazuron and hexaflumuron against imported cabbage worm ( Pieris rapae L.) and diamondback moth ( Plutella xylostella ), respectively.

Design, synthesis, and insecticidal activities of new N-benzoyl-N'-phenyl-N'-sulfenylureas

A series of new N'-alkylaminothio, N'-arylaminothio (or dithio), and N',N'-thio (or dithio) derivatives of N-benzoyl-N'-phenylureas were designed and synthesized as insect-growth regulators with sulfur dichloride or disulfur dichloride as the original reactant. The new compounds were identified by (1)H nuclear magnetic resonancee (NMR) spectroscopy, elemental analysis [or high-resolution mass spectrometry (HRMS)], and single-crystal X-ray diffraction analysis. The X-ray results demonstrated that there exist N-S-N or N-S-S-N bonds in these new compounds. In comparison to the parent N-benzoyl-N'-phenylureas, these derivatives displayed better solubility. The insecticidal activities of the target compounds were evaluated. The results of bioassays showed that compounds 1-24 retained the larvicidal activities of the corresponding benzoylphenylureas (BPUs) and some compounds exhibited better larvicidal activities against oriental armyworm and mosquitoes than the parent BPUs. The larvicidal activities of the selected target compounds 1 and 24 against diamondback moth were better than that of the corresponding parent compounds E and triflumuron.

Synthesis and in vitro characterization of radioiodinatable benzodiazepines selective for type 1 and type 2 cholecystokinin receptors

Radiolabeled antagonists of specific peptide receptors identify a higher number of receptor binding sites than agonists and may thus be preferable for in vivo tumor targeting. In this study, two novel radioiodinated 1,4-benzodiazepines, (S)-1-(3-iodophenyl)-3-(1-methyl-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)urea (9) and (R)-1-(3-iodophenyl)-3-(1-methyl-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)urea (7), were developed. They were characterized in vitro as high affinity selective antagonists at cholecystokinin types 1 and 2 (CCK(1) and CCK(2)) receptors using receptor binding, calcium mobilization, and internalization studies. Their binding to human tumor tissues was assessed with in vitro receptor autoradiography and compared with an established peptidic CCK agonist radioligand. The (125)I-labeled CCK(1) receptor-selective compound 9 often revealed a substantially higher amount of CCK(1) receptor binding sites in tumors than the agonist (125)I-CCK. Conversely, the radioiodinated CCK(2) receptor-selective compound 7 showed generally weaker tumor binding than (125)I-CCK. In conclusion, compound 9 is an excellent radioiodinated nonpeptidic antagonist ligand for direct and selective labeling of CCK(1) receptors in vitro. Moreover, it represents a suitable candidate to test antagonist binding to CCK(1) receptor-expressing tumors in vivo.

Design, synthesis, bioactivity, and structure-activity relationship (SAR) studies of novel benzoylphenylureas containing oxime ether group

Novel benzoylphenylureas containing an oxime ether group were designed and synthesized by four schemes. These benzoylphenylureas were identified by (1)H NMR spectroscopy and element analysis (or HRMS). The bioactivities of the new compounds were evaluated. These benzoylphenylureas exhibited excellent larvicidal activities against oriental armyworm, some of which were much better in comparison with the commercial Flucycloxuron. In particular, the larvicidal activities against oriental armyworm of compounds 1 and 23 were 5-10 times better than that of Flucycloxuron. Most of these benzoylphenyureas exhibited excellent larvicidal activities against mosquito. At the same time, some of these compounds have good plant growth regulatory activities as well.

1,3-disubstituted ureas functionalized with ether groups are potent inhibitors of the soluble epoxide hydrolase with improved pharmacokinetic properties

Soluble epoxide hydrolase (sEH) is a therapeutic target for treating hypertension and inflammation. 1,3-Disubstituted ureas functionalized with an ether group are potent sEH inhibitors. However, their relatively low metabolic stability leads to poor pharmacokinetic properties. To improve their bioavailability, we investigated the effect of incorporating various polar groups on the ether function on the inhibition potencies, physical properties, in vitro metabolic stability, and pharmacokinetic properties. The structure-activity relationship studies showed that a hydrophobic linker between the urea group and the ether function is necessary to keep their potency. In addition, urea-ether inhibitors having a polar group such as diethylene glycol or morpholine significantly improved their physical properties and metabolic stability without any loss of inhibitory potency. Furthermore, improved pharmacokinetic properties in murine and canine models were obtained with the resulting inhibitors. These findings will facilitate the usage of sEH inhibitors in animal models of hypertension and inflammation.

RSV604, a novel inhibitor of respiratory syncytial virus replication

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infections worldwide, yet no effective vaccine or antiviral treatment is available. Here we report the discovery and initial development of RSV604, a novel benzodiazepine with submicromolar anti-RSV activity. It proved to be equipotent against all clinical isolates tested of both the A and B subtypes of the virus. The compound has a low rate of in vitro resistance development. Sequencing revealed that the resistant virus had mutations within the nucleocapsid protein. This is a novel mechanism of action for anti-RSV compounds. In a three-dimensional human airway epithelial cell model, RSV604 was able to pass from the basolateral side of the epithelium effectively to inhibit virus replication after mucosal inoculation. RSV604, which is currently in phase II clinical trials, represents the first in a new class of RSV inhibitors and may have significant potential for the effective treatment of RSV disease.

Synthesis and Biological Evaluation of N-Pyrazolyl-N‘-alkyl/benzyl/phenylureas: a New Class of Potent Inhibitors of Interleukin 8-Induced Neutrophil Chemotaxis

Neutrophils chemotaxis is a complex multistep process that, if upregulated, causes acute inflammation and a number of autoimmune diseases. We report here the synthesis of a new N-(4-substituted)pyrazolyl-N'-alkyl/benzyl/phenylureas that are potent inhibitors of interleukin-8 (IL8)-induced neutrophil chemotaxis. The first series of compounds, obtained by functionalization with a urea moiety of the 5-amino-1-(2-hydroxy-2-phenylethyl)-1H-pyrazole-4-carboxylic acid ethyl ester 3, blocked the IL8-induced neutrophil chemotaxis, while they did not block N-formylmethionylleucylphenylalanine-mediated chemotaxis. The most active compounds, 3-benzyl- (4d), 3-(4-benzylpiperazinyl)- (4i), 3-phenyl- (4k) and 3-isopropylureido (4a) derivatives, showed an IC50 of 10, 14, 45, and 55 nM, respectively. Several different molecules were then synthesized to obtain more information for SAR study. Compounds 4a, 4d, and 4k were inactive in the binding assays on CXCR1 and CXCR2 (IL8 receptors), whereas they inhibited the phosphorylation of PTKs (protein tyrosine kinases) in the 50-70 kDa region. Moreover, in the presence of the same derivatives, we observed a complete block of F-actin rise and pseudopod formation.

In Vitro Structure−Activity Relationship and In Vivo Characterization of 1-(Aryl)-3-(4-(amino)benzyl)urea Transient Receptor Potential Vanilloid 1 Antagonists

The synthesis and structure-activity relationship of 1-(aryl)-3-(4-(amino)benzyl)urea transient receptor potential vanilloid 1 (TRPV1) antagonists are described. A variety of cyclic amine substituents are well tolerated at the 4-position of the benzyl group on compounds containing either an isoquinoline or indazole heterocyclic core. These compounds are potent antagonists of capsaicin activation of the TRPV1 receptor in vitro. Analogues, such as compound 45, have been identified that have good in vivo activity in animal models of pain. Further optimization of 45 resulted in compound 58 with substantially improved microsome stability and oral bioavailability, as well as in vivo activity.

Development of two novel benzoylphenylurea sulfur analogues and evidence that the microtubule-associated protein tau is predictive of their activity in pancreatic cancer

In this work, we evaluated two lead compounds, referred to as SG410 and SG430, obtained from a screen of sulfur benzoylphenylurea analogues, against in vitro and in vivo models of pancreas cancer. Both drugs showed a similar mechanism of action profile, with SG410 being more potent as an inhibitor of tubulin assembly. We determined the best in vivo administration schedule and tested SG410 and SG430 in nine cases of a novel platform of direct pancreas cancer xenografts. Both compounds had antiproliferative activity in vitro in the low nanomolar range, but only SG410 showed significant activity in vivo. Administration of SG410 resulted in significant tumor growth delay in five of nine groups tested. In a direct comparison in three of the cases, SG410 was at least as efficacious as docetaxel. We also sought markers that would be predictive of the efficacy of these agents, and we found such a marker in microtubule-associated protein tau (MAPT). This protein enhances the assembly and stability of microtubules. In both the cell lines and the direct human xenografts, MAPT mRNA and protein levels correlated well. There was also a statistically significant inverse correlation between MAPT expression and sensitivity to the tested agents. In summary, the novel sulfur benzoylphenylurea SG410 showed activity inversely related to MAPT expression in a preclinical model of pancreatic cancer comparable with that observed with docetaxel, another microtubule-targeting agent.

Insecticidal benzoylphenylurea-S-carbamate: a new propesticide with two effects of both benzoylphenylureas and carbamates

New propesticides with two effects of both benzoylphenylureas and carbamates were designed and synthesized by the key intermediate N-chlorosulfenyl-N-methylcarbamate, which was prepared for the first time. These benzoylphenylurea-S-carbamates were identified by 1H NMR spectroscopy and elemental analyses. The bioactivities of the new compounds were evaluated. These benzoylphenylurea-S-carbamates exhibited excellent larvicidal activities against Oriental armyworm, some of which were good as compared to the parent benzoylphenylureas. Toxicity assays indicated that these benzoylphenylurea-S-carbamates had knockdown activities of carbamates at higher concentrations and insect growth regulator activities of benzoylphenylureas at lower concentrations. We found that the title compounds exhibited good systemic larvicidal activities against Oriental armyworm, which were especially advantageous when combating sucking pests. Some of these title compounds can kill aphids and mosquitoes as well.

Understanding the degradation pathway of a poorly water-soluble drug formulated in PEG-400

VX-497 is a poorly water-soluble compound. It is formulated in PEG-400 and encapsulated in softgel capsules. Although the drug product is stable at refrigerated conditions, many degradation peaks have been observed at accelerated storage conditions. An investigation utilizing high performance liquid chromatography-mass spectrometry (HPLC-MS) was conducted to understand the degradation mechanism of the active pharmaceutical ingredient (VX-497) in PEG-400 formulation. Results revealed that the degradation was mainly caused by the reaction between VX-497 with moisture (hydrolysis) and PEG-400 (PEGylation). The numerous degradation peaks observed in the samples stored at accelerated conditions were PEG adducts covalently attached to portions of the VX-497 molecule, which were confirmed by comparison with synthetic markers. Investigation also found that an impurity, which was present in the VX-497 drug substance, reacted with PEG-400 following the same reaction mechanism, and generated additional impurities in the VX-497 drug product. By changing the process for drug substance synthesis, pure batches of VX-497 were obtained. Furthermore, it was found that the reaction between VX-497 and PEG-400 was temperature and time dependent. When the drug product was manufactured at 45 degrees C and the processing time was controlled, the PEG degradants and by-products were reduced to non-detectable levels, resulting in greatly improved drug product quality. This paper presents an integrated effort among analytical, process, and formulation scientists on how to develop a better drug product by understanding the fundamental issues of the drug product, namely the degradation mechanism.

Discovery of N-(4-(3-amino-1H-indazol-4-yl)phenyl)-N'-(2-fluoro-5-methylphenyl)urea (ABT-869), a 3-aminoindazole-based orally active multitargeted receptor tyrosine kinase inhibitor

In our continued efforts to search for potent and novel receptor tyrosine kinase (RTK) inhibitors as potential anticancer agents, we discovered, through a structure-based design, that 3-aminoindazole could serve as an efficient hinge-binding template for kinase inhibitors. By incorporating an N,N'-diaryl urea moiety at the C4-position of 3-aminodazole, a series of RTK inhibitors were generated, which potently inhibited the tyrosine kinase activity of the vascular endothelial growth factor receptor and the platelet-derived growth factor receptor families. A number of compounds with potent oral activity were identified by utilizing an estradiol-induced mouse uterine edema model and an HT1080 human fibrosarcoma xenograft tumor model. In particular, compound 17p (ABT-869) was found to possess favorable pharmacokinetic profiles across different species and display significant tumor growth inhibition in multiple preclinical animal models.

1,4-Benzodiazepines as Inhibitors of Respiratory Syncytial Virus. The Identification of a Clinical Candidate

Respiratory syncytial virus (RSV) is the cause of one-fifth of all lower respiratory tract infections worldwide and is increasingly being recognized as representing a serious threat to patient groups with poorly functioning or immature immune systems. Racemic 1,4-benzodiazepines show potent anti-RSV activity in vitro. Anti-RSV evaluation of 3-position R- and S-benzodiazepine enantiomers and subsequent optimization of this series resulted in selection of a clinical candidate. Antiviral activity was found to reside mainly in the S-enantiomer, and the R-enantiomers were consistently less active against RSV. Analogues of 1,4-(S)-benzodiazepine were synthesized as part of the lead optimization program at Arrow and tested in the XTT assay. From this exercise, (S)-1-(2-fluorophenyl)-3-(2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]-diazepin-3-yl)-urea, 17b (RSV-604) was identified as a clinical candidate, exhibiting potent anti-RSV activity in the XTT assay, which was confirmed in secondary assays. Compound 17b also possessed a good pharmacokinetic profile and has now progressed into the clinic.