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[Image: see text] We report herein the discovery of quinazolindiones as potent and selective tankyrase inhibitors. Elucidation of the structure–activity relationship of the lead compound 1g led to truncated analogues that have good potency in cells, pharmacokinetic (PK) properties, and excellent selectivity. Compound 21 exhibited excellent potencies in cells and proliferation studies, good selectivity, in vitro activities, and an excellent PK profile. Compound 21 also inhibited H292 xenograft tumor growth in nude mice. The synthesis, biological, pharmacokinetic, in vivo efficacy studies, and safety profiles of compounds are presented.

[Image: see text] We report herein the discovery of isoxazole amides as potent and selective SET and MYND Domain-Containing Protein 3 (SMYD3) inhibitors. Elucidation of the structure–activity relationship of the high-throughput screening (HTS) lead compound 1 provided potent and selective SMYD3 inhibitors. The SAR optimization, cocrystal structures of small molecules with SMYD3, and mode of inhibition (MOI) characterization of compounds are described. The synthesis and biological and pharmacokinetic profiles of compounds are also presented.

[20667-12-3] Ag2O (MW 231.74) InChI = 1/2Ag.O/rAg2O/c1-3-2 InChIKey = KHJDQHIZCZTCAE-FQKFHCGGAZ (oxidizing reagent for conversion of hydroquinones to quinones,1 alkylphenols to quinone methides,5 and aldehydes to acids;7 oxidative coupling reactions;12, 13 a Lewis acid with halides18, 20 and thioethers;24 Wolff rearrangement26) Physical Data: dec at about 200 °C; d 7.22 g cm−3. Solubility: practically insol alcohol; sol 40 000 parts H2O; sol dilute nitric acid, ammonia; moderately sol NaOH. Form Supplied in: brownish-black, heavy, odorless powder; widely available. Handling, Storage, and Precautions: protect from light. Reduced by hydrogen, carbon monoxide, and most metals. Skin contact with this toxic reagent should be carefully avoided.

SMYD3 is a lysine methyltransferase overexpressed in colorectal, breast, prostate, and hepatocellular tumors, and has been implicated as an oncogene in human malignancies. Methylation of MEKK2 by SMYD3 is important for regulation of the MEK/ERK pathway, suggesting the possibility of selectively targeting SMYD3 in RAS-driven cancers. Structural and kinetic characterization of SMYD3 was undertaken leading to a co-crystal structure of SMYD3 with a MEKK2-peptide substrate bound, and the observation that SMYD3 follows a partially processive mechanism. These insights allowed for the design of GSK2807, a potent and selective, SAM-competitive inhibitor of SMYD3 (Ki = 14 nM). A high-resolution crystal structure reveals that GSK2807 bridges the gap between the SAM-binding pocket and the substrate lysine tunnel of SMYD3. Taken together, our data demonstrate that small-molecule inhibitors of SMYD3 can be designed to prevent methylation of MEKK2 and these could have potential use as anticancer therapeutics.

Activation of the inositol-requiring enzyme-1 alpha (IRE1α) protein caused by endoplasmic reticulum stress results in the homodimerization of the N-terminal endoplasmic reticulum luminal domains, autophosphorylation of the cytoplasmic kinase domains, and conformational changes to the cytoplasmic endoribonuclease (RNase) domains, which render them functional and can lead to the splicing of X-box binding protein 1 (XBP 1) mRNA. Herein, we report the first crystal structures of the cytoplasmic portion of a human phosphorylated IRE1α dimer in complex with (R)-2-(3,4-dichlorobenzyl)-N-(4-methylbenzyl)-2,7-diazaspiro(4.5)decane-7-carboxamide, a novel, IRE1α-selective kinase inhibitor, and staurosporine, a broad spectrum kinase inhibitor. (R)-2-(3,4-dichlorobenzyl)-N-(4-methylbenzyl)-2,7-diazaspiro(4.5)decane-7-carboxamide inhibits both the kinase and RNase activities of IRE1α. The inhibitor interacts with the catalytic residues Lys599 and Glu612 and displaces the kinase activation loop to the DFG-out conformation. Inactivation of IRE1α RNase activity appears to be caused by a conformational change, whereby the αC helix is displaced, resulting in the rearrangement of the kinase domain-dimer interface and a rotation of the RNase domains away from each other. In contrast, staurosporine binds at the ATP-binding site of IRE1α, resulting in a dimer consistent with RNase active yeast Ire1 dimers. Activation of IRE1α RNase activity appears to be promoted by a network of hydrogen bond interactions between highly conserved residues across the RNase dimer interface that place key catalytic residues poised for reaction. These data implicate that the intermolecular interactions between conserved residues in the RNase domain are required for activity, and that the disruption of these interactions can be achieved pharmacologically by small molecule kinase domain inhibitors.

We report the critical residues for the interaction of the kinins with human bradykinin receptor 1 (B1) using site-directed mutagenesis in conjunction with molecular modeling of the binding modes of the kinins in the homology model of the B1 receptor. Mutation of Lys118 in transmembrane (TM) helix 3, Ala270 in TM6, and Leu294 in TM7 causes a significant decrease in the affinity for the peptide agonists des-Arg10kallidin (KD) and des-Arg9BK but not the peptide antagonist des-Arg10Leu9KD. In contrast, mutations in TM2, TM3, TM6, and TM7 cause a significant decrease in the affinity for both the peptide agonists and the antagonist. These data indicate that the B1 bradykinin binding pocket for agonists and antagonists is similar, but the manners in which they interact with the receptor do not completely overlap. Therefore, there is a potential to influence the receptor's ligand selectivity.

A three‐step sequence affects the regio‐ and stereospecific elaboration of an aryl C‐aminoglycoside from a simple aminoglycal and a quinone. Direct lithiation of the glycal followed by addition of the quinone, reduction of the quinol adduct, and hydroboration gives a product with a trans‐trans stereochemical relationship between the substituents at C1′, C2′, and C3′, appropriate for compounds in the ravidomycin series.

A two‐step sequence converts protected glycal‐substituted quinols to aryl bis C‐glycals in which one or both of the substituents is an aminoglycal. First, a lithiated glycal undergoes 1,2‐addition to the carbonyl group of a protected glycal‐bearing quinol, leading to a mono‐protected cyclohexadienediol. Then a BF3‐etherate‐catalyzed “dienol phenol‐type” rearrangement converts the adduct to an aryl bis C‐glycal. The glycal moiety that was originally a substituent on the quinol substrate is the substituent that migrates. The presence of the amino group does not introduce complications. This sequence provides models for the rapid access to intermediates for pluramycin synthesis.

We have developed an efficient and selective radioligand, the [35S]-radiolabeled dihydroquinoxalinone derivative, 4, for an ex vivo receptor occupancy assay in transgenic rats over-expressing the human bradykinin B1 receptor.

A simple, novel, and efficient route for the synthesis of 5-amino-3-aryl-1-(tert-butyl)-1H-pyrazole-4-carboxamides 1 has been devised. Preparation of pyrazole bromide 3 from potassium tricyanomethanide can be accomplished in only two steps in good yield and features a selective Sandmeyer reaction on the corresponding diaminopyrazole. This allows for a more versatile synthesis of 5-amino-3-aryl-1-(tert-butyl)-1H-pyrazole-4-carboxamides 1 than was previously possible.

Epothilones are a new class of natural products that bind to tubulin and prevent the depolymerization of microtubules, although they have no structural similarity to paclitaxel. Taxanes are only marginally effective in the treatment of disseminated prostate cancer, although they may have useful activity when administered in combination with estramustine. Unlike paclitaxel, epothilones are not substrates for P-glycoprotein and are active in multidrug resistant cells. Epothilones A and B (EA, EB) have recently been synthesized in toto. In this report, we examine the effects of synthetic epothilones and their desoxy derivatives, as well as paclitaxel, on prostate cancer cell lines. EB was the most active of these compounds in tissue culture (IC(50): 50-75 pM), four to ten-fold more potent than paclitaxel. EA and the desoxyderivatives of EA and EB (dEA, dEB) were also active, but less potent than EB. Each of these compounds causes mitotic block followed by apoptotic cell death. The relative potencies for cell cycle arrest and cytotoxicity directly correlate with the ability of the drugs to bind microtubules, stabilize mitotic spindles and induce the formation of interphase microtubule bundles. Therefore, synthetic epothilones are potent inhibitors of prostate cancer cell lines and work in a fashion similar to paclitaxel. Recently, we showed that farnesyl transferase inhibitors sensitize tumor cells to paclitaxel-induced mitotic arrest. We now have extended these observations to show that paclitaxel and the epothilones synergize with FTI to arrest the growth of prostate cancer cells. Moreover, this occurs in DU145, a cell line that is not particularly sensitive to the FTI. The combination of FTI and epothilone represent a new potential clinical strategy for the treatment of advanced prostatic cancer.

A new class of 16-membered macrolides, the epothilones (Epos), has been synthesized and evaluated for antitumor potential in vitro and in vivo. Recent studies in these and other laboratories showed that epothilones and paclitaxel (paclitaxel) share similar mechanisms of action in stabilizing microtubule arrays as indicated by binding-displacement studies, substitution for paclitaxel in paclitaxel-dependent cell growth, and electron microscopic examinations. The present study examined cell growth-inhibitory effects in two rodent and three human tumor cell lines and their drug-resistant sublines. Although paclitaxel showed as much as 1,970-fold cross-resistance to the sublines resistant to paclitaxel, adriamycin, vinblastine, or actinomycin D, most epothilones exhibit little or no cross-resistance. In multidrug-resistant CCRF-CEM/VBL 100 cells, IC 50 values for EpoA (1), EpoB (2), desoxyEpoA (3) (dEpoA), desoxyEpoB (4) (dEpoB), and paclitaxel were 0.02, 0.002, 0.012, 0.017, and 4.14 μM, respectively. In vivo studies, using i.p. administration, indicated that the parent, EpoB, was highly toxic to mice and showed little therapeutic effect when compared with a lead compound, dEpoB. More significantly, dEpoB (25–40 mg/kg, Q2Dx5, i.p.) showed far superior therapeutic effects and lower toxicity than paclitaxel, doxorubicin, camptothecin, or vinblastine (at maximal tolerated doses) in parallel experiments. For mammary adenocarcinoma xenografts resistant to adriamycin, MCF-7/Adr, superior therapeutic effects were obtained with dEpoB compared with paclitaxel when i.p. regimens were used. For ovarian adenocarcinoma xenografts, SK-OV-3, dEpoB (i.p.), and paclitaxel (i.v.) gave similar therapeutic effects. In nude mice bearing a human mammary carcinoma xenograft (MX-1), marked tumor regression and cures were obtained with dEpoB.

Important progress towards the total syntheses of the title compounds, potent inhibitors of squalene synthase and farnesyl transferase, has been accomplished by the construction of the highly functionalized compound 1.

Ein entscheidender Schritt auf dem Weg zur Totalsynthese der Titelverbindungen, die die Squalen-Synthase und Farnesyl-Transferase inhibieren, gelang durch den Aufbau der hochfunktionalisierten zentralen Ausgangsverbindung 1.

An important class of cellular proteins, which includes members of the p21ras family, undergoes posttranslational farnesylation, a modification required for their partition to membranes. Specific farnesyl transferase inhibitors (FTIs) have been developed that selectively inhibit the processing of these proteins. FTIs have been shown to be potent inhibitors of tumor cell growth in cell culture and in murine models and at doses that cause little toxicity to the animal. These data suggest that these drugs might be useful therapeutic agents. We now report that, when FTI is combined with some cytotoxic antineoplastic drugs, the effects on tumor cells are additive. No interference is noted. Furthermore, FTI and agents that prevent microtubule depolymerization, such as taxol or epothilones, act synergistically to inhibit cell growth. FTI causes increased sensitivity to induction of metaphase block by these agents, suggesting that a farnesylated protein may regulate the mitotic check point. The findings imply that FTI may be a useful agent for the treatment of tumors with wild-type ras that are sensitive to taxanes.

Convergent, stereocontrolled total syntheses of the microtubule-stabilizing macrolides epothilones A (2) and B (3) have been achieved. Four distinct ring-forming strategies were pursued (see Scheme...

The title compounds have been synthesized in a convergent way by recourse to a Weiler type dianion construction.

A simple, novel, and efficient route for the synthesis of 5-amino-3-aryl-1-(tert-butyl)-1H-pyrazole-4-carboxamides 1 has been devised. Preparation of pyrazole bromide 3 from potassium tricyanomethanide can be accomplished in only two steps in good yield and features a selective Sandmeyer reaction on the corresponding diaminopyrazole. This allows for a more versatile synthesis of 5-amino-3-aryl-1-(tert-butyl)-1H-pyrazole-4-carboxamides 1 than was previously possible.

A three-step sequence including selective iodination and ring closure with KOtBu via a Modified Madelung reaction yields iodo precursors of type (VI), which can be coupled with arylboronic acids.

The title compounds have been synthesized in a convergent way by recourse to a Weiler type dianion construction.

Convergent, stereocontrolled total syntheses of the microtubule-stabilizing macrolides epothilones A (2) and B (3) have been achieved. Four distinct ring-forming strategies were pursued (see Scheme...

Important progress towards the total syntheses of the title compounds, potent inhibitors of squalene synthase and farnesyl transferase, has been accomplished by the construction of the highly functionalized compound 1.

Biaryl ethers were recently reported as potent NNRTIs. Herein, we disclose a detailed effort to modify the previously reported compound 1. We have designed and synthesized a series of novel pyrazole derivatives as a surrogate for pyrazolopyridine motif that were potent inhibitors of HIV-1 RT with nanomolar intrinsic activity on the WT and key mutant enzymes and potent antiviral activity in infected cells.

Biaryl ethers were recently reported as potent NNRTIs. Herein we disclose a detailed SAR study that led to the biaryl ether 6. This compound possessed excellent potency against WT RT and key clinically observed RT mutants and had an excellent pharmacokinetic profile in rats, dogs, and rhesus macaques. The compound also exhibited a clean safety profile in preclinical safety studies.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are key elements of multidrug regimens, called HAART (Highly Active Antiretroviral Therapy), that are used to treat HIV-1 infections. Elucidation of the structure-activity relationships of the thiocarbamate moiety of the previous published lead compound 2 provided a series of novel tetrahydroquinoline derivatives as potent inhibitors of HIV-1 RT with nanomolar intrinsic activity on the WT and key mutant enzymes and potent antiviral activity in infected cells. The SAR optimization, mutation profiles, preparation of compounds, and pharmacokinetic profile of compounds are described.

Selective bradykinin (BK) B 1 receptor antagonists could be novel therapeutic agents for the treatment of pain and inflammation. Elucidation of the structure activity relationships of the structurally novel HTS lead compound 1 provided potent hBK B 1 receptor antagonists with excellent receptor occupancy in the CNS of hBK B 1 transgenic rats.

Selective bradykinin (BK) B1 receptor antagonists have been shown to be antinociceptive in animal models and could be novel therapeutic agents for the treatment of pain and inflammation. Elucidation of the structure–activity relationships of the biphenyl moiety of the lead compound 1 provided a potent new structural class of BK B1 receptor antagonists.

The EZH2 histone methyltransferase is frequently mutated in diffuse large B-cell lymphoma leading to increased trimethylation of histone H3 lysine 27 (H3K27me3). Drug discovery efforts have previously identified a pyridone-based chemical series of EZH2 inhibitors that potently and selectively inhibit EZH2 catalytic activity. These compounds are capable of globally decreasing H3K27me3 levels, de-repressing EZH2 target genes, and inducing growth inhibition of many lymphoma cell lines both in cell culture and in vivo. Through medicinal chemistry optimization, we have developed EZH2 inhibitors with significantly improved potency in both biochemical and cellular assays. These compounds exhibit a prolonged enzyme residence time that can be further extended in vitro through the addition of an H3K27me3 peptide. Herein, we report the biochemical and cellular activity of these new EZH2 inhibitors. Citation Format: Heidi Ott, Glenn van Aller, Jessica Ward, BaoChau Le, Cynthia Rominger, James Foley, Susan Korenchuk, Charles McHugh, Michael Butticello, Charles Blackledge, James Brackley, Joelle Burgess, Celine Duquenne, Neil Johnson, Jiri Kasparec, Louis LaFrance, Mei Li, Kenneth McNulty, Kenneth Newlander, Stuart Romeril, Stanley Schmidt, Mark Schulz, Dai-Shi Su, Dominic Suarez, Xinrong Tian, Christopher Carpenter, Juan Luengo, Ryan Kruger, Steven Knight, Michael T. McCabe. A potent EZH2 inhibitor exhibits long residence time and anti-tumor activity. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5379. doi:10.1158/1538-7445.AM2015-5379

Das quartare Stereozentrum an C7 einer Vorstufe der Titelverbindungen konnte durch Addition des von Trost beschriebenen Ylids an 1 aufgebaut werden. Dies und eine Photooxidation, die die Maleinsaureanhydrid-Einheit liefert, sind zwei weitere wichtige Schritte fur die Totalsynthese der beiden Verbindungen.

A three‐step sequence affects the regio‐ and stereospecific elaboration of an aryl C‐aminoglycoside from a simple aminoglycal and a quinone. Direct lithiation of the glycal followed by addition of the quinone, reduction of the quinol adduct, and hydroboration gives a product with a trans‐trans stereochemical relationship between the substituents at C1′, C2′, and C3′, appropriate for compounds in the ravidomycin series.

We report the first homology model of human bradykinin receptor B1 generated from the crystal structure of bovine rhodopsin as a template. Using an automated docking procedure, two B1 receptor antagonists of the dihydroquinoxalinone structural class were docked into the receptor model. Site-directed mutagenesis data of the amino acid residues in TM1, TM3, TM6, and TM7 were incorporated to place the compounds in the binding site of the homology model of the human B1 bradykinin receptor. The best pose in agreement with the mutation data was selected for detailed study of the receptor-antagonist interaction. To test the model, the calculated antagonist-receptor binding energy was correlated with the experimentally measured binding affinity (K(i)) for nine dihydroquinoxalinone analogs. The model was used to gain insight into the molecular mechanism for receptor function and to optimize the dihydroquinoxalinone analogs.

Compound A (N-[2-[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]ethyl]-2-[(2R)-1-(2-napthylsulfonyl)-3-oxo-1,2,3,4-tetrahydroquinoxalin-2-yl]acetamide) is a member of a new class of aryl sulfonamide dihydroquinoxalinone bradykinin B1 receptor antagonists that should be useful pharmacological tools. Here we report on some of the pharmacological properties of compound A as well as the characterization of [35S]compound A as the first nonpeptide bradykinin B1 receptor radioligand. Compound A inhibited tritiated peptide ligand binding to the cloned human, rabbit, dog, and rat bradykinin B1 receptors expressed in CHO cells with Ki values of 0.016, 0.050, 0.56, and 29 nM, respectively. It was inactive at 10 microM in binding assays with the cloned human bradykinin B2 receptor. In functional antagonist assays with the cloned bradykinin B1 receptors, compound A inhibited agonist-induced signaling with activities consistent with the competition binding results, but had no antagonist activity at the bradykinin B2 receptor. Compound A was also found to be a potent antagonist in a rabbit aorta tissue bath preparation and to effectively block des-Arg9 bradykinin depressor responses in lipopolysaccharide-treated rabbit following intravenous administration. The binding of [35S]compound A was evaluated with the cloned bradykinin B1 receptors. In assays with human, rabbit, and dog receptors, [35S]compound A labeled a single site with Kd values of 0.012, 0.064, and 0.37 nM, respectively, and with binding site densities equivalent to those obtained using the conventional tritiated peptide ligands. Binding assays with the cloned rat bradykinin B1 receptor were not successful, presumably due to the low affinity of the ligand for this species receptor. There was no specific binding of the ligand detected in CHO cells expressing the human bradykinin B2 receptor. In assays with the cloned human bradykinin B1 receptor, the pharmacologies of the binding of [35S]compound A and [3H][Leu9]des-Arg10-kallidin were the same. The high signal-to-noise ratio obtained with [35S]compound A will allow this ligand to be a very useful tool for future investigations of the bradykinin B1 receptor.

Antagonists of the B1 bradykinin receptor (B1R) offer the promise of novel therapeutic agents for the treatment of inflammatory and neuropathic pain. However, the in vivo characterization of the pharmacodynamics of B1R antagonists is hindered by the low level of B1R expression in healthy tissue and the profound species selectivity exhibited by many compounds for the human B1R. To circumvent these issues, we generated a transgenic rat expressing the human B1R under the control of the neuron-specific enolase promoter. Membranes prepared from whole brain homogenates of heterozygous transgenic rats indicate a B1R expression level of 30 to 40 fmol/mg; there is no detectable B1R expression in control nontransgenic rats. The pharmacological profile of the B1R expressed in the transgenic rat matches that expected of the human, but not the rat receptor. The mapping of the transgene insertion site to rat chromosome 1 permitted the development of a reliable assay for the identification of homozygous transgenic rats. Significantly, homozygous transgenic rats express 2-fold more B1R than heterozygous animals. Autoradiographic analyses of tissue sections from transgenic rats reveal that the B1R is broadly expressed in both the brain and spinal cord. The human B1R expressed in the transgenic rat functions in an in vitro contractile assay and thus has the potential to elicit a functional response in vivo. Using the humanized B1R transgenic rat, an assay was developed that is suitable for the routine evaluation of a test compound's ability to occupy the human B1R in the central nervous system.