- Synthesis of 5-Methyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one in Supercritical Carbon Dioxide
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5-Methyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one, an intermediate product in the synthesis of the antiviral drug Triazid, was obtained for the first time by condensation of 3H-1,2,4-triazol-5-amine with ethyl acetoacetate in the presence of a catalytic a
- Baklykov,Rusinov,Rusinov,Charushin,Kopchuk,Zyryanov,Artem’ev
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- 6-Nitrotriazolo[1,5-a]pyrimidines as promising structures for pharmacotherapy of septic conditions
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Promising 6-nitro-1,2,4-triazolo[1,5-a]pyrimidine analogues, structural analogues of synthetic inhibitors of adenosine receptors, were sorted out on the basis of quantum-chemical calculations. The compounds were synthesized by nitration and chlorodeoxygenation reactions. The in vivo activity of 6-nitroheterocycles was studied and the affinity to adenosine receptor A2A was demonstrated in regard to septic conditions.
- Savateev,Ulomsky,Fedotov,Rusinov,Sivak,Lyubishin,Kuzmich,Aleksandrov
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- Design and synthesis of new indole containing biaryl derivatives as potent antiproliferative agents
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A new series of indole containing biaryl derivatives were designed and synthesized, and further biological evaluations of their antiproliferative activity against cancer cell lines (MGC-803 and TE-1 cells) were also conducted. Of these synthesized biaryls, compound 4-methyl-2-((5-methyl-[1,2,4]triazolo[1,5-a]pyrimidin-7-yl)methyl)quinazoline (23) performed as the most potent antiproliferative agent that inhibited cell viability of MGC-803 cells with an IC50 value of 8.28 μM. In addition, investigation of mechanism exhibited that the compound 4-methyl-2-((5-methyl-[1,2,4]triazolo[1,5-a]pyrimidin-7-yl)methyl)quinazoline (23) could inhibit the expression of c-Myc and glycolysis related proteins, decrease the ATP and lactate production, and further induce apoptosis by activating the AMP-activated protein kinase (AMPK) and p53 signaling pathways.
- Yuan, Shuo,Feng, Si-Qi,Li, An-Qi,Zuo, Jia-Hui,Zhang, Dan-Qing,Xing, Yu-Jie,Xie, Zhiyu,Yu, Bin,Liu, Hong-Min
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supporting information
(2021/07/25)
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- Discovery of the Triazolo[1,5- a]Pyrimidine-Based Derivative WS-898 as a Highly Efficacious and Orally Bioavailable ABCB1 Inhibitor Capable of Overcoming Multidrug Resistance
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Targeting P-glycoprotein (ABCB1 or P-gp) has been recognized as a promising strategy to overcome multidrug resistance. Here, we reported our medicinal chemistry efforts that led to the discovery of the triazolo[1,5-a]pyrimidine derivative WS-898 as a highly effective ABCB1 inhibitor capable of reversing paclitaxel (PTX) resistance in drug-resistant SW620/Ad300, KB-C2, and HEK293/ABCB1 cells (IC50 = 5.0, 3.67, and 3.68 nM, respectively), more potent than verapamil and zosuquidar. WS-898 inhibited the efflux function of ABCB1, thus leading to decreased efflux and increased intracellular PTX concentration in SW620/Ad300 cells. The cellular thermal shift assay indicated direct engagement of WS-898 to ABCB1. Furthermore, WS-898 stimulated the ATPase activity of ABCB1 but had minimal effects on cytochrome P450 3A4 (CYP3A4). Importantly, WS-898 increased PTX sensitization in vivo without obvious toxicity. The results suggest that WS-898 is a highly effective triazolo[1,5-a]pyrimidine-based ABCB1 inhibitor and shows promise in reversing ABCB1-mediated PTX resistance.
- Wang, Shuai,Wang, Sai-Qi,Teng, Qiu-Xu,Lei, Zi-Ning,Chen, Zhe-Sheng,Chen, Xiao-Bing,Liu, Hong-Min,Yu, Bin
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p. 16187 - 16204
(2021/11/18)
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- Comparative study between the anti-P. falciparum activity of triazolopyrimidine, pyrazolopyrimidine and quinoline derivatives and the identification of new PfDHODH inhibitors
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In this work, we designed and synthesized 35 new triazolopyrimidine, pyrazolopyrimidine and quinoline derivatives as P. falciparum inhibitors (3D7 strain). Thirty compounds exhibited anti-P. falciparum activity, with IC50 values ranging from 0.030 to 9.1 μM. The [1,2,4]triazolo[1,5-a]pyrimidine derivatives were more potent than the pyrazolo[1,5-a]pyrimidine and quinoline analogues. Compounds 20, 21, 23 and 24 were the most potent inhibitors, with IC50 values in the range of 0.030–0.086 μM and were equipotent to chloroquine. In addition, the compounds were selective, showing no cytotoxic activity against the human hepatoma cell line HepG2. All [1,2,4]triazolo[1,5-a]pyrimidine derivatives inhibited PfDHODH activity in the low micromolar to low nanomolar range (IC50 values of 0.08–1.3 μM) and did not show significant inhibition against the HsDHODH homologue (0–30% at 50 μM). Molecular docking studies indicated the binding mode of [1,2,4]triazolo[1,5-a]pyrimidine derivatives to PfDHODH, and the highest interaction affinities for the PfDHODH enzyme were in agreement with the in vitro experimental evaluation. Thus, the most active compounds against P. falciparum parasites 20 (R = CF3, R1 = F; IC50 = 0.086 μM), 21 (R = CF3; R1 = CH3; IC50 = 0.032 μM), 23, (R = CF3, R1 = CF3; IC50 = 0.030 μM) and 24 (R = CF3, 2-naphthyl; IC50 = 0.050 μM) and the most active inhibitor against PfDHODH 19 (R = CF3, R1 = Cl; IC50 = 0.08 μM - PfDHODH) stood out as new lead compounds for antimalarial drug discovery. Their potent in vitro activity against P. falciparum and the selective inhibition of the PfDHODH enzyme strongly suggest that this is the mechanism of action underlying this series of new [1,2,4]triazolo[1,5-a]pyrimidine derivatives.
- Silveira, Flávia F.,de Souza, Juliana O.,Hoelz, Lucas V.B.,Campos, Vinícius R.,Jabor, Valquíria A.P.,Aguiar, Anna C.C.,Nonato, M. Cristina,Albuquerque, Magaly G.,Guido, Rafael V.C.,Boechat, Nubia,Pinheiro, Luiz C.S.
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- Applications of alkaloid essramycin and derivative thereof in resisting of plant viruses
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The invention relates to applications of alkaloid essramycin and a derivative thereof in resisting of plant viruses, wherein the chemical structural formula of the alkaloid essramycin is represented in the specification, specifically the alkaloid essramyc
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Paragraph 0051-0056
(2020/01/30)
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- Discovery, Structural Optimization, and Mode of Action of Essramycin Alkaloid and Its Derivatives as Anti-Tobacco Mosaic Virus and Anti-Phytopathogenic Fungus Agents
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Plant diseases seriously affect crop yield and quality and are difficult to control. Marine natural products (MNPs) have become an important source of drug candidates with new biological mechanisms. Marine natural product essramycin (1) was found to have
- Wang, Tienan,Yang, Shan,Li, Hongyan,Lu, Aidang,Wang, Ziwen,Yao, Yingwu,Wang, Qingmin
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p. 471 - 484
(2020/02/18)
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- Discovery of [1,2,4]triazolo[1,5-a]pyrimidine derivatives as new bromodomain-containing protein 4 (BRD4) inhibitors
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Targeting bromodomain-containing protein 4 (BRD4) has been proved to be an effective strategy for cancer therapy. To date, numerous BRD4 inhibitors and degraders have been identified, some of which have advanced into clinical trials. In this work, a focused library of new [1,2,4]triazolo[1,5-a]pyrimidine derivatives were discovered to be able to inhibit BRD4. WS-722 inactivated BRD4 (BD1/BD2), BRD2 (BD1/BD2) and BRD3 (BD1/BD2) broadly with the IC50 values less than 5 μmol/L. Besides, WS-722 inhibited growth of THP-1 cells with an IC50 value of 3.86 μmol/L. Like (+)-JQ1, WS-722 inhibited BRD4 in a reversible manner and enhanced protein stability. Docking studies showed that WS-722 occupied the central acetyl-lysine (Kac) binding cavity and formed a hydrogen bond with Asn140. In THP-1 cells, WS-722 showed target engagement to BRD4. Cellular effects of WS-722 on THP-1 cells were also examined, showing that WS-722 could block c-MYC expression, induce G0/G1 phase arrest and p21 up-regulation, and promote differentiation of THP-1 cells. BRD4 inhibition by WS-722 resulted in cell apoptosis and up-regulated expression of cleaved caspased-3/7 and PARP in THP-1 cell lines. The [1,2,4]triazolo[1,5-a]pyrimidine is a new template for the development of new BRD4 inhibitors.
- Wang, Shuai,Shen, Dandan,Zhao, Lijie,Yuan, Xiaohan,Cheng, Jialing,Yu, Bin,Zheng, Yichao,Liu, Hongmin
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supporting information
p. 418 - 422
(2019/09/03)
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- Discovery of tofacitinib derivatives as orally active antitumor agents based on the scaffold hybridization strategy
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In this work, a novel series of tofacitinib analogs were designed and synthesized based on the scaffold hybridization strategy and then evaluated for their antiproliferative activity toward three gastric cancer cell lines, leading to the identification of compound C18 which exhibited potent inhibitory activity against MGC-803 cell lines with an IC50 value of 2.68 μM. Compound C18 could effectively inhibit the colony formation, suppress the cell migration and induce apoptosis of MGC-803 cells through activating the p38 and JNK signaling pathways, while C18 showed no obvious effect on the cell cycle distribution in MGC-803 cells. In addition, C18 could initiate mitochondrial dysfunction of MGC-803 cells. Besides, in vivo antitumor studies indicated that C18 could inhibit gastric cancer tumor growth in vivo without obvious global toxicity.
- Shi, Xiao-Jing,Wang, Shuai,Li, Xiao-Jing,Yuan, Xiao-Han,Cao, Li-Juan,Yu, Bin,Liu, Hong-Min
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- Br?nsted acid-promoted ‘on–water’ C(sp3)-H functionalization for the synthesis of isoindolinone/[1,2,4]triazolo[1,5-a]pyrimidine derivatives targeting the SKP2-CKS1 interaction
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The isoindolinone and biaryl scaffolds are prevalent in natural products and drug molecules, which have showed broad and interesting biological activities. The efficient construction of such hybridized molecules and biological evaluation are of great interest to medicinal chemistry community. In this communication, we report an efficient Br?nsted acid-promoted C(sp3)-H functionalization approach that enables the rapid construction of biologically important isoindolinone/[1,2,4]triazolo[1,5-a]pyrimidine hybrids from 5-methyl-7-(2,4,6-trimethoxyphenyl)-[1,2,4]triazolo[1,5-a]pyrimidine, 2-formylbenzoic acid and various anilines. The title compounds were generated in high to excellent yields (up to 96%) regardless of the electronic nature and steric effects of the substituents. In this reaction, an isoindolinone scaffold, one C[sbnd]C single bond, and two C[sbnd]N bonds were formed simultaneously with high atom economy. In this work, we have envisioned that the methyl group linked to the electron-deficient N-heterocycles could be used as a new synthetic handle for late-state diversification and may have broad applications in the field of organic and medicinal chemistry. Besides, the title compounds have exhibited promising activity against the SKP2-CKS1 interaction.
- Yuan, Shuo,Wang, Sixi,Zhao, Min,Zhang, Danqing,Chen, Jinjie,Li, Jian-Xin,Zhang, Jingya,Song, Yihui,Wang, Jinyi,Yu, Bin,Liu, Hongmin
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supporting information
p. 349 - 352
(2019/08/30)
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- Discovery of new [1,2,4] Triazolo[1,5-a]Pyrimidine derivatives that Kill gastric cancer cells via the mitochondria pathway
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Mitochondria are known as “powerhouse of cells” and play the role of a bridge in redox balance, cell apoptosis, and autophagy. ROS accumulation can cause mitochondria damage, while the injured mitochondria will further enhance ROS levels reciprocally. Herein, we synthesized a novel series of [1,2,4]triazolo[1,5-a]pyrimidine-based compounds 4a-4v and tested their anti-proliferation efficacy against gastric cancer cell line MGC-803. Among them, compounds 4o and 4p inhibited gastric cancer cells at micromolar level. Compound 4o caused G2/M arrest and induced mitochondria-dependent apoptosis in MGC-803 and SGC-7901. However, inhibiting apoptosis pathway cannot prevent the inhibitory activity of compound 4o against gastric cancer cell. To our surprising, ROS level was increased by compound 4o and elevation of ROS could be rescued by NAC. In accordance with that, NAC absolutely prevented the anti-proliferation efficacy of compound 4o. We further found that autophagy inhibitor CQ rather than 3-MA partially reversed inhibitory activity of compound 4o in MGC-803 cells. Taken together, compound 4o exhibited its anti-proliferative activity via increasing ROS level and inducing autophagy, thus leading to apoptosis of gastric cancer cells. Therefore, compound 4o may support further development of lead compounds for gastric cancer therapy via mitochondria pathway.
- Wang, Shuai,Ma, Xu-Bin,Yuan, Xiao-Han,Yu, Bin,Xu, Yi-Chao,Liu, Hong-Min
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- Development of Highly Potent, Selective, and Cellular Active Triazolo[1,5- a]pyrimidine-Based Inhibitors Targeting the DCN1-UBC12 Protein-Protein Interaction
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The cullin-RING ubiquitin ligases (CRLs) are responsible for about 20% of cellular protein degradation and regulate diverse cellular processes, and the dysfunction of CRLs is implicated in human diseases. Targeting the CRLs has become an emerging strategy for the treatment of human diseases. Herein, we describe the discovery of a hit compound from our in-house library and further structure-based optimizations, which have enabled the identification of new triazolo[1,5-a]pyrimidine-based inhibitors targeting the DCN1-UBC12 interaction. Compound WS-383 blocks the DCN1-UBC12 interaction (IC50 = 11 nM) reversibly and shows selectivity over selected kinases. WS-383 exhibits cellular target engagement to DCN1 in MGC-803 cells. WS-383 inhibits Cul3/1 neddylation selectively over other cullins and also induces accumulation of p21, p27, and NRF2. Collectively, targeting the DCN1-UBC12 interaction would be a viable strategy for selective neddylation inhibition of Cul3/1 and may be of therapeutic potential for disease treatment in which Cul3/1 is dysregulated.
- Wang, Shuai,Zhao, Lijie,Shi, Xiao-Jing,Ding, Lina,Yang, Linlin,Wang, Zhi-Zheng,Shen, Dandan,Tang, Kai,Li, Xiao-Jing,Mamun,Li, Huiju,Yu, Bin,Zheng, Yi-Chao,Wang, Shaomeng,Liu, Hong-Min
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- Experience-based discovery (EBD) of aryl hydrazines as new scaffolds for the development of LSD1/KDM1A inhibitors
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Phenelzine was first employed to design new aryl hydrazine-based LSD1 inhibitors based on the experience-based discovery (EBD) strategy. Among these compounds, D8 potently inhibited LSD1 (IC50 = 882.30 nM) in a reversible manner. Compound D8 was selective to LSD1 over MAO-A/B and showed H3K4me2 competitive binding to LSD1. The interaction between H3K4me2 and LSD1 was also confirmed by the Co-IP assay. In LSD1 overexpressed A549 cells, compound D8 dose-dependently induced accumulation of LSD1 substrates H3K4me1/2 and H3K9me1/2, showed cellular target engagement to LSD1 and significantly inhibited cell migration of A549 cells. Docking studies suggested that compound D8 occupied the peptide binding region and therefore blocked the access of the peptide substrate to the FAD, finally leading to the demethylase activity inhibition of LSD1. The findings indicate that aryl hydrazines are new scaffolds for the design of LSD1 inhibitors, the identification of D8 provides further evidence for our previously proposed general principle that fused heterocycles with an amine group are potentially active toward LSD1 by competitive binding to LSD1 with H3 peptide substrates.
- Li, Zhong-Rui,Wang, Shuai,Yang, Linlin,Yuan, Xiao-Han,Suo, Feng-Zhi,Yu, Bin,Liu, Hong-Min
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p. 432 - 444
(2019/02/12)
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- Synthesis, structure-activity relationship studies and biological characterization of new [1,2,4]triazolo[1,5-a]pyrimidine-based LSD1/KDM1A inhibitors
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The histone lysine specific demethylase 1 (LSD1/KDM1A) is implicated in the development of cancers, targeting LSD1 has been recognized as a promising strategy for cancer therapy. To date, some small-molecule inhibitors are currently being investigated in clinical trials. Herein we report the design, synthesis and biochemical characterization of [1,2,4]triazolo[1,5-a]pyrimidine derivatives as new LSD1 inhibitors. Of these compounds, compound C26 inhibited LSD1 in a reversible manner (IC50 = 1.72 μM) and showed selectivity to LSD1 over MAO-A/B. Besides, compound C26 displayed FAD-competitive binding to LSD1. Interestingly, C26 did not inhibit horseradish peroxidase (HRP) and quench H2O2, thus excluding the possibility that LSD1 inhibition by C26 was due to the HRP inhibition and consumption of H2O2. In LSD1 overexpressed A549 cells, compound C26 concentration-dependently induced accumulation of H3K4me1/me2 and H3K9me2 and showed cellular target engagement to LSD1. Additionally, compound C26 significantly inhibited migration of A549 cells in a concentration-dependent manner, further western blot analysis showed that C26 increased expression levels of epithelial cell markers E-Cadherin and Claudin-1, down-regulated mesenchymal cell marker N-Cadherin and the upstream transcription factors Snail and Slug. Docking studies were also performed to rationalize the potency of C26 toward LSD1. To conclude, the [1,2,4]triazolo[1,5-a]pyrimidine could serve as a promising scaffold for the development of new LSD1 inhibitors.
- Wang, Shuai,Li, Zhong-Rui,Suo, Feng-Zhi,Yuan, Xiao-Han,Yu, Bin,Liu, Hong-Min
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supporting information
p. 388 - 401
(2019/02/19)
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- Br?nsted Acid-Catalyzed Direct C(sp2)?H Heteroarylation Enabling the Synthesis of Structurally Diverse Biaryl Derivatives
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Biaryl scaffold is an important class of structural frameworks that exists in many natural products and drug molecules. The development of transition metal-catalyzed approaches for the efficient construction of biaryl scaffolds has long been pursued because of the interesting structural features and broad biological profiles of biaryl scaffolds. Herein, we describe the Br?nsted acid-catalyzed direct C(sp2)?H heteroarylation that enables the synthesis of biaryl fragments (70 examples) in moderate to excellent yields (up to 99% yield), which was also performed at a gram scale and successfully applied to the privileged quinazoline scaffolds of the first-generation epidermal growth factor receptor (EGFR) inhibitors Gefitinib and Erlotinib, offering rapid access to a series of quinazoline-based biaryl compounds. Additionally, the late-stage diversifications were performed based on the compound 3 b, generating a library of structurally diverse and complex biaryl compounds. (Figure presented.).
- Yuan, Shuo,Yu, Bin,Liu, Hong-Min
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supporting information
p. 59 - 66
(2019/01/16)
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- Synthetic Versatility of β-Alkoxyvinyl Trichloromethyl Ketones for Obtaining [1,2,4]Triazolo[1,5- a ]pyrimidines
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The synthetic versatility of 4-alkoxy-4-alkyl/aryl-1,1,1-trichloroalk-3-en-2-ones (enones) for the synthesis of [1,2,4]triazolo[1,5- a ]pyrimidines, in which the trichloromethyl group is either maintained or eliminated from the product by simply controlli
- Souza, Laura A.,Santos, Josiane M.,Mittersteiner, Mateus,Andrade, Valquiria P.,Lobo, Marcio M.,Santos, Felipe B.,Bortoluzzi, Adailton J.,Bonacorso, Helio G.,Martins, Marcos A. P.,Zanatta, Nilo
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p. 3686 - 3695
(2018/07/21)
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- Pyrimidotriazole-indole compound and preparation method and application thereof
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The invention discloses a pyrimidotriazole-indole compound having a general formula as shown in I (shown in the description). The invention also provides a preparation method and application of the above compound. An in vitro BRD4 enzymatic activity inhibition test proves that the pyrimidotriazole-indole compound has potential inhibition effects on various tumor cells by inhibiting the enzymatic activity of BRD4, and can be used as a lead compound for antitumor drug preparation. In addition, a preparation method of the compound, provided by the present invention, has the advantages of mild reaction conditions, simple operation and high yield.
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Paragraph 0058; 0064; 0068
(2019/01/08)
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- Novel Selective Inhibitor of Leishmania (Leishmania) amazonensis Arginase
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Arginase is a glycosomal enzyme in Leishmania that is involved in polyamine and trypanothione biosynthesis. The central role of arginase in Leishmania (Leishmania) amazonensis was demonstrated by the generation of two mutants: one with an arginase lacking
- Da Silva, Edson R.,Boechat, Nubia,Pinheiro, Luiz C. S.,Bastos, Monica M.,Costa, Carolina C. P.,Bartholomeu, Juliana C.,Da Costa, Talita H.
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p. 969 - 978
(2015/10/28)
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- New trifluoromethyl triazolopyrimidines as Anti-Plasmodium falciparum agents
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According to the World Health Organization, half of the World's population, approximately 3.3 billion people, is at risk for developing malaria. Nearly 700,000 deaths each year are associated with the disease. Control of the disease in humans still relies on chemotherapy. Drug resistance is a limiting factor, and the search for new drugs is important. We have designed and synthesized new 2-(trifluoromethyl)[1,2,4]triazolo[1,5-a]pyrimidine derivatives based on bioisosteric replacement of functional groups on the anti-malarial compounds mefloquine and amodiaquine. This approach enabled us to investigate the impact of: (i) ring bioisosteric replacement; (ii) a CF3 group substituted at the 2-position of the [1,2,4]triazolo[1,5-a]pyrimidine scaffold and (iii) a range of amines as substituents at the 7-position of the of heterocyclic ring; on in vitro activity against Plasmodium falciparum. According to docking simulations, the synthesized compounds are able to interact with P. falciparum dihydroorotate dehydrogenase (PfDHODH) through strong hydrogen bonds. The presence of a trifluoromethyl group at the 2-position of the [1,2,4]triazolo [1,5-a]pyrimidine ring led to increased drug activity. Thirteen compounds were found to be active, with IC50 values ranging from 0.023 to 20 μM in the anti-HRP2 and hypoxanthine assays. The selectivity index (SI) of the most active derivatives 5, 8, 11 and 16 was found to vary from 1,003 to 18,478.
- Boechat, Nubia,Pinheiro, Luiz C.S.,Silva, Thiago S.,Aguiar, Anna C.C.,Carvalho, Alcione S.,Bastos, Monica M.,Costa, Carolina C.P.,Pinheiro, Sergio,Pinto, Angelo C.,Mendonca, Jorge S.,Dutra, Karen D.B.,Valverde, Alessandra L.,Santos-Filho, Osvaldo A.,Ceravolo, Isabela P.,Krettli, Antoniana U.
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scheme or table
p. 8285 - 8302
(2012/10/08)
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- Unexpected alternative direction of a Biginelli-like multicomponent reaction with 3-amino-1,2,4-triazole as the urea component
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A Biginelli-like three-component condensation using 3-amino-1,2,4-triazole as urea component resulted in an unexpected alternative direction of the tetrahydropyrimidine ring formation.
- Gorobets, Nikolay Yu.,Sedash, Yuriy V.,Ostras, Konstantin S.,Zaremba, Oleg V.,Shishkina, Svetlana V.,Baumer, Vyacheslav N.,Shishkin, Oleg V.,Kovalenko, Sergiy M.,Desenko, Sergey M.,Van der Eycken, Erik V.
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p. 2095 - 2098
(2010/06/14)
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- SYNTHESIS AND REARRANGEMENTS OF IMIDAZOLO- AND TRIAZOLO-DIAZINES
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3-Methylimidazolopyridine and 3-methyl-1,2,4-triazolopyrazine were prepared by coupling ethyl dithioacetate with 2-(aminomethyl)pyridine and 2-hydrazinopyrazine, respectively.Both compounds are stable in dilute acids and bases, unlike 3-methyl-1,2,4-triazolopyrimidine obtained by coupling the same dithioacetate with 2-hydrazinopyrimidine, which quickly undergoes a Dimroth type rearrangement.Coupling ethyl dithioacetate with 2-hydrazino-4-hydroxy-6-methylpyrimidine yielded a mixture of 3,5-dimethyl-1,2,4-triazolo-7(8H)-pyrimidone and 3,7-dimethyl-1,2,4-triazolo-5(8H)-pyrimidone, which were identified by 2D nmr.The last compound underwent a Dimroth rearrangement with acids to yield 2,5-dimethyl-1,2,4-triazolo-7(4H)-pyrimidone, whereas the first did not.Finally, coupling ethyl dithioacetate with 5-chloro-4-hydrazinopyrimidine afforded 8-chloro-3-methyl-1,2,4-triazolopyrimidine, which upon treatment with acids underwent a reversible ring opening to afford 2-chloro-1-formamido-2-(5-methyl-1,3,4-triazolo-2-yl)ethene.The latter on pyrolysis gave the starting base without undergoing rearrangement.
- Khadem, H. S. El,Kawai, J.,Swartz, D. L.
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p. 239 - 248
(2007/10/02)
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