- Gold(I) NHC Complexes: Antiproliferative Activity, Cellular Uptake, Inhibition of Mammalian and Bacterial Thioredoxin Reductases, and Gram-Positive Directed Antibacterial Effects
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Gold complexes with N-heterocyclic carbene (NHC) ligands represent a promising class of metallodrugs for the treatment of cancer or infectious diseases. In this report, the synthesis and the biological evaluation of halogen-containing NHC-AuI-Cl complexes are described. The complexes 1 and 5 a–5 f displayed good cytotoxic activity against tumor cells, and cellular uptake studies suggested that an intact Au-NHC fragment is essential for the accumulation of high amounts of both the metal and the NHC ligand. However, the bioavailability was negatively affected by serum components of the cell culture media and was influenced by likely transformations of the complex. One example (5 d) efficiently induced apoptosis in vincristine- and daunorubicin-resistant P-glycoprotein overexpressing Nalm-6 leukemia cells. Cellular uptake studies with this compound showed that both the wild-type and resistant Nalm-6 cells accumulated comparable amounts of gold, indicating that the gold drug was not excreted by P-glycoprotein or other efflux transporters. The effective inhibition of mammalian and bacterial thioredoxin reductases (TrxR) was confirmed for all of the gold complexes. Antibacterial screening of the gold complexes showed a particularly high activity against Gram-positive strains, reflecting their high dependence on an intact Trx/TrxR system. This result is of particular interest as the inhibition of bacterial TrxR represents a relatively little explored mechanism of new anti-infectives.
- Schmidt, Claudia,Karge, Bianka,Misgeld, Rainer,Prokop, Aram,Franke, Raimo,Br?nstrup, Mark,Ott, Ingo
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Read Online
- Convenient two-step one-pot synthesis of benzimidazoles using 2-nitroanilines and thiourea dioxide
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A new convenient method for the conversion of 2-nitroanilines into benzimidazoles by two-step one-pot procedure is reported. The procedure involves the reduction of nitro group followed by the intramolecular cyclisation of the corresponding o-phenylenediamines utilising thiourea dioxide and sodium hydroxide at 70 °C in mixed solvents of H2O and EtOH (v/v, 3/1). The yields are good to excellent and the workup is simple.
- Pu, Shuai,Liang, Qiuxiang,Luo, Xi,Luo, Juan
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Read Online
- Cyclization of o-phenylenediamines by CO2 in the presence of H2 for the synthesis of benzimidazoles
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The cyclization of o-phenylenediamines by CO2 in the presence of H2 was presented to directly synthesize benzimidazoles, and a series of benzimidazoles were obtained in excellent yields using RuCl 2(dppe)2 as the catalyst.
- Yu, Bo,Zhang, Hongye,Zhao, Yanfei,Chen, Sha,Xu, Jilei,Huang, Changliang,Liu, Zhimin
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Read Online
- One-Pot Transformation of Lignin and Lignin Model Compounds into Benzimidazoles
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It is a challenging task to simultaneously achieve selective depolymerization and valorization of lignin due to their complex structure and relatively stable bonds. We herein report an efficient depolymerization strategy that employs 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as oxidant/catalyst to selectively convert different oxidized lignin models to a wide variety of 2-phenylbenzimidazole-based compounds in up to 94 % yields, by reacting with o-phenylenediamines with varied substituents. This method could take full advantage of both Cβ and/or Cγ atom in lignin structure to furnish the desirable products instead of forming byproducts, thus exhibiting high atom economy. Furthermore, this strategy can effectively transform both the oxidized hardwood (birch) and softwood (pine) lignin into the corresponding degradation products in up to 45 wt% and 30 wt%, respectively. Through a “one-pot” process, we have successfully realized the oxidation/depolymerization/valorization of natural birch lignin at the same time and produced the benzimidazole derivatives in up to 67 wt% total yields.
- Guo, Tao,He, Jianghua,Liu, Tianwei,Zhang, Yuetao
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supporting information
(2022/02/07)
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- SOCE INHIBITORS AND THERAPEUTIC USES THEREOF
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The present invention provides SOCE inhibitors that are useful as therapeutic agents in a variety of applications. The present invention also relates to pharmaceutical compositions, products and kits comprising such SOCE inhibitors, and methods of using t
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Page/Page column 45-46
(2021/11/26)
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- Highly efficient one pot synthesis of benzimidazoles from 2-nitroaniline and PhSiH3 as reducing agent catalyzed by Pd/C as a heterogeneous catalyst
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This work reports an efficient route for the synthesis of benzimidazole from o-nitroaniline in the presence of carbon dioxide atmosphere, PhSiH3 as a reducing agent catalyzed by Pd/C as a catalyst. Benzimidazoles have become the focus of organic chemists, as benzimidazole is an important intermediate in medicinal chemistry. We have developed more efficient route for the synthesis benzimidazole and various substituted benzimidazoles have been synthesized in good to excellent yield. The TBD (1,5,7-Triazabicyclo [4.4.0] dec-5-ene) is selected as a base as it promotes the CO2 insertion. Benzimidazoles were synthesized through reduction of nitro group followed by cyclization of amine using CO2 as a carbon source. Moreover, the Pd/C catalyst can be recycled up to five recycle run without significant changes in the yield of the product.
- Phatake, Vishal V.,Bhanage, Bhalchandra M.
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- Highly Efficient and Catalyst-Free Synthesis of Benzimidazoles in Aqueous Media
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Abstract: A convenient and highly efficient, catalysts-free synthesis of benzimidazoles in an aqueous medium has been developed. The conditions of the synthesis were optimized, and its scope was successfully extended to various substrates with good to excellent yields. The experimental procedure is simple, and the products can be isolated by filtration followed by recrystallization from water.
- Huang, W.-H.,Jin, Y.-J.,Ma, L.-F.,Wu, Y.,Zhou, L.-H.
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p. 825 - 830
(2021/06/12)
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- A substituent- And temperature-controllable NHC-derived zwitterionic catalyst enables CO2upgrading for high-efficiency construction of formamides and benzimidazoles
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Chemocatalytic upgrading of the greenhouse gas CO2 to valuable chemicals and biofuels has attracted broad attention in recent years. Among the reported approaches, N-formylation of CO2 with an amine is of great significance due to its versatility in the construction of N-containing linear and cyclic skeletons. Herein, a stable N-heterocyclic carbene-carboxyl adduct (NHC-CO2) was facilely prepared and could be used as a recyclable zwitterionic catalyst for efficient CO2 reductive upgrading via either N-formylation or further coupling with cyclization under mild conditions (25 °C, 1 atm CO2) using hydrosilane as a hydrogen source. More than 30 different alkyl and aromatic amines could be transformed into the corresponding formamides or benzimidazoles with remarkable yields (74%-98%). The electronic effect of the introduced substituent on NHC-CO2 was found to evidently affect the thermostability and nucleophilicity of the zwitterionic catalyst, which is directly correlated with its catalytic activity. Moreover, NHC-CO2 could supply CO2 by in situ decarboxylation at a specific temperature that is dependent on the introduced substituent type. Experimental and computational studies showed that the carboxyl species on NHC-CO2 was not only a nucleophilic center, but also a C1 source which rapidly captures or substitutes ambient CO2 during hydrosilylation. In addition, a simple and green conceptual process was designed for the product purification and catalyst recycling, with a good feasibility for small-scale production.
- Li, Hu,Li, Zhengyi,Wu, Hongguo,Yang, Song,Yu, Zhaozhuo,Zhang, Lilong,Zhu, Kaixun
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supporting information
p. 5759 - 5765
(2021/08/23)
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- Reductive cyclization of o-phenylenediamine with CO2 and BH3NH3 to synthesize 1H-benzoimidazole derivatives
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A simple and green protocol was developed for the reductive cyclization of o-phenylenediamine with CO2 and BH3NH3 to yield 1H-benzimidazole. The desired 1H-benzimidazole derivatives were produced under mild conditions. Mechanism investigation indicated that the coordination of o-phenylenediamine with the boron atom of BH3NH3 promoted the transfer of the formyl group to form a stable intermediate, which facilitated the intramolecular nucleophilic addition-elimination for the formation of target product. In this process, BH3NH3 served multifunctional roles, acting as a reducing agent and a formylation catalyst.
- Li, Xiao,Zhang, Junhua,Yang, Yue,Hong, Hailong,Han, Limin,Zhu, Ning
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supporting information
(2021/09/28)
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- Sustainable Synthesis of 2-Hydroxymethylbenzimidazoles using D-Fructose as a C2 Synthon
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D-fructose, a biomass-derived carbohydrate has been identified as an environmentally benign C2 synthon in the preparation of synthetically useful 2-hydroxymethylbenzimidazole derivatives by coupling with 1,2-phenylenediamines. Proof of concept was established by synthesizing 23 examples using BF3.OEt2 (20 mol%), TBHP (5.5 M, decane) (1.0 equiv.) in CH3CN at 90 °C for 1 h. The pivotal features of this method include metal-free conditions, short time, good functional group tolerance, gram scale feasibility and the synthesis of benzimidazole fused 1,4-oxazine. Control studies with conventional C2 synthons did not produce the desired product, thus suggesting a new reaction pathway from D-fructose.
- Raja, Dineshkumar,Philips, Abigail,Sundaramurthy, Devikala,Chandru Senadi, Gopal
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supporting information
p. 3754 - 3759
(2021/10/14)
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- Metal-Free Synthesis of Benzimidazoles via Oxidative Cyclization of d -Glucose with o-Phenylenediamines in Water
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d-Glucose has been identified as an efficient C1 synthon in the synthesis of benzimidazoles from o-phenylenediamines via an oxidative cyclization strategy. Isotopic studies with 13C6-d-glucose and D2O unambiguously confirmed the source of methine. The notable features of this method include the following: broad functional group tolerance, a biorenewable methine source, excellent reaction yields, a short reaction time, water as an environmentally benign solvent, and the synthesis of vitamin B12 component on the gram scale.
- Raja, Dineshkumar,Philips, Abigail,Palani, Pushbaraj,Lin, Wei-Yu,Devikala, Sundaramurthy,Senadi, Gopal Chandru
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p. 11531 - 11540
(2020/10/12)
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- Facile access to: N-formyl imide as an N-formylating agent for the direct synthesis of N-formamides, benzimidazoles and quinazolinones
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N-Formamide synthesis using N-formyl imide with primary and secondary amines with catalytic amounts of p-toluenesulfonic acid monohydrate (TsOH·H2O) is described. This reaction is performed in water without the use of surfactants. Moreover, N-formyl imide is efficiently synthesized using acylamidines with TsOH·H2O in water. In addition, N-formyl imide was successfully used as a carbonyl source in the synthesis of benzimidazole and quinazolinone derivatives. Notable features of N-formylation of amines by using N-formyl imide include operational simplicity, oxidant- A nd metal-free conditions, structurally diverse products, and easy applicability to gram-scale operation.
- Huang, Hsin-Yi,Liang, Chien-Fu,Lin, Xiu-Yi,Yen, Shih-Yao
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supporting information
p. 5726 - 5733
(2020/08/21)
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- Endogenous X-C=O species enable catalyst-free formylation prerequisite for CO2reductive upgrading
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CO2, the main component of greenhouse gas, is currently developed as a promising surrogate of carbon feedstock. Among various conversion routes, CO2undergoing catalytic reduction can furnish hydrogen/energy carriers and value-added chemicals, while specific metal-containing catalysts or organocatalysts are often prerequisite for smooth proceeding of the involved reaction processes. In this work, both formic acid and N-containing benzoheterocyclic compounds (including various benzimidazoles, benzothiazole, and benzoxazole) along with silanols could be synthesized with high yields (>90%) from catalyst-free reductive upgrading of CO2under mild conditions (50 °C). The endogenous X-CO species, derived from the N-methyl-substituted amide-based solvent [Me2N-C(O)-R], especially PolarClean, and O-formyl group [O-C(O)-H] of in situ formed silyl formate, were found to play a prominent promotional role in the activation of the used hydrosilane for reductive CO2insertion, as demonstrated by density functional theory (DFT) calculations and isotopic labeling experiments. Moreover, reaction mechanisms and condition-based sensitivity assessment were also delineated.
- Dai, Wenshuai,Li, Hu,Saravanamurugan, Shunmugavel,Wu, Hongguo,Yang, Song
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p. 5822 - 5832
(2020/10/21)
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- Visible-light-induced aerobic oxidative desulfurization of 2-mercaptobenzimidazolesviaa sulfinyl radical
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A mild transition-metal-free non-toxic aerobic photoredox system was found to enable highly efficient desulfurization of 2-mercaptobenzimidazoles. This viable catalytic system includes Rose Bengal in a low catalyst loading as a photosensitizer and cheap, non-toxic NaCl in a catalytic amount as an additive, combined with an oxygen atmosphere. This protocol provides an important alternative access to a broad range of benzimidazole and deuterated benzimidazole products in generally high yields with good tolerance of various synthetically and pharmaceutically useful functionalities. The mechanistic studies reveal that both single electron transfer and energy transfer probably occur in the initial step and a sulfinyl radical intermediate is involved in the key desulfurization process.
- Deng, Guo-Jun,Fu, Mei,Huang, Huawen,Ji, Xiaochen,Li, Yongtong
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supporting information
p. 5594 - 5598
(2020/09/21)
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- K2S as Sulfur Source and DMSO as Carbon Source for the Synthesis of 2-Unsubstituted Benzothiazoles
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We describe a three-component reaction of o-iodoanilines with K2S and DMSO that provides 2-unsubstituted benzothiazoles in moderate to good isolated yields with good functional group tolerance. Electron-rich aromatic amines and o-phenylenediamines instead of o-iodoanilines provided 2-unsubstituted benzothiazoles and 2-unsubstituted benzimidazoles with and without K2S under similar conditions. Notably, DMSO plays three vital roles: carbon source, solvent, and oxidant.
- Deng, Guobo,Kuang, Daizhi,Liang, Yun,Yang, Yuan,Yu, Jiangxi,Zhang, Fuxing,Zhu, Xiaoming
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supporting information
p. 3789 - 3793
(2020/06/04)
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- Synthesis method of ammonium acetate mediated benzimidazole compound
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The invention discloses a synthesis method of a benzimidazole compound mediated by ammonium acetate. The synthesis method comprises the following steps: adding an o-phenylenediamine compound, dimethylsulfoxide, an additive 1 and an additive 2 into a reaction tube, carrying out a stirring reaction at 130-150 DEG C, cooling the reaction product to room temperature after the reaction is finished, and carrying out separation and purification on the product to obtain the benzimidazole compound. The invention develops a method for synthesizing a benzimidazole compound under the mediation of ammonium acetate by taking DMSO as a carbon source and an oxidant and an o-phenylenediamine compound as a substrate under the condition of no metal catalyst. The synthesis method does not need a metal catalyst, and the required carbon source and oxidant have the characteristics of low toxicity, low price, easiness in obtaining, stable performance and the like. The method has the advantages of easiness inoperation, few steps, mild reaction conditions, better functional group tolerance and the like, and provides a new valuable way for synthesizing benzimidazole compounds.
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Paragraph 0039-0041
(2020/11/23)
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- Transition-metal and oxidant-free approach for the synthesis of diverse N-heterocycles by TMSCl activation of isocyanides
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A highly efficient TMSCl-mediated addition of N-nucleophiles to isocyanides has been achieved. This transition-metal and oxidant-free strategy has been applied to the construction of various N-heterocyles such as quinazolinone, benzimidazole and benzothiazole derivatives by the use of distinct amino-based binucleophiles. The notable feature of this protocol includes its mild reaction condition, broad functional group tolerance and excellent yield. This journal is
- Chen, Fen-Er,Dong, Lin,Li, Hongyan,Liu, Jinxin,Luo, Liangliang,Xiao, You-Cai,Zhou, Yuan
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p. 29257 - 29262
(2020/10/02)
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- METHODS OF TREATING LIVER FIBROSIS USING CALPAIN INHIBITORS
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Disclosed herein are methods of treating liver fibrosis by administering calpain inhibitors to subjects in need thereof.
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Paragraph 0318
(2020/01/24)
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- Microwave use of amidine compounds in the aqueous phase benzoate synthesis of benzimidazole compounds method
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The invention discloses a microwave the use of amidine compounds in the aqueous phase benzoate synthesis of benzimidazole compounds, in the aqueous phase under microwave conditions adding benzoic amidine compound under alkaline condition [...] into benzimidazole reaction, invention an environment-friendly, the operation is simple, cheap and safe, efficient process for preparing benzimidazole method. Compared with the prior art, this method not only can be applied to a large number of functional groups, the productive rate is high, few by-products, and the operation is simple, safe, low cost, environmental protection; .
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Paragraph 0070
(2019/03/28)
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- A benzimidazole and synthetic method of derivative thereof (by machine translation)
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The present invention provides a benzimidazole and its derivative synthesis method, the method through the imidazole chloride catalyzed O-phenylenediamine cyclized, realizes the multi-functional chain dibasic and imidazole and 2 - substituted benzimidazole synthesis, method is simple and economic, and the practicability is strong. This invention does not have any other catalyst or additive, synthetic method has good functional group tolerance and excellent yield and purity, reaction time is short, and does not need the harsh reaction conditions, is suitable for industrial production. (by machine translation)
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Paragraph 0040; 0042; 0050; 0051
(2019/02/10)
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- Cu@U-g-C3N4 Catalyzed Cyclization of o-Phenylenediamines for the Synthesis of Benzimidazoles by Using CO2 and Dimethylamine Borane as a Hydrogen Source
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Abstract: This work reports a green and sustainable route for the synthesis of benzimidazoles via C–N bond formation using carbon dioxide (CO2) as a C1 carbon source. In this work, Cu@U-g-C3N4 catalyst was prepared from urea derived porous graphitic carbon?nitride (U-g-C3N4) and CuCl2 and characterized by FT-IR, XRD, XPS, SEM, TPD etc. The Cu@U-g-C3N4 as a heterogeneous recyclable catalyst has been employed first time for the cyclization of o-phenylenediamines (OPD) with CO2 to benzimidazoles using dimethylamine borane (DMAB). The proposed protocol becomes sustainable and efficient due to the use of propylene carbonate/water as a suitable biodegradable, economical and environmentally benign solvent system. The proposed catalytic system showed a wide range of substrate scope for the synthesis of benzimidazoles in good to excellent yields. Graphical Abstract: [Figure not available: see fulltext.]
- Phatake, Vishal V.,Bhanage, Bhalchandra M.
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p. 347 - 359
(2018/11/23)
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- Cobalt-catalyzed synthesis of N-containing heterocycles: Via cyclization of ortho -substituted anilines with CO2/H2
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The CO2-involved synthesis of chemicals is of great significance from the green and sustainable chemistry viewpoint. Herein, we report a non-noble metal catalytic system composed of CoF2, CsF and P(CH2CH2PPh2)3 (denoted as PP3) for the synthesis of N-containing heterocycles from ortho-substituted anilines and CO2/H2. Mechanism investigation indicates that [Co(PP3)H(CO2)]+ is a catalytically active intermediate under working conditions; and CsF plays important roles in activating ortho-substituted anilines via hydrogen bond interactions, thus promoting the formation of the final products. This catalytic system is highly efficient, and allows a wide scope of ortho-substituted anilines, together with excellent functional group tolerance, affording various N-containing heterocycles in good to excellent yields.
- Ke, Zhengang,Yu, Bo,Wang, Huan,Xiang, Junfeng,Han, Juanjuan,Wu, Yunyan,Liu, Zhenghui,Yang, Peng,Liu, Zhimin
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p. 1695 - 1701
(2019/04/10)
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- Supported Rhodium (Rh@PS) Catalyzed Benzimidazoles Synthesis Using Ethanol/Methanol as C2H3/CH Source
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An effective and stable polystyrene supported rhodium (Rh@PS) nano-catalyst has been synthesized by following reduction-deposition approach and applied for the selective benzimidazoles synthesis from 1,2-phenylenediamines and ethanol/methanol as C2H3/CH source. The ethanol/methanol in the presence of trace amounts of aerobic oxygen under Rh@PS catalysed condition, first participated in oxidation of alcohol followed by consecutive condensation, cyclization and hydrogen elimination reactions with 1,2-phenylenediamine gave the desired products in good yields. The Rh@PS catalyst in a single system performed both oxidation and reduction reactions in a selective/specific manner and applied for large substrate scope. Easy recovery, handling, stability, recyclability of the catalyst and less chance of metal contamination with the products are the added advantages of the process. (Figure presented.).
- Sharma, Saurabh,Sharma, Ajay,Yamini,Das, Pralay
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supporting information
p. 67 - 72
(2018/12/05)
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- Catalytic synthesis of benzimidazoles and organic carbamates using a polymer supported zinc catalyst through CO2 fixation
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Utilization of carbon dioxide in chemical fixation for synthesis of fine chemicals like benzimidazoles, organic carbamates, etc. is in high demand in recent years as carbon dioxide is a cost effective, sustainable, and green renewable C1 source. In this article we present the design and synthesis of an organically modified polystyrene bound heterogeneous [PS-Zn(ii)-SALTETA] catalyst. The catalyst has been characterized thoroughly by Fourier transform infrared spectroscopy, atomic absorption spectroscopy, thermo gravimetric analysis, PXRD, SEM and EDAX studies. The catalyst was used for cyclization of o-phenylenediamines through insertion of carbon dioxide in order to produce benzimidazoles in the presence of dimethylamine borane (DMAB). The developed catalytic procedure is sustainable, economical and efficient owing to the utilization of ethanol/water as a biodegradable and environment friendly solvent system. Besides benzimidazole production the catalyst was also very active for manufacture of organic carbamates from anilines and n-butyl bromide under atmospheric CO2 pressure under solvent free conditions at room temperature and the catalytic protocol showed outstanding functional group tolerance. Moreover the catalyst is highly recyclable and reusable.
- Biswas, Imdadul Haque,Biswas, Surajit,Islam, Md Sarikul,Riyajuddin, Sk,Sarkar, Priyanka,Ghosh, Kaushik,Islam, Sk Manirul
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p. 14643 - 14652
(2019/09/30)
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- CALPAIN MODULATORS AND THERAPEUTIC USES THEREOF
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Small molecule calpain modulator compounds, including their pharmaceutically acceptable salts, can be included in pharmaceutical compositions. The compounds can be useful in inhibiting calpain, or competitive binding with calpastatin, by contacting them with CAPN1, CAPN2, and/or CAPN9 enzymes residing inside a subject. The compounds and composition can also be administered to a subject in order to treat a fibrotic disease or a secondary disease state or condition of a fibrotic disease.
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Paragraph 0372
(2019/10/23)
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- Novel pyrrolo-imidazole derivatives and preparation method and application thereof
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The invention discloses novel pyrrolo-imidazole derivatives and a preparation method and application thereof, and relates to the field of organic synthesis and medical chemistry. The derivatives referto benzimidazo-pyrrole compounds and medicinal salts, enantiomers, diastereoisomers or racemes; a synthetic method of the novel pyrrolo-imidazole derivatives is simple and high in yield; the derivatives are of good antibacterial activity against various fungi and have a promising application prospect in antibacterial anti-cancer activity application.
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Paragraph 0041; 0042; 0044-0050
(2018/09/12)
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- Oxalic/malonic acids as carbon building blocks for benzazole, quinazoline and quinazolinone synthesis
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An oxidant, base and metal free methodology has been developed for the synthesis of various 2-substituted and non-substituted benzazoles, quinazolines and quinazolinones using oxalic/malonic acids as an in situ carbon source. This methodology is applicable for a wide range of substituted o-phenylenediamine, o-aminothiophenol, o-aminophenol and o-aminobenzamide containing various functional groups and provides good to excellent yields of the corresponding product. Furthermore an easy workup procedure, high yield and easy isolation of products are key features of this methodology. The developed protocol is also applicable for the gram scale synthesis of benzimidazoles.
- Sharma, Saurabh,Bhattacherjee, Dhananjay,Das, Pralay
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supporting information
p. 1337 - 1342
(2018/03/06)
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- Imidazolium chloride-catalyzed synthesis of benzimidazoles and 2-substituted benzimidazoles from o-phenylenediamines and DMF derivatives
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A facile, general, and economical synthesis of diversely functionalized benzimidazoles and 2-substituted benzimidazoles has been realized via the imidazolium chloride-catalyzed cyclization of o-phenylenediamines with DMF derivatives. This protocol shows a broad substrate scope for aliphatic, aromatic, and heteroaromatic amides. A series of benzimidazoles and 2-substituted benzimidazoles have been obtained in moderate to excellent yields.
- Gan, Zongjie,Tian, Qingqiang,Shang, Suqin,Luo, Wen,Dai, Zeshu,Wang, Huajun,Li, Dan,Wang, Xuetong,Yuan, Jianyong
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p. 7450 - 7456
(2018/11/27)
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- B(C6F5)3: a robust catalyst for the activation of CO2 and dimethylamine borane for the N-formylation reactions
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In this work, B(C6F5)3 is utilized as an organocatalyst for the transition-metal-free N-formylation of amines using carbon dioxide (CO2) as a C1 source and dimethylamine borane (Me2NH·BH3) as a green hydrogen transfer source at 80 °C. Most reported works utilize silane and hydrogen for the N-formylation reactions using CO2 which have thus far been limited by low atom economy, high cost or the use of harsh reaction conditions. This catalytic protocol affords a broad range of formylated products in moderate to excellent yields under mild reaction conditions with a high TON and TOF. The bulky boron (B(C6F5)3) catalyst reacts with amines and forms a Frustrated Lewis Pair (FLP) and activates CO2 and Me2NH·BH3 molecules. Additionally, this boron catalyst shows high catalytic activity for the cyclization of o-phenylenediamines using CO2 and Me2NH·BH3 to synthesize benzimidazoles.
- Saptal, Vitthal B.,Juneja, Gaurav,Bhanage, Bhalchandra M.
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supporting information
p. 15847 - 15851
(2018/10/04)
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- Efficient N-Heterocyclic Carbene/Ruthenium Catalytic Systems for the Alcohol Amidation with Amines: Involvement of Poly-Carbene Complexes?
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The atom-economic direct amidation of alcohols with amines has been recently highlighted as an attractive and promising transformation. Among the versatile reported catalytic systems, in situ generated N-heterocyclic carbene (NHC)/ruthenium (Ru) catalytic systems have demonstrated their advantages such as easy operation and use of commercial Ru compounds. However, the existing catalyst loadings are relatively high, and additional insights for the in situ catalyst generation are still not well-documented. In this work, a variety of benzimidazole-based NHC precursors were initially synthesized. Through the screening of various NHC precursors and other reaction conditions, active in situ catalytic systems were discovered for the efficient amide synthesis. Notably, the catalyst loading is as low as 0.5 mol %. Furthermore, additional experiments were performed to validate the rationale for the superiority of the current catalytic systems over our previous system. It was observed that the ligand structure is one of the reasons for the higher activity. In addition, the higher ratio of the NHC precursor/[Ru] is another important factor for the improvement. Further HR-MS analysis identified the formation of two mono-NHC-Ru species as major species and two Ru species bearing multiple NHC ligands as minor species. Hopefully, the efficient and readily-accessible catalytic systems reported herein could demonstrate great potential for further practical applications.
- Cheng, Hua,Xiong, Mao-Qian,Zhang, Ni,Wang, Hua-Jing,Miao, Yang,Su, Wei,Yuan, Ye,Chen, Cheng,Verpoort, Francis
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p. 4338 - 4345
(2018/09/06)
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- Synthesis of benzimidazoles from o-phenylenediamines and DMF derivatives in the presence of PhSiH3
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A simple approach to preparation of benzimidazoles from o-phenylenediamines and DMF derivatives, only employing PhSiH3 as promoter without any other additives, was reported. This route provided moderate to high yields with a broad substrate scope. A plausible mechanism for the reaction is proposed based on the spectroscopic characterization (e.g., HRMS and 1H NMR) of the reaction mixture.
- Zhu, Jianhua,Zhang, Zhenbei,Miao, Chengxia,Liu, Wei,Sun, Wei
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p. 3458 - 3462
(2017/05/31)
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- CO2 as a C1 Source: B(C6F5)3-Catalyzed Cyclization of o-Phenylene-diamines To Construct Benzimidazoles in the Presence of Hydrosilane
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The catalytic construction of benzimidazoles using CO2 as a carbon source represents a facile and sustainable approach to obtaining these valuable compounds. Herein, we describe the B(C6F5)3-catalyzed synthesis of benzimidazoles via cyclization of o-phenylenediamines with CO2 and PhSiH3. This metal-free catalytic route achieves the desired products in high yield under convenient reaction conditions and is applicable to a broad substrate scope. A plausible mechanism for the reaction involving a frustrated Lewis pair pathway is proposed based on spectroscopic characterization (e.g., 13C NMR) of the reaction intermediates.
- Zhang, Zhenbei,Sun, Qiangsheng,Xia, Chungu,Sun, Wei
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supporting information
p. 6316 - 6319
(2016/12/23)
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- Atmospheric CO2 promoted synthesis of N-containing heterocycles over B(C6F5)3 catalyst
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B(C6F5)3 combined with atmospheric CO2 was found to be highly effective for the cyclization of ortho-substituted aniline derivatives with N,N-dimethylformamide (DMF), and a series of N-containing heterocycles including benzothiazoles, benzimidazoles, quinazolinone and benzoxazole were obtained in good to excellent yields.
- Gao, Xiang,Yu, Bo,Mei, Qingqing,Yang, Zhenzhen,Zhao, Yanfei,Zhang, Hongye,Hao, Leiduan,Liu, Zhimin
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p. 8282 - 8287
(2016/10/11)
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- Cu-Pd/γ-Al2O3 catalyzed the coupling of multi-step reactions: Direct synthesis of benzimidazole derivatives
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The coupling of multi-step reactions catalyzed by a heterogeneous catalyst is an important path to accomplish some unconventional chemical transformations. Since the starting materials generated from previous steps were adsorbed on the catalyst, the activation energy of following steps was largely decreased, and thus the reaction conditions were more mild and environmental friendly. Catalyzed by a multifunctional Cu-Pd/γ-Al2O3 catalyst, the transfer hydrogenation and successive cyclization coupling reaction from o-nitroaniline and alcohol to afford benzimidazole derivatives in high yield was realized. The catalyst could be reused several times without loss of activity. The synergies of reforming hydrogenation of Cu-Pd bimetal and support acidity of γ-Al2O3 were responsible for this catalytic transformation.
- Feng, Feng,Ye, Jia,Cheng, Zheng,Xu, Xiaoliang,Zhang, Qunfeng,Ma, Lei,Lu, Chunshan,Li, Xiaonian
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p. 72750 - 72755
(2016/08/09)
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- Synthesis and evaluation of selected benzimidazole derivatives as potential antimicrobial agents
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A library of 53 benzimidazole derivatives, with substituents at positions 1, 2 and 5, were synthesized and screened against a series of reference strains of bacteria and fungi of medical relevance. The SAR analyses of the most promising results showed that the antimicrobial activity of the compounds depended on the substituents attached to the bicyclic heterocycle. In particular, some compounds displayed antibacterial activity against two methicillin-resistant Staphylococcus aureus (MRSA) strains with minimum inhibitory concentrations (MICs) comparable to the widely-used drug ciprofloxacin. The compounds have some common features; three possess 5-halo substituents; two are derivatives of (S)-2-ethanaminebenzimidazole; and the others are derivatives of one 2-(chloromethyl)-1Hbenzo[ d]imidazole and (1H-benzo[d]imidazol-2-yl)methanethiol. The results from the antifungal screening were also very interesting: 23 compounds exhibited potent fungicidal activity against the selected fungal strains. They displayed equivalent or greater potency in their MIC values than amphotericin B. The 5-halobenzimidazole derivatives could be considered promising broad-spectrum antimicrobial candidates that deserve further study for potential therapeutic applications.
- Alasmary, Fatmah A.S.,Snelling, Anna M.,Zain, Mohammed E.,Alafeefy, Ahmed M.,Awaad, Amani S.,Karodia, Nazira
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supporting information
p. 15206 - 15223
(2015/09/21)
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- Ionic Liquid-Catalyzed C-S Bond Construction using CO2 as a C1 Building Block under Mild Conditions: A Metal-Free Route to Synthesis of Benzothiazoles
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The construction of the C-S bond using CO2 as a C1 feedstock can be considered as a green route for the synthesis of S-containing compounds and is of great significance. Herein, we report the acetate-based ionic liquids (ILs)-catalyzed synthesis of benzothiazoles via cyclization of 2-aminothiophenols with CO2 and hydrosilane under mild conditions (e.g., 60 °C, 0.5 MPa). It was found that the IL (e.g., 1-butyl-3-methylimidazolium acetate, [Bmim][OAc]) served as a multifunctional catalyst with activating CO2 and hydrosilane to form a formoxysilane intermediate, as well as simultaneously activating 2-aminothiophenols through a hydrogen bond, finally resulting in the production of benzothiazoles. [Bmim][OAc] showed the best performance, and a series of benzothiazoles were obtained in high yields. To the best of our knowledge, this is the first protocol for the synthesis of benzothiazoles using CO2 as a C1 building block under metal-free and mild conditions.
- Gao, Xiang,Yu, Bo,Yang, Zhenzhen,Zhao, Yanfei,Zhang, Hongye,Hao, Leiduan,Han, Buxing,Liu, Zhimin
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p. 6648 - 6652
(2015/11/23)
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- FUSED IMIDAZOLE DERIVATIVE
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Provided is a novel compound which shows an antagonistic effect against T-type calcium channels, and is useful as a pharmaceutical product. A compound represented by general formula (I), and a pharmaceutical agent containing the same, are disclosed: where
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Paragraph 0298
(2013/03/28)
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- Building heterocyclic systems with RC(OR)2+ carbocations in recyclable bronsted acidic ionic liquids: Facile synthesis of 1-substituted 1H-1,2,3,4-tetrazoles, benzazoles and other ring systems with CH(OEt)3 and EtC(OEt)3 in [EtNH 3][NO3] and [PMIM(SO3H)][OTf]
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1-Aryl/alkyl-1H-1,2,3,4-tetrazoles can conveniently be synthesized in one-pot reactions from the corresponding amines by reaction with TMSN 3 and CH(OEt)3 using the readily available, recyclable, Bronsted acidic ionic liquids [EtNH3][NO3] IL-1 and [PMIM(SO3H)][OTf] IL-2 under mild conditions in high yields. Based on comparative reactions, whereas both ILs are excellent promoters, reactions are completed with shorter reaction times and in higher yields with IL-2. Among 24 examples provided, identical products were obtained via the two ILs, except in the case of 2-aminobenzoic acid where tetrazole was formed with IL-2 and 2-ethylquinazolin-4(3H)-one was formed with IL-1. By leaving out TMS-N 3 from the reaction, the in-situ formed CH(OEt)2 + and EtC(OEt)2+ (via their corresponding orthoesters) react under sonication with o-phenylenediamine bearing various substituents, o-aminothiophenol and o-aminophenol to form a wide array of benzazoles (benzimidazole, benzothiazole and benzoxazole) and quinazolin-4(3H)-one in high yields (18 examples). The two ILs reacted differently in reaction with 2-aminobenzamide, whereas quinazolin-4(3H)one was formed with IL-2/CH(OEt)3, the "unexpected" N-ethylquinazolin-4(3H)one was isolated with IL-1/CH(OEt)3. The latter was also formed from 2-aminobenzoic acid in IL-1/CH(OEt)3. Mechanistic implications are addressed. The reported protocols enable rapid assembly of a host of heterocyclic systems in high yields with the added advantage of recycling and re-use of the ILs.
- Aridoss, Gopalakrishnan,Laali, Kenneth K.
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experimental part
p. 2827 - 2835
(2011/06/23)
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- Ag-TiO2/clay composite photocatalyst for the oxidation-cyclization of 1,2-diamine compounds with propylene glycol or alcohols
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Silver-loaded TiO2 (Ag-TiO2) and acidic clay (K10 montmorillonite) composite photocatalyst has been successfully applied for the light-induced conversion of o-phenylenediamine (OPD) and its derivatives to substituted benzimidazoles with various alcohols in acetonitrile using UV-A and solar light. The influence of the various photocatalysts, solvents, and substituents on the yield and selectivity of the products has been investigated. The mechanism of photocatalysis is proposed. Loading silver on TiO2 enhances product yield and selectivity both in UV and solar light. In the presence of primary alcohols, 2-aminothiophenol forms only disulfide and hence Ag-TiO2/ clay can be used as a green catalyst for the synthesis of disulfides.
- Selvam, Kaliyamoorthy,Annadhasan, Mari,Velmurugan, Rengasamy,Swaminathan, Meenakshisundaram
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experimental part
p. 831 - 837
(2010/09/06)
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- PYRAZINE COMPOUNDS AS PHOSPHODIESTERASE 10 INHIBITORS
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Pyrazine compounds, and compositions containing them, and processes for preparing such compounds. Provided herein also are methods of treating disorders or diseases treatable by inhibition of PDE10, such as obesity, non-insulin dependent diabetes, schizophrenia, bipolar disorder, obsessive-compulsive disorder, and the like.
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Page/Page column 70
(2010/06/15)
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- SMALL MOLECULE INHIBITORS OF PLASMODIUM FALCIPARUM DIHYDROOROTATE DEHYDROGENASE
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Inhibitors of dihydroorotate dehydrogenase (DHODH) for the Plasmodium enzyme have been identified and characterized. The inhibitors have high specificity, submicromolar efficacy against cultured parasite strains, exhibit drug-like properties, and are not overtly cytotoxic.
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Page/Page column 30
(2010/01/29)
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- A facile one-pot synthesis of benzimidazoles from 2-nitroanilines by reductive cyclization
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A facile one-pot process to prepare benzimidazole derivatives is described. Reductive cyclization of a serial of 2-nitroanilines with orthoesters in the presence of Pd/C in methanol at room temperature, which is promoted by a catalytic amount of acetic acid, affords the corresponding benzimidazole derivatives in high yields.
- Liu, Zheng,Li, Haihong,Zhao, Qingjie,Shen, Jingshan
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scheme or table
p. 1907 - 1911
(2009/04/06)
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- Pyrimidine derivatives as IL-8 receptor antagonists
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Compounds containing the pyrimidine nucleus and their use to treat diseases and conditions related to inappropriate Interleukin-8 receptor activity are disclosed. The compounds are of the formula I In these compounds, Q is preferably unsubstituted and substituted heterocyclyl; U is usually hydrogen or fluorine; and V is preferably hydrogen, halogen, alkyl, —O—alkyl or —S-alkyl. A representative example is:
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- (2S)-2-((PYRIMIDIN-4-YL)AMINO)-4-METHYLPENTANOIC ACID AMINOETHYLAMID DERIVATIVES AS IL-8 RECEPTOR MODULATORS FOR THE TREATMENT OF ATHEROSCLEROSIS AND RHEUMATOID ARTHRITIS
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The invention relates to compounds of the formula: (I); wherein R1 is a basic moiety having the structure -NH(CH2)2NR5R6, (Formula II) or (Formula II); wherein R5, R6 and R7 are independently selected from H, (1-6C)alkyl, (2-6C)alken
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- The studies of the intramolecular C-F---H-N hydrogen bonding using covalently-linked base pair models of F and A
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Both 1H NMR and X-ray studies revealed that C-F---H-N intramolecular hydrogen bonding is not observed even in covalently-linked base pair models of F and A. These results strongly support the Kool's hypothesis.
- Shibata,Das,Harada,Takeuchi,Bando
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p. 1755 - 1758
(2007/10/03)
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- 6-beta(substituted)-(S)-hydroxymethylpenicillanic acids and derivatives thereof
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Antibacterial penicillins of the formula STR1 or a pharmaceutically acceptable salt thereof wherein R1 is a heterocyclic group and R is hydrogen, the residue of certian carboxy protecting groups or the residue of an ester group readily hydrolyzable in vivo having activity against resistant organisms.
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