- Rational principles for modulating fluorescence properties of fluorescein
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Rational design strategies based on practical fluorescence modulation mechanisms would enable us to rapidly develop novel fluorescence probes for target molecules. Here, we present a practical and general principle for modulating the fluorescence properti
- Ueno, Tasuku,Urano, Yasuteru,Setsukinai, Ken-Ichi,Takakusa, Hideo,Kojima, Hirotatsu,Kikuchi, Kazuya,Ohkubo, Kei,Fukuzumi, Shunichi,Nagano, Tetsuo
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Read Online
- COMPOUNDS, COMPOSITIONS AND METHODS OF USE
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Herein, compounds, compositions and methods for modulating inclusion formation and stress granules in cells related to the onset of neurodegenerative diseases, musculoskeletal diseases, cancer, ophthalmological diseases, and viral infections are described.
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Page/Page column 277
(2020/07/06)
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- Site-Selective Cross-Coupling of Remote Chlorides Enabled by Electrostatically Directed Palladium Catalysis
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Control of site-selectivity in chemical reactions that occur remote from existing functionality remains a major challenge in synthetic chemistry. We describe a strategy that enables three of the most commonly used cross-coupling processes to occur with high site-selectivity on dichloroarenes that bear acidic functional groups. We have achieved this by repurposing an established sulfonylated phosphine ligand to exploit its inherent bifunctionality. Mechanistic studies suggest that the sulfonate group engages in attractive electrostatic interactions with the cation associated with the deprotonated substrate, guiding cross-coupling to the chloride at the arene meta position. This counterintuitive combination of anionic ligand and anionic substrate demonstrates an alternative design principle when considering the application of noncovalent interactions to direct catalysis.
- Golding, William A.,Pearce-Higgins, Robert,Phipps, Robert J.
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supporting information
p. 13570 - 13574
(2018/10/20)
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- Ni-Catalyzed chemoselective alcoholysis of: N -acyloxazolidinones
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Although N-acyloxazolidinone-based (catalytic) asymmetric synthetic methodologies occupy an important position in modern organic synthesis, the catalytic cleavage of a chiral auxiliary remains underdeveloped. We report the Ni(cod)2/bipyr.-catalyzed alcoholysis of N-acyloxazolidinones to deliver esters. The reaction is broad in scope for both N-acyloxazolidinone substrates and alcohol nucleophiles, and displays good functional group tolerance and excellent chemoselectivity. A gram-scale methanolysis allowed the enantioselective synthesis of the C22-C26 segment of a close analogue of the potent immunosuppressant agent FK506.
- Huang, Pei-Qiang,Geng, Hui
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supporting information
p. 593 - 599
(2018/02/14)
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- Azabicyalo derivative as well as preparation and application thereof
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The invention relates to an azabicyalo derivative as well as preparation and application thereof, and particularly discloses a compound with a structure shown in to the formula (A) or salt thereof acceptable in agricultural pharmacology. The compound in the formula (A) is described in the description in detail, and has an excellent killing effect on nematode.
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Paragraph 0203; 0204
(2016/10/07)
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- Ultrasound assisted direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone
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A sonochemical procedure for direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone in an alcoholic solvent is described. Mild reaction conditions, short reaction times, cost-effectiveness, and facile isolation of the products make the present system as a practical method.
- Mirza-Aghayan, Maryam,Zonoubi, Somayeh,Molaee Tavana, Mahdieh,Boukherroub, Rabah
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p. 359 - 364
(2014/10/16)
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- Calcium and magnesium chlorides-catalyzed oxidative esterification of aromatic aldehydes
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An interesting procedure for the oxidative esterification of aromatic aldehydes has been developed. By using catalytic amount of CaCl2 or MgCl2, various methyl benzoates were isolated in good yields with hydrogen peroxide as the terminal oxidant.
- Feng, Jian-Bo,Gong, Jin-Long,Li, Qin,Wu, Xiao-Feng
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p. 1657 - 1659
(2014/03/21)
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- Copper-catalyzed methyl esterification of aromatic aldehydes and benzoic alcohols by TBHP as both oxidant and methyl source
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A copper-catalyzed synthesis of methyl esters from aromatic aldehydes in the presence of tert-butyl hydrogen peroxide (TBHP) was developed via a radical reaction mechanism. TBHP acts not only as an efficient oxidant, but also as a green methyl source in such transformation. Moreover, this method could also be efficiently extended to the methyl esterification of benzylic alcohols.
- Li, Pan,Zhao, Jingjing,Lang, Rui,Xia, Chungu,Li, Fuwei
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supporting information
p. 390 - 393
(2014/01/06)
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- Synthesis, antibacterial activities, and 3d-qsar of sulfone derivatives containing 1, 3, 4-oxadiazole moiety
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A series of sulfone derivatives containing 1, 3, 4-oxadiazole moiety were prepared and evaluated for their antibacterial activities by the turbidimeter test. Most compounds inhibited growth of Ralstonia solanacearum (R. solanacearum) from tomato and tobacco bacterial wilt with high potency, among which compounds 5a and 5b exhibited the most potent inhibition against R. solanacearum from tomato and tobacco bacterial wilts with EC50 values of 19.77 and 8.29 μg/mL, respectively. Our results also demonstrated that 5a, 5b, and a number of other compounds were more potent than commercial bactericides Kocide 3000 and Thiodiazole Copper, which inhibited R. solanacearum from tomato bacterial wilt with EC50 values of 93.59 and 99.80 μg/mL and tobacco bacterial wilt with EC50 values of 45.91 and 216.70 μg/mL, respectively. The structure-activity relationship (SAR) of compounds was studied using three-dimensional quantitative structure-activity relationship (3D-QSAR) models created by comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) based on compound bioactivities against tomato and tobacco bacterial wilts. The 3D-QSAR models effectively predicted the correlation between inhibitory activity and steric-electrostatic properties of compounds.
- Li, Pei,Yin, Juan,Xu, Weiming,Wu, Jian,He, Ming,Hu, Deyu,Yang, Song,Song, Baoan
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p. 546 - 556
(2013/11/06)
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- Novel benzofuroxan derivatives against multidrug-resistant Staphylococcus aureus strains: Design using Topliss' decision tree, synthesis and biological assay
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The aim of this study was the design of a set of benzofuroxan derivatives as antimicrobial agents exploring the physicochemical properties of the related substituents. Topliss' decision tree approach was applied to select the substituent groups. Hierarchical cluster analysis was also performed to emphasize natural clusters and patterns. The compounds were obtained using two synthetic approaches for reducing the synthetic steps as well as improving the yield. The minimal inhibitory concentration method was employed to evaluate the activity against multidrug-resistant Staphylococcus aureus strains. The most active compound was 4-nitro-3-(trifluoromethyl)[N′-(benzofuroxan-5-yl) methylene]benzhydrazide (MIC range 12.7-11.4 μg/mL), pointing out that the antimicrobial activity was indeed influenced by the hydrophobic and electron-withdrawing property of the substituent groups 3-CF3 and 4-NO2, respectively.
- Jorge, Salomao Doria,Palace-Berl, Fanny,Masunari, Andrea,Cechinel, Cleber Andre,Ishii, Marina,Pasqualoto, Kerly Fernanda Mesquita,Tavares, Leoberto Costa
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supporting information; experimental part
p. 5031 - 5038
(2011/10/05)
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- Synthesis and antihyperlipidemic activity of some novel 4-(substitutedamino)-5-substituted-3-mercapto-(4H)-1,2,4-triazoles
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Hyperlipidemia is considered one of the key factors for cardiovascular diseases. Based on earlier work on a series of 5-alkyl-4-aryl-3-mercapto-(4H)-1, 2,4-triazoles, for further lead modification, a series of 4-(substituted)amino- 5-substituted-3-mercapto-(4H)-1,2,4-triazoles was designed. Target compounds were synthesized by the well known Hoggarth synthesis of substituted 1,2,4-triazoles. Synthesized compounds were screened for lipid lowering activity using the "Poloxamer 407 induced hyperlipidemia in rats" model at a dose of 100 mg/kg p. o. Compounds were found to alter serum lipid levels significantly. Most of the compounds significantly reduced serum cholesterol and triglyceride levels. Some of the compounds were found to reduce triglycerides and elevate high density lipoprotein (HDL) levels more than the standard drug atorvastatin (CAS 134523-03-8). Compounds with chloro substitution on aryl rings were found more active in reducing serum lipid levels than other substitutions. ECV ? Editio Cantor Verlag.
- Chhabria, Mahesh T.,Suhagia, Bhanubhai N.,Brahmkshatriya, Pathik S.,Raval, Priyesha M.
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scheme or table
p. 452 - 457
(2012/06/16)
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- Electroreduction of organic compounds, 36 [1]. Electroreduction of chlorinated methyl benzoates
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The preparative electroreduction of the three methyl monochlorobenzoates, the six methyl dichlorobenzoates, and methyl 2,3,4-trichlorobenzoate in different solvent-supporting electrolytes (SSE) was studied. The rate of the dechlorination, which is the main reaction, is dependent on the substitution pattern. Pronounced regioselectivity is therefore observed in case of the oligochloro derivatives. Hydrogenation of the benzene ring and reduction of the methoxycarbonyl group with formation of a hydroxymethyl group are observed as side-reactions. Quantum chemical calculations on the reaction mechanism were performed. The theoretical results are in accordance with the experimental observations.
- Gassmann, Joerg,Voss, Juergen
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scheme or table
p. 1291 - 1299
(2009/06/19)
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- Antileishmanial activity screening of 5-nitro-2-heterocyclic benzylidene hydrazides
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A series of 53 nitro derivatives rationally designed were obtained by parallel synthesis and screened against Leishmania donovani. Six compounds exhibited IC50 values lower than standard drugs. Brief SAR analysis revealed that substitution is important to the activity. Nitrothiophene analogues were more potent than the nitrofuran ones. This was attributed to the ability of sulfur atoms in accommodating electrons from nitro group, which facilitate its reduction and therefore the formation of free radicals lethal to parasites.
- Rando, Daniela G.,Avery, Mitchell A.,Tekwani, Babu L.,Khan, Shabana I.,Ferreira, Elizabeth I.
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p. 6724 - 6731
(2008/12/22)
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- A new class of nifuroxazide analogues: Synthesis of 5-nitrothiophene derivatives with antimicrobial activity against multidrug-resistant Staphylococcus aureus
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Hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) has been an increasing problem worldwide since the initial reports over 40 years ago. To examine new drug leads with potential antibacterial activities, 14 p-substituted benzoic acid [(5-nitro-thiophen-2-yl)-methylene]-hydrazides were designed, synthesized, and tested against standard and multidrug-resistant S. aureus strains by serial dilution tests. All compounds exhibited significant bacteriostatic activity and some of them also showed bactericidal activity. The results confirmed the potential of this class of compounds as an alternative for the development of selective antimicrobial agents.
- Masunari, Andrea,Tavares, Leoberto Costa
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p. 4229 - 4236
(2008/03/13)
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- Relative reactivity of methyl iodide to ethyl iodide in nucleophilic substitution reactions in acetonitrile and partial desolvation accompanying activation
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Through the examination of empirical correlations involving activation parameters for nucleophilic substitution of methyl iodide and of ethyl iodide, nucleophiles have been classified into three series: (1) nucleophiles with two equivalent reaction sites, (2) nucleophiles with a chlorine atom in the para-position, and (3) nucleophiles with a single reaction site. Three types of partial desolvation processes accompanying activation have been deduced on the basis of these classifications. A major factor determining the relative reactivity of methyl iodide to ethyl iodide in the substitution reaction of an anionic nucleophile having a single reaction site in acetonitrile (kMeI/kEtI) is suggested to be partial desolvation around the nucleophilic center on going from reactant to transition-state.
- Kondo, Yasuhiko,Urade, Miyuki,Yamanishi, Yukari,Chen, Xinyu
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p. 1449 - 1454
(2007/10/03)
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- Triazole derivative and pharmaceutical use thereof
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An agent for the prophylaxis and treatment of immune-related diseases, in particular, immunosuppressant, an agent for the prophylaxis and treatment of allergic diseases, an agent for the prophylaxis and treatment of eosinophil-related diseases and an eosinophilia inhibitor, comprising, as an active ingredient, a series of triazole derivatives of the following formula (I) STR1 or the following formula (III) STR2 wherein each symbol is as defined in the specification, or a pharmaceutically acceptable salt thereof. A novel monocyclic or bicyclic triazole derivative. The agent for the prophylaxis and treatment of immune-related diseases, in particular, immunosuppressant, the agent for the prophylaxis and treatment of allergic diseases, the agent for the prophylaxis and treatment of eosinophil-related diseases, the eosinophilia inhibitor and the novel triazole derivative of the present invention all, have superior eosinophilia-inhibitory action and lymphocyte activation-inhibitory action. They are low toxic and persistent in action. They are particularly effective in the treatment of accumulation and activation of eosinophil and lymphocytes, inflammatory respiratory tract diseases, eosinophil-related diseases such as eosinophilia, and immune-related diseases.
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- Natural formation of chlorobenzoic acids (CBA) and distinction between PCB-degraded CBA
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Mono- and dichlorobenzoic acid (CBA) could be found in samples of remote bog pond water and sediment. The 2,4-CBA always had the highest concentrations. In bog water samples the concentrations ranged between 0.11 and 0.48 μg/l. Besides 2,4-CBA most only 2,5-CBA could be found as dichlorobenzoic acid. In all samples we could detect also trichloroacetic acid (TCAA). The TCAA concentrations correlate with the CBA concentrations. As TCAA is known as a naturally produced organohalogen, this correlation can be seen as an indication to a natural formation of CBA. A confirmation of this presumption is our detection CBA in a reaction of benzoic acid with the chlorinating enzyme chloroperoxidase (CPO).
- Niedan,Schoeler
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p. 1233 - 1241
(2007/10/03)
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- Structural modifications of the primary amino group of anticonvulsant aryl semicarbazones
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A number of aryl semicarbazones had been shown previously to possess significant anticonvulsant properties. The principal objective of the present investigation was to determine the importance of the primary amino group in this series of compounds by replacing it with other substituents. The results indicate that the amino group was not essential for anticonvulsant activity. However its replacement by an aryl ring generally abolished activity while a terminal phenylamino function was better tolerated. Thus both the size of the group and its hydrogen bonding capabilities appear to influence bioactivity. Alteration of the oxygen atom of the semicarbazones by isosteres did not enhance anticonvulsant properties.
- Dimmock,Puthucode,Lo,Quail,Yang,Stables
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- Acylated 2,2-dimethylaziridines: Regioselectivity of ring opening by sodium thiophenolate; borderline S(N)2 due to planarization of nitrogen pyramid
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2,2-Dimethylaziridines 1 carrying a COR group on nitrogen are opened by PhS(Θ) with a regioselectivity RS = abnormal:normal ≥ 20 in MeOH and 5-16 in THF. Practically no influence of COR on RS was found except for the poorest oxidant 1g (R = tBu) that gave the highest RS (95, MeOH). This rules out an SET mechanism for the abnormal opening. Absence of homolytic ring opening is directly shown by the failure to detect products resulting from cyclization of a homolytically formed radical when COR is cinnamoyl (1f). Direct nucleophilic attack is indicated by suppression of any reaction with PhS(Θ) when the steric hindrance is increased (N-benzoylaziridine 13). The observed S(N)2 borderline behaviour with 1 is explained by reaction in a flattened nitrogen conformation of the otherwise poorly reactive 1. Carboxamide resonance in this (nearly) planar conformation generates a substantial positive charge on N which will shift the mechanism closer to S(N)1 by partial heterolysis of the N-CMe2 bond prior to attack by PhS(Θ).
- Lin,Bellos,Stamm,Onistschenko
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p. 2359 - 2372
(2007/10/02)
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- THE METHYLATION OF CARBOXYLIC ACIDS USING METHYL TRICHLOROACETATE
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Metyl trichloroacetate has been shown to methylate carboxylic acids with the loss of chloroform and carbon dioxide.
- Renga, James M.,Wang, Pen-Chung
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