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2-Substituted quinazolines: Partial agonistic and antagonistic ligands of the constitutive androstane receptor (CAR). Eur J Med Chem 2023; 259:115631. [PMID: 37473690 DOI: 10.1016/j.ejmech.2023.115631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 07/05/2023] [Accepted: 07/07/2023] [Indexed: 07/22/2023]
Abstract
Following the discovery of 2-(3-methoxyphenyl)-3,4-dihydroquinazoline-4-one and 2-(3-methoxyphenyl)quinazoline-4-thione as potent, but non-specific activators of the human Constitutive Androstane Receptor (CAR, NR1I3), a series of quinazolinones substituted at the C2 phenyl ring was prepared to examine their ability to selectively modulate human CAR activity. Employing cellular and in vitro TR-FRET assays with wild-type CAR or its variant 3 (CAR3) ligand binding domains (LBD), several novel partial human CAR agonists and antagonists were identified. 2-(3-Methylphenyl) quinazolinone derivatives 7d and 8d acted as partial agonists with the recombinant CAR LBD, the former in nanomolar units (EC50 = 0.055 μM and 10.6 μM, respectively). Moreover, 7d did not activate PXR, and did not show any signs of cytotoxicity. On the other hand, 2-(4-bromophenyl)quinazoline-4-thione 7l possessed significant CAR antagonistic activity, although the compound displayed no agonistic or inverse agonistic activities. A compound possessing purely antagonistic effect was thus identified for the first time. These and related compounds may serve as a remedy in xenobiotic intoxication or, conversely, in suppression of undesirable hepatic CAR activation.
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Sustainable ionic liquids-based molecular platforms for designing acetylcholinesterase reactivators. Chem Biol Interact 2023; 385:110735. [PMID: 37802409 DOI: 10.1016/j.cbi.2023.110735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/09/2023] [Accepted: 09/25/2023] [Indexed: 10/10/2023]
Abstract
We report a green chemistry approach for preparation of oxime-functionalized ILs as AChE reactivators: amide/ester linked IL, l-alanine, and l-phenylalanine derived salts bearing pyridinium aldoxime moiety. The reactivation capacities of the novel oximes were evaluated towards AChE inhibited by typical toxic organophosphates, sarin (GB), VX, and paraoxon (PON). The studied compounds are mostly non-toxic up to the highest concentrations screened (2 mM) towards Gram-negative and Gram-positive bacteria cell lines and both filamentous fungi and yeasts in the in vitro screening experiments as well as towards the eukaryotic cell (CHO-K1 cell line). Introduction of the oxime moiety in initially biodegradable structure decreases its ability to biodegradation. The compound 3d was shown to reveal remarkable activity against the AChE inhibited by VX, exceeding conventional reactivators 2-PAM and obidoxime. The regularities on antidotal activity, cell viability, plasma stability, biodegradability as well as molecular docking study of the newly synthesized oximes will be used for further improvement of their structures.
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Biobased natural deep eutectic system as versatile solvents: Structure, interaction and advanced applications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 881:163002. [PMID: 37003333 DOI: 10.1016/j.scitotenv.2023.163002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/13/2023] [Accepted: 03/18/2023] [Indexed: 06/01/2023]
Abstract
The increasing emphasis on the development of green replacements to traditional organic solvents and ionic liquids (ILs) can be attributed to the rising concerns over human health and detrimental impacts of conventional solvents towards the environment. A new generation of solvents inspired by nature and extracted from plant bioresources has evolved over the last few years, and are referred to as natural deep eutectic solvents (NADES). NADES are mixtures of natural constituents like sugars, polyalcohols, sugar-based alcohols, amino acids and organic acids. Interest in NADES has exponentially grown over the last eight years, which is evident from an upsurge in the number of research projects undertaken. NADES are highly biocompatible as they can be biosynthesized and metabolized by nearly all living organisms. These solvents pose several noteworthy advantages, such as easy synthesis, tuneable physico-chemical properties, low toxicity, high biodegradability, solute sustainability and stabilization and low melting point. Research on the applicability of NADES in diverse areas is gaining momentum, which includes as - media for chemical and enzymatic reactions; extraction media for essential oils; anti-inflammatory and antimicrobial agent; extraction of bioactive composites; as chromatographic media; preservatives for labile compounds and in drug synthesis. This review gives a complete overview of the properties, biodegradability and toxicity of NADES which we propose can assist in further knowledge generation on their significance in biological systems and usage in green and sustainable chemistry. Information on applications of NADES in biomedical, therapeutic and pharma-biotechnology fields is also highlighted in the current article along with the recent progress and future perspectives in novel applications of NADES.
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Sustainable Phenylalanine-Derived SAILs for Solubilization of Polycyclic Aromatic Hydrocarbons. Molecules 2023; 28:molecules28104185. [PMID: 37241924 DOI: 10.3390/molecules28104185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023] Open
Abstract
The solubilization capacity of a series of sustainable phenylalanine-derived surface-active ionic liquids (SAILs) was evaluated towards polycyclic aromatic hydrocarbons-naphthalene, anthracene and pyrene. The key physico-chemical parameters of the studied systems (critical micelle concentration, spectral properties, solubilization parameters) were determined, analyzed and compared with conventional cationic surfactant, CTABr. For all studied PAH solubilization capacity increases with extension of alkyl chain length of PyPheOCn SAILs reaching the values comparable to CTABr for SAILs with n = 10-12. A remarkable advantage of the phenylalanine-derived SAILs PyPheOCn and PyPheNHCn is a possibility to cleave enzymatically ester and/or amide bonds under mild conditions, to separate polycyclic aromatic hydrocarbons in situ. A series of immobilized enzymes was tested to determine the most suitable candidates for tunable decomposition of SAILs. The decomposition pathway could be adjusted depending on the choice of the enzyme system, reaction conditions, and selection of SAILs type. The evaluated systems can provide selective cleavage of the ester and amide bond and help to choose the optimal decomposition method of SAILs for enzymatic recycling of SAILs transformation products or as a pretreatment towards biological mineralization. The concept of a possible practical application of studied systems for PAHs solubilization/separation was also discussed focusing on sustainability and a green chemistry approach.
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Stereoselective Synthesis of γ‐(Acyloxy)Carboxylic Acids and γ‐Lactones Features the Switch of Stereopreference of CalB Along Sodium γ‐Hydroxycarboxylate Homologues. European J Org Chem 2022. [DOI: 10.1002/ejoc.202201329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Role of Bacterial-Fungal Consortium for Enhancement in the Degradation of Industrial Dyes. Curr Genomics 2020; 21:283-294. [PMID: 33071621 PMCID: PMC7521038 DOI: 10.2174/1389202921999200505082901] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 11/22/2022] Open
Abstract
Background The presence of anthraquinone (Disperse blue 64) and azodyes (Acid yellow 17) in a waterbody are considered among the most dangerous pollutants. Methods In this study, two different isolated microbes, bacterium and fungus, were individually and as a co-culture applied for the degradation of Disperse Blue 64 (DB 64) and Acid Yellow 17 (AY 17) dyes. The isolates were genetically identified based upon 16S (for bacteria) and ITS/5.8S (for fungus) rRNA genes sequences as Pseudomoans aeruginosa and Aspergillus flavus, respectively. Results The fungal/bacterial consortium exhibited a higher percentage of dyes degradation than the individual strains, even at a high concentration of 300 mg/L. Azoreductase could be identified as the main catabolic enzyme and the consortium could induce azoreductase enzyme in the presence of both dyes. However, the specific substrate which achieved the highest azoreductase specific activity was Methyl red (MR) (3.5 U/mg protein). The tentatively proposed metabolites that were detected by HPLC/MS suggested that the reduction process catalyzed the degradation of dyes. The metabolites produced by the action consortium on two dyes were safe on Vicia faba and Triticum vulgaris germination and health of seedlings. Toxicity of the dyes and their degradation products on the plant was different according to the type and chemistry of these compounds as well as the type of irrigated seeds. Conclusion We submit that the effective microbial degradation of DB64 and AY17 dyes will lead to safer metabolic products.
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Ionic liquid based pretreatment of lignocellulosic biomass for enhanced bioconversion. BIORESOURCE TECHNOLOGY 2020; 304:123003. [PMID: 32081446 DOI: 10.1016/j.biortech.2020.123003] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/06/2020] [Accepted: 02/08/2020] [Indexed: 05/12/2023]
Abstract
Lignocellulosic biomass is the most plentiful renewable biomolecule and an alternative bioresource for the production of biofuels and biochemicals in biorefineries. But biomass recalcitrance is a bottleneck in their usage, thus necessitating their pretreatment for hydrolysis. Most pretreatment technologies, result in toxic by-products or have lower yield. Ionic liquids (ILs) have successfully advanced as 'greener and recyclable' alternatives to volatile organic solvents for lignocellulosic biomass dissolution. This review covers recent developments made in usage of IL-based techniques with focus on biomass breakdown mechanism, process parameter design, impact of cation and anion groups, and the advantageous impact of ILs on the subsequent processing of the fractionated biomass. Progress and barriers for large-scale commercial usage of ILs in emerging biorefineries were critically evaluated using the principles of economies of scale and green chemistry in an environmentally sustainable way.
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An example of green surfactant systems based on inherently biodegradable IL-derived amphiphilic oximes. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.112857] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Toxicity profiling of 24 l-phenylalanine derived ionic liquids based on pyridinium, imidazolium and cholinium cations and varying alkyl chains using rapid screening Vibrio fischeri bioassay. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 172:556-565. [PMID: 30776578 DOI: 10.1016/j.ecoenv.2018.12.076] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 12/20/2018] [Accepted: 12/23/2018] [Indexed: 06/09/2023]
Abstract
A library of 24 pyridinium-, imidazolium-, and cholinium-based ionic liquids (ILs) with varying alkyl chain from C2 to C16 was toxicologically profiled using naturally luminescent marine bacteria Vibrio fischeri. The toxicity (30-min EC50) of studied ILs to Vibrio fischeri ranged from 7.82 µM (4.2 mg/L) (PyC12Phe) to 3096 µM (1227 mg/L) (ImidC2Phe), i.e. from "toxic" (EC50 1-10 mg/L) to "not harmful" (EC50 > 100 mg/L). Inhibition of the bacterial luminescence upon 30-min exposure to ILs correlated well with bacterial viability (exposure for 4 h). The toxicity of studied ILs was largely driven by the length of the alkyl chain (hydrophobicity) and not the type of cationic part of the IL: starting from C10 all the ILs irrespective of the cationic part proved "toxic". The toxicity of the studied ILs was increasing in parallel to their hydrophobicity up to log Kow = 1 (C8-C10) and then levelling up, being consistent with the previously obtained analogous data sets. The "cut-off" effect reported in this study for longer chain length members of the ILs series leads to the "limit" toxicity level for this type of ILs to be ca. 8 mM. Two open-access online tools (www.molinspiration.com and www.vcclab.org) have been applied for the calculation of the Kow values for the 24 ILs reported in this study and 21 ILs reported in the literature. This lead to plotting two nonlinear monotonic correlations between the values of experimental log (1/EC50) and calculated log Kow. The limitation of the online tools and an effect of the ILs structure on the "cut-off" effect have been discussed. The challenge of developing low microbial toxicity surface active ILs remains a significant task to overcome. Our results shed light on the new approaches for designing environmentally benign ILs and functional surfactants. As the hydrophobicity of the ILs significantly correlated with the toxicity, the Vibrio fischeri assay could be considered a powerful tool in providing toxicity data for building and evaluating the QSAR toxicity models for ILs.
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Site-Selective and Stereoselective C-H Functionalization of N-Cyclopropylamides via a Directed Remote Metalation Strategy. Org Lett 2019; 21:969-973. [PMID: 30715898 DOI: 10.1021/acs.orglett.8b03955] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A new methodology for site-selective and stereoselective C-H functionalization of aminocyclopropanes via directed remote lithiation has been developed. Treatment of N-directing group (DG = pivaloyl, tetramethylsuccinimidoyl) arylcyclopropanes with t-BuLi results in a clean β-lithiation and, following quench with electrophiles, leads to a range of cyclopropane derivatives. Sequential double lithiation-methylation to give a dimethylated cyclopropane has been achieved. X-ray, NMR, and computational studies allow rationalization of syn-DG β-deprotonation selectivity via a DG-lithium base coordinated complex.
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A new class of prophylactic metallo-antibiotic possessing potent anti-cancer and anti-microbial properties. Dalton Trans 2019; 48:8578-8593. [DOI: 10.1039/c9dt00250b] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A family of metallo-antibiotics of general formula [Cu(N,N)(CipA)Cl] where N,N is a phenanthrene ligand and CipA is a derivative of the clinically used fluoroquinolone antibiotic ciprofloxacin – targeting immunocompromised cancer patients undergoing chemotherapy.
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12
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Efficient DNA Condensation by a C3‐Symmetric Codeine Scaffold. Chempluschem 2018; 84:38-42. [DOI: 10.1002/cplu.201800480] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/12/2018] [Indexed: 12/12/2022]
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Abstract
Novel ionic liquids have been synthesised directly from the renewable resource mandelic acid and evaluated for their antimicrobial activity and biodegradability.
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C 3-symmetric opioid scaffolds are pH-responsive DNA condensation agents. Nucleic Acids Res 2016; 45:527-540. [PMID: 27899572 PMCID: PMC5314759 DOI: 10.1093/nar/gkw1097] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 10/11/2016] [Accepted: 10/27/2016] [Indexed: 01/28/2023] Open
Abstract
Herein we report the synthesis of tripodal C3-symmetric opioid scaffolds as high-affinity condensation agents of duplex DNA. Condensation was achieved on both supercoiled and canonical B-DNA structures and identified by agarose electrophoresis, viscosity, turbidity and atomic force microscopy (AFM) measurements. Structurally, the requirement of a tris-opioid scaffold for condensation is demonstrated as both di- (C2-symmetric) and mono-substituted (C1-symmetric) mesitylene-linked opioid derivatives poorly coordinate dsDNA. Condensation, observed by toroidal and globule AFM aggregation, arises from surface-binding ionic interactions between protonated, cationic, tertiary amine groups on the opioid skeleton and the phosphate nucleic acid backbone. Indeed, by converting the 6-hydroxyl group of C3-morphine (MC3) to methoxy substituents in C3-heterocodeine (HC3) and C3-oripavine (OC3) molecules, dsDNA compaction is retained thus negating the possibility of phosphate—hydroxyl surface-binding. Tripodal opioid condensation was identified as pH dependent and strongly influenced by ionic strength with further evidence of cationic amine-phosphate backbone coordination arising from thermal melting analysis and circular dichroism spectroscopy, with compaction also witnessed on synthetic dsDNA co-polymers poly[d(A-T)2] and poly[d(G-C)2]. On-chip microfluidic analysis of DNA condensed by C3-agents provided concentration-dependent protection (inhibition) to site-selective excision by type II restriction enzymes: BamHI, HindIII, SalI and EcoRI, but not to the endonuclease DNase I.
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Effect of structure of polycyclic aromatic substrates on solubilization capacity and size of cationic monomeric and gemini 14-s-14 surfactant aggregates. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.09.068] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Amphiphilic glycosylated block copolypeptides as macromolecular surfactants in the emulsion polymerization of styrene. Polym Chem 2015. [DOI: 10.1039/c5py00548e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bio-inspired amphiphilic block copolymer surfactants fully derived from amino acids and sugars are synthesised. The materials are successfully employed in the synthesis of polystyrene latexes by emulsion polymerization.
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Abstract
The importance of biodegradation data as part of the design of safer chemicals is presented using ionic liquids (ILs) as a model study.
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An Organocatalytic Process for the Hydrolytic Cleavage of Dithianes Mediated by Imidazolium Ions: No Harsh Agents Required. European J Org Chem 2014. [DOI: 10.1002/ejoc.201402947] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Facile Synthesis of Fluorescent Latex Nanoparticles with Selective Binding Properties Using Amphiphilic Glycosylated Polypeptide Surfactants. Macromolecules 2014. [DOI: 10.1021/ma5020462] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Low Antimicrobial Toxicity Ionic Liquids: Solvents for Asymmetric Carbonyl- Ene Reactions of Phenylglyoxal. CURRENT GREEN CHEMISTRY 2014. [DOI: 10.2174/2213346101666140421220156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Novel bronchodilatory quinazolines and quinoxalines: synthesis and biological evaluation. Eur J Med Chem 2014; 74:65-72. [PMID: 24445313 DOI: 10.1016/j.ejmech.2013.12.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 11/27/2013] [Accepted: 12/18/2013] [Indexed: 11/27/2022]
Abstract
A series of heterocyclic derivatives analogous to (-)vasicinone, in which the vasicinone C-ring was replaced with alkyl chain terminated by tertiary amine was prepared. N3, C4-O, C4-S or C4-N were used as the sites of attachment. The 4-[3-(1-piperidyl)propylsulfanyl]derivatives displayed bronchodilatory effect at low micromolar concentrations on isolated rat trachea, and low toxicity both on Balb/c 3T3 mouse fibroblast cells and in mice.
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Regulating Bioactivity of Cu2+ Bis-1,10-phenanthroline Artificial Metallonucleases with Sterically Functionalized Pendant Carboxylates. J Med Chem 2013; 56:8599-615. [DOI: 10.1021/jm401465m] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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25
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Designing Safer and Greener Antibiotics. Antibiotics (Basel) 2013; 2:419-38. [PMID: 27029311 PMCID: PMC4790272 DOI: 10.3390/antibiotics2030419] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/17/2013] [Accepted: 08/21/2013] [Indexed: 11/29/2022] Open
Abstract
Since the production of the first pharmaceutically active molecules at the beginning of the 1900s, drug molecules and their metabolites have been observed in the environment in significant concentrations. In this review, the persistence of antibiotics in the environment and their associated effects on ecosystems, bacterial resistance and health effects will be examined. Solutions to these problems will also be discussed, including the pharmaceutical industries input, green chemistry, computer modeling and representative ionic liquid research.
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Synthesis of Polypeptide Block Copolymer Hybrids by the Combination of N
-Carboxyanhydride Polymerization and RAFT. Macromol Rapid Commun 2013; 34:1325-9. [DOI: 10.1002/marc.201300402] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/15/2013] [Indexed: 01/02/2023]
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Tetrabutylammonium prolinate-based ionic liquids: a combined asymmetric catalysis, antimicrobial toxicity and biodegradation assessment. RSC Adv 2013. [DOI: 10.1039/c3ra43785j] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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The catalytic versatility of low toxicity dialkyltriazolium salts: in situ modification facilitates diametrically opposed catalysis modes in one pot. Chem Commun (Camb) 2013; 49:5316-8. [DOI: 10.1039/c3cc41588k] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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A new phenanthroline–oxazine ligand: synthesis, coordination chemistry and atypical DNA binding interaction. Chem Commun (Camb) 2013; 49:2341-3. [DOI: 10.1039/c3cc38710k] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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The presence of functional groups key for biodegradation in ionic liquids: effect on gas solubility. CHEMSUSCHEM 2010; 3:377-385. [PMID: 20049767 DOI: 10.1002/cssc.200900241] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The effect of the incorporation of either ester or ester and ether functions into the side chain of an 1-alkyl-3-methylimidazolium cation on the physico-chemical properties of ionic liquids containing bis(trifluoromethylsulfonyl)imide or octylsulfate anions is studied. It is believed that the introduction of an ester function into the cation of the ionic liquids greatly increases their biodegradability. The density of three such ionic liquids is measured as a function of temperature, and the solubility of four gases-carbon dioxide, ethane, methane, and hydrogen-is determined between 303 K and 343 K and at pressures close to atmospheric level. Carbon dioxide is the most soluble gas, followed by ethane and methane; the mole fraction solubilities vary from 1.8 x 10(-3) to 3.7 x 10(-2). These solubilities are of the same order of magnitude as those determined for alkylimidazolium-based ionic liquids. The chemical modification of the alkyl side chain does not result in a significant change of the solvation properties of the ionic liquid. All of the solubilities decrease with increasing temperature, corresponding to an exothermal solvation process. From the variation of this property with temperature, the thermodynamic functions of solvation (Gibbs energy, enthalpy, and entropy) are calculated and provide information about the solute-solvent interactions and the molecular structure of the solutions.
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Abstract
Ionic liquids are highly polar solvents with negligible vapour pressure and low flammability that offer a potentially "green" alternative to volatile organic compounds (VOCs). However in order to confidently label this class of solvents as "green", their affect on the environment must be thoroughly examined. As a result various toxicity, ecotoxicity and biodegradation studies have been carried out on ionic liquids. Although toxicity evaluations of ionic liquids have been widely reported in the literature, biodegradation data are comparatively scarce. In this tutorial review we present an overview of studies into the biodegradability of ionic liquids, including the various methods of biodegradation assessment, trends observed for structurally related ionic liquids, and applications of biodegradable ionic liquids in synthetic chemistry.
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Synthesis, X-ray Crystal Studies and Metal Picrates Extraction Properties of Lipophilic Benzocrown Ethers. Aust J Chem 2010. [DOI: 10.1071/ch10112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The preparation of 16 macrocycles based on 2-(2-hydroxyethoxy) phenol with both aliphatic and aromatic linkers has been achieved. Macrocycles varying in ring sizes (23–28 atoms), number of aromatic groups (2–4), and donor atoms (6–10 including oxygen and nitrogen) were synthesized. Binding affinities were also assessed by extraction studies against a series of metal picrates. X-ray crystal structures were solved for four macrocycles.
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Pyridinium Ion Catalysis of Carbonyl Protection Reactions. SYNTHESIS-STUTTGART 2009. [DOI: 10.1055/s-0029-1217022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
3-Methyl-1-(propyloxycarbonylmethyl)imidazolium octylsulfate 1a and 3-methyl-1-(pentyloxycarbonylmethyl)imidazolium octylsulfate 2a are ionic liquids that have previously been shown to be readily biodegradable in the CO2 headspace test (ISO 14593). In the present study, these ionic liquids were evaluated as reaction media for Diels–Alder and hydrogenation reactions. The comparison of the performance of these two designer solvents in these reactions with those conducted in other, non-biodegradable ionic liquids has demonstrated that they are comparable and viable solvents.
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Oxidised guanidinohydantoin (Ghox) and spiroiminodihydantoin (Sp) are major products of iron- and copper-mediated 8-oxo-7,8-dihydroguanine and 8-oxo-7,8-dihydro-2′-deoxyguanosine oxidation. ACTA ACUST UNITED AC 2005; 1:373-81. [PMID: 16881006 DOI: 10.1039/b511756a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
8-Oxo-7,8-dihydroguanine (8-oxoGua), an important biomarker of DNA damage in oxidatively generated stress, is highly reactive towards further oxidation. Much work has been carried out to investigate the oxidation products of 8-oxoGua by one-electron oxidants, singlet oxygen, and peroxynitrite. This report details for the first time, the iron- and copper-mediated Fenton oxidation of 8-oxoGua and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo). Oxidised guanidinohydantoin (Gh(ox)) was detected as the major product of oxidation of 8-oxoGua with iron or copper and hydrogen peroxide, both at pH 7 and pH 11. Oxaluric acid was identified as a final product of 8-oxoGua oxidation. 8-oxodGuo was subjected to oxidation under the same conditions as 8-oxoGua. However, dGh(ox) was not generated. Instead, spiroiminodihydantoin (Sp) was detected as the major product for both iron and copper mediated oxidation at pH 7. It was proposed that the oxidation of 8-oxoGua was initiated by its one-electron oxidation by the metal species, which leads to the reactive intermediate 8-oxoGua (+), which readily undergoes further oxidation. The product of 8-oxoGua and 8-oxodGuo oxidation was determined by the 2'-deoxyribose moiety of the 8-oxodGuo, not whether copper or iron was the metal involved in the oxidation.
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Direct catalytic asymmetric aldol reactions of pyruvates: scope and mechanism. Org Biomol Chem 2004; 2:1077-85. [PMID: 15034632 DOI: 10.1039/b316092k] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The direct aldol reaction of 2-ketoesters catalyzed by chiral bisoxazoline copper(II) complexes has been investigated. First the direct homo-aldol reaction of ethyl pyruvate is reported which proceeds to give diethyl 2-hydroxy-2-methyl-4-oxoglutarate. This was isolated as the more stable optically active isotetronic acid in good yield and enantiomeric excess in the absence of bases such as amines. Detailed investigations of the use of different chiral Lewis acids as the catalyst, amines, ratios of chiral bisoxazoline copper(II) salts:amine, and solvents gave up to 96% ee of the isotetronic acid. Then the reaction was extended to a cross-aldol reaction of various 2-ketoesters with activated carbonyl compounds to give the cross-aldol adduct with excellent enantiomeric excess. Furthermore, the synthesis of the isotetronic acids was investigated from these cross-aldol adducts giving important information about the formation of the stereogenic centers during the aldol reaction. Based on the absolute configuration of the homo-aldol adduct the mechanism for the aldol reaction is discussed.
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Abstract
Ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate [bmIm][BF4] and 1-butyl-3-methylimidazolium hexafluorophosphate [bmIm][PF6] were evaluated as reaction media for allylic and benzylic oxidation reactions using manganese dioxide. The use of ionic liquids as an extractant in the reaction work-up was also investigated. Procedures for recycling of the [bmIm][PF6] ionic liquids used in these MnO2 oxidation reactions were also developed.
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Inter- and intramolecular C-H...pi interactions in morphine bis(1-naphthoate). Acta Crystallogr C 2003; 59:o485-7. [PMID: 12944652 DOI: 10.1107/s0108270103015622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2003] [Accepted: 07/15/2003] [Indexed: 11/11/2022] Open
Abstract
The crystal structure of morphine bis(1-naphthoate) [or 7,8-didehydro-4,5-epoxy-17-methylmorphinan-2,6-diyl bis(naphthalene-1-carboxylate)], C(39)H(31)NO(5), determined at 123 K, shows extensive C--H...pi interactions in the crystal lattice. Of particular interest is an intramolecular C--H...pi interaction within the unit cell between the two naphthoyl groups. Comparison of the opiate scaffolds of morphine bis(1-naphthoate) and morphine shows only a small increase in strain due to the steric bulk of the naphthoyl groups. The crystal packing shows distinct areas of packing for the naphthalene/aromatic groups and the opiate backbone. Extensive inter- and intramolecular C--H...pi interactions lead to a densely packed aromatic region in the crystal lattice.
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Abstract
The first catalytic asymmetric direct Mannich reaction of malonates and beta-keto esters has been developed. Malonates react with an activated N-tosyl-alpha-imino ester catalyzed by chiral tert-butyl-bisoxazoline/Cu(OTf)(2) to give the Mannich adducts in high yields and with up to 96% ee. These reactions create a chiral quaternary carbon center and it is demonstrated that this new direct Mannich reactions provides for example a new synthetic procedure for the formation of optically active beta-carboxylic ester alpha-amino acid derivatives. A series of different beta-keto esters with various ester substituents has been screened as substrates for the catalytic asymmetric direct Mannich reaction and it was found that the best results in terms of yield, diastereo- and enantioselectivity were obtained when tert-butyl esters of beta-keto esters were used as the substrate. The reaction of different beta-keto tert-butyl esters with the N-tosyl-alpha-imino ester gave the Mannich adducts in high yields, diastereo- and enantioselectivities (up to 95% ee) in the presence of chiral tert-butyl-bisoxazoline/Cu(OTf)(2) as the catalyst. To expand the synthetic utility of this direct Mannich reaction a diastereoselective decarboxylation reaction was developed for the Mannich adducts leading to a new synthetic approach to attractive optically active beta-keto alpha-amino acid derivatives. Based on the stereochemical outcome of the reactions, various approaches of the N-tosyl-alpha-imino ester to the chiral bisoxazoline/Cu(II)-substrate intermediate are discussed.
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Preparation of the 4-hydroxytryptamine scaffold via palladium-catalyzed cyclization: a practical and versatile synthesis of psilocin. Org Lett 2003; 5:921-3. [PMID: 12633106 DOI: 10.1021/ol0341039] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] The 4-hydroxytryptamine scaffold of psilocin was successfully prepared via palladium-catalyzed cyclization of protected N-tert-butoxycarbonyl-2-iodo-3-methoxyaniline and an appropriately substituted silyl acetylene. Removal of the protecting groups afforded psilocin in good yield.
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Abstract
The development of a direct catalytic asymmetric Mannich reaction is shown and its potential demonstrated by the synthesis of optically active lactones via 4-hydroxyglutamic acid ester derivatives. The catalytic asymmetric Mannich reaction of carbonyl compounds with α-imino esters [Eq. (1); Ts = p-toluenesulfonyl] gives good yields and diastereoselectivities, as well as excellent enantioselectivities.
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Design and Preparation of Room-Temperature Ionic Liquids Containing Biodegradable Side Chains. Aust J Chem 2002. [DOI: 10.1071/ch02148] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Novel room-temperature ionic liquids with potential sites of enzymatic hydrolysis have been prepared and tested for biodegradable properties.
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Catalytic, highly enantioselective Friedel-Crafts reactions of aromatic and heteroaromatic compounds to trifluoropyruvate. A simple approach for the formation of optically active aromatic and heteroaromatic hydroxy trifluoromethyl esters. J Org Chem 2001; 66:1009-13. [PMID: 11430064 DOI: 10.1021/jo001176m] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new catalytic enantioselective synthetic method for the formation of optically active aromatic and heteroaromatic hydroxy-trifluoromethyl ethyl esters is presented. This catalytic enantioselective Friedel-Crafts reaction of trifluoromethyl pyruvate with aromatic and heteroaromatic compounds is catalyzed by a chiral bisoxazoline copper(II) complex and proceeds in good yield and with high enantiomeric excess. For a series of substituted indoles, the corresponding 3-substituted hydroxy-trifluoromethyl ethyl esters are formed in up to 93% yield and 94% ee. Pyrrole and 2-substituted pyrroles also react with trifluoromethyl pyruvate in a highly enantioselective aromatic electrophilic reaction and up to 93% ee and good yields are obtained. Furanes and thiophenes give the corresponding 2-hydroxy-trifluoromethyl ethyl esters in high enantiomeric excess; however, the yields of the products are only moderate. Various types of aromatic compounds react in this catalytic reaction with trifluoromethyl pyruvate to give the aromatic electrophilic addition product in good yield. To obtain high enantiomeric excess (> 80% ee) it is necessary that aromatic amines are protected with sterically demanding protecting groups such as benzyl or allyl. This prevents coordination of the amine nitrogen atom to the catalyst, as aromatic amines having a N,N-dimethyl group probably coordinate to the catalyst, leading to a significant reduction of the enantioselective properties of the catalyst. On the basis of the experimental results and the absolute configuration of the formed chiral center, the mechanism for the catalytic enantioselective Friedel-Crafts reaction is discussed.
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Catalytic Enantioselective Friedel−Crafts Reactions of Aromatic Compounds with Glyoxylate: A Simple Procedure for the Synthesis of Optically Active Aromatic Mandelic Acid Esters. J Am Chem Soc 2000. [DOI: 10.1021/ja002593j] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Formation of Optically Active Aromaticα-Amino Acids by Catalytic Enantioselective Addition of Imines to Aromatic Compounds. Angew Chem Int Ed Engl 2000. [DOI: 10.1002/1521-3757(20001117)112:22<4280::aid-ange4280>3.0.co;2-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Formation of Optically Active Aromatic alpha-Amino Acids by Catalytic Enantioselective Addition of Imines to Aromatic Compounds This work was made possible by a grant from the Danish National Research Foundation. Thanks are provided to Dr. Rita G. Hazell for X-ray analysis. Angew Chem Int Ed Engl 2000; 39:4114-4116. [PMID: 11093224 DOI: 10.1002/1521-3773(20001117)39:22<4114::aid-anie4114>3.0.co;2-v] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Catalytic asymmetric homo-aldol reaction of pyruvate—a chiral Lewis acid catalyst that mimics aldolase enzymes. Chem Commun (Camb) 2000. [DOI: 10.1039/b007125k] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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