- A SIMPLE SYNTHESIS OF 3-SUBSTITUTED FURANS. THE PREPARATIONS OF DENDROLASIN, PERILLENE AND CONGENERS
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The Grignard reagent 7, derived from 3-chloromethyl furan, reacts with various alkyl- and allylic halides, in the presence of Li2CuCl4, to provide high yields of 3-substituted furans.
- Tanis, Steven P.
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- Structure-guided optimization of 1H-imidazole-2-carboxylic acid derivatives affording potent VIM-Type metallo-β-lactamase inhibitors
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Production of metallo-β-lactamases (MBLs) in bacterial pathogens is an important cause of resistance to the ‘last-resort’ carbapenem antibiotics. Development of effective MBL inhibitors to reverse carbapenem resistance in Gram-negative bacteria is still needed. We herein report X-ray structure-guided optimization of 1H-imidazole-2-carboxylic acid (ICA) derivatives by considering how to engage with the active-site flexible loops and improve penetration into Gram-negative bacteria. Structure-activity relationship studies revealed the importance of appropriate substituents at ICA 1-position to achieve potent inhibition to class B1 MBLs, particularly the Verona Integron-encoded MBLs (VIMs), mainly by involving ingenious interactions with the flexible active site loops as observed by crystallographic analyses. Of the tested ICA inhibitors, 55 displayed potent synergistic antibacterial activity with meropenem against engineered Escherichia coli strains and even intractable clinically isolated Pseudomonas aeruginosa producing VIM-2 MBL. The morphologic and internal structural changes of bacterial cells after treatment further demonstrated that 55 crossed the outer membrane and reversed the activity of meropenem. Moreover, 55 showed good pharmacokinetic and safety profile in vivo, which could be a potential candidate for combating VIM-mediated Gram-negative carbapenem resistance.
- Yan, Yu-Hang,Li, Wenfang,Chen, Wei,Li, Chao,Zhu, Kai-Rong,Deng, Ji,Dai, Qing-Qing,Yang, Ling-Ling,Wang, Zhenling,Li, Guo-Bo
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- NOVEL THYROMIMETICS
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Compounds are provided having the structure of Formula (I): or a pharmaceutically acceptable isomer, racemate, hydrate, solvate, isotope, or salt thereof, wherein A, X1, X2, Q, R1, R2 and n are as defined herein. Such compounds function as thyromimetics and have utility for treating diseases such as neurodegenerative disorders and fibrotic diseases. Pharmaceutical compositions containing such compounds are also provided, as are methods of their use and preparation.
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- A general strategy for the stereoselective synthesis of the furanosesquiterpenes structurally related to pallescensins 1-2
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Here, we describe a general stereoselective synthesis of the marine furanosesquiterpenes structurally related to pallescensins 1-2. The stereoisomeric forms of the pallescensin 1, pallescensin 2, and dihydropallescensin 2 were obtained in high chemical and isomeric purity, whereas isomicrocionin-3 was synthesized for the first time. The sesquiterpene framework was built up by means of the coupling of the C10 cyclogeranyl moiety with the C5 3-(methylene)furan moiety. The key steps of our synthetic procedure are the stereoselective synthesis of four cyclogeraniol isomers, their conversion into the corresponding cyclogeranylsulfonylbenzene derivatives, their alkylation with 3-(chloromethyl)furan, and the final reductive cleavage of the phenylsulfonyl functional group to afford the whole sesquiterpene framework. The enantioselective synthesis of the α-, 3,4-dehydro-γ- and γ-cyclogeraniol isomers was performed using both a lipase-mediated resolution procedure and different regioselective chemical transformations.
- Serra, Stefano
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- IMIDAZO-PYRIDINE COMPOUNDS AS PAD INHIBITORS
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Heterocyclic compounds of Formula (I), (II), and (III) are described herein along with their polymorphs, stereoisomers, prodrugs, solvates, co-crystals, intermediates, pharmaceutically acceptable salts, and metabolites thereof. The compounds described herein, their polymorphs, stereoisomers, prodrugs, solvates, co-crystals, intermediates, pharmaceutically acceptable salts, and metabolites thereof are PAD4 inhibitors and may be useful in the treatment of various disorders, for example rheumatoid arthritis, vasculitis, systemic lupus erythematosis, cutaneous lupus erythematosis, ulcerative colitis, cancer, cystic fibrosis, asthma, multiple sclerosis and psoriasis. The process of preparation of the compounds of Formula (I), (II), and (III), their polymorphs, stereoisomers, prodrugs, solvates, co-crystals, intermediates, pharmaceutically acceptable salts, and metabolites thereof, along with a pharmaceutical composition comprising a compound of Formula (I), Formula (II), Formula (III), or a pharmaceutically acceptable salt thereof have also been described.
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- Domino Direct Arylation and Cross-Aldol for Rapid Construction of Extended Polycyclic π-Scaffolds
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Five-membered aromatic heterocycles are a ubiquitous skeleton of π-conjugated organic compounds, and their incorporation requires synthetic protocols that are not easily industrially sustainable or scalable. Improved methodologies for their insertion into π-scaffolds are therefore necessary. We report an efficient and scalable protocol involving a one-pot cross-Aldol direct arylation reaction protocol for the rapid construction of thiophene- and furan-based π-extended organic materials.
- Nitti, Andrea,Bianchi, Gabriele,Po, Riccardo,Swager, Timothy M.,Pasini, Dario
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p. 8788 - 8791
(2017/07/12)
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- Construction of polyaromatics via photocyclization of 2-(fur-3-yl) ethenylarenes, using a 3-furyl group as an isopropenyl equivalent synthon
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The construction of different types of substituted arenes was demonstrated through the photocyclization of 2-(fur-3-yl)ethenylarenes using a 3-furyl group as an isopropenyl equivalent synthon in the photocyclization reaction. The furan portion of the photocyclization intermediate could be fragmented via a base-induced elimination reaction to yield a series of substituted polyaromatics, including naphthalene, benzofuran, benzothiophene, phenanthrene, phenalene, acenaphthene, and triphenylene. Using different reagents, this method made it possible to introduce methyl or 2-hydroxyethyl groups as substituents at specific positions in these arenes.
- Chen, Ying-Zhe,Ni, Ching-Wen,Teng, Fu-Lin,Ding, Yi-Shun,Lee, Tunng-Hsien,Ho, Jinn-Hsuan
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p. 1748 - 1762
(2014/03/21)
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- The interaction of heteroaryl-acrylates and alanines with phenylalanine ammonia-lyase from parsley
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Acrylic acids and alanines substituted with heteroaryl groups at the β-position were synthesized and spectroscopically characterized (UV, HRMS, 1H NMR, and 13C NMR spectroscopy). The heteroaryl groups were furanyl, thiophenyl, benzofuranyl, and benzothiophenyl and contained the alanyl side chains either at the 2- or 3-positions. While the former are good substrates for phenylalanine ammonia lyase (PAL), the latter compounds are inhibitors. Exceptions are thiophen-3-yl-alanine, a moderate substrate and furan-3-yl-alanine, which is inert. Possible reasons for these exceptions are discussed. Starting from racemic het eroaryl-2-alanines their D-enantiomers were prepared by using a stereodestructive procedure. From the heteroaryl-2- acrylates, the L-enantiomers of the heteroaryl-2-alanines were prepared at high ammonia concentration. These results can be best explained by a Friedel - Crafts-type electrophilic attack at the aromatic part of the substrates as the initial step of the PAL reaction.
- Paizs, Csaba,Katona, Adrian,Retey, Janos
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p. 2739 - 2744
(2008/02/03)
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- Probing structural effects on replication efficiency through comparative analyses of families of potential self-replicators
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A formidable synthetic apparatus for the creation of nanoscale molecular structures and supramolecular assemblies through molecular structures can potentially be created from systems that are capable of parallel automultiplication (self-replication). In order to achieve this goal, a detailed understanding of the relationship be tween molecular structure and replication efficiency is necessary. Diastereoisomeric templates that are capable of specific and simultaneous autocatalysis have been synthesised. A systematic experimental and theoretical evaluation of their behaviour and that of structurally-related systems reveals the key determinants that dictate the emergence of self-replicative function and defines the structural space within which this behaviour is observed.
- Kassianidis, Eleftherios,Pearson, Russell J.,Philp, Douglas
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p. 8798 - 8812
(2007/10/03)
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- Thermodynamics of Protonation of Some Five-membered Heteroarylcarboxylates, -alkanoates and -trans-propenoates
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Thermodynamic parameters for the proton complex formation of some five-membered heteroaryl-carboxylates, -alkanoates and -trans-propenoates have been determined in aqueous solution at 25 deg C and I = 0.10 mol dm-3 (KNO3) by means of potentiometric and calorimetric measurements.The acidity of heteroarylcarboxylic acids follows the order 2-furoic > 2-thenoic > selenophene-2-carboxylic > 3-furoic > 3-thenoic > pyrrole-2-carboxylic > N-methylpyrrole-2-carboxylic.Such a sequence agrees with the different effects of the heteroaryl groups on the carboxylic side chain.A similar trend is observed for the corresponding furyl- and thienyl-alkanoic acids, even though polar effects of heteroatoms on the acidity are less pronounced owing to the presence of the methylenic spacers.The pK values of trans-heteroarylpropenoic acids turn out to be independent of both the heteroatom and the carboxylic group position.Enthalpic and entropic changes are typical of a "hard-hard" interaction.
- Arena, Giuseppe,Cali, Rosario,Maccarone, Emanuele,Passerini, Amedeo
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p. 1941 - 1946
(2007/10/02)
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- Halogenation of benzyl- and (heteroaromatic methyl)cobaloximes: Direct competition between ring halogenation and cobalt-carbon bond cleavage
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(4-Acetamidobenzyl)- and (4-(dimethylamino)benzyl)cobaloximes react rapidly with low concentrations of chlorine and bromine in acetic acid or chloroform at room temperature under nitrogen. Both ring-halogenated organometallic products and direct Co-C cleavage products are formed. However, (4-methoxybenzyl)cobaloxime forms 4-methoxy-2-halotoluene as the exclusive product. (3-Methylbenzyl)cobaloxime undergoes a substantial proportion of ring substitution by both Br2 and Cl2 in competition with the cleavage of the Co-C bond. (3-Methoxybenzyl)cobaloxime forms only the ring-substituted organometallic product. A remarkable difference in reactivity between 2- and 3-isomers of the (thienylmethyl)- and (furylmethyl)cobaloximes is observed; for example, Co-C cleavage is the primary process in furfuryl- and (2-thienylmethyl)cobaloximes whereas ring halogenation occurs much faster in the 3-isomer. The results are discussed in terms of a σ-π delocalization phenomenon by which the electronic effect of a substituent in the benzyl group is effectively transmitted to the Co-C bond reactivity. The substituent effect of the metallomethyl group -CH2Co(dmgH)2py is found to be more than that of the methoxy group. The mechanism of the Co-C cleavage is described.
- Gupta,Kumar, Manoj,Roy, Sujit
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- A Study of the Terpenoids of the Sponge Euryspongia sp.
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The metabolites of the sponge Euryspongia sp. (Dysideidae) were investigated.The sponge was shown to contain the previously unknown sesquiterpene epoxides (15) and (16), and three known compounds, dehydrodendrolasin (1), thiofurodysinin acetate (13) and thiofurodysin acetate (14).Based on the spectral data of (1) and the synthetic compounds (1'E)- and (1'Z)-3-(4',8'-dimethylnon-1-enyl)furan (5) and (6), the structures of 'the cis isomer of dehydrodendrolasin' (2), tetradehydrofurospongian-1 (3) and the related C21 furanoterpene (4) should be reevaluated.
- Altena, Ian A. van,Miller, Darren A.
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p. 2181 - 2190
(2007/10/02)
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- Acetals useful for the preparation of polysaccharide derivatives
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Polysaccharide aldehydes having the formula Sacch-O-CH2 -CH=CH-CHO, Sacch-O-CH2 -C C-CHO, STR1 such as starch, cellulose, and gum aldehydes, are useful for imparting wet, dry, or temporary wet strength to paper. They are prepared by a non-oxidative method which involves reacting the polysaccharide base, in the presence of alkali, with a derivatizing acetal reagent having the general structure STR2 and then hydrolyzing the acetal by adjusting the pH to less than 7, preferably 2-4. In the formulas, n is 1-3; R11 and R12 are independently an alkyl, aryl, aralkyl, or alkaryl group when n is 1, R11 or R12 is one of the groups when n is 2, or R11 and R12 are not present when n is 3; R13 is an alkyl group, optionally containing an ether linkage, or an aralkyl group; R14 and R15 are individually a hydrogen or a methyl group; R16, R17, and R18 are individually an alkyl group; Y- is an anion; Z is an organic group capable of reacting with the polysaccharide base to form an ether derivative and selected from the group consisting of an epoxide, ethylenically unsaturated group, halohydrin, and halogen; R19, if present, is a divalent organic group containing no reactive substiuents; and A and A' are lower alkyls or together form at least a 5-membered cyclic acetal.
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