Versatile Entry Research Articles

Copper-Catalyzed 1,3-Aminocyclization of Cyclopropanes as a Rapid Entry to γ-Amino Heterocycles.

We herein report a copper-catalyzed 1,3-aminocyclization of cyclopropanes as a direct and versatile entry into important heterocycles. This reaction was initiated by a copper-catalyzed, NFSI-promoted ring opening of cyclopropanes, followed by nucleophilic cyclization. A variety of nucleophiles successfully participate in this transformation, including alcohols, carboxylic acids, sulfonamides, and amides, for the construction of diverse cyclic ethers, pyrrolidines, lactones, and iminolactones.

Exploring cultural hybridity, questioning cultural appropriation: Peruvian fans’ responses to Latin tropes in K-pop

Drawing on qualitative interviews with K-pop fans in Lima, Peru, this study explores how Latin fans think about and negotiate K-pop industries’ citations of Latin pop music tropes. It addresses the ways in which K-pop's practices of citing other cultures are perceived by the audience whose culture is cited. The Peruvian fans in this study suggest that the citations of other cultures observed in K-pop offer versatile entry points for them to easily engage in the cultural genre. For them, K-pop is a novel cultural genre that has become an alternative yet intimate cultural resource, especially compared to hegemonic American pop music. By providing an analysis of Latin K-pop fans’ lived experiences through the lens of cultural hybridity and appropriation, this audience study contributes to the field of transcultural media research.

Modulated spin dynamics of [Co2] coordination helicates via differential strand composition.

Coordination supramolecular chemistry provides a versatile entry into materials with functionalities of technological relevance at the nanoscale. Here, we describe how two different bis-pyrazolylpyridine ligands (L1 and L2) assemble with Co(II) ions into dinuclear triple-stranded helicates, in turn, encapsulating different anionic guests. These constructs are described as (Cl@[Co2(L1)3])3+, (SiF6@[Co2(L1)(L2)3])2+ and (ClO4@[Co2(L2)3])3+, as established by single-crystal X-ray diffraction. Extensive magnetic and calorimetric measurements, numerical treatments and theoretical calculations reveal that the individual Co(II) centers of these supramolecular entities exhibit field-induced slow relaxation of magnetization, dominated by direct and Raman mechanisms. While the small variations in the spin dynamics are not easily correlated with the evident structural differences among the three species, the specific heat measurements suggest two vibronic pathways of magnetic relaxation: one that would be associated with the host lattice and another linked with the guest.

Photocatalyzed sulfoximination/amidation of (Het)arylethenes tethered N-tosyl amide: a versatile entry to sulfoximidoyl β- and γ-lactams

Lactamization through C–N bond formation between CC and amide motifs enables access to various sulfoximidoyl lactams via a 1,2-diamination process.

Heterocycles by Consecutive Multicomponent Syntheses via Catalytically Generated Alkynoyl Intermediates

Multicomponent processes are beneficial tools for the synthesis of heterocycles. As densely substituted bifunctional electrophiles, ynones are essential intermediates by applying cyclocondensations or cycloadditions in numerous heterocycle syntheses. The respective alkynoyl intermediates are generally accessible by palladium-, copper- and palladium/copper-catalyzed alkynylation. In turn, the mild reaction conditions allow for a fast and versatile entry to functional heterocycles in the sense of consecutive multicomponent processes. This review collates and presents recent advances in accessing thirteen heterocycle classes and their applications by virtue of catalytic alkynoyl generation in diversity-oriented multicomponent syntheses in a one-pot fashion.

Nanosized copper stabilized on ternary P, N, S-doped graphene from chitosan shellfish waste: preparation and catalysis of single and double A3-type amine coupling

Heteroatom-doping carbons are conventionally accessed through multistep procedures, often necessitating tedious postgrafting and the use of harsh conditions, while providing less-defined heterogeneous catalysts. We herein disclose a time-saving approach based on straightforward modification of chitosan, an abundant marine waste, followed by its graphitization to access texturally tunable, ternary-doped nitrogen, phosphorus, and sulfur-containing porous carbon material. The presence of functional groups in the edges ensures total exfoliation and dispersion of the sheets, whereas the presence of different coordinating sites inside accounts for efficient stabilization of the embedded metal nanoclusters. Preliminarily, good catalytic activity was noticed for the synthesis of propargylamines and dipropargylamines. The following approach combining active metals and discarded biowaste constitutes a highly versatile entry to heterogeneous carbon-based catalysts.

Tandem-catalysis-enabled highly chemoselective deoxygenative alkynylation and alkylation of tertiary amides: a versatile entry to functionalized α-substituted amines

We report a unified relay catalysis strategy for the direct reductive alkynylation and reductive alkylation of tertiary amides to afford α-alkynylamines and α-branched amines.

Continuous flow as an enabling technology: a fast and versatile entry to functionalized glyoxal derivatives

We herein report two complementary strategies employing organolithium chemistry for the synthesis of glyoxal derivatives. Micro-mixer technology allows for the generation of unstable organometallic intermediates and their instantaneous in-line quenching with esters as electrophiles. Selective mono-addition was observed via putative stabilized tetrahedral intermediates. Advantages offered by flow chemistry technologies facilitate direct and efficient access to masked 1,2-dicarbonyl compounds while mitigating undesired by-product formation. These two approaches enable the production of advanced and valuable synthetic building blocks for heterocyclic chemistry with throughputs of grams per minute.

The intersectional genetics landscape for humans.

ABSTRACTBackgroundThe human body is made up of hundreds—perhaps thousands—of cell types and states, most of which are currently inaccessible genetically. Intersectional genetic approaches can increase the number of genetically accessible cells, but the scope and safety of these approaches have not been systematically assessed. A typical intersectional method acts like an “AND" logic gate by converting the input of 2 or more active, yet unspecific, regulatory elements (REs) into a single cell type specific synthetic output.ResultsHere, we systematically assessed the intersectional genetics landscape of the human genome using a subset of cells from a large RE usage atlas (Functional ANnoTation Of the Mammalian genome 5 consortium, FANTOM5) obtained by cap analysis of gene expression sequencing (CAGE-seq). We developed the heuristics and algorithms to retrieve and quality-rank “AND" gate intersections. Of the 154 primary cell types surveyed, >90% can be distinguished from each other with as few as 3 to 4 active REs, with quantifiable safety and robustness. We call these minimal intersections of active REs with cell-type diagnostic potential “versatile entry codes" (VEnCodes). Each of the 158 cancer cell types surveyed could also be distinguished from the healthy primary cell types with small VEnCodes, most of which were robust to intra- and interindividual variation. Methods for the cross-validation of CAGE-seq–derived VEnCodes and for the extraction of VEnCodes from pooled single-cell sequencing data are also presented.ConclusionsOur work provides a systematic view of the intersectional genetics landscape in humans and demonstrates the potential of these approaches for future gene delivery technologies.

Stereocontrolled Syntheses of Functionalized cis- and trans-Siladecalins.

We report the synthesis of both diastereomers of an all-silicon analog of decalin. Carbocyclic decalin is aubiquitousbicyclic structural motif. The siladecalinsynthesis provides materials functionalized with either Si-Ph or Si-H groups, versatile entry points for further chemical diversification. The synthesis of silicon-stereogenic silanes is significantly less precedented than the synthesis of asymmetric carbon centers, and strategies for control of relative stereochemistry in oligosilanes are hardly described. This study offers insights of potential generality, such as the epimerization of the cis-isomer to the thermodynamically downhill trans-isomer via a hypothesized pentavalent intermediate. Decalin is a classic example in the conformational analysis of organic ring systems, and the carbocyclic diastereomers have highly divergent conformational profiles. Like the carbocycle, we observe different conformational properties in cis- and trans-siladecalins with consequences for NMR spectroscopy, optical properties, and vibrational spectroscopy. This study showcases the utility of targeted synthesis for preparing complex and functionalized polycyclic silanes.

Radical-mediated hydroalkylation of 2-vinylpyrrolidine derivatives: a versatile entry into indolizidine alkaloids

A concise route for the preparation of two simple optically pure indolizidin-5-ones has been developed. The key chain elongation process was achieved using a triethylborane/catechol mediated hydroalkylation of Boc-protected 2-vinylpyrrolidines. By using complementary strategies, these two bicyclic lactams can be alkylated with complete control of the stereochemistry at C(5) and their conversion to a variety of indolizidine alkaloids such as coniceine, indolizidine 209D and 167B, 5-epi-indolizidine 249A and monomorine has been reported in the literature.

Heterotrimetallic complexes of iron and ruthenium based on vinyliminium dithiocarboxylate ligands

The diiron vinyliminium compounds [Fe2{μ-η1:η3-C(R2) = C(H)C=N(Me)R1}(μ-CO)(CO)(Cp)2]OSO2CF3 (R1 = Xyl = 2,6-C6H3Me2, R2 = Me; R1 = Me, R2 = CO2Me) provide a versatile entry point for many subsequent transformations, such as their reaction with carbon disulfide to provide zwitterionic dithiocarboxylate products. These compounds react with the coordinatively-unsaturated ruthenium vinyl precursors [Ru(CH=CHR3)Cl(CO)(PPh3)2] (R3 = C6H4Me-4, 1-Pyrenyl) to yield heterotrimetallic Fe2Ru compounds, exhibiting vinyl moieties at both iron and ruthenium centres. The emission associated with the pyrenyl unit is enhanced in the diiron vinyliminium ruthenium pyrenyl complex compared to the diethyldithiocarbamate analogue.

Palladium triggered diene formation from nitro allylic compounds: a versatile entry into naphthalene derivatives.

Nitro allylic derivatives were converted into dienes through the elimination of the nitro group under basic treatment, in the presence of a palladium catalyst. This reaction probably involves the formation of a palladium π-allyl complex followed by a base-promoted β-hydride elimination. This reaction, combined with the condensation of ketones with nitromethane and the functionalization of the resulting nitrocycloalkenes, constitutes a very powerful synthetic tool for the formation of dienes. Particular attention has been brought to the application of this methodology to the formation of 1-substituted naphthalenes from 1-tetralone.

ChemInform Abstract: An Easy One‐Pot Synthesis of Diverse 2,5‐Di(2‐pyridyl)pyrroles: A Versatile Entry Point to Metal Complexes of Functionalized, Meridial and Tridentate 2,5‐Di(2‐pyridyl)pyrrolato Ligands.

AbstractAlthough only moderate yields are obtained an easy one‐pot route to 2,5‐dipyridylpyrrole ligands (IV) is described.

ChemInform Abstract: A Practical and Versatile Entry into α‐Amino Boronic Esters via Iridium‐Catalyzed Chemoselective and Enantioselective Hydrogenation of Boron Moiety Containing Vinyl Chlorides

ChemInformVolume 45, Issue 21 Reviews ChemInform Abstract: A Practical and Versatile Entry into α-Amino Boronic Esters via Iridium-Catalyzed Chemoselective and Enantioselective Hydrogenation of Boron Moiety Containing Vinyl Chlorides Ivana Gazic Smilovic, Ivana Gazic Smilovic API Dev., Sandoz Dev. Cent. Slovenia, Lek Pharm., SI-1234 Menges, SloveniaSearch for more papers by this authorZdenko Casar, Zdenko Casar API Dev., Sandoz Dev. Cent. Slovenia, Lek Pharm., SI-1234 Menges, SloveniaSearch for more papers by this author Ivana Gazic Smilovic, Ivana Gazic Smilovic API Dev., Sandoz Dev. Cent. Slovenia, Lek Pharm., SI-1234 Menges, SloveniaSearch for more papers by this authorZdenko Casar, Zdenko Casar API Dev., Sandoz Dev. Cent. Slovenia, Lek Pharm., SI-1234 Menges, SloveniaSearch for more papers by this author First published: 08 May 2014 https://doi.org/10.1002/chin.201421281AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume45, Issue21May 27, 2014 RelatedInformation

ChemInform Abstract: A Practical and Versatile Entry into α‐Amino Boronic Esters via Iridium‐Catalyzed Chemoselective and Enantioselective Hydrogenation of Boron Moiety Containing Vinyl Chlorides.

ChemInform Abstract: A Practical and Versatile Entry into α‐Amino Boronic Esters via Iridium‐Catalyzed Chemoselective and Enantioselective Hydrogenation of Boron Moiety Containing Vinyl Chlorides.

3D-QSAR Methodologies and Molecular Modeling in Bioinformatics for the Search of Novel Anti-HIV Therapies: Rational Design of Entry Inhibitors

Human immunodeficiency virus (HIV) is the responsible causal agent of acquired immunodeficiency syndrome (AIDS), a condition in humans where the immune system begins to fail, permitting the entry of diverse opportunistic infections. Until now, there is currently no available vaccine or cure for HIV or AIDS. Thus, the search for new anti-HIV therapies is a very active area. The viral infection takes place through a phenomenon called entry process, and proteins known as gp120, CCR5 and CXCR4 are essential for the prevention of the HIV entry. Bioinformatics has emerged as a powerful science to provide better understanding of biochemical or biological processes or phenomena, where 3D-QSAR methodologies and molecular modeling techniques have served as strong support. The present review is focused on the 3D-QSAR methodologies and molecular modeling techniques as parts of Bioinformatics for the rational design of entry inhibitors. Also, we propose here, a chemo-bioinformatic approach which is based on a model using substructural descriptors and allowing the prediction of multi-target (mt) inhibitors against five proteins related with the HIV entry process. By employing the model we calculated the quantitative contributions of some fragments to the inhibitory activity against all the proteins. This allowed us to automatically extract the desirable fragments for design of new, potent and versatile entry inhibitors. Keywords: 3D-QSAR, Anti-HIV, CCR5, CXCR4, fragments, gp120, homology modeling, linear discriminant analysis, molecular docking, QSAR, quantitative contributions.

Palladium-Catalyzed Cascade Reactions of 1-(3-Arylprop-2-ynyloxy)-2-bromo Benzene Derivatives with Organoboron Compounds

Applications of the cascade cyclocarbopalladation reaction followed by Suzuki-Miyaura coupling reactions of the readily available aryl-substituted propargylic aryl ethers with arylboronic acid and potassium trans-β-styryltrifluoroborate accomplish a new versatile entry in the synthesis of benzofuran derivatives. Notably, a new approach to the challenging synthesis of C3 functionalized 2-unsubstituted benzofurans has been developed by a cyclocarbopalladation/cross-coupling/aromatization process.

Memory enhancement by traditional Chinese medicine?

Cognitive repair by insulin-like growth factor-I (IGF-I) through activation of insulin-like growth factor-I receptor (IGF-IR) is well established, but not used for clinical therapy due to its link to cancer. We hypothesize that IGF-IR activation rather than IGF-I per se may be essential for cognitive repair and attempted to identify ligands from traditional Chinese medicine (TCM) with drug-like potential towards IGF-IR. TCM ligands, 3-(2-carboxyphenyl)-4(3H)-quinazolinone from Isatisin digotica, (+)-N-methyllaurotetanine from Lindera aggregate, and (+)-1(R)-Coclaurine from Nelumbonucifera Gaertn, exhibited high binding affinities and good blood brain barrier (BBB) penetration crucial for accessing IGF-IR. Stable complex formation of the candidates was observed during molecular dynamics (MD) simulation. Interactions with Leu975 and Gly1055 or Asp1056 were important for ligand binding. Amino acid distance analysis revealed residues 974/975, 984–986, 996–1006, 1040–1056, and 1122–1135 as “hotspots” for ligand binding in IGF-IR. Versatile entry pathways for the TCM candidates suggest high accessibility to the binding site. Blockage of the binding site opening by the TCM candidates limits binding site access by other compounds. Multiple linear regression (R2 = 0.9715), support vector machine (R2 = 0.9084), Bayesian network (R2 = 0.8233) comparative molecular field analysis (CoMFA, R2 = 0.9941), and comparative molecular similarity indices analysis (CoMSIA, R2 = 0.9877) models consistently suggest that the TCM candidates might exert bioactivity on IGF-IR. Contour of representative MD conformations to CoMFA and CoMSIA maps exhibits similar results. Properties including BBB passage, evidence of ability to form stable complexes with IGF-IR by MD simulation, and predicted bioactivity suggest that the TCM candidates have drug-like properties and might have potential as cognitive-enhancing drugs.An animated interactive 3D complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:JBSD:38

Boroalkyl Group Migration Provides a Versatile Entry into α-Aminoboronic Acid Derivatives

A reaction exemplifying migration of boron-substituted carbon is described. We show that α-boroalkyl groups of transient boroalkyl acyl azide intermediates readily migrate from carbon to nitrogen. This process allows access to a new class of stable molecules, α-boryl isocyanates, from α-borylcarboxylic acid precursors. The methodology facilitates synthesis of a wide range of α-aminoboronic acid derivatives, including α,α-disubstituted analogues.