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    2301 results match your criteria Beilstein Journal of Organic Chemistry [Journal]

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    Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines.
    Beilstein J Org Chem 2017 27;13:2273-2296. Epub 2017 Oct 27.
    Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan.
    Phthalocyanines and subphthalocyanines are attracting attention as functional dyes that are applicable to organic solar cells, photodynamic therapy, organic electronic devices, and other applications. However, phthalocyanines are generally difficult to handle due to their strong ability to aggregate, so this property must be controlled for further applications of phthalocyanines. On the other hand, trifluoroethoxy-substituted phthalocyanines are known to suppress aggregation due to repulsion of the trifluoroethoxy group. Read More

    Curcuminoid-BF2 complexes: Synthesis, fluorescence and optimization of BF2 group cleavage.
    Beilstein J Org Chem 2017 26;13:2264-2272. Epub 2017 Oct 26.
    Institute for Inorganic and Analytical Chemistry, Friedrich-Schiller-Universität Jena, Humboldtstrasse 8, 07743 Jena, Germany.
    Eight difluoroboron complexes of curcumin derivatives carrying alkyne groups containing substituents have been synthesized following an optimised reaction pathway. The complexes were received in yields up to 98% and high purities. Their properties as fluorescent dyes have been investigated. Read More

    Structural diversity in the host-guest complexes of the antifolate pemetrexed with native cyclodextrins: gas phase, solution and solid state studies.
    Beilstein J Org Chem 2017 25;13:2252-2263. Epub 2017 Oct 25.
    Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
    The complexation of the antifolate pemetrexed (PTX) with native cyclodextrins was studied. This process, along with the findings gathered for the structurally related folic acid was treated as a model for exploiting host-guest interactions of this class of guest molecules in the gas phase, in solution and in the solid state. Mass spectrometry was employed for the investigation of the architecture and relative gas-phase stabilities of these supramolecular complexes. Read More

    Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies.
    Beilstein J Org Chem 2017 24;13:2235-2251. Epub 2017 Oct 24.
    Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Switzerland.
    The scope of applications of dialkyl dicyanofumarates and maleates as highly functionalized electron-deficient dipolarophiles, dienophiles and Michael acceptors is summarized. The importance for the studies on reaction mechanisms of cycloadditions is demonstrated. Multistep reactions with 1,2-diamines and β-aminoalcohols leading to diverse five- and six-membered heterocycles are discussed. Read More

    Conjugated nitrosoalkenes as Michael acceptors in carbon-carbon bond forming reactions: a review and perspective.
    Beilstein J Org Chem 2017 23;13:2214-2234. Epub 2017 Oct 23.
    N. D. Zelinsky Institute of Organic Chemistry, 119991, Leninsky prospect, 47, Moscow, Russia.
    Despite of their chemical instability and high reactivity, conjugated nitrosoalkenes are useful intermediates in target-oriented organic synthesis. The present review deals with carbon-carbon bond forming reactions involving Michael addition to α-nitrosoalkenes with a particular focus on recent developments in this methodology and its use in total synthesis. Read More

    Phosphonic acid: preparation and applications.
    Beilstein J Org Chem 2017 20;13:2186-2213. Epub 2017 Oct 20.
    CEMCA UMR CNRS 6521, Université de Brest, IBSAM. 6 Avenue Victor Le Gorgeu, 29238 Brest, France.
    The phosphonic acid functional group, which is characterized by a phosphorus atom bonded to three oxygen atoms (two hydroxy groups and one P=O double bond) and one carbon atom, is employed for many applications due to its structural analogy with the phosphate moiety or to its coordination or supramolecular properties. Phosphonic acids were used for their bioactive properties (drug, pro-drug), for bone targeting, for the design of supramolecular or hybrid materials, for the functionalization of surfaces, for analytical purposes, for medical imaging or as phosphoantigen. These applications are covering a large panel of research fields including chemistry, biology and physics thus making the synthesis of phosphonic acids a determinant question for numerous research projects. Read More

    Regiodivergent condensation of 5-alkoxycarbonyl-1H-pyrrol-2,3-diones with cyclic ketazinones en route to spirocyclic scaffolds.
    Beilstein J Org Chem 2017 19;13:2179-2185. Epub 2017 Oct 19.
    Department of Chemistry, North Caucasus Federal University, 1a Pushkin St., Stavropol 355009, Russian Federation.
    The condensation of 5-alkoxycarbonyl-1H-pyrrolediones with cyclic ketazinones was systematically investigated. It was discovered that the regioselectivity of this reaction can be easily swapped between two alternative directions affording derivatives of partially hydrogenated indole or benzofurane. The control of this regioselectivity is efficiently governed by steric effects at the hydrazone moiety of the ketazinone reagent. Read More

    A mechanochemical approach to access the proline-proline diketopiperazine framework.
    Beilstein J Org Chem 2017 19;13:2169-2178. Epub 2017 Oct 19.
    Institut des Biomolécules Max Mousseron (IBMM), UMR 5247, CNRS, Université de Montpellier, ENSCM, Campus Triolet, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France.
    Ball milling was exploited to prepare a substituted proline building block by mechanochemical nucleophilic substitution. Subsequently, the mechanocoupling of hindered proline amino acid derivatives was developed to provide proline-proline dipeptides under solvent-free conditions. A deprotection-cyclization sequence yielded the corresponding diketopiperazines that were obtained with a high stereoselectivity which could be explained by DFT calculations. Read More

    The effect of milling frequency on a mechanochemical organic reaction monitored by in situ Raman spectroscopy.
    Beilstein J Org Chem 2017 18;13:2160-2168. Epub 2017 Oct 18.
    Department of Chemistry, McGill University, Montreal, QC, Canada.
    We provide the first in situ and real-time study of the effect of milling frequency on the course of a mechanochemical organic reaction conducted using a vibratory shaker (mixer) ball mill. The use of in situ Raman spectroscopy for real-time monitoring of the mechanochemical synthesis of a 2,3-diphenylquinoxaline derivative revealed a pronounced dependence of chemical reactivity on small variations in milling frequency. In particular, in situ measurements revealed the establishment of two different regimes of reaction kinetics at different frequencies, providing tentative insight into processes of mechanical activation in organic mechanochemical synthesis. Read More

    Synthesis of 2-aminosuberic acid derivatives as components of some histone deacetylase inhibiting cyclic tetrapeptides.
    Beilstein J Org Chem 2017 17;13:2153-2156. Epub 2017 Oct 17.
    Department of Chemistry, University of Kalyani, Kalyani - 741235, West Bengal, India.
    A new synthesis of the important amino acid 2-aminosuberic acid from aspartic acid is reported. The methodology involves the alternate preparation of (S)-2-aminohept-6-enoate ester as a building block and its diversification through a cross-metathesis reaction to prepare the title compounds. The utility of the protocol is demonstrated through the preparation of three suberic acid derivatives of relevance to the design and the synthesis of peptides of biological relevance. Read More

    An efficient synthesis of a C12-higher sugar aminoalditol.
    Beilstein J Org Chem 2017 16;13:2146-2152. Epub 2017 Oct 16.
    Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
    The C12-aminoalditol H2NCH2-(CHOBn)10-CH2OH was prepared from two simple monosaccharide building blocks. The synthesis was realized by a regioselective introduction of the azide group and subsequent protection-deprotection transformations. The chemical reactivity of the aminoalditol was tested in the reductive amination reaction with a selectively protected sucrose monoaldehyde. Read More

    Solid-state studies and antioxidant properties of the γ-cyclodextrin·fisetin inclusion compound.
    Beilstein J Org Chem 2017 13;13:2138-2145. Epub 2017 Oct 13.
    QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
    Fisetin is a natural antioxidant with a wide range of nutraceutical properties, including antidiabetic, neuroprotecting, and suppression or prevention of tumors. The present work describes the preparation of a water-soluble, solid inclusion compound of fisetin with gamma-cyclodextrin (γ-CD), a cyclic oligosaccharide approved for human consumption. A detailed physicochemical analysis of the product is carried out using elemental analysis, powder X-ray diffraction (PXRD), Raman, infrared and (13)C{(1)H} CP-MAS NMR spectroscopies, and thermal analysis (TGA) to verify fisetin inclusion and to present a hypothetical structural arrangement for the host-guest units. Read More

    Novel approach to hydroxy-group-containing porous organic polymers from bisphenol A.
    Beilstein J Org Chem 2017 12;13:2131-2137. Epub 2017 Oct 12.
    CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
    We successfully employed bisphenol A and several different formyl-containing monomers as useful building blocks to construct a series of hydroxy-group-containing porous organic polymers in a sealed tube at high temperature. Fourier transform infrared and solid-state (13)C CP/MAS NMR spectroscopy are utilized to characterize the possible structure of the obtained polymers. The highest Brunauer-Emmet-Teller specific surface area of the phenolic-resin porous organic polymers (PPOPs) is estimated to be 920 m(2) g(-1). Read More

    Synthesis of substituted Z-styrenes by Hiyama-type coupling of oxasilacycloalkenes: application to the synthesis of a 1-benzoxocane.
    Beilstein J Org Chem 2017 11;13:2122-2127. Epub 2017 Oct 11.
    Department of Chemistry, Western Washington University, 516 High Street, Bellingham, WA 98225, USA.
    Several Hiyama cross-coupling reactions of oxasilacycloalkenes and aryl iodides are described that produce trisubstituted Z-styrenes in moderate to excellent yields. Both electron-rich and electron-poor aryl iodides are tolerated in the cross-coupling reaction. The oxasilacycloalkene coupling partners were prepared by ruthenium-catalyzed intramolecular anti-hydrosilylation of alkynols. Read More

    Preparation of imidazo[1,2-a]-N-heterocyclic derivatives with gem-difluorinated side chains.
    Beilstein J Org Chem 2017 10;13:2115-2121. Epub 2017 Oct 10.
    Laboratory for Medicinal Chemistry and Natural Products, Lebanese University, Faculty of Sciences (1) and PRASE-EDST, Hadath, Beirut, Lebanon.
    Using an aerobic oxidative coupling, different new imidazo[1,2-a]-N-heterocycles with gem-difluroroalkyl side chains have been prepared in fair yields by the reaction of gem-difluoroenones with aminopyridines, -pyrimidines and -pyridazines. Condensed heterocycles of this type play an important role as key core structures of various bioactive compounds. Further, starting with a chloroimidazopyridazine derivative, Pd-catalyzed coupling reactions as well as nucleophilic substitutions have been performed successfully in order to increase the molecular diversity. Read More

    Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly.
    Beilstein J Org Chem 2017 9;13:2094-2114. Epub 2017 Oct 9.
    Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, MI 48824, USA.
    Most glycosylation reactions are performed by mixing the glycosyl donor and acceptor together followed by the addition of a promoter. While many oligosaccharides have been synthesized successfully using this premixed strategy, extensive protective group manipulation and aglycon adjustment often need to be performed on oligosaccharide intermediates, which lower the overall synthetic efficiency. Preactivation-based glycosylation refers to strategies where the glycosyl donor is activated by a promoter in the absence of an acceptor. Read More

    Enzymatic separation of epimeric 4-C-hydroxymethylated furanosugars: Synthesis of bicyclic nucleosides.
    Beilstein J Org Chem 2017 5;13:2078-2086. Epub 2017 Oct 5.
    Bioorganic Laboratory, Department of Chemistry, University of Delhi, Delhi-110 007, India.
    Conversion of D-glucose to 4-C-hydroxymethyl-1,2-O-isopropylidene-α-D-ribofuranose, which is a key precursor for the synthesis of different types of bicyclic/spiro nucleosides, led to the formation of an inseparable 1:1 mixture of the desired product and 4-C-hydroxymethyl-1,2-O-isopropylidene-α-D-xylofuranose. A convenient environment friendly Novozyme(®)-435 catalyzed selective acetylation methodology has been developed for the separation of an epimeric mixture of ribo- and xylotrihydroxyfuranosides in quantitative yields. The structure of both the monoacetylated epimers, i. Read More

    Main group mechanochemistry.
    Beilstein J Org Chem 2017 5;13:2068-2077. Epub 2017 Oct 5.
    Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, 21 Nanyang Link, 637371, Singapore.
    Over the past decade, mechanochemistry has emerged as a powerful methodology in the search for sustainable alternatives to conventional solvent-based synthetic routes. Mechanochemistry has already been successfully applied to the synthesis of active pharmaceutical ingredients (APIs), organic compounds, metal oxides, coordination compounds and organometallic complexes. In the main group arena, examples of synthetic mechanochemical methodologies, whilst still relatively sporadic, are on the rise. Read More

    Complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives.
    Beilstein J Org Chem 2017 4;13:2056-2067. Epub 2017 Oct 4.
    Department of Fine Organic Synthesis, A.V. Bogatsky Physico-Chemical Institute, National Academy of Sciences of Ukraine, Lustdorfskaya doroga 86, Odesa 65080, Ukraine.
    The complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives has been studied both in solution and in the solid state. In this paper we studied the influence of the crown ether ring size and the nature of the substituents at the nitrogen atoms of the paraquat derivatives on the composition and stability of these complexes. Read More

    Mechanically induced oxidation of alcohols to aldehydes and ketones in ambient air: Revisiting TEMPO-assisted oxidations.
    Beilstein J Org Chem 2017 2;13:2049-2055. Epub 2017 Oct 2.
    Dipartimento di Chimica e Farmacia, Università degli Studi di Sassari, via Vienna 2, 07100 Sassari, Italy.
    The present work addresses the development of an eco-friendly and cost-efficient protocol for the oxidation of primary and secondary alcohols to the corresponding aldehydes and ketones by mechanical processing under air. Ball milling was shown to promote the quantitative conversion of a broad set of alcohols into carbonyl compounds with no trace of an over-oxidation to carboxylic acids. The mechanochemical reaction exhibited higher yields and rates than the classical, homogeneous, TEMPO-based oxidation. Read More

    Intramolecular glycosylation.
    Beilstein J Org Chem 2017 29;13:2028-2048. Epub 2017 Sep 29.
    Department of Chemistry and Biochemistry, University of Missouri - St. Louis, One University Blvd., 434 Benton Hall (MC27), St. Louis, MO 63121, USA.
    Carbohydrate oligomers remain challenging targets for chemists due to the requirement for elaborate protecting and leaving group manipulations, functionalization, tedious purification, and sophisticated characterization. Achieving high stereocontrol in glycosylation reactions is arguably the major hurdle that chemists experience. This review article overviews methods for intramolecular glycosylation reactions wherein the facial stereoselectivity is achieved by tethering of the glycosyl donor and acceptor counterparts. Read More

    Difunctionalization of alkenes with iodine and tert-butyl hydroperoxide (TBHP) at room temperature for the synthesis of 1-(tert-butylperoxy)-2-iodoethanes.
    Beilstein J Org Chem 2017 28;13:2023-2027. Epub 2017 Sep 28.
    Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou, 510315, P. R. China. ; Tel: +86- 20 -62789464.
    We developed a direct vicinal difunctionalization of alkenes with iodine and TBHP at room temperature. This iodination and peroxidation in a one-pot synthesis produces 1-(tert-butylperoxy)-2-iodoethanes, which are inaccessible through conventional synthetic methods. This method generates multiple radical intermediates in situ and has excellent regioselectivity, a broad substrate scope and mild conditions. Read More

    Transition-metal-free synthesis of 3-sulfenylated chromones via KIO3-catalyzed radical C(sp(2))-H sulfenylation.
    Beilstein J Org Chem 2017 27;13:2017-2022. Epub 2017 Sep 27.
    College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, P.R. China.
    The reactions between o-hydroxylphenyl-functionalized enaminones and sulfonyl hydrazines providing 3-sulfenylated chromones via domino chromone ring construction and C(sp(2))-H bond sulfenylation have been achieved under transition-metal-free conditions by using KIO3 as the only catalyst. Read More

    Mechanochemical Knoevenagel condensation investigated in situ.
    Beilstein J Org Chem 2017 26;13:2010-2014. Epub 2017 Sep 26.
    BAM Federal Institute for Materials Research and Testing, Richard-Willstaetter-Str. 11, 12489 Berlin, Germany.
    The mechanochemical Knoevenagel condensation of malononitrile with p-nitrobenzaldehyde was studied in situ using a tandem approach. X-ray diffraction and Raman spectroscopy were combined to yield time-resolved information on the milling process. Under solvent-free conditions, the reaction leads to a quantitative conversion to p-nitrobenzylidenemalononitrile within 50 minutes. Read More

    Remarkable functions of sn-3 hydroxy and phosphocholine groups in 1,2-diacyl-sn-glycerolipids to induce clockwise (+)-helicity around the 1,2-diacyl moiety: Evidence from conformation analysis by (1)H NMR spectroscopy.
    Beilstein J Org Chem 2017 25;13:1999-2009. Epub 2017 Sep 25.
    Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba 305-8565, Japan.
    Cell-membrane glycerolipids exhibit a common structural backbone of asymmetric 1,2-diacyl-sn-glycerol bearing polar head groups in the sn-3 position. In this study, the possible effects of sn-3 head groups on the helical conformational property around the 1,2-diacyl moiety in the solution state were examined. (1)H NMR Karplus relation studies were carried out using a series of 1,2-dipalmitoyl-sn-glycerols bearing different sn-3 substituents (namely palmitoyl, benzyl, hydrogen, and phosphates). Read More

    1,3-Dibromo-5,5-dimethylhydantoin as promoter for glycosylations using thioglycosides.
    Beilstein J Org Chem 2017 22;13:1994-1998. Epub 2017 Sep 22.
    Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.
    1,3-Dibromo-5,5-dimethylhydantoin (DBDMH), an inexpensive, non-toxic and stable reagent, is a competent activator of thioglycosides for glycosidic bond formation. Excellent yields were obtained when triflic acid (TfOH) or trimethylsilyl trifluoromethanesulfonate (TMSOTf) were employed as co-promoters in solution or automated glycan assembly on solid phase. Read More

    New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions.
    Beilstein J Org Chem 2017 21;13:1982-1993. Epub 2017 Sep 21.
    Departamento de Química Orgánica, Grupo FQM-383, Universidad de Cordoba, Campus de Rabanales, Edificio Marie Curie (C-3), Ctra Nnal IV-A, Km 396, E14014, Cordoba, Spain.
    Polysaccharides from natural sources and iron precursors were applied to develop new bio-nanocomposites by mechanochemical milling processes. The proposed methodology was demonstrated to be advantageous in comparison with other protocols for the synthesis of iron oxide based nanostructures. Additionally, mechanochemistry has enormous potential from an environmental point-of-view since it is able to reduce solvent issues in chemical syntheses. Read More

    Solvent-free and room temperature synthesis of 3-arylquinolines from different anilines and styrene oxide in the presence of Al2O3/MeSO3H.
    Beilstein J Org Chem 2017 20;13:1977-1981. Epub 2017 Sep 20.
    Department of Chemistry, Shiraz University, Shiraz, 71454, I. R. Iran, Tel.: +98 711 2284822.
    A highly efficient, simple and environmentally friendly synthesis of 3-arylquinolines has been developed in the presence of Al2O3/MeSO3H via one-pot reaction of anilines and styrene oxide. This methodology provides very rapid access to 3-arylquinolines in good to excellent yields under solvent-free conditions at room temperature in air. Read More

    Are boat transition states likely to occur in Cope rearrangements? A DFT study of the biogenesis of germacranes.
    Beilstein J Org Chem 2017 19;13:1969-1976. Epub 2017 Sep 19.
    Instituto de Química, Universidad Nacional Autónoma de México, Apdo. Postal 70213, 04510, Coyoacán, Circuito Exterior, Ciudad de México, Mexico.
    It has been proposed that elemanes are biogenetically formed from germacranes by Cope sigmatropic rearrangements. Normally, this reaction proceeds through a transition state with a chair conformation. However, the transformation of schkuhriolide (germacrane) into elemanschkuhriolide (elemane) may occur through a boat transition state due to the final configuration of the elemanschkuhriolide, but this transition state is questionable due to its high energy. Read More

    Solid-state mechanochemical ω-functionalization of poly(ethylene glycol).
    Beilstein J Org Chem 2017 18;13:1963-1968. Epub 2017 Sep 18.
    Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, QC, H3A 0B8, Canada.
    Poly(ethylene glycol) (PEG) is a linear polymer with a wide range of applications in chemical manufacturing, drug development and nanotechnology. PEG derivatives are being increasingly used to covalently modify small molecule and peptide drugs, as well as bioactive nanomaterials in order to improve solubility in biological serum, reduce immunogenicity, and enhance pharmacokinetic profiles. Herein we present the development of mechanochemical procedures for PEG functionalization without the need for bulk solvents, offering a cleaner and more sustainable alternative to existing solution-based PEG procedures. Read More

    High-speed vibration-milling-promoted synthesis of symmetrical frameworks containing two or three pyrrole units.
    Beilstein J Org Chem 2017 15;13:1957-1962. Epub 2017 Sep 15.
    Departamento de Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain.
    The pseudo-five-component reaction between β-dicarbonyl compounds (2 molecules), diamines and α-iodoketones (2 molecules), prepared in situ from aryl ketones, was performed efficiently under mechanochemical conditions involving high-speed vibration milling with a single zirconium oxide ball. This reaction afforded symmetrical frameworks containing two pyrrole or fused pyrrole units joined by a spacer, which are of interest in the exploration of chemical space for drug discovery purposes. The method was also extended to the synthesis of one compound containing three identical pyrrole fragments via a pseudo-seven-component reaction. Read More

    One-pot multistep mechanochemical synthesis of fluorinated pyrazolones.
    Beilstein J Org Chem 2017 14;13:1950-1956. Epub 2017 Sep 14.
    School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK.
    Solventless mechanochemical synthesis represents a technique with improved sustainability metrics compared to solvent-based processes. Herein, we describe a methodical process to run one solventless reaction directly into another through multistep mechanochemistry, effectively amplifying the solvent savings. The approach has to consider the solid form of the materials and compatibility of any auxiliary used. Read More

    p-tert-Butylthiacalix[4]arenes functionalized by N-(4'-nitrophenyl)acetamide and N,N-diethylacetamide fragments: synthesis and binding of anionic guests.
    Beilstein J Org Chem 2017 13;13:1940-1949. Epub 2017 Sep 13.
    Kazan Federal University, Kremlevskaya, 18, Kazan 420008, Russian Federation.
    New p-tert-butylthiacalix[4]arenes, which are mono-, 1,2-di- and tetrasubstituted at the lower rim containing N-(4'-nitrophenyl)acetamide and N,N-diethylacetamide groups in cone and partial cone conformations have been synthesized. Their complexation ability towards a number of tetrabutylammonium salts n-Bu4NX (X = F(-), Cl(-), Br(-), I(-), CH3CO2(-), H2PO4(-), NO3(-)) was studied by UV spectroscopy. The effective receptor for the anions studied as well as selective receptors for F(-), CH3CO2(-) and H2PO4(-) ions, which based on the synthesized thiacalix[4]arenes, have been obtained. Read More

    Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides.
    Beilstein J Org Chem 2017 12;13:1932-1939. Epub 2017 Sep 12.
    St. Petersburg State University, 7/9 Universitetskaya nab, St. Petersburg 199034, Russia.
    A new and efficient approach to five- and six-membered benzannelated sultams by intramolecular C-arylation of tertiary 1-(methoxycarbonyl)methanesulfonamides under palladium catalysis is described. In case of the α-toluenesulfonamide derivative, an unexpected formation of a 2,3-diarylindole was observed under the same conditions. Read More

    Mechanochemical synthesis of small organic molecules.
    Beilstein J Org Chem 2017 11;13:1907-1931. Epub 2017 Sep 11.
    School of Chemical Sciences, National Institute of Science Education and Research (NISER) Bhubaneswar, HBNI, P.O. Bhimpur-Padanpur, Via Jatni, Khurda 752050, Odisha, India.
    With the growing interest in renewable energy and global warming, it is important to minimize the usage of hazardous chemicals in both academic and industrial research, elimination of waste, and possibly recycle them to obtain better results in greener fashion. The studies under the area of mechanochemistry which cover the grinding chemistry to ball milling, sonication, etc. are certainly of interest to the researchers working on the development of green methodologies. Read More

    A novel application of 2-silylated 1,3-dithiolanes for the synthesis of aryl/hetaryl-substituted ethenes and dibenzofulvenes.
    Beilstein J Org Chem 2017 8;13:1900-1906. Epub 2017 Sep 8.
    Department of Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
    Trimethylsilyldiazomethane (TMS-CHN2) reacts readily with hetaryl thioketones to give sterically crowded 2-trimethylsilyl-4,4,5,5-tetrahetaryl-1,3-dithiolanes with complete regioselectivity at -75 °C as well as at rt. Thiofluorenone, a relatively stable and highly reactive aryl thioketone, yields upon treatment with TMS-CHN2 at -60 °C the corresponding 1,3,4-thiadiazoline. This unstable cycloadduct undergoes decomposition at ca. Read More

    Influence of the milling parameters on the nucleophilic substitution reaction of activated β-cyclodextrins.
    Beilstein J Org Chem 2017 7;13:1893-1899. Epub 2017 Sep 7.
    Dipartimento di Scienza e Tecnologia del Farmaco, University of Turin, via P. Giuria 9, 10125 Turin, Italy.
    The present work focuses on the mechanochemical preparation of industrially important β-cyclodextrin (CD) derivatives. Activated CDs have been reacted with nitrogen and sulfur nucleophiles using a planetary mill equipped with stainless steel, zirconia and glass milling tools of different sizes. It is shown that the milling frequency and the number as well as the size of the milling balls have an effect on the nucleophilic reaction. Read More

    β-Cyclodextrin- and adamantyl-substituted poly(acrylate) self-assembling aqueous networks designed for controlled complexation and release of small molecules.
    Beilstein J Org Chem 2017 7;13:1879-1892. Epub 2017 Sep 7.
    Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia.
    Three aqueous self-assembling poly(acrylate) networks have been designed to gain insight into the factors controlling the complexation and release of small molecules within them. These networks are formed between 8.8% 6(A)-(2-aminoethyl)amino-6(A)-deoxy-6(A)-β-cyclodextrin, β-CDen, randomly substituted poly(acrylate), PAAβ-CDen, and one of the 3. Read More

    Accessing simply-substituted 4-hydroxytetrahydroisoquinolines via Pomeranz-Fritsch-Bobbitt reaction with non-activated and moderately-activated systems.
    Beilstein J Org Chem 2017 6;13:1871-1878. Epub 2017 Sep 6.
    Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, BA2 7AY Bath, UK.
    Background: 1,2,3,4-Tetrahydroisoquinolines (THIQs) are common motifs in alkaloids and in medicinal chemistry. Synthetic access to THIQs via the Pomeranz-Fritsch-Bobbit (PFB) methodology using mineral acids for deactivated, electron-poor aromatic systems, is scarcely represented in the literature. Here, the factors controlling the regiochemical outcome of cyclization are evaluated. Read More

    Synthesis of benzothiophene and indole derivatives through metal-free propargyl-allene rearrangement and allyl migration.
    Beilstein J Org Chem 2017 6;13:1866-1870. Epub 2017 Sep 6.
    College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, P. R. China.
    An efficient base-catalyzed protocol for the synthesis of benzothiophene is described. The reaction proceeds via base-promoted propargyl-allenyl rearrangement followed by cyclization and allyl migration. Phosphine-substituted indoles can be synthesized by a similar strategy. Read More

    Enzymatic synthesis of glycosides: from natural O- and N-glycosides to rare C- and S-glycosides.
    Beilstein J Org Chem 2017 5;13:1857-1865. Epub 2017 Sep 5.
    ICOA UMR CNRS 7311, University of Orléans, rue de Chartres, BP 6759, 45067 Orléans cedex 2, France.
    Carbohydrate related enzymes, like glycosyltransferases and glycoside hydrolases, are nowadays more easily accessible and are thought to represent powerful and greener alternatives to conventional chemical glycosylation procedures. The knowledge of their corresponding mechanisms has already allowed the development of efficient biocatalysed syntheses of complex O-glycosides. These enzymes can also now be applied to the formation of rare or unnatural glycosidic linkages. Read More

    Solvent-free sonochemistry: Sonochemical organic synthesis in the absence of a liquid medium.
    Beilstein J Org Chem 2017 4;13:1850-1856. Epub 2017 Sep 4.
    School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, 39-123 Stranmillis Road, Belfast, BT9 5AG, Northern Ireland, UK.
    Sonochemistry, i.e., the application of mechanical energy in the form of sound waves, has recently been recognised for its similarity to mechanochemistry and is now included under the umbrella term of mechanochemistry. Read More

    Mechanochemical synthesis of thioureas, ureas and guanidines.
    Beilstein J Org Chem 2017 1;13:1828-1849. Epub 2017 Sep 1.
    Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
    In this review, the recent progress in the synthesis of ureas, thioureas and guanidines by solid-state mechanochemical ball milling is highlighted. While the literature is abundant on their preparation in conventional solution environment, it was not until the advent of solvent-free manual grinding using a mortar and pestle and automated ball milling that new synthetic opportunities have opened. The mechanochemical approach not only has enabled the quantitative synthesis of (thio)ureas and guanidines without using bulk solvents and the generation of byproducts, but it has also been established as a means to develop "click-type" chemistry for these classes of compounds and the concept of small molecule desymmetrization. Read More

    Iodoarene-catalyzed cyclizations of N-propargylamides and β-amidoketones: synthesis of 2-oxazolines.
    Beilstein J Org Chem 2017 31;13:1823-1827. Epub 2017 Aug 31.
    Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK. Tel: +44-1484-473741.
    Two complementary iodoarene-catalyzed methods for the preparation of 2-oxazolines are presented. The first involves the cyclization of N-propargylamides and the second involves the cyclization of β-amidoketones. These are proposed to proceed through different mechanisms and have different substrate scopes. Read More

    NHC-catalyzed cleavage of vicinal diketones and triketones followed by insertion of enones and ynones.
    Beilstein J Org Chem 2017 30;13:1816-1822. Epub 2017 Aug 30.
    Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8527, Japan.
    Thiazolium carbene-catalyzed reactions of 1,2-diketones and 1,2,3-triketones with enones and ynones have been investigated. The diketones gave α,β-double acylation products via unique Breslow intermediates isolable as acid salts, whereas the triketones formed stable adducts with the NHC instead of the coupling products. Read More

    Pd(OAc)2/Ph3P-catalyzed dimerization of isoprene and synthesis of monoterpenic heterocycles.
    Beilstein J Org Chem 2017 29;13:1807-1815. Epub 2017 Aug 29.
    Institute of Organic Chemistry, University of Regensburg, Universitätsstr. 31, 93040 Regensburg, Germany.
    The palladium-catalyzed dimerization of isoprene is a practical approach of synthesizing monoterpenes. Though several highly selective methods have been reported, most of them still required pressure or costly ligands for attaining the active system and desired selectivity. Herein, we present a simple and economical procedure towards the tail-to-tail dimer using readily available Pd(OAc)2 and inexpensive triphenylphosphine as ligand. Read More

    Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C-S cross-coupling reaction.
    Beilstein J Org Chem 2017 28;13:1796-1806. Epub 2017 Aug 28.
    Department of Chemistry, University of North Bengal, Darjeeling 734013, India. ; Tel: +91 353 2776381.
    The present work demonstrates the C-S cross-coupling reaction between aryl halides and thiols using nickel nanoparticles (Ni NPs) supported on reduced graphene oxide (Ni/RGO) as a heterogeneous catalyst. It is observed that the uniformly dispersed Ni NPs supported on RGO could exhibit excellent catalytic activity in C-S cross-coupling reactions and the catalytic application is generalized with diverse coupling partners. Although the electron-rich planar RGO surface helps in stabilizing the agglomeration-free Ni NPs, the catalytic process is found to occur involving Ni(II) species and the recovered catalyst containing both Ni(0)/Ni(II) species is equally efficient in recycle runs. Read More

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