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Journal Cover Tetrahedron
  [SJR: 0.991]   [H-I: 189]   [125 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0040-4020
   Published by Elsevier Homepage  [3089 journals]
  • An unusual [4 + 4] cycloadduct from an o-quinodimethane:
           Characterisation and computational studies
    • Authors: Raghunath O. Ramabhadran; Mohamed Husaini bin Abdul Rahman; Steven J. Collier; Richard C. Storr; Roderick W. Bates
      Pages: 1 - 5
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Raghunath O. Ramabhadran, Mohamed Husaini bin Abdul Rahman, Steven J. Collier, Richard C. Storr, Roderick W. Bates
      Trapping of a pyrimidinone-derived o-quinodimethane with tetraphenylcyclopentadienone gives a mixture of the [4 + 2] and formal [4 + 4] adducts. Computational studies show that the latter arises by a sequence of [4 + 2] cycloaddition, homolysis, radical recombination to a spiro-tetrahydrofuran and Claisen rearrangement under the thermolytic conditions.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.10.076
       
  • Design and synthesis of novel 1,4-benzodiazepine surrogates as potential
           CCKA and CCKB antagonists via palladium-catalyzed three-component cascade
           reactions
    • Authors: H. Ali Dondas; Samet Belveren; Samet Poyraz; Ronald Grigg; Colin Kilner; Marcos Ferrándiz-Saperas; Elisabet Selva; José M. Sansano
      Pages: 6 - 11
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): H. Ali Dondas, Samet Belveren, Samet Poyraz, Ronald Grigg, Colin Kilner, Marcos Ferrándiz-Saperas, Elisabet Selva, José M. Sansano
      Structurally diverse novel 1,4-benzodiazepine analogues related to selective CCKA antagonist MK-329, and CCKB antagonists L-365,260 and YM022 are prepared via palladium-catalyzed three component domino reactions involving allenylation-carbonylation-anion capture in one-pot cascade protocol in good to excellent yields.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.017
       
  • Novel methodology for the synthesis of the benz[a]anthracene skeleton of
           the angucyclines using a Suzuki-Miyaura/isomerization/ring closing
           metathesis strategy
    • Authors: Myron M. Johnson; Kennedy J. Ngwira; Amanda L. Rousseau; Andreas Lemmerer; Charles B. de Koning
      Pages: 12 - 18
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Myron M. Johnson, Kennedy J. Ngwira, Amanda L. Rousseau, Andreas Lemmerer, Charles B. de Koning
      The synthesis of the benz[a]anthracene skeleton of the angucyclines is described. Key steps involve the Suzuki-Miyaura reaction, isomerization of an aromatic allyl substituent to the corresponding styrene, and the use of the ring closing metathesis reaction to construct a benzene ring. For example, exposure of 3-allyl-2-bromo-1,4,5-trimethoxynaphthalene to (2-formyl-4-methoxyphenyl)boronic acid under palladium catalysis conditions resulted in the formation of 2-(3-allyl-1,4,5-trimethoxynaphthalen-2-yl)-5-methoxybenzaldehyde. This 2-naphthyl benzaldehyde then underwent a Wittig reaction to furnish 3-allyl-1,4,5-trimethoxy-2-(4-methoxy-2-vinylphenyl)naphthalene. Isomerization of the allyl group of this compound afforded the diene, (E)-1,4,5-trimethoxy-2-(4-methoxy-2-vinylphenyl)-3-(prop-1-en-1yl)naphthalene. Exposure of the formed diene to the Grubbs II catalyst resulted in the formation of the benzanthracene, 3,7,8,12-tetramethoxytetraphene, which was easily oxidized to the corresponding quinone.
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      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.023
       
  • N,N-dimethyl-d-glucosamine as an efficient ligand for copper-catalyzed
           Ullmann-type coupling of N-H heterocycles with aryl halides
    • Authors: Jiao Jiao Wei; Wei Bin Song; Ye Fu Zhu; Bo Le Wei; Li Jiang Xuan
      Pages: 19 - 27
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Jiao Jiao Wei, Wei Bin Song, Ye Fu Zhu, Bo Le Wei, Li Jiang Xuan
      A new N,N-dimethyl-d-glucosamine ligand has been developed for the copper-catalyzed Ullmann-type coupling of N-H heterocycles (e.g., indoles, benzimidazoles, pyrazoles and triazoles) with aryl halides. This method was accomplished not only featuring excellent yields, mild reaction conditions and simple operation, but also showing eco-friendly and broad-spectrum substrates, and could be widely used in the construction of N-aryl heterocyclic systems.
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      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.027
       
  • Puckering behavior in six new phosphoric triamides containing aliphatic
           six- and seven-membered ring groups and a database survey of analogous
           ring-containing structures
    • Authors: Banafsheh Vahdani Alviri; Mehrdad Pourayoubi; Anahid Saneei; Mojtaba Keikha; Arie van der Lee; Aurélien Crochet; A. Abdul Ajees; Marek Nečas; Katharina M. Fromm; Krishnan Damodaran; Titus A. Jenny
      Pages: 28 - 41
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Banafsheh Vahdani Alviri, Mehrdad Pourayoubi, Anahid Saneei, Mojtaba Keikha, Arie van der Lee, Aurélien Crochet, A. Abdul Ajees, Marek Nečas, Katharina M. Fromm, Krishnan Damodaran, Titus A. Jenny
      The influence of a N heteroatom on the ring conformations of six- and seven-membered aliphatic rings in six new C(O)NHP(O)-based phosphoric triamide structures (analysed by X-ray crystallography) is investigated. Additionally the influence of steric and crystal packing effects is also studied by the analysis of Hirshfeld surfaces. The results are compared to analogous structures with three- to seven- aliphatic membered rings deposited in the Cambridge Structural Database. In the newly determined structures, the six-membered rings only show the near-chair conformation with a maximum deviation of the θ puckering parameter of 4.4° from the ideal chair value of 0°/180°, while the seven-membered rings are found in different conformations such as near-chair, twist chair and twist sofa.
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      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.030
       
  • One-pot synthesis of novel 3,10-dihydro-2H-1,3-oxazepino[7,6-b]indoles via
           1,4-dipolar cycloaddition reaction
    • Authors: Mervat S. Sammor; Ahmad Q. Hussein; Firas F. Awwadi; Mustafa M. El-Abadelah
      Pages: 42 - 48
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Mervat S. Sammor, Ahmad Q. Hussein, Firas F. Awwadi, Mustafa M. El-Abadelah
      3,10-Dihydro-2H-1,3-oxazepino[7,6-b]indoles are synthesized via a convenient one-pot three-component 1,4-dipolar cycloaddition reaction, involving 3-alkyl(aryl)imidazo[1,5-a]pyridines, dimethyl acetylenedicarboxylate (DMAD) and N-alkylisatins. Structures of the newly synthesized heterocycles are evidenced from spectral data and further confirmed by single crystal X-ray diffraction. A plausible reaction mechanism is advanced, whereby the intermediate 1,4-dipole, generated in situ from imidazo[1,5-a]pyridine and DMAD, initially adds to the keto group of N-alkylisatins to form the corresponding 1,3-oxazin-spiro-oxindole cycloadduct. The latter undergoes subsequent unprecedented skeletal rearrangement through a cascade of bond breaking and bond making processes, eventually leading to ring enlargement, furnishing the tricyclic oxazepino[7,6-b]indole ring system as the end product.
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      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.031
       
  • Evidence for involvement of cationic intermediate in epoxidation of chiral
           allylic alcohols and unfunctionalised alkenes catalysed by
           MnIII(quinazolinone) complexes
    • Authors: Murat Çakıcı; Hamdullah Kılıç; Sabri Ulukanlı; Duygu Ekinci
      Pages: 49 - 57
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Murat Çakıcı, Hamdullah Kılıç, Sabri Ulukanlı, Duygu Ekinci
      A pair of MnIII(quinazolinone) complexes was prepared and evaluated in the catalytic epoxidation of the chiral allylic alcohols and unfunctionalised alkenes with iodosylbenzene. Epoxidation of chiral allylic alcohols with 1,3-allylic strain proceeded chemo- and diastereoselectively to give threo-epoxy alcohol (up to 99% d.r). Epoxidation of unfunctionalised alkenes by the proposed catalyst system proceeded nonselectively, as evidenced by the formation of isomerization and rearrangement products in the epoxidation of (Z)-stilbene. A three-step pathway involving a cationic intermediate is proposed for the formation of isomerization and rearrangement products. The fact that only products resulting from the cationic intermediate were detected in the oxidation of a mechanistic probe, (2-methoxy-3-vinylcyclopropyl)benzene, with MnIII(quinazolinone) and PhIO substantiated the cationic oxygen transfer mechanism.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.034
       
  • Solvent-free, catalyst-free aza-Michael addition of cyclohexylamine to
           diethyl maleate: Reaction mechanism and kinetics
    • Authors: Michal Bláha; Olga Trhlíková; Jiří Podešva; Sabina Abbrent; Miloš Steinhart; Jiří Dybal; Miroslava Dušková-Smrčková
      Pages: 58 - 67
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Michal Bláha, Olga Trhlíková, Jiří Podešva, Sabina Abbrent, Miloš Steinhart, Jiří Dybal, Miroslava Dušková-Smrčková
      The aza-Michael reaction is the addition of an amine to an electron deficient C=C double bond. This reaction is also used in the synthesis of precursors of polymeric networks. In this study, we paid attention to the kinetics and mechanism of the aza-Michael addition of cyclohexylamine (CHXA) to diethyl maleate (DEM) performed as a solvent-free, catalyst-free reaction and to concurrent reactions. In situ Raman spectroscopy, NMR spectroscopy and gas chromatography/mass spectrometry have shown the occurrence of three simultaneous reactions: (i) the aza-Michael addition of CHXA to DEM leading to diethyl 2-(cyclohexylamino)succinate, (ii) isomerization of DEM to diethyl fumarate (DEF), and (iii) the aza-Michael addition of CHXA to DEF formed by the reaction (ii). All of these reactions proceed with third order kinetics, first order in DEM or DEF and second order in CHXA. We propose a kinetic model that allows kinetic constants to be estimated. Furthermore, a numerical solution of the set of differential equations confirms the expected kinetic equations of reactions (i) and (ii) and gives values of rate constants comparable to the estimated ones. A DFT mechanistic study illustrates the structure of the reaction intermediates and transition states of all reactions and explains the contribution of the second amine molecule in the reaction mechanism.
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      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.033
       
  • Modification of Kagan's amide for improved activity as Chiral Solvating
           Agent in enantiodiscrimination during NMR analysis
    • Authors: Nilesh Jain; Aditya N. Khanvilkar; Sibaprasad Sahoo; Ashutosh V. Bedekar
      Pages: 68 - 76
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Nilesh Jain, Aditya N. Khanvilkar, Sibaprasad Sahoo, Ashutosh V. Bedekar
      A modification is proposed in Kagan's amide in order to improve its ability to offer stronger hydrogen bonding and hence better ability to bind with substrates. Introduction of chlorine in the amide aromatic ring along with the two nitro groups, increases the acidic character of amide hydrogen and makes the hydrogen bond stronger, the concept is tested by making three derivatives of Kagan's amide and the effect is confirmed by nmr analysis. The modified chlorinated Kagan's amides were then tested as chiral solvating agents for detection of optical purity of several types of substrates where the supramolecular recognition is measured by in situ nmr analysis. Several guest molecules such as amide, sulfoxide, epoxy-keto, hydroxy acid, diacid and phosphoric acid were scanned for this study and its efficiency is further established by comparison with samples of known optical purity.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.036
       
  • Prenylated indole alkaloids and chromone derivatives from the fungus
           Penicillium sp. SCSIO041218
    • Authors: Bin Yang; Huaming Tao; Xiuping Lin; Junfeng Wang; Shengrong Liao; Junde Dong; Xuefeng Zhou; Yonghong Liu
      Pages: 77 - 82
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Bin Yang, Huaming Tao, Xiuping Lin, Junfeng Wang, Shengrong Liao, Junde Dong, Xuefeng Zhou, Yonghong Liu
      Four new prenylated indole alkaloids (1–4), and four new chromone derivatives (7–10), together with six known compounds (5, 6, and 11–14), have been isolated from the mangrove sediment derived fungus Penicillium sp. SCSIO041218, cultured in the 1% NaCl PDB substrate. The structures of new compounds were determined by analysis of the NMR and MS spectroscopic data. The absolute configuration of the prenylated indole alkaloids were elucidated based on the comparison of ECDs with known analogues. The absolute configurations of the chromone derivatives were determined by time-dependent density functional theory calculations of the ECD spectra. In all of these isolated compounds, penixanthones A and B (12 and 13) exhibited antiallergic activities in vitro.
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      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.038
       
  • Chemical-epigenetic method to enhance the chemodiversity of the marine
           algicolous fungus, Aspergillus terreus OUCMDZ-2739
    • Authors: Kunlai Sun; Guoliang Zhu; Jiejie Hao; Yi Wang; Weiming Zhu
      Pages: 83 - 87
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Kunlai Sun, Guoliang Zhu, Jiejie Hao, Yi Wang, Weiming Zhu
      Four new meroterpenoids identified as (4S)-4-decarboxylflavipesolide C (1), 1-(2,2-dimethylchroman-6-yl)-3-(4-hydroxyphenyl)propan-2-one (2), (R,E)-3-(2,2-dimethylchroman-6-yl)-4-hydroxy-5-((2-(2-hydroxypropan-2-yl)-2,3-dihydrobenzofuran-5-yl)methylene)furan-2(5H)-one (3), methyl (R)-2-(2-(2-hydroxypropan-2-yl)-2,3-dihydrobenzofuran-5-yl) acetate (4), along with nine known compounds (5–13) were isolated from a chemical-epigenetic culture of Aspergillus terreus OUCMDZ-2739 with 10 μM trichostatin A (TSA). Under the same condition without TSA, A. terreus OUCMDZ-2739 produced different compounds (14–20), supporting that the chemical-epigenetic modification of fungi could enrich the chemodiversity of the fungal products. The cytotoxicity was observed for compound 8 against K562 cell, 9 against MCF-7 and K562 cells and 12 against MCF-7 cell with IC50 values of 9.5, 10.1, 13.0 and 8.5 μM, respectively. Compounds 3, 8 and 17 exhibited stronger α-glucosidase inhibition than 1-deoxynojirimycin and acarbose (positive controls) with IC50 values of 24.8, 1.2, 61.6, 191.7 and 555.1 μM, respectively. The enzyme kinetics study further indicated that compound 8 was an anticompetitive inhibitor with K i value of 1.42 μM.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.039
       
  • A new enantioselective synthesis of the four stereoisomers of pallantione,
           the male-produced sex pheromone of Pallantia macunaima (Heteroptera:
           Pentatomidae)
    • Authors: Rafael Augusto Soldi; Daiane Szczerbowski; Paulo Henrique Gorgatti Zarbin
      Pages: 88 - 95
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Rafael Augusto Soldi, Daiane Szczerbowski, Paulo Henrique Gorgatti Zarbin
      In a previous study we reported the identification of the first ketone found in the Pentatomidae family, the sex attractant pheromone of the male stink bug Pallantia macunaima, (6R,10S)-6,10,13-trimethyltetradecan-2-one. Here we describe an efficient enantioselective route for the synthesis of the four stereoisomers of this pheromone. The synthesis was conceived as the connection of two chiral building blocks, employing (R)- or (S)-citronellol and methyl (S)-3-hydroxy-2-methylpropionate as the source of chirality.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.043
       
  • First synthetic approach towards K-259-2, a unique calmodulin antagonist
    • Authors: Shyam Basak; Smita Mandal; Dipakranjan Mal
      Pages: 96 - 103
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Shyam Basak, Smita Mandal, Dipakranjan Mal
      K-259-2, a unique calmodulin antagonist, is an allyl chain containing anthraquinone natural product. A regiospecific synthetic approach towards K-259-2 is herein represented. The study also showcases a protocol for synthesizing heavily substituted bromo naphthoate which was found to be suitable for fabricating the K-259-2 motif.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.037
       
  • Enantioselective approach to indolizidine and quinolizidine scaffolds.
           Application to the synthesis of peptide mimics
    • Authors: Yuanyuan Lu; Sílvia Alujas-Burgos; Cristina Oliveras-González; Laura Vázquez-Jiménez; Pep Rojo; Ángel Álvarez-Larena; Pau Bayón; Marta Figueredo
      Pages: 104 - 116
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Yuanyuan Lu, Sílvia Alujas-Burgos, Cristina Oliveras-González, Laura Vázquez-Jiménez, Pep Rojo, Ángel Álvarez-Larena, Pau Bayón, Marta Figueredo
      An enantioselective approach to substituted indolizidine and quinolizidine frameworks has been developed. Key steps of the synthesis are the enantioselective, palladium-catalyzed N-allylation of an imide, the nucleophilic allylation of an acyliminium ion and a ring closing metathesis. This general strategy has been applied to the synthesis of indolizidine peptide mimics, starting from a chiral imide derived from l-aspartic acid. It was observed that the preexisting stereogenic center of this substrate has a moderate influence on the stereoselectivity of the electrophilic allylation, which is mainly determined by the sense of chirality of the catalyst.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.042
       
  • Phloroglucinol derivatives and a chromone glucoside from the leaves of
           Myrtus communis
    • Authors: Naonobu Tanaka; Yuyu Jia; Kanji Niwa; Kiyoshi Imabayashi; Yutaka Tatano; Hideki Yagi; Yoshiki Kashiwada
      Pages: 117 - 123
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Naonobu Tanaka, Yuyu Jia, Kanji Niwa, Kiyoshi Imabayashi, Yutaka Tatano, Hideki Yagi, Yoshiki Kashiwada
      Seven new phloroglucinol derivatives, myrtucommunins A–D (1–4), 6-methylisomyrtucommulone B (5), 4-methylmyrtucommulone B (6), and 2-isobutyryl-4-methylphloroglucinol 1-O-β-d-glucopyranoside (7), and one new chromone derivative, undulatoside A 6′-O-gallate (8), were isolated from the leaves of Myrtus communis (Myrtaceae). Myrtucommunins A–D (1–4) were conjugates of polymethylated acylphloroglucinol and flavonol rhamnoside. The absolute configurations of the rhamnosyl moieties for 1–4 were confirmed to be l in each case by HPLC analyses, while those of the aglycones were assigned by comparisons of the experimental and TDDFT calculated ECD spectra. 6-Methylisomyrtucommulone B (5) and 4-methylmyrtucommulone B (6) were assigned as 6/6/6 tricyclic acylphloroglucinol derivatives with a racemic nature. Antimicrobial activities of 1–8 and related known compounds were evaluated.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.044
       
  • Deracemization of α-monosubstituted cyclopentanones in the presence of a
           TADDOL-type host molecule
    • Authors: Hiroto Kaku; Minami Ito; Mitsuyo Horikawa; Tetsuto Tsunoda
      Pages: 124 - 129
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Hiroto Kaku, Minami Ito, Mitsuyo Horikawa, Tetsuto Tsunoda
      Racemic α-monosubstituted cyclopentanones were converted to optically active forms by a thermodynamically controlled deracemization using TADDOL-type host molecule 1 in alkaline aqueous MeOH. The efficiency of this conversion was strongly influenced by the ratio of the solvent components (H2O/MeOH) and the functionality and architecture of the α-side-chain on the cyclopentanones. For example, (R)-2-(2-benzyloxyethyl)cyclopentanone (9) was obtained in 89% yield with 97% ee using a 7:3 mixture of H2O/MeOH as the solvent. X-ray analytical studies were also carried out and disclosed the nature of this chiral molecular recognition process in the solid phase.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.045
       
  • Synthesis of 2,4,6,8,9,11-hexaaza[3.3.3]propellanes as a new molecular
           skeleton for explosives
    • Authors: Byeongil Lee; Moonyong Shin; Youngran Seo; Myeong Hak Kim; Hye Ryoung Lee; Jin Seok Kim; Kyu-hyun Chung; Dongwon Yoo; Young Gyu Kim
      Pages: 130 - 134
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Byeongil Lee, Moonyong Shin, Youngran Seo, Myeong Hak Kim, Hye Ryoung Lee, Jin Seok Kim, Kyu-hyun Chung, Dongwon Yoo, Young Gyu Kim
      Azapropellanes are of great interest in many disciplines, including materials science and medicinal chemistry. Various synthetic approaches for azapropellanes have been explored; however, the synthetic study of the polyazapropellane skeleton containing five or more nitrogen atoms is rare. Here, we report a simple yet highly efficient protocol for the synthesis of the hexaaza[3.3.3]propellane skeleton as a building block for high energy materials for the first time. The key reactions include the Boc2O-assisted cyclization of glycoluril diamine without a column purification step and the first full reduction of all the three carbonyl groups to the methylene groups through a combination of LiAlH4 and DIBAL-H. All the structures were confirmed by spectroscopic and X-ray analyses.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.046
       
  • Novel synthesis of perfluoroalkylated indolizinylphosphonates via a
           DIPEA-promoted one-pot process
    • Authors: Hao Liu; Dong He; Zhenhua Sun; Weimin He; Jing Han; Jie Chen; Hongmei Deng; Min Shao; Hui Zhang; Weiguo Cao
      Pages: 135 - 141
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Hao Liu, Dong He, Zhenhua Sun, Weimin He, Jing Han, Jie Chen, Hongmei Deng, Min Shao, Hui Zhang, Weiguo Cao
      DIPEA-promoted one-pot synthesis of perfluoroalkylated indolizinylphosphonates by the reaction of pyridines 1, bromomethyl ketones 2 with perfluoroalkynylphosphonates 3 is described. This procedure is compatible with a broad range of functional groups in both pyridines and ketones with good yields. The reaction proceeds through a tandem CN bond formation followed by an intramolecular cyclization.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.050
       
  • New pyridinium based ionic dyes for the hydrogen evolution reaction
    • Authors: Dagny D. Konieczna; Harry Biller; Matthias Witte; Wolf Gero Schmidt; Adam Neuba; René Wilhelm
      Pages: 142 - 149
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Dagny D. Konieczna, Harry Biller, Matthias Witte, Wolf Gero Schmidt, Adam Neuba, René Wilhelm
      The presented work comprised the synthesis and characterization of new ionic organic dyes as potential photosensitizer (PS) in the photocatalytic H2 evolution reaction. The presented dyes are consisting of donor-π-acceptor (D-π-A) structures that are commonly used for organic dyes for organic solar cells. The acceptor is based on a cationic pyridinium moiety. Furthermore, a complex was synthesized, in which a D-π-A photosensitizer is linked as ligand to cobaloxime. The latter is a common proton reduction catalyst. The attached ligand enabled a fast intramolecular electron transfer to the cobalt center. The resulted complex showed high stability and potential in the homogeneous photocatalytic H2 evolution reaction. Finally, one ionic dye showed a high activity when combined with TiO2 and Pt in a heterogeneous hydrogen evolution reactions with a TOF of up to 407 h−1.
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      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.053
       
  • One-pot palladium-catalyzed synthesis of functionalized
           10H-pyrido[1,2-a]quinoxalin-10-ones under copper-free conditions
    • Authors: Atena Soozani; Ali Keivanloo; Mohammad Bakherad
      Pages: 150 - 156
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Atena Soozani, Ali Keivanloo, Mohammad Bakherad
      Reactions of 3-substituted-2-chloroquinoxalines, terminal alkynes, and 1,3-dicarbonyl compounds in the presence of palladium catalyst afforded a number of 6,8,9-trisubstituted-10H-pyrido[1,2-a]quinoxalin-10-ones in 60–86% reaction yields. This one-pot protocol provided an efficient, practical, and direct method for the synthesis of pyrido[1,2-a]quinoxalines from readily available starting materials in the absence of a copper salt.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.055
       
  • Green asymmetric synthesis of tetrahydroquinolines in carbon
           dioxide medium promoted by lipophilic bifunctional tertiary amine –
           squaramide organocatalysts
    • Authors: Evgeniya V. Filatova; Olga V. Turova; Albert G. Nigmatov; Sergei G. Zlotin
      Pages: 157 - 164
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Evgeniya V. Filatova, Olga V. Turova, Albert G. Nigmatov, Sergei G. Zlotin
      Novel pseudo-enantiomeric bifunctional tertiary amine-squaramides modified with long-chained alkoxy or polyfluoroalkoxy groups, have been synthesized. They catalyzed the asymmetric double-Michael cascade reactions of o-N-tosylaminophenyl α,β-unsaturated ketones with α-nitroolefins in carbon dioxide medium at significantly lower pressure (75 bar) and temperature (35 °C), than known less lipophilic catalysts. Both enantiomers of the pharmacologically valuable methoxy-substituted tetrahydroquinoline derivatives can be prepared in moderate to high yield with promising enantioselectivity (up to 98% ee) under the optimized conditions.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.057
       
  • The Sonogashira coupling of 2- and 4-ethynyl derivatives of proton sponge
           with 1,8-diiodonaphthalene: Novel cascade transformations into
           naphtho[1,2-k]fluoranthenes and acenaphtho[1,2-b]benzo[g]indoles
    • Authors: Ekaterina A. Filatova; Anna V. Gulevskaya; Alexander F. Pozharskii; Vitaliy V. Suslonov
      Pages: 165 - 173
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Ekaterina A. Filatova, Anna V. Gulevskaya, Alexander F. Pozharskii, Vitaliy V. Suslonov
      The Sonogashira coupling of 2-ethynyl, 4-ethynyl and 2,7-diethynyl derivatives of 1,8-bis(dimethylamino)naphthalene (proton sponge) with 1-iodo- and 1,8-diiodonaphthalenes has been studied. The reaction of the above alkynes with 1-iodonaphthalene gave the expected naphthylethynyl derivatives of proton sponge. At the same time, the coupling of 2-ethynyl- and 2,7-diethynyl-1,8-bis(dimethylamino)naphthalenes with 1,8-diiodonaphthalene resulted in the formation of N,N,7-trimethyl-7H-acenaphtho[1,2-b]benzo[g]indol-8-amines. The reaction of 1,8-diiodonaphthalene with 4-ethynyl-1,8-bis(dimethylamino)naphthalene produced 14-(4,5-bis(dimethylamino)naphthalen-1-yl)-N 11,N 11,N 12,N 12-tetramethylnaphtho[1,2-k]fluoranthene-11,12-diamine together with 4-((8-iodonaphthalen-1-yl)ethynyl)-N 1,N 1,N 8,N 8-tetramethylnaphthalene-1,8-diamine. It was suggested that the mechanisms of the two novel cascade transformations stem from the specific nature of the proton sponge substrates.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.058
       
  • Regio- and diastereoselectivity of the cycloaddition of nitrones with
           N-propadienylindole and pyrroles
    • Authors: Mariia M. Efremova; Alexander S. Novikov; Rafael R. Kostikov; Taras L. Panikorovsky; Andrey V. Ivanov; Alexander P. Molchanov
      Pages: 174 - 183
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Mariia M. Efremova, Alexander S. Novikov, Rafael R. Kostikov, Taras L. Panikorovsky, Andrey V. Ivanov, Alexander P. Molchanov
      The 1,3-dipolar cycloaddition of nitrones to N-propadienyl indoles and pyrroles proceeds predominantly via the C1-C2 bond to form 4-methyleneisoxazolidines. In the case of aldonitrones, the cis-isomers are predominantly formed.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.056
       
  • One-pot synthesis of quinazolin-4(3H)-ones and fused quinazolinones by a
           palladium-catalyzed domino process
    • Authors: Zhi-Lin Ren; Han-Han Kong; Wen-Ting Lu; Mei Sun; Ming-Wu Ding
      Pages: 184 - 193
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Zhi-Lin Ren, Han-Han Kong, Wen-Ting Lu, Mei Sun, Ming-Wu Ding
      An efficient one-pot synthesis of quinazolin-4(3H)-ones, benzoimidazo[2,1-b]quinazolin-12(6H)-ones and imidazo[2,1-b]quinazolin-5(1H)-ones via a palladium-catalyzed domino process has been developed. The Pd-catalyzed reactions of 2-azidobenzamides 1 with isocyanides 2 produced quinazolin-4(3H)-ones 4 at room temperature by a domino Pd-catalyzed cross-coupling/carbodiimide-mediated cyclization. However, as 2-azido-N-(2-bromophenyl)benzamides 1 were used under heating condition in the presence of Cs2CO3, the benzoimidazo[2,1-b]quinazolin-12(6H)-ones 5 were directly obtained by twice Pd-catalyzed domino cyclization. A domino reogioselective 5-exo-dig intramolecular cyclization reaction of alkynyl-containing azides 6 with isocyanides 2 generated imidazo[2,1-b]quinazolin-5(1H)-ones 9 in 74–93% yields in the presence of catalyst Pd(PPh3)4 and K2CO3.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.060
       
  • 6,6′-Thiobis(methylene)-β-cyclodextrin dimer as a dimeric host and
           reusable promoter for synthesis of chromenones in water
    • Authors: Vijay Vilas Shinde; Daham Jeong; Eunae Cho; Seunho Jung
      Pages: 194 - 198
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Vijay Vilas Shinde, Daham Jeong, Eunae Cho, Seunho Jung
      Herein, two unit of β-cyclodextrin linked by thiomethylene bridge was synthesized and employed as a novel efficient supramolecular host for the synthesis of biologically active chromenones templates via three-component single-pot reaction. A possible reaction mechanism through molecular complexation is suggested based on 2D ROESY NMR spectroscopic analysis. Moreover, the catalyst could be easily recycled, while a 94% yield and 89% rate of catalyst recovery could be achieved after four cycles of catalyst recycling. Environmentally benign reaction conditions, excellent yields, and avoidance of organic solvent and conventional isolation as well as purification are the noteworthy credits of this developed protocol.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.065
       
  • Genome mining of Streptomyces olivaceus SCSIO T05: Discovery of olimycins
           A and B and assignment of absolute configurations
    • Authors: Changli Sun; Chunyan Zhang; Xiangjing Qin; Xiaoyi Wei; Qing Liu; Qinglian Li; Jianhua Ju
      Pages: 199 - 203
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Changli Sun, Chunyan Zhang, Xiangjing Qin, Xiaoyi Wei, Qing Liu, Qinglian Li, Jianhua Ju
      Naphthoquinone macrolides have attracted considerable synthetic interest due to their unique scaffolds, but there was no completion of total synthesis reported. In this study, genome mining and genetic manipulations were applied to stimulate the production of naphthoquinone macrolides from the deep-sea actinomycete Streptomyces olivaceus SCSIO T05; as a result, new metabolites olimycins A and B (1, 2) were isolated. The structures were elucidated on the basis of extensive spectroscopic data and X-ray single crystal diffraction studies. The results of these efforts enabled rectification of a key structural error made during previous efforts to characterize naphthoquinone macrolides.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.069
       
  • A simple metal free highly diastereoselective synthesis of heteroaryl
           substituted (±) cyclohexanols by a branched domino reaction
    • Authors: Paresh N. Patel; Anju Chadha
      Pages: 204 - 216
      Abstract: Publication date: 4 January 2018
      Source:Tetrahedron, Volume 74, Issue 1
      Author(s): Paresh N. Patel, Anju Chadha
      A self diastereoselective, simple metal free and efficient branch domino reaction gave multiple heteroaryl substituted (±) cyclohexanols with five chiral centres in >95% yields. The reactions that occur are Claisen Schmidt condensation followed by Michael addition and Aldol reactions of heteroaryl carbaldehydes and acetyl pyridine derivatives. Mechanistic study of the reactions shows excellent self diastereoselectivity (dr > 99%) in the intermediate steps which results selectively in the formation of one set of enantiomers out of sixteen possible enantiomeric pairs. The self diastereoselectivity of reaction in all the steps dominates due to the steric hindrance induced by the bulky heteroaryl groups. The stereochemistry of the synthesized compounds is established using single crystal XRD.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.070
       
  • Synthesis of 3-acyl, methylene and epoxy substituted isoindolinone
           derivatives via the ortho-lithiation/cyclization procedures of aromatic
           imines with carbon monoxide
    • Authors: Yi Xu; Xiao-Yu Liu; Zhi-Hong Wang; Liang-Fu Tang
      Pages: 7245 - 7253
      Abstract: Publication date: 28 December 2017
      Source:Tetrahedron, Volume 73, Issue 52
      Author(s): Yi Xu, Xiao-Yu Liu, Zhi-Hong Wang, Liang-Fu Tang
      A simple and convenient one-pot synthesis of 3-acyl, methylene and epoxy isoindolinone derivatives via the reaction of o-lithiated aromatic imines with carbon monoxide followed with acyl chlorides or PhCO(CH2)nBr (n = 1 or 3) under mild reaction conditions has been developed. Preliminary in vitro tests for fungicidal activity of these isoindolinone derivatives indicated that most of them exhibit good fungicidal activity against Sclerotinia sclerotiorum.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.001
       
  • Selective reaction of benzyl alcohols with HI gas: Iodination, reduction,
           and indane ring formations
    • Authors: Shoji Matsumoto; Masafumi Naito; Takehisa Oseki; Motohiro Akazome; Yasuhiko Otani
      Pages: 7254 - 7259
      Abstract: Publication date: 28 December 2017
      Source:Tetrahedron, Volume 73, Issue 52
      Author(s): Shoji Matsumoto, Masafumi Naito, Takehisa Oseki, Motohiro Akazome, Yasuhiko Otani
      Reactions of benzyl alcohols with HI in solvent-free conditions were examined. Three types of reactions (iodination, reduction, and ring formation) occurred depending on the degree of crowding around the benzyl position and the benzylic stabilization of substrates. Results also showed that the ring formation to give indanes proceeded efficiently when HI was used, and that compounds with electron-rich aromatic rings gave indane derivatives in good yields.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.009
       
  • Atranones with enhancement neurite outgrowth capacities from the
           crinoid-derived fungus stachybotrys chartarum 952
    • Authors: Yong-Fang Li; Pan-Pan Zhang; Su-Jun Yan; Jia-Yi Xu; Shah-Iram Niaz; Raza Chand; Chi Him Eddie Ma; Yong-Cheng Lin; Jing Li; Lan Liu
      Pages: 7260 - 7266
      Abstract: Publication date: 28 December 2017
      Source:Tetrahedron, Volume 73, Issue 52
      Author(s): Yong-Fang Li, Pan-Pan Zhang, Su-Jun Yan, Jia-Yi Xu, Shah-Iram Niaz, Raza Chand, Chi Him Eddie Ma, Yong-Cheng Lin, Jing Li, Lan Liu
      Seven new atranones (1–5, 7, 10) and three known analogues (6, 8, 9) were isolated from the marine crinoid-derived toxigenic fungus Stachybotrys chartarum 952. The structures of these compounds were elucidated by spectroscopic analysis as well as X-ray crystallographic analysis and electronic circular dichroism calculations. The absolute configurations of three known compounds 6, 8, 9 were first determined. Compound 8 promoted neurite outgrowth from adult DRG neurons significantly without affecting cell survival at 1 μg/mL concentrations.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.006
       
  • Sesquiterpenes from a deep-sea-derived fungus Graphostroma sp. MCCC
           3A00421
    • Authors: Siwen Niu; Chun-Lan Xie; Tianhua Zhong; Wei Xu; Zhu-Hua Luo; Zongze Shao; Xian-Wen Yang
      Pages: 7267 - 7273
      Abstract: Publication date: 28 December 2017
      Source:Tetrahedron, Volume 73, Issue 52
      Author(s): Siwen Niu, Chun-Lan Xie, Tianhua Zhong, Wei Xu, Zhu-Hua Luo, Zongze Shao, Xian-Wen Yang
      Two structurally corrected sesquiterpenes (1 and 2) and nine new ones (3–11) were isolated from Graphostroma sp. MCCC 3A00421, a deep-sea-derived fungus obtained from hydrothermal sulfide deposits of the Atlantic Ocean. Their structures were elucidated mainly by extensive analyses of NMR and MS spectroscopic data, and their absolute configurations were determined by Cu-Kα single-crystal X-ray diffraction, the modified Mosher's method, as well as ECD spectra. Xylariterpenoid E (3) is the first example of trinor-bergamotane and graphostromabisabol B (11) is the first trinor-bisabolane found in nature. Interestingly, khusinol B (6) exhibited significant anti-inflammatory effect with IC50 value of 17 μM, which was stronger than that of the positive control, aminoguanidine, whose IC50 value was 23 μM. In addition, it also showed weak anti-allergic effect (IC50 = 150 μM).
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.013
       
  • Total synthesis of (+)-epiquinamide and (−)-epiepiquinamide from
           d-mannose
    • Authors: Withsakorn Sangsuwan; Boonsong Kongkathip; Pitak Chuawong; Ngampong Kongkathip
      Pages: 7274 - 7281
      Abstract: Publication date: 28 December 2017
      Source:Tetrahedron, Volume 73, Issue 52
      Author(s): Withsakorn Sangsuwan, Boonsong Kongkathip, Pitak Chuawong, Ngampong Kongkathip
      The total synthesis of (+)-epiquinamide and (−)-epiepiquinamide has been achieved starting from a 3,5-dihydroxyfuranoside synthon derived from d-mannose. The methods featured Bernet-Vasella reaction followed by Horner-Wadsworth-Emmons (HWE) reaction to provide a new chiral building block diene as the key steps. The bicyclic framework of this quinolizidine was constructed by using ring-closing metathesis, selective reduction of ester and intramolecular nucleophilic substitution-cyclization.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.016
       
  • Metal-free one-pot synthesis of benzofurans with ynones and quinones
           through aza-Michael/Michael/annulation sequence
    • Authors: Hai-Lei Cui; Hui-Qing Deng; Jin-Ju Lei
      Pages: 7282 - 7290
      Abstract: Publication date: 28 December 2017
      Source:Tetrahedron, Volume 73, Issue 52
      Author(s): Hai-Lei Cui, Hui-Qing Deng, Jin-Ju Lei
      A convenient metal-free one-pot synthesis of benzofuran derivatives starting from simple ynones has been developed. Various functionalized benzofurans closely related to bioactive molecules can be obtained in moderate to good yields (up to 90%) through aza-Michael/Michael/annulation sequence. Preparative scale synthesis of benzofurans has also been successfully achieved. The application of the benzofuran products has been shown by easy transformations to highly functionalized molecules holding significant promise for medicinal chemistry and organic material chemistry.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.014
       
  • A novel, three-component reaction to the synthesis of
           3-amino-4-cyano-5-aryl-1H-pyrrole-2-carboxamides
    • Authors: Bagher Mohammadi; Bahareh Rezaei Khorrami; Mahdi Ghorbani; Michal Dusek
      Pages: 7291 - 7294
      Abstract: Publication date: 28 December 2017
      Source:Tetrahedron, Volume 73, Issue 52
      Author(s): Bagher Mohammadi, Bahareh Rezaei Khorrami, Mahdi Ghorbani, Michal Dusek
      This work described a novel and efficient synthesis of 3-amino-4-cyano-5-phenyl-1H-pyrrole-2-carboxamides. The synthesis was carried out via a simple three-component reaction between arylidenmalononitrile, malononitrile and hydroxylamine hydrochloride in solvent-free conditions. Short reaction times, good to excellent yields of products, inexpensive and readily available starting material, and time and energy saving are the main advantages of this method. The structures of the products were confirmed by 1HNMR, 13CNMR, IR and single crystal X-ray analysis.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.022
       
  • Microwave-assisted synthesis of hydroxymethyl ketones using
           azolium-2-carboxylate zwitterions as catalyst precursors
    • Authors: Evanthia Papadaki; Lionel Delaude; Victoria Magrioti
      Pages: 7295 - 7300
      Abstract: Publication date: 28 December 2017
      Source:Tetrahedron, Volume 73, Issue 52
      Author(s): Evanthia Papadaki, Lionel Delaude, Victoria Magrioti
      Following an initial screening of six common imidazolium, imidazolinium, and dithiolium salts in the presence of a base, 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IDip) and 1,3-dimesitylimidazolin-2-ylidene (SIMes) were identified as promising organocatalysts for the microwave-assisted synthesis of hydroxymethyl ketones from aldehydes and paraformaldehyde. The azolium-2-carboxylate zwitterions IDip·CO2 and SIMes·CO2 were then tested as single-component N-heterocyclic carbene (NHC) precursors in the hydroxymethylation of heptanal and benzaldehyde. The latter adduct was an efficient precatalyst for the two reactions. It was successfully applied to a broad range of aliphatic and aromatic substrates (14 examples, 10–97% yields).
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.024
       
  • Efficient and selective palladium-catalyzed direct oxidative
           esterification of benzylic alcohols under aerobic conditions
    • Authors: Yongke Hu; Bindong Li
      Pages: 7301 - 7307
      Abstract: Publication date: 28 December 2017
      Source:Tetrahedron, Volume 73, Issue 52
      Author(s): Yongke Hu, Bindong Li
      A highly efficient palladium-catalyzed approach for the direct oxidative esterification of benzylic alcohols with methanol and long-chain aliphatic alcohols under mild conditions has been achieved. This practical catalyst system exhibits a broad substrate scope and good functional group tolerance. Catalytic amount of Bi(OTf)3 is used as co-catalyst to improve the activity and selectivity of the reactions. A variety of esters are obtained in yields of 43–96%.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.025
       
  • Synthesis of N-heterocyclic carbene-Pd(II) complexes and their catalytic
           activity in the Buchwald-Hartwig amination of aryl chlorides
    • Authors: Zhi-Mao Zhang; Yu-Jue Gao; Jian-Mei Lu
      Pages: 7308 - 7314
      Abstract: Publication date: 28 December 2017
      Source:Tetrahedron, Volume 73, Issue 52
      Author(s): Zhi-Mao Zhang, Yu-Jue Gao, Jian-Mei Lu
      Novel N-heterocyclic carbene-palladium(II) complexes using 2-picolinic acid as the ancillary ligand have been successfully developed under mild conditions. Their catalytic activity in organic synthesis has been initially tested in the Buchwald-Hartwig amination of secondary and primary amines with aryl chlorides. Various substituents on both substrates can be tolerated, giving the desired coupling products in good to almost quantitative yields. The minimum catalyst loading can be 0.01 mol%, implying their potential application toward industrial processes.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.026
       
  • Preparation and characterization of new ionic liquid forms of 2,4-DP
           herbicide
    • Authors: Michał Niemczak; Agnieszka Biedziak; Kamil Czerniak; Katarzyna Marcinkowska
      Pages: 7315 - 7325
      Abstract: Publication date: 28 December 2017
      Source:Tetrahedron, Volume 73, Issue 52
      Author(s): Michał Niemczak, Agnieszka Biedziak, Kamil Czerniak, Katarzyna Marcinkowska
      In this study, a series of new 2-(2,4-dichlorophenoxy)propionate-based herbicidal ionic liquids (HILs), incorporating well-known, commercially available tetraalkylammonium cations, were synthesized in high yield (≥89%) via a simple two-step procedure. Generally, at room temperature, the products comprising at least one long alkyl substituent in the cation were viscous liquids. All the synthesized salts maintained biological activity against the selected dicotyledonous weeds (common lambsquarters and cornflower). Among the tested salts, the HILs with dodecyltrimethylammonium, trimethyl(tetradecyl)ammonium and trimethyl(octadecyl)ammonium cations were characterized by the highest herbicidal efficacy against both plants. The spray solutions of the prepared HILs revealed their good surface-activation and wetting properties (contact angle = 43–63° and surface tension = 27–29 mN m−1), justifying an enhancement of the biological activity caused by the facilitated penetration of the active substance into the interior of the plant. The values of the octanol–water partition coefficient of the new salts indicate their low potential for bioaccumulation in the soil.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.032
       
  • Recent advances in catalytic C−H borylation reactions
    • Authors: Liang Xu; Guanghui Wang; Shuai Zhang; Hong Wang; Linghua Wang; Li Liu; Jiao Jiao; Pengfei Li
      Pages: 7123 - 7157
      Abstract: Publication date: 21 December 2017
      Source:Tetrahedron, Volume 73, Issue 51
      Author(s): Liang Xu, Guanghui Wang, Shuai Zhang, Hong Wang, Linghua Wang, Li Liu, Jiao Jiao, Pengfei Li
      In the past decades, the iridium-catalyzed C–H bond borylation and other newly discovered catalytic borylation reactions have received extensive research interests and developed into a practical approach for functionalization of C−H bonds and therefore an effective and versatile tool in synthesis of novel organic materials, natural products and fine chemicals. The advances of this booming field include significant improvements of the venerable iridium-catalyzed borylation and development of other transition-metal, especially the first-row transition-metal catalyzed borylation. More recently, a metal-free catalytic borylation system has been disclosed. These new methodologies has dramatically expanded the substate scope, increased the reaction efficiency, lowered the cost, and more importantly, provided previously unknown complementary chemical and regioselectivity. During these discoveries, novel catalyst design concepts and/or principles have been generated. In this context, this review aims to detail the recent evolution in the exciting research direction, focusing on the discovery and development of new reactivity, new selectivity.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.005
       
  • Novel xanthene push-pull chromophores and luminophores: Synthesis and
           study of their spectral properties
    • Authors: Oleg K. Farat; Svetlana A. Farat; Ivan V. Ananyev; Sergiy I. Okovytyy; Anatoliy L. Tatarets; Victor I. Markov
      Pages: 7159 - 7168
      Abstract: Publication date: 21 December 2017
      Source:Tetrahedron, Volume 73, Issue 51
      Author(s): Oleg K. Farat, Svetlana A. Farat, Ivan V. Ananyev, Sergiy I. Okovytyy, Anatoliy L. Tatarets, Victor I. Markov
      Spectral properties of five derivatives of 4-aminochromene containing formylated partially hydrogenated five or six-membered cycles, and two derivatives of 4-aminochromen-2-ylidene-malonaldehyde have been studied. The cyclic derivatives absorb light with the maxima around 430, nm and emit near 550 nm with a luminescence quantum yield of 0.056–0.135 in acetonitrile solution. The non-cyclized derivatives of 4-aminochromene with a malonaldehyde moiety possess emission in solid state in the red region with a moderate Stokes shift of 43 nm and 67 nm. Derivatives of 4-aminochromene containing formylated partially hydrogenated five or six-membered cycles were derivatized with active CH-acids to give seven Knoevenagel condensation products. Absorption spectra of these condensation products in acetonitrile solutions are red-shifted by 102–184 nm, while emission maxima are red-shifted by only 71–117 nm, as compared to the corresponding initial formyl derivatives. In addition, the condensation products have 1.5–1.9 times higher extinction coefficient (60,600–79,600 M−1cm−1), while fluorescence quantum yields decreased to (0.003–0.034).
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.10.027
       
  • Iron porphyrin-catalyzed C(SP3) -H activation for the formation of CO bond
           via cross-dehydrogenative coupling of cycloether and aromatic acid
    • Authors: Wei-Hong Wen; An-Na Xie; Hua-Hua Wang; Dong-Xu Zhang; Atif Ali; Xiao Ying; Hai-Yang Liu
      Pages: 7169 - 7176
      Abstract: Publication date: 21 December 2017
      Source:Tetrahedron, Volume 73, Issue 51
      Author(s): Wei-Hong Wen, An-Na Xie, Hua-Hua Wang, Dong-Xu Zhang, Atif Ali, Xiao Ying, Hai-Yang Liu
      An efficient cyclic ether benzoxylation was achieved by using iron porphyrin as the catalyst and di-tert-butyl peroxide oxidant. The benzoic acid substrates bearing electron donating or withdrawing groups could react with cyclic ether smoothly to afford the desired products. It was found iron porphyrin catalyzed oxidative C (sp3)-H activating esterification had the advantage of short reaction time and low catalyst loading. The reaction had been proved to proceed via a radical process.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.10.046
       
  • Synthesis and properties of microenvironment-sensitive oligonucleotides
           containing a small fluorophore, 3-aminobenzonitrile or 3-aminobenzoic acid
           
    • Authors: Hiroaki Ozaki; Takeshi Kawai; Masayasu Kuwahara
      Pages: 7177 - 7184
      Abstract: Publication date: 21 December 2017
      Source:Tetrahedron, Volume 73, Issue 51
      Author(s): Hiroaki Ozaki, Takeshi Kawai, Masayasu Kuwahara
      Two C-nucleosides bearing small fluorescent groups as a base were synthesized by Heck-type coupling reaction and incorporated into DNA. They exhibited environment-sensitive fluorescence and opposite solvatochromic properties. The modified DNAs containing 3-aminobenzonitrile or 3-aminobenzoic acid retained the duplexes and their fluorescence reflected the microenvironment.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.10.062
       
  • CH3CO2H-prompted three components tandem reaction: An efficient and
           practical approach to trisubstituted pyrrolo[1,2-a]pyrazines
    • Authors: Xianglong Chu; Zeyuan Zhang; Congcong Wang; Xuan Chen; Bin Wang; Chen Ma
      Pages: 7185 - 7189
      Abstract: Publication date: 21 December 2017
      Source:Tetrahedron, Volume 73, Issue 51
      Author(s): Xianglong Chu, Zeyuan Zhang, Congcong Wang, Xuan Chen, Bin Wang, Chen Ma
      An efficient protocol for the synthesis of trisubstitued pyrrolo[1,2-a]pyrazines through three components cyclization and one-pot cascade reaction is presented. Various trisubstitued pyrrolo[1,2-a]pyrazines are obtained by this metal-free process in moderate to good yields.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.10.066
       
  • Exploiting cooperative binding of ion-pair to boost anion recognition in
           water/acetonitrile mixtures
    • Authors: Dominika Załubiniak; Joanna Kos; Piotr Piątek
      Pages: 7190 - 7194
      Abstract: Publication date: 21 December 2017
      Source:Tetrahedron, Volume 73, Issue 51
      Author(s): Dominika Załubiniak, Joanna Kos, Piotr Piątek
      An L-arginine based compound was designed and prepared as a heteroditopic ion-pair receptor. The cation binding is provided by a sodium selective N-acyl-aza-18-crown-6 subunit whereas for anion complexation, urea and guanidinium groups were introduced. As shown by 1H NMR titrations this receptor is capable of binding sodium halide ion-pairs in solutions containing up to 20% of water. The halide binding is stronger in the presence of co-coordinated sodium cation than in the presence of non-coordinated TBA cation.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.10.077
       
  • Microbial oxidation of harzianone by Bacillus sp. IMM-006
    • Authors: Min Zhang; Jimei Liu; Ridao Chen; Jinlian Zhao; Kebo Xie; Dawei Chen; Keping Feng; Jungui Dai
      Pages: 7195 - 7199
      Abstract: Publication date: 21 December 2017
      Source:Tetrahedron, Volume 73, Issue 51
      Author(s): Min Zhang, Jimei Liu, Ridao Chen, Jinlian Zhao, Kebo Xie, Dawei Chen, Keping Feng, Jungui Dai
      Harzianols A−E (2–6) and harziane acid (7), six new oxidized derivatives of harzianone (1), were obtained from the microbial transformation by a bacterial strain Bacillus sp. IMM-006. The structures of these products, including the stereochemistry, were elucidated by extensive spectroscopic analysis. The absolute configuration of 2 was unambiguously determined by single-crystal X-ray diffraction. Moreover, a plausible bioconversion pathway was proposed.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.002
       
  • Facile TMSOI catalysed stereoselective synthesis of 2-Methylene
           selanyl-4-chromanols and anti-cancer activity
    • Authors: Debayan Sarkar; Sagarika Behera; Sarbani Ashe; Bismita Nayak; Saikat Kumar Seth
      Pages: 7200 - 7209
      Abstract: Publication date: 21 December 2017
      Source:Tetrahedron, Volume 73, Issue 51
      Author(s): Debayan Sarkar, Sagarika Behera, Sarbani Ashe, Bismita Nayak, Saikat Kumar Seth
      In the present study, a catalytic synthesis of 2-methylene selanyl-4-chromanols has been described. The manuscript highlights a facile Trimethylsulphoxonium iodide (TMSOI) catalysed intramolecular 6-exo-trig coupling reaction in metal-free environment. The reaction exhibits satisfactory yields in presence of multiple free -hydroxyl groups. A stereoselective generation of syn-3-hex-yne-1,5diols has been explored. The relative stereochemistry has been confirmed by single-crystal X-ray of crystalline-selanyl-chromanols. To determine the anticancer efficacy of the synthesized compounds, cell viability assay using MTT was performed against MCF-7 breast cancer cell line. Notably, Compound 9j (IC50 = 3.157 μmol) was found to exhibit potent cytotoxic activity. Compounds 9a and 9e also showed activity with IC50 values of 31.60 ± 4.012 and 36.797 ± 2.72 μmol respectively highlighting the potential of the synthesized compounds as novel lead molecules for future development of potent anti-cancer therapeutics.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.007
       
  • Efficient regioselective approach for polysubstituted benzene derivatives
           by intermolecular [2+2+2] cyclotrimerization of alkynes
    • Authors: Yao-I. Wang; Wei-Lun Hsu; Feng-Cheng Ho; Chia-Pei Li; Chaun-Fu Wang; Hsiu-Hui Chen
      Pages: 7210 - 7216
      Abstract: Publication date: 21 December 2017
      Source:Tetrahedron, Volume 73, Issue 51
      Author(s): Yao-I. Wang, Wei-Lun Hsu, Feng-Cheng Ho, Chia-Pei Li, Chaun-Fu Wang, Hsiu-Hui Chen
      We present an important opinion about the electron effect of the intermolecular cyclcotrimerization of unsymmetrical diaryalkynes in the presence of Co2(CO)8 on the production of corresponding 1,2,4-regioisomer or 1,3,5-regioisomer derivatives with excellent yields and high regioselectivity.
      Graphical abstract image

      PubDate: 2017-12-11T17:40:14Z
      DOI: 10.1016/j.tet.2017.11.012
       
 
 
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