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1. Correction: Spatially-varying inversion near grain boundaries in MgAl₂O₄ spinel

Author:
Uberuaga, Blas P.; Perriot, Romain
Source:
RSC advances 2020 v.10 no.42 pp. 25107
ISSN:
2046-2069
Subject:
chemical structure,   etc   ; minerals;     Show all 2 Subject
Abstract:
... Correction for ‘Spatially-varying inversion near grain boundaries in MgAl₂O₄ spinel’ by Blas P. Uberuaga et al., RSC Adv., 2020, 10, 11737–11742, DOI: 10.1039/D0RA00700E. ...
DOI:
10.1039/d0ra90071k

2. Omega, Sadhana, and PI Polynomials of Quasi-Hexagonal Benzenoid Chain

Author:
Idrees, Nazeran; Saif, Muhammad Jawwad; Nasir, Sumiya; Farooq, Fozia Bashir; Rauf, Asia; Ashfaq, Fareeha
Source:
Journal of Analytical Methods in Chemistry (Online) 2020 v.2020
ISSN:
2090-8873
Subject:
chemical structure,   etc   ; equations; graphs;     Show all 3 Subjects
Abstract:
... Counting polynomials are important graph invariants whose coefficients and exponents are related to different properties of chemical graphs. Three closely related polynomials, i.e., Omega, Sadhana, and PI polynomials, dependent upon the equidistant edges and nonequidistant edges of graphs, are studied for quasi-hexagonal benzenoid chains. Analytical closed expressions for these polynomials are der ...
DOI:
10.1155/2020/9057815
PubMed:
32309011
PubMed Central:
PMC7136778

3. Route to 1,2,4- and 1,2,5-oxadiazole ring assemblies via a one-pot condensation/oxidation protocol

Author:
Teslenko, Fedor E.; Churakov, Artem I.; Larin, Alexander A.; Ananyev, Ivan V.; Fershtat, Leonid L.; Makhova, Nina N.
Source:
Tetrahedron letters 2020 v.61 no.13 pp. 151678
ISSN:
0040-4039
Subject:
chemical structure,   etc   ; aldehydes; oxidation;     Show all 3 Subjects
Abstract:
... A novel one-pot approach for the synthesis of 1,2,4- and 1,2,5-oxadiazole ring assemblies has been developed. The synthetic strategy involves the condensation of furoxanyl amidoximes with aldehydes and subsequent iodine-mediated oxidation of the intermediate 1,2,4-oxadiazolines. The analogous reaction of 4-aminofuroxanyl-3-carboxamidoxime results not only in formation of the 1,2,4-oxadiazole subun ...
DOI:
10.1016/j.tetlet.2020.151678

4. Reticulating 1D Ribbons into 2D Covalent Organic Frameworks by Imine and Imide Linkages

Author:
Nguyen, Ha L.; Gropp, Cornelius; Yaghi, Omar M.
Source:
Journal of the American Chemical Society 2020 v.142 no.6 pp. 2771-2776
ISSN:
1520-5126
Subject:
chemical structure,   etc   ; amines; imines;     Show all 3 Subjects
Abstract:
... The design and synthesis of 2D and 3D crystalline covalent organic frameworks (COFs) from macromolecular and even infinite building units is largely undeveloped. Here, we report a strategy to link molecules and 1D ribbons into 2D cystalline frameworks. Triangular, tris(4-aminophenyl)amine (TAA), and square, 1,3,6,8-tetrakis(p-formylphenyl)pyrene (TFPPy), organic building units are joined substoich ...
DOI:
10.1021/jacs.9b13971

5. A convergent approach to sulfonimide-based dendrimers and dendrons

Author:
Bondareva, Julia; Kolotylo, Mykola; Rozhkov, Vladimir; Burilov, Vladimir; Lukin, Oleg
Source:
Tetrahedron letters 2020 v.61 no.25 pp. 152011
ISSN:
0040-4039
Subject:
chemical structure,   etc   ; dendrimers; regioselectivity; sulfonylation;     Show all 4 Subjects
Abstract:
... A study towards a convergent synthesis of sulfonimide-type dendrons and dendrimers was undertaken. Dendrons up to the third-generation bearing chlorosulfo-groups at their focal points were synthesized using both convergent and divergent routes. The convergent synthesis of dendrons reached its practical limit in the third-generation that makes the divergent route more practical. The synthetic utili ...
DOI:
10.1016/j.tetlet.2020.152011

6. Visible light promoted sulfonylation and sulfonylcarbonylation of alkenes

Author:
Min, Wenjian; Guo, Guozhe; Yang, Caixia; Huo, Congde
Source:
Tetrahedron letters 2020 v.61 no.25 pp. 152029
ISSN:
0040-4039
Subject:
chemical structure,   etc   ; alkenes; light; sulfonylation;     Show all 4 Subjects
Abstract:
... Visible light promoted sulfonylation and sulfonylcarbonylation reactions of readily available alkenes with TosMIC for the synthesis of valuable vinyl sulfones and β-keto sulfones were described. A reasonable radical involved mechanism is proposed. ...
DOI:
10.1016/j.tetlet.2020.152029

7. Synthesis of botryolide E, ophiocerins A, B and C from d-glucono-δ-lactone

Author:
Zhou, Faling; Liu, Xiaojing; Jia, Yuanliang; Hu, Yue; Luo, Guiyin; Chen, Xiaochuan
Source:
Tetrahedron letters 2020 v.61 no.23 pp. 151960
ISSN:
0040-4039
Subject:
chemical structure,   etc   ; chemical reactions; lactones;     Show all 3 Subjects
Abstract:
... A concise synthesis of a chiral hexane-tetraol intermediate is achieved from d-glucono-δ-lactone in 6 steps featuring the successively selective deoxygenation. The versatile intermediate can be easily converted into the γ-lactone compound botryolide E and tetrahydropyran derivative ophiocerins A-C respectively. In addition, the direct transformation of ophiocerin C to ophiocerins A and B by Mitsun ...
DOI:
10.1016/j.tetlet.2020.151960

8. A Sterically Congested Nitrogenated Benzodipentaphene with a Double π-Expanded Helicene Structure

Author:
Chen, Fengkun; Gu, Wenting; Saeki, Akinori; Melle-Franco, Manuel; Mateo-Alonso, Aurelio
Source:
Organic letters 2020 v.22 no.9 pp. 3706-3711
ISSN:
1523-7052
Subject:
chemical structure,   etc   ; chemical reactions; helicenes;     Show all 3 Subjects
Abstract:
... Herein, we describe a series of three sterically congested nitrogenated benzodipentaphenes, one of which shows a highly distorted aromatic backbone with an unprecedented double π-expanded helicene structure. ...
DOI:
10.1021/acs.orglett.0c01202

9. Radical cascade cyclization for synthesizing 3,4-fused tricyclic benzofuran derivatives

Author:
Nakajima, Masaya; Kondo, Yusuke; Nakano, Shun-ichi; Adachi, Yusuke; Choi, Dongil; Franzén, Robert; Nemoto, Tetsuhiro
Source:
Tetrahedron letters 2020 v.61 no.15 pp. 151754
ISSN:
0040-4039
Subject:
chemical structure,   etc   ; benzofurans; cyclization reactions;     Show all 3 Subjects
Abstract:
... A new method for synthesizing 3,4-fused tricyclic 3-alkylidene dihydrobenzofuran derivatives was developed. Treatment of propargyl iodophenol derivatives with a tethered alkene at the three contiguous positions under the radical cascade reaction conditions induced the reaction of the generated vinyl radical intermediates with the internal alkene, producing tricyclic 3-alkylidene dihydrobenzofurans ...
DOI:
10.1016/j.tetlet.2020.151754

10. Computation-Guided Development of the “Click” ortho-Quinone Methide Cycloaddition with Improved Kinetics

Author:
Zhang, Xiaoyun; Zhang, Shuo-Qing; Li, Qiang; Xiao, Fan; Yue, Zongwei; Hong, Xin; Lei, Xiaoguang
Source:
Organic letters 2020 v.22 no.8 pp. 2920-2924
ISSN:
1523-7052
Subject:
chemical structure,   etc   ; cycloaddition reactions; quinones;     Show all 3 Subjects
Abstract:
... We report here a deep mechanistic study of the “click” ortho-quinone methide (oQM) cycloaddition between ortho-quinolinone quinone methide (oQQM) and thio-vinyl ether (TV), named as TQ-ligation. DFT calculations revealed the unexpected fact that dehydration of oQQM precursors is the rate-determining step of this transformation, and two highly reactive oQQM precursors were predicted. Guided by the ...
DOI:
10.1021/acs.orglett.0c00578

11. Total Synthesis of (±)-Thebainone A by Intramolecular Nitrone Cycloaddition

Author:
Wang, Yuzhou; Hennig, André; Küttler, Thomas; Hahn, Christian; Jäger, Anne; Metz, Peter
Source:
Organic letters 2020 v.22 no.8 pp. 3145-3148
ISSN:
1523-7052
Subject:
chemical structure,   etc   ; cycloaddition reactions; morphine;     Show all 3 Subjects
Abstract:
... Using an intramolecular nitrone cycloaddition and a Heck cyclization as the crucial transformations, a total synthesis of the racemic morphine alkaloid thebainone A was accomplished in 22 steps commencing with isovanillin. ...
DOI:
10.1021/acs.orglett.0c00905

12. Dipleosporalones A and B, Dimeric Azaphilones from a Marine-Derived Pleosporales sp. Fungus

Author:
Cao, Fei; Meng, Zhi-Hui; Wang, Pu; Luo, Du-Qiang; Zhu, Hua-Jie
Source:
Journal of natural products 2020 v.83 no.4 pp. 1283-1287
ISSN:
1520-6025
Subject:
chemical structure,   etc   ; Pleosporales; cytotoxicity; fungi;     Show all 4 Subjects
Abstract:
... Dipleosporalones A and B (1 and 2), two new [2 + 2] azaphilone dimers, were obtained from a marine-derived Pleosporales sp. fungus. The absolute configurations of 1 and 2 were elucidated by calculations of their ECD spectra. Dipleosporalone A (1) possessed an unprecedented skeleton with an uncommon 6/4/6 ring system. Compounds 1 and 2 showed cytotoxicity about 30–90-fold more potent than that of t ...
DOI:
10.1021/acs.jnatprod.0c00132

13. Convergent Strategy for the Synthesis of Oxa-, Thia-, and Selena[5]helicenes by Acetylene-Activated SNAr Reactions

Author:
Hoenig, Samuel M.; Yan, Youmian; Dougherty, Emily A.; Hudson, Reuben; Petovic, Sava; Lee, Christopher K.; Hu, Yusheng; Gomez, Lucas S.; Katz, Jeffrey L.
Source:
Journal of organic chemistry 2020 v.85 no.6 pp. 4553-4559
ISSN:
1520-6904
Subject:
chemical structure,   etc   ; chemical reactions; helicenes;     Show all 3 Subjects
Abstract:
... A tandem acetylene-activated SNAr-anionic cyclization strategy is presented for the synthesis of chalcogen-containing hetero[5]helicenes. Oxa-, thia-, and selena[5]helicenes are accessed from common ortho-fluoro-ethynylarene precursors, allowing the heteroatoms to be installed at the 1-position or 1- and 12-positions of the hetero[5]helicene inner core surface. ...
DOI:
10.1021/acs.joc.0c00052

14. The selective condensation of pyrazolones to isatins in aqueous medium

Author:
Zhang, Yong; Nie, Long-Jun; Luo, Liang; Mao, Jia-Xin; Liu, Jin-Xiang; Xu, Guo-Hai; Chen, Deliang; Luo, Hai-Qing
Source:
Tetrahedron 2020 v.76 no.7 pp. 130916
ISSN:
0040-4020
Subject:
chemical structure,   etc   ; chemical reactions; pyrazolones;     Show all 3 Subjects
Abstract:
... The selective condensation of pyrazolones with isatins using water as the reaction medium is presented. This strategy provides an environmentally benign synthetic route to synthesize various potentially bioactive pyrazolone substituted oxindoles. ...
DOI:
10.1016/j.tet.2019.130916

15. Synthesis of γ-lactams via trifluoromethylative aminocarbonylation of unactivated olefins

Author:
Liu, Jige; Chen, Dong; Ji, Meishan; Wu, Xinxin; Zhu, Chen
Source:
Tetrahedron letters 2020 v.61 no.7 pp. 151479
ISSN:
0040-4039
Subject:
chemical structure,   etc   ; alkenes; chemical reactions;     Show all 3 Subjects
Abstract:
... An efficient approach for the synthesis of γ-lactams through radical-mediated trifluoromethylative aminocarbonylation of unactivated olefins is described. The transformation is initiated by the addition of an external CF₃ radical to alkene followed by interception with intramolecular cyanamide. This protocol provides a useful method to furnish the synthetically valuable CF₃-functionalized γ-lactam ...
DOI:
10.1016/j.tetlet.2019.151479

16. Aromaticity as a Guide to Planarity in Conjugated Molecules and Polymers

Author:
Wood, Brandon M.; Forse, Alexander C.; Persson, Kristin A.
Source:
Journal of physical chemistry 2020 v.124 no.10 pp. 5608-5612
ISSN:
1932-7455
Subject:
chemical structure,   etc   ; electronics; polymers; semiconductors;     Show all 4 Subjects
Abstract:
... Conjugated molecules and polymers have the ability to be transformative semiconducting materials; however, to reach their full potential a detailed understanding of the factors governing the molecular structure is crucial for establishing design principles for improved materials. Creating planar or “locking” structures is of particular interest for tuning electronic properties. While noncovalent l ...
DOI:
10.1021/acs.jpcc.0c01064

17. Methods for the Analysis of Polyphosphate in the Life Sciences

Author:
Christ, Jonas Johannes; Willbold, Sabine; Blank, Lars Mathias
Source:
Analytical chemistry 2020 v.92 no.6 pp. 4167-4176
ISSN:
1520-6882
Subject:
chemical structure,   etc   ; cations; orthophosphates; polymers;     Show all 4 Subjects
Abstract:
... Inorganic polyphosphate (polyP) is the polymer of orthophosphate and can be found in all living organisms. For polyP characterization, one or more of six parameters are of interest: the molecular structure (linear, cyclic, or branched), the concentration, the average chain length, the chain length distribution, the cellular localization, and the cation composition. Here, the merits, limitations, a ...
DOI:
10.1021/acs.analchem.9b05144

18. Construction of Cyclopropa[c]coumarins via cascade Michael-alkylation process of 3-cyanocoumarin with 2-bromomalonate

Author:
Sun, Jun-Chao; Li, Jun-Lin; Ji, Cong-Bin; Peng, Yi-Yuan; Zeng, Xing-Ping
Source:
Tetrahedron 2020 v.76 no.5 pp. 130852
ISSN:
0040-4020
Subject:
chemical structure,   etc   ; chemical reactions; coumarin;     Show all 3 Subjects
Abstract:
... A convenient and efficient method for the synthesis of highly functionalized cyclopropa[c]coumarin derivatives in good to excellent yields via cascade Michael-alkylation process of 3-substituted coumarins and 2-bromomalonate was developed. Preliminary results indicated that using a chiral PTC strategy, the desired cyclopropanation product could be obtained in up to 41% ee. ...
DOI:
10.1016/j.tet.2019.130852

19. High-Angular-Momentum Orbitals and Superatomic Characteristics of Boron-Nitrogen Cages

Author:
Xie, Weiyu; Wang, Jia; Wang, Jianpeng; Wu, Xiaochen; Wang, Zhigang; Zhang, Rui-Qin
Source:
Journal of physical chemistry 2020 v.124 no.6 pp. 3881-3885
ISSN:
1932-7455
Subject:
chemical structure,   etc   ; boron; electrons; nitrogen;     Show all 4 Subjects
Abstract:
... The functional structures at the nanoscale containing high-angular-momentum (HAM) electrons possess wide potential applications. However, HAM electrons generally exist in high-Z elements, while the related materials are difficult to obtain through either mining or synthesis. Therefore, it is significant to design new materials building blocks to mimic the electronic properties of high-Z elements. ...
DOI:
10.1021/acs.jpcc.9b11351

20. Precise Construction of SCF₂H or SeCF₂H Groups on Heteroarenes Generated in Situ from CF₃-Containing 1,3-Enynes

Author:
Jin, Shengnan; Kuang, Zhijie; Song, Qiuling
Source:
Organic letters 2020 v.22 no.2 pp. 615-619
ISSN:
1523-7052
Subject:
chemical structure,   etc   ; chemical reactions; thiophene;     Show all 3 Subjects
Abstract:
... A divergent strategy for precise construction of SCF₂H or SeCF₂H groups on heteroarenes generated in situ from CF₃-containing 1,3-enynes was developed. Reactions of readily available 1,3-enynes with S₈ and ClCF₂H provided 3-SCF₂H-4-CF₃-thiophenes via a cascade thiophene construction/selective C3 position thiolation/difluoromethylthiolation process, as did a series of 3-SeCF₂H-4-CF₃-selenophenes by ...
DOI:
10.1021/acs.orglett.9b04389