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You searched for: Publication year rev 7983-2017 Remove constraint Publication year rev: 7983-2017 Publication Year 2017 Remove constraint Publication Year: 2017 Subject chemical structure Remove constraint Subject: chemical structure
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1. (+)- and (−)-Ecarlottones, Uncommon Chalconoids from Fissistigma latifolium with Pro-Apoptotic Activity

Author:
Charlotte Gény; Alma Abou Samra; Pascal Retailleau; Bogdan I. Iorga; Hristo Nedev; Khalijah Awang; Fanny Roussi; Marc Litaudon; Vincent Dumontet
Source:
Journal of natural products 2017 v.80 no.12 pp. 3179-3185
ISSN:
1520-6025
Subject:
apoptosis; bark; chemical structure; nuclear magnetic resonance spectroscopy; spectral analysis
Abstract:
... Four new compounds, (+)- and (−)-ecarlottone (1), (±)-fislatifolione (5), (±)-isofislatifolione (6), and (±)-fislatifolic acid (7), and the known desmethoxyyangonin (2), didymocarpin-A (3), and dehydrodidymocarpin-A (4) were isolated from the stem bark of Fissistigma latifolium, by means of bioassay-guided purification using an in vitro affinity displacement assay based on the modulation of Bcl-xL ...
DOI:
10.1021/acs.jnatprod.7b00494

2. (+)-Thalianatriene and (−)-Retigeranin B Catalyzed by Sesterterpene Synthases from Arabidopsis thaliana

Author:
Shao Jie; Chen Qing-Wen; Lv Hua-Jun; He Juan; Liu Zhi-Feng; Lu Yan-Na; Liu Hai-Li; Wang Guo-Dong; Wang Yong
Source:
Organic letters 2017 v.19 no.7 pp. 1816-1819
ISSN:
1523-7052
Subject:
Arabidopsis thaliana; X-ray diffraction; biosynthesis; chemical structure; derivatization; genes; nuclear magnetic resonance spectroscopy; organic compounds
Abstract:
... Two GFPPS linked (+)-thalianatriene (1) and (−)-retigeranin B (2) sesterterpene synthase genes were identified from the genome of Arabidopsis thaliana. 1 possesses an unprecedented 11–6–5 tricyclic ring system, while 2 contains a characteristic 5–5–5–6–5 pentacyclic ring system. Their structures were determined by extensive NMR spectroscopy, chemical derivatization, and X-ray crystallography. The ...
DOI:
10.1021/acs.orglett.7b00586

3. (2+1)-Cycloaddition Reactions Give Further Evidence of the Nitrenium-like Character of 1-Aza-2-azoniaallene Salts

Author:
Al-Bataineh Nezar; Houk K. N.; Brewer Matthias; Hong Xin
Source:
Journal of organic chemistry 2017 v.82 no.7 pp. 4001-4005
ISSN:
1520-6904
Subject:
alkenes; chemical reactions; chemical structure; organic chemistry; salts
Abstract:
... Cationic 1-aza-2-azoniaallene salts react with structurally constrained alkenes in intramolecular reactions by C–H insertion at the allylic position, or by (2+1)-cycloaddition with the alkene followed by ring opening. The latter reaction gives further evidence of the nitrenium-like character of 1-aza-2-azoniaallene salts. DFT calculations show that alkene addition is intrinsically more favorable, ...
DOI:
10.1021/acs.joc.7b00407

4. (2S,4R)-Hyp-(S)-Phe-OMe dipeptide supported on imidazolium tagged molecules as recoverable organocatalysts for asymmetric aldol reactions using water as reaction medium

Author:
Arturo Obregón-Zúñiga; Eusebio Juaristi
Source:
Tetrahedron 2017 v.73 pp. 5373-5380
ISSN:
0040-4020
Subject:
catalysts; chemical elements; chemical reactions; chemical structure; organic compounds; solvents; stereochemistry
Abstract:
... Four novel chiral imidazolium tagged molecules derived from dipeptide (2S,4R)-Hyp-(S)-Phe-OMe were prepared and evaluated as organocatalysts in the asymmetric aldol reaction using water as solvent. It was found that catalysts incorporating the hexanoyl linker are active down to 5 mol% and afford aldol products with up to 94% yield, up to 98:2 dr and up to 97:3 er. This chiral imidazolium catalyst ...
DOI:
10.1016/j.tet.2017.07.037

5. (3 + 2)-Annulation of p-Quinamine and Aryne: A Strategy To Construct the Multisubstituted Hydrocarbazoles

Author:
Xu Dengyu; Zhao Yulong; Song Dengpeng; Zhong Zhuliang; Feng Shangbiao; Xie Xingang; Wang Xiaolei; She Xuegong
Source:
Organic letters 2017 v.19 no.13 pp. 3600-3603
ISSN:
1523-7052
Subject:
carbon; chemical reactions; chemical structure; organic compounds
Abstract:
... A strategy for the synthesis of multisubstituted hydrocarbazoles has been developed through (3 + 2)-annulation of p-quinamines and arynes. In this way, new analogs of hydrocarbazoles with quaternary carbon center can be synthesized in satisfactory yield under mild conditions. Furthermore, this (3 + 2)-annulation can be easily scaled-up, and the products can be modified through simple transformatio ...
DOI:
10.1021/acs.orglett.7b01578

6. (Diacetoxy)iodobenzene-Mediated Oxidative C–H Amination of Imidazopyridines at Ambient Temperature

Author:
Mondal Susmita; Samanta Sadhanendu; Jana Sourav; Hajra Alakananda
Source:
Journal of organic chemistry 2017 v.82 no.8 pp. 4504-4510
ISSN:
1520-6904
Subject:
ambient temperature; amination; chemical structure; indolizines; organic chemistry; regioselectivity
Abstract:
... (Diacetoxy)iodobenzene (PIDA)-mediated direct oxidative C–H amination for the synthesis of 3-amino substituted imidazopyridines has been achieved under metal-free conditions at room temperature in short reaction times. This methodology is also applicable for the regioselective amination of indolizines. Experimental results suggest that the reaction likely proceeds through a radical pathway. ...
DOI:
10.1021/acs.joc.7b00564

7. (Oligo-)Thiophene Functionalized Tetraazaperopyrenes: Donor–Acceptor Dyes and Ambipolar Organic Semiconductors

Author:
Hahn Lena; Hermannsdorfer André; Günther Benjamin; Wesp Tobias; Bühler Bastian; Zschieschang Ute; Wadepohl Hubert; Klauk Hagen; Gade Lutz H.
Source:
Journal of organic chemistry 2017 v.82 no.23 pp. 12492-12502
ISSN:
1520-6904
Subject:
X-ray diffraction; chemical reactions; chemical structure; dyes; electrochemistry; fluorescence emission spectroscopy; organic chemistry; terthiophenes; thiophene; transistors; ultraviolet-visible spectroscopy
Abstract:
... Tetraazaperopyrenes (TAPPs) have been functionalized with thiophene and terthiophene units of different architecture resulting in a variety of organic donor–acceptor (D–A) compounds. The influence of the connection of the thiophenes to the TAPP core on their structural, photophysical and electrochemical properties has been studied in detail by a combination of X-ray crystallography, UV–vis and flu ...
DOI:
10.1021/acs.joc.7b02286

8. (Propargylsulfanyl)-2-aza-1,3,5-trienes as a direct source for novel family of highly functionalized 4,5-dihydro-1,3-thiazoles

Author:
Nina A. Nedolya; Ol'ga A. Tarasova; Alexander I. Albanov; Lyudmila V. Klyba; Boris A. Trofimov
Source:
Tetrahedron 2017 pp. -
ISSN:
0040-4020
Subject:
chemical reactions; chemical structure; dimethyl sulfoxide; isothiocyanates
Abstract:
... A novel, simple approach to 2-(1-alkoxyprop-1-enyl)-5-ethenylidene-4,5-dihydro-1,3-thiazoles has been disclosed through the reaction of (propargylsulfanyl)-2-aza-1,3,5-trienes (readily available from alkoxyallenes, isothiocyanates, and propargyl bromide) with potassium or sodium tert-butoxide (1.1–1.4 equiv) under mild conditions [DMSO/THF (∼1:4–5), ca. −30 °C, 15–30 min]. The process proceeds thr ...
DOI:
10.1016/j.tet.2016.12.064

9. (Z)-Selective Hydrosilylation of Terminal Alkynes with HSiMe(OSiMe3)2 Catalyzed by a Ruthenium Complex Containing an N-Heterocyclic Carbene

Author:
Yuichiro Mutoh; Yusei Mohara; Shinichi Saito
Source:
Organic letters 2017 v.19 no.19 pp. 5204-5207
ISSN:
1523-7052
Subject:
alkynes; antineoplastic agents; bioactive compounds; carbenes; catalytic activity; chemical structure; derivatization; heterocyclic nitrogen compounds; ruthenium
Abstract:
... The N-heterocyclic-carbene-ligated ruthenium complex [RuHCl(CO)(H₂IMes)(PCy₃)] exhibits high catalytic activity for the (Z)-selective hydrosilylation of various terminal alkynes with 1,1,1,3,5,5,5-heptamethyltrisiloxane (HSiMe(OSiMe₃)₂). The stereoretentive derivatization of the (Z)-alkenylsiloxanes allows the synthesis of biologically active compounds, e.g. potent antitumor agents and inhibitors ...
DOI:
10.1021/acs.orglett.7b02477

10. A (salicylaldiminato)Pt(II) complex with dimethylpropylene linkage: Synthesis, structural characterization and antineoplastic activity

Author:
Mohammad Azam; Saud I. Al-Resayes; Saied M. Soliman; Agata Trzesowska-Kruszynska; Rafal Kruszynski; Zahid Khan
Source:
Journal of photochemistry and photobiology 2017 v.176 pp. 150-156
ISSN:
1011-1344
Subject:
ambient temperature; antineoplastic activity; cell proliferation; cell viability; chemical structure; colorectal neoplasms; dimethyl sulfoxide; ethanol; humans; ligands; monitoring; nuclear magnetic resonance spectroscopy; solvents
Abstract:
... A novel (salicylaldiminato)Pt(II) complex with two different molecular structures, one solventless ((salicylaldiminato)Pt(II)) 1 and another one solvated ((salicylaldiminato)Pt(II). C2H5OH), 1·C2H5OH, has been obtained by the reaction of a salen ligand with [PtCl2(DMSO)2] in ethanol at room temperature. The asymmetric unit of solventless 1 contains 9 such complex molecules whereas 1·C2H5OH contain ...
DOI:
10.1016/j.jphotobiol.2017.10.005

11. (±)-Rubioncolin D, a pair of enantiomeric naphthohydroquinone dimers from Rubia oncotricha

Author:
Si-Meng Zhao; Zhe Wang; Xiao-Qiang Chen; Mao-Bo Huang; Ning-Hua Tan
Source:
Tetrahedron letters 2017 pp. -
ISSN:
0040-4039
Subject:
Rubia; carbon; chemical reactions; chemical structure; chromatography; circular dichroism spectroscopy; cytotoxicity; neoplasms; organic compounds; spectral analysis; stereochemistry
Abstract:
... A pair of novel enantiomeric naphthohydroquinone dimers with an unprecedented spiro[4.5] carbon core, (±)-rubioncolin D (1), were isolated from Rubia oncotricha. The racemic mixture of 1 was separated by chiral column chromatography. Their structures and stereochemistry were elucidated by extensive spectroscopic analysis and electronic circular dichroism calculation. Both compounds (+)-1 and (-)-1 ...
DOI:
10.1016/j.tetlet.2017.06.063

12. (π-Allyl)palladium coupling of 2-(tributylstannyl)cyclopent-2-enone for the synthesis of jasmonoid analogs

Author:
Florencia Parpal; Enrique Pandolfi; Viviana Heguaburu
Source:
Tetrahedron letters 2017 v.58 pp. 1965-1968
ISSN:
0040-4039
Subject:
Lewis acids; chemical structure; geometry; isomerization; jasmonic acid; olefin; palladium; pest resistance; plant development
Abstract:
... The coupling of 2-(tributylstannyl)cyclopent-2-enone with several (π-allyl)palladium complexes derived from allylic electrophiles was investigated as the key step in the synthesis of jasmonoids. These compounds have an important role in plant development, triggering direct and indirect responses when harmed to induce pest resistance. Palladium-catalyzed coupling conditions to obtain a jasmonoid li ...
DOI:
10.1016/j.tetlet.2017.04.018

13. (−)-Pseudodistomin E: First Asymmetric Synthesis and Absolute Configuration Assignment

Author:
Davies Stephen G.; Fletcher Ai M.; Roberts Paul M.; Thomson James E.; Zimmer David
Source:
Organic letters 2017 v.19 no.7 pp. 1638-1641
ISSN:
1523-7052
Subject:
chemical reactions; chemical structure; iodides; lithium; nitrogen; organic compounds
Abstract:
... (−)-Pseudodistomin E has been prepared for the first time, allowing its structure and absolute configuration to be confirmed. The established conjugate addition of lithium (S)-N-allyl-N-(α-methyl-p-methoxybenzyl)amide to methyl (E,E)-hepta-2,5-dienoate generated the C(2)-stereocenter, and iodolactonisation of a derivative generated the remaining two stereogenic centers. Ensuing iodide displacement ...
DOI:
10.1021/acs.orglett.7b00434

14. 1,3-Dipolar Cycloaddition Reactions of Low-Valent Rhodium and Iridium Complexes with Arylnitrile N-Oxides

Author:
Ugur Ilke; Agopcan Cinar Sesil; Dedeoglu Burcu; Aviyente Viktorya; Hawthorne M. Frederick; Liu Peng; Liu Fang; Houk K. N.; Jiménez-Osés Gonzalo
Source:
Journal of organic chemistry 2017 v.82 no.10 pp. 5096-5101
ISSN:
1520-6904
Subject:
chemical structure; cycloaddition reactions; energy; iridium; ligands; methodology; organic chemistry; organic compounds; oxidation; oxides; rhodium
Abstract:
... The reactions between low-valent Rh(I) and Ir(I) metal–carbonyl complexes and arylnitrile oxides possess the electronic and structural features of 1,3-dipolar cycloadditions. Density functional theory (DFT) calculations on these reactions, involving both cyclopentadienyl and carboranyl ligands on the metal carbonyl, explain the ease of the chemical processes and the stabilities of the resulting me ...
DOI:
10.1021/acs.joc.7b00282
PubMed:
28414468
PubMed Central:
PMC5679111

15. 1,3-Dipolar Cycloaddition of Nitrile Imine with Carbon Dioxide: Access to 1,3,4-Oxadiazole-2(3H)-ones

Author:
Guo Chun-Xiao; Zhang Wen-Zhen; Zhang Ning; Lu Xiao-Bing
Source:
Journal of organic chemistry 2017 v.82 no.14 pp. 7637-7642
ISSN:
1520-6904
Subject:
carbon dioxide; chemical reactions; chemical structure; imines; organic chemistry; oxadiazon
Abstract:
... Efficient synthesis of 1,3,4-oxadiazole-2(3H)-one was achieved by CsF/18-crown-6 mediated 1,3-dipolar cycloaddition of nitrile imine and 2.0 MPa of CO₂. CsF/18-crown-6 played a key role in enhancing the reactivity of CO₂ as a 1,3-dipolarophile. The practical utility of this transition-metal-free approach to 1,3,4-oxadiazole-2(3H)-one is highlighted by the convenient synthesis of a commercial herbi ...
DOI:
10.1021/acs.joc.7b00963

16. 1,3-Dipolar cycloaddition of uracil derivatives with nitrile oxides: Synthesis of [1,2,4]oxadiazolo[4,5-c]pyrimidine-5,7(6H)-dione derivatives

Author:
Kun-Ming Jiang; Yi Jin; Jun Lin
Source:
Tetrahedron 2017 pp. -
ISSN:
0040-4020
Subject:
bioactive properties; chemical reactions; chemical structure; oxides; uracil; uracil derivatives
Abstract:
... An efficient method of synthesizing bicyclic fused [1,2,4]oxadiazolo[4,5-c]pyrimidine-5,7(6H)-dione derivatives was developed through a [3 + 2] cycloaddition of uracil derivatives and nitrile oxides. In the one step reaction, CN and CO bonds were constructed, the target compounds were efficiently obtained in good yields. The method represents a valuable way to obtain highly functional fused bicycl ...
DOI:
10.1016/j.tet.2017.10.024

17. 1,4-Dicarbofunctionalization of 4-Fluoroaryl Grignard and Lithium Reagents with Disubstituted Malononitriles

Author:
Malapit Christian A.; Luvaga Irungu K.; Reeves Jonathan T.; Volchkov Ivan; Busacca Carl A.; Howell Amy R.; Senanayake Chris H.
Source:
Journal of organic chemistry 2017 v.82 no.9 pp. 4993-4997
ISSN:
1520-6904
Subject:
Grignard reagents; aromatic hydrocarbons; bromine; chemical reactions; chemical structure; lithium; magnesium; organic chemistry
Abstract:
... An efficient one-pot 1,4-dicarbofunctionalization of 4-fluoroaryl Grignard or lithium reagents with 2,2-disubstituted malononitriles is described. The reaction proceeds by sequential transnitrilation and SNAr reactions. Commercial Grignard solutions, Grignard reagents prepared in situ by halogen/magnesium exchange with i-PrMgCl, or aryllithium reagents prepared in situ by bromine/lithium exchange ...
DOI:
10.1021/acs.joc.7b00567

18. 1-Butyl-3-methylimidazol-2-ylidene Borane: A Readily Available, Liquid N-Heterocyclic Carbene Borane Reagent

Author:
Bolt Daniel A.; Curran Dennis P.
Source:
Journal of organic chemistry 2017 v.82 no.24 pp. 13746-13750
ISSN:
1520-6904
Subject:
bromides; carbenes; chemical reactions; chemical structure; heterocyclic nitrogen compounds; liquids; organic chemistry; sodium
Abstract:
... 1-Butyl-3-methylimidazol-2-ylidene borane has been synthesized directly from two inexpensive commercial reagents: 1-butyl-3-methylimidazolium bromide and sodium borohydride. This NHC-borane reagent is a stable, free-flowing liquid that shows promise for use in radical, ionic, and metal-catalyzed reactions. ...
DOI:
10.1021/acs.joc.7b02730

19. 1-Naphthylmethyl and 1-naphthylmethoxymethyl protecting groups: New members of the benzyl- and benzyloxymethyl-type family

Author:
Takuya Sato; Yohei Joh; Tohru Oishi; Kohei Torikai
Source:
Tetrahedron letters 2017 pp. -
ISSN:
0040-4039
Subject:
Lewis bases; acids; ambient temperature; ceric ammonium nitrate; chemical structure; organic compounds; oxidation
Abstract:
... 1-Naphthylmethyl (NAPI) and 1-naphthylmethoxymethyl (NAPOMI) protecting groups were developed as new members of the benzyl- and benzyloxymethyl-type family. NAPI and NAPOMI can be introduced under conventional conditions, such as NAPIBr/NaH/room temperature (rt), or NAPOMICl/i-Pr2EtN/rt. They can also be removed under conventional conditions, e.g., by dichlorodicyanobenzoquinone (DDQ)- or ceric am ...
DOI:
10.1016/j.tetlet.2017.04.046

20. 1-Trifluoromethylisoquinolines from α-Benzylated Tosylmethyl Isocyanide Derivatives in a Modular Approach

Author:
Lin Wang; Armido Studer
Source:
Organic letters 2017 v.19 no.20 pp. 5701-5704
ISSN:
1523-7052
Subject:
catalysts; catalytic activity; chemical reactions; chemical structure; organic compounds
Abstract:
... The preparation of various 1-trifluoromethylisoquinolines from α-benzylated tosylmethyl isocyanide derivatives and the commercial Togni reagent using a radical cascade is reported. The starting isocyanides are readily prepared in a modular sequence from commercial tosylmethyl isocyanide via sequential double α-alkylation, and the radical reaction proceeds under mild conditions with high efficiency ...
DOI:
10.1021/acs.orglett.7b02882

21. A 1-hydroxy-2,3,1-benzodiazaborine-containing π-conjugated system: Synthesis, optical properties and solvent-dependent response toward anions

Author:
Yusuke Satta; Ryuhei Nishiyabu; Tony D. James; Yuji Kubo
Source:
Tetrahedron 2017 pp. -
ISSN:
0040-4020
Subject:
anions; boron; chemical reactions; chemical structure; colorimetry; dimethyl sulfoxide; fluorescence; hydrogen bonding; nuclear magnetic resonance spectroscopy; optical properties; solvents; spectral analysis
Abstract:
... Our interest in the functionalization of OH-substituted azaborines prompted us to synthesize a 1-hydroxy-2,3,1-benzodiazaborine conjugated with 1,8-naphthalimide 1. Its fluorescence was dramatically affected by the nature of the solvent. In particular, the use of DMSO, which has a relatively high donor number (DN = 29.8), led to a remarkable decrease in the fluorescence intensity (ΦF = 0.0014), po ...
DOI:
10.1016/j.tet.2017.02.050

22. 13C NMR spectroscopic studies of the behaviors of carbonyl compounds in various solutions

Author:
Yoshikazu Hiraga; Saori Chaki; Satomi Niwayama
Source:
Tetrahedron letters 2017 pp. -
ISSN:
0040-4039
Subject:
carbonyl compounds; chemical reactions; chemical structure; hydrogen bonding; nuclear magnetic resonance spectroscopy; solvents; spectral analysis
Abstract:
... 13C NMR spectroscopic studies were performed for carbonyl compounds having a hydroxyl group, a carboalkoxy group, an acetoxy group, or a carboxyl group in various solvents with different polarities for observation of their behaviors of 13C NMR chemical shifts of carbonyl carbons in solutions. It was found that the chemical shifts of the carbonyl carbons in 13C NMR have good correlation with the em ...
DOI:
10.1016/j.tetlet.2017.10.071

23. 13C-Labeled Idohexopyranosyl Rings: Effects of Methyl Glycosidation and C6 Oxidation on Ring Conformational Equilibria

Author:
Bose-Basu Bidisha; Zhang Wenhui; Kennedy Jamie L. W.; Hadad Matthew J.; Carmichael Ian; Serianni Anthony S.
Source:
Journal of organic chemistry 2017 v.82 no.3 pp. 1356-1370
ISSN:
1520-6904
Subject:
aqueous solutions; chemical structure; conformational isomerization; methodology; molecular dynamics; organic chemistry; organic compounds; oxidation; pH
Abstract:
... An ensemble of JHH, JCH, and JCC values was measured in aqueous solutions of methyl α- and β-d-idohexopyranosides containing selective ¹³C-enrichment at various carbons. By comparing these J-couplings to those reported previously in the α- and β-d-idohexopyranoses, methyl glycosidation was found to affect ring conformational equilibria, with the percentages of ⁴C₁ forms based on ³JHH analysis as f ...
DOI:
10.1021/acs.joc.6b02399

24. 1H NMR-based kinetic and theoretical studies of the simultaneous formation of two discrete rotameric systems of a novel difenchyl sulfite ester

Author:
Alicia Singh; Perry T. Kaye; Kevin A. Lobb
Source:
Tetrahedron 2017 pp. -
ISSN:
0040-4020
Subject:
chemical reactions; chemical structure; models; nuclear magnetic resonance spectroscopy; organic compounds; quantum mechanics; spectral analysis; sulfites
Abstract:
... Attempted repetition of a reported synthesis of fenchene from fenchol has afforded, in high overall yield, a mixture shown by spectroscopic and elemental analysis to comprise a pair of discrete rotameric systems of a novel 2-endo-2′-endo-difenchyl sulfite ester. The kinetics of the formation of these dimeric rotameric systems (I and II) has been explored experimentally, using 1H NMR spectroscopic ...
DOI:
10.1016/j.tet.2017.10.059

25. 2-(Trimethylsilyl)phenyl Trimethylsilyl Ethers as Stable and Readily Accessible Benzyne Precursors

Author:
Ikawa Takashi; Masuda Shigeaki; Nakajima Hiroki; Akai Shuji
Source:
Journal of organic chemistry 2017 v.82 no.8 pp. 4242-4253
ISSN:
1520-6904
Subject:
chemical reactions; chemical structure; ethers; fluorides; organic chemistry; phenols; tetrabutylammonium compounds
Abstract:
... Stable 2-(trimethylsilyl)phenyl trimethylsilyl ethers, readily obtained from the corresponding halogenated phenols in two steps, were identified as novel benzyne precursors. These species were converted to benzynes by a domino reaction of O-desilylation, O-nonaflylation, and β-elimination under mild conditions using nonafluorobutanesulfonyl fluoride (NfF) and tetrabutylammonium triphenyldifluorosi ...
DOI:
10.1021/acs.joc.7b00238

26. 2-Hydroxyindoline-3-triethylammonium Bromide: A Reagent for Formal C3-Electrophilic Reactions of Indoles

Author:
Abe Takumi; Suzuki Takuro; Anada Masahiro; Matsunaga Shigeki; Yamada Koji
Source:
Organic letters 2017 v.19 no.16 pp. 4275-4278
ISSN:
1523-7052
Subject:
Lewis bases; bromides; chemical reactions; chemical structure; indoles; oxygen
Abstract:
... A novel indole-2,3-epoxide equivalent, 2-hydroxyindoline-3-triethylammonium bromide, was found to be a convenient reagent for formal C3-electrophilic reactions of indoles with various nucleophiles. By taking advantage of the nucleophilic character of the oxygen of the 2-hydroxyindoline, the interrupted retro-Claisen and interrupted Feist–Bénary reactions with 1,3-dicarbonyl compounds were efficie ...
DOI:
10.1021/acs.orglett.7b01940

27. 2D hetero-structures based on transition metal dichalcogenides: Fabrication, properties and applications

Author:
Ping Liu; Bin Xiang
Source:
Science bulletin 2017 pp. -
ISSN:
2095-9273
Subject:
chemical structure; physical properties; synthesis; van der Waals forces
Abstract:
... Recently, two dimensional transition metal dichalcogenides MX2 (M=Mo, W, etc; X=S, Se, Te) have ignited immense interests because of their unique structural and physical properties for the potential applications in the nano-optoelectronics, valley-spintronics etc. In terms of the structural compatibility and van der Waals interaction, two dimensional (2D) MX2 layers can be fabricated into various ...
DOI:
10.1016/j.scib.2017.08.007

28. 2D-IR Spectroscopy Shows that Optimized DNA Minor Groove Binding of Hoechst33258 Follows an Induced Fit Model

Author:
Ramakers Lennart A. I.; Hithell Gordon; May John J.; Greetham Gregory M.; Donaldson Paul M.; Towrie Michael; Parker Anthony W.; Burley Glenn A.; Hunt Neil T.
Source:
Journal of physical chemistry 2017 v.121 no.6 pp. 1295-1303
ISSN:
1520-5207
Subject:
DNA; chemical structure; hydrogen bonding; infrared spectroscopy; ligands; models
Abstract:
... The induced fit binding model describes a conformational change occurring when a small molecule binds to its biomacromolecular target. The result is enhanced noncovalent interactions between the ligand and biomolecule. Induced fit is well-established for small molecule–protein interactions, but its relevance to small molecule–DNA binding is less clear. We investigate the molecular determinants of ...
DOI:
10.1021/acs.jpcb.7b00345

29. 2H-Pyran-2-ones and their annelated analogs as multifaceted building blocks for the fabrication of diverse heterocycles

Author:
Ramendra Pratap; Vishnu Ji Ram
Source:
Tetrahedron 2017 v.73 pp. 2529-2590
ISSN:
0040-4020
Subject:
Lewis bases; bioactive properties; carbon; chemical reactions; chemical structure; dibenzofuran; isocoumarins; isoquinolines; nitrogen; oxazoles; oxygen; pyridines; pyrroles; quinolines; sulfur; thiazoles
Abstract:
... 2H-Pyran-2-ones are widely present in nature and found as either isolated or in fused form. Depending on the fusion of benzene ring, pyran can give coumarins, isocoumarins, dibenzopyrans etc. This class of molecules exhibit excellent biological activity and photophysical properties. Apart from these, 2H-pyran-2-one also acts as very good Michael acceptor, therefore act as very important synthetic ...
DOI:
10.1016/j.tet.2017.02.028

30. 3,14-Bis(4-formylphenyl)-17,17-di(n-pentyl)tetrabenzo[a,c,g,i]fluorene showing solvatochromism and crystallochromism in fluorescence

Author:
Masanori Ueki; Yusuke Kimura; Yuma Yamamoto; Jun-ich Nishida; Chitoshi Kitamura; Mirai Tanaka; Hiroshi Ikeda; Takeshi Kawase
Source:
Tetrahedron 2017 pp. -
ISSN:
0040-4020
Subject:
chemical reactions; chemical structure; fluorenes; fluorescence; methylene chloride; optical properties; prediction
Abstract:
... The substituent effect on optical properties of 3,14-diphenyl-17,17-di(n-pentyl)tetrabenzofluorene derivatives bearing electron-withdrawing groups (NC, CH3OCO, CH3SO2, and OHC) at 4-position of the phenyl groups were investigated. These compounds were readily prepared by using Suzuki–Miyaura cross-coupling as a key step. The 4-cyano, 4-methoxycarbonyl, and 4-methylsulfonyl derivatives display inte ...
DOI:
10.1016/j.tet.2017.01.014

31. 3,4,5-Trimethylphenol and Lewis Acid Dual-Catalyzed Cascade Ring-Opening/Cyclization: Direct Synthesis of Naphthalenes

Author:
Ma He; Hu Xiu-Qin; Luo Yong-Chun; Xu Peng-Fei
Source:
Organic letters 2017 v.19 no.24 pp. 6666-6669
ISSN:
1523-7052
Subject:
Lewis acids; catalysts; chemical bonding; chemical reactions; chemical structure; cleavage (chemistry); naphthalenes
Abstract:
... A 3,4,5-trimethylphenol and Lewis acid dual-catalyzed cascade reaction of donor–acceptor (D–A) cyclopropanes via ring-opening and cyclization is developed. In this reaction, a phenolic compound was used as a covalent catalyst for the first time. Additionally, control experiments proved that 3,4,5-trimethylphenol completed the catalytic cycle by accomplishing the C–C bond cleavage. Using this strat ...
DOI:
10.1021/acs.orglett.7b03392

32. 3,4-Dihydroisocoumarin derivatives from the marine-derived fungus Paraconiothyrium sporulosum YK-03

Author:
Li-Hua Zhang; Sheng-Ge Li; Hong-Hua Wu; Gang Chen; Li Li; Jiao Bai; Hui-Ming Hua; Hai-Feng Wang; Yue-Hu Pei
Source:
Phytochemistry letters 2017 v.20 pp. 200-203
ISSN:
1874-3900
Subject:
anticarcinogenic activity; chemical structure; circular dichroism spectroscopy; cytotoxicity; fungi; high performance liquid chromatography; humans; neoplasms
Abstract:
... Two new 3,4-dihydroisocoumarin derivatives, (3S, 4S)-4,5-dihydroxymellein (1) and R-(−)-mellein-8-O-β-d-glucopyranoside (2), together with six known analogs (3–8) were isolated from the marine-derived fungus Paraconiothyrium sporulosum YK-03. Their structures including absolute configurations were elucidated by extensive spectroscopic methods in combination with computational electronic circular d ...
DOI:
10.1016/j.phytol.2017.04.039

33. 3-(2-Azidoethyl)oxindoles: Advanced Building Blocks for One-Pot Assembly of Spiro[pyrrolidine-3,3′-oxindoles]

Author:
Akaev Andrey A.; Villemson Elena V.; Vorobyeva Nataliya S.; Majouga Alexander G.; Budynina Ekaterina M.; Melnikov Mikhail Ya
Source:
Journal of organic chemistry 2017 v.82 no.11 pp. 5689-5701
ISSN:
1520-6904
Subject:
Lewis bases; azides; chemical reactions; chemical structure; cytotoxicity; in vitro studies; neoplasm cells; organic chemistry
Abstract:
... A new synthetic approach to biologically relevant spiro[pyrrolidine-3,3′-oxindoles] was developed on the basis of the cascade transformation of 3-(2-azidoethyl)oxindoles via Staudinger/aza-Wittig/Mannich reactions. The parent azides were readily synthesized through a nucleophilic ring opening of spiro[cyclopropane-1,3′-oxindoles] with the azide ion. A series of new spiro[pyrrolidine-3,3′-oxindoles ...
DOI:
10.1021/acs.joc.7b00529

34. 3-Acylindoles Synthesis: Ruthenium-Catalyzed Carbonylative Coupling of Indoles and Aryl Iodides

Author:
Wang Zechao; Yin Zhiping; Wu Xiao-Feng
Source:
Organic letters 2017 v.19 no.17 pp. 4680-4683
ISSN:
1523-7052
Subject:
carbon-hydrogen bond activation; chemical reactions; chemical structure; indoles; ketones; molybdenum; organoiodine compounds
Abstract:
... A novel and convenient procedure for the synthesis of 3-acylindoles from simple indoles and aryl iodides has been established. Through ruthenium-catalyzed carbonylative C–H functionalization of indoles, with Mo(CO)₆ as the solid CO source, the desired indol-3-yl aryl ketones were isolated in moderate to good yields. Not only N-alkylindoles but also N-H indoles can be applied here. ...
DOI:
10.1021/acs.orglett.7b02320

35. 3-Hydroxy-2-(trialkylsilyl)phenyl Triflate: A Benzyne Precursor Triggered via 1,3-C-sp2-to-O Silyl Migration

Author:
Kwon Yong-Ju; Jeon Young-Kyo; Sim Ha-Bin; Oh In-Young; Shin Inji; Kim Won-Suk
Source:
Organic letters 2017 v.19 no.22 pp. 6224-6227
ISSN:
1523-7052
Subject:
chemical reactions; chemical structure; phenol; regioselectivity
Abstract:
... 3-Hydroxy-2-(trialkylsilyl)phenyl triflates are presented as new versatile hydroxyaryne precursors. These are base-activated aryne precursors induced via a C-sp²-to-O 1,3-Brook rearrangement. The reaction of various arynophiles and 3-trialkylsiloxybenzyne generated from 3-hydroxy-2-(trialkylsilyl)phenyl triflate efficiently afforded highly regioselective phenol derivatives. Furthermore, through cr ...
DOI:
10.1021/acs.orglett.7b03160

36. 3-Methyl-4-nitro-5-isatylidenyl-isoxazoles as 1,3-dipolarophiles for synthesis of polycyclic 3,3′-pyrrolidinyl-dispirooxindoles and their biological evaluation for anticancer activities

Author:
Bing Lin; Wen-Hui Zhang; Dan-Dan Wang; Yi Gong; Qi-Di Wei; Xiong-Li Liu; Ting-Ting Feng; Ying Zhou; Wei-Cheng Yuan
Source:
Tetrahedron 2017 pp. -
ISSN:
0040-4020
Subject:
antineoplastic activity; chemical elements; chemical reactions; chemical structure; organic compounds; proline
Abstract:
... Developed herein is a diversity-oriented one-pot multicomponent synthesis of polycyclic 3,3′- pyrrolidinyl-dispirooxindoles 3via a multicomponent 1,3-dipolar cycloaddition event of 3-methyl-4-nitro-5-isatylidenyl-isoxazoles 2 with azomethine ylides (thermally generated in situ from isatins and proline or thioproline). Products bearing four consecutive stereocenters consist of two oxindole moieties ...
DOI:
10.1016/j.tet.2017.07.011

37. 3-Methylene-4-amido-1,2-diazetidine as a Formal 1,4-Dipole Precursor: Lewis Acid-Catalyzed Nucleophilic Addition with Silylated Nucleophiles

Author:
Okitsu Takashi; Kobayashi Keiko; Kan Ryosuke; Yoshida Yuji; Matsui Yuki; Wada Akimori
Source:
Organic letters 2017 v.19 no.17 pp. 4592-4595
ISSN:
1523-7052
Subject:
Lewis bases; chemical structure; cycloaddition reactions; silyl enol ethers
Abstract:
... 3-Methylene-4-amido-1,2-diazetidine (MADA) was prepared for the first time via formal [2 + 2] cycloaddition of an allenamide and an azodicarboxylate. MADA worked as a formal 1,4-dipole precursor toward nucleophilic addition with various silyl enol ethers and allyltrimethylsilanes. ...
DOI:
10.1021/acs.orglett.7b02194

38. 3D Printing Polymers with Supramolecular Functionality for Biological Applications

Author:
Pekkanen Allison M.; Mondschein Ryan J.; Williams Christopher B.; Long Timothy E.
Source:
Biomacromolecules 2017 v.18 no.9 pp. 2669-2687
ISSN:
1526-4602
Subject:
adhesion; chemical structure; drugs; hydrogen bonding; manufacturing; mechanical properties; medical equipment; polymers; tissue scaffolds; viscoelasticity
Abstract:
... Supramolecular chemistry continues to experience widespread growth, as fine-tuned chemical structures lead to well-defined bulk materials. Previous literature described the roles of hydrogen bonding, ionic aggregation, guest/host interactions, and π–π stacking to tune mechanical, viscoelastic, and processing performance. The versatility of reversible interactions enables the more facile manufactur ...
DOI:
10.1021/acs.biomac.7b00671

39. 4-(Azulen-1-yl) six-membered heteroaromatics substituted in 2- and 6- positions with 2-(2-furyl)vinyl, 2-(2-thienyl)vinyl or 2-(3-thienyl)vinyl moieties

Author:
Liviu Birzan; Mihaela Cristea; Constantin C. Draghici; Victorita Tecuceanu; Anamaria Hanganu; Eleonora-Mihaela Ungureanu; Alexandru C. Razus
Source:
Tetrahedron 2017 pp. -
ISSN:
0040-4020
Subject:
ammonium acetate; chemical reactions; chemical structure; metal ions; perchlorates; pyridines; redox potential
Abstract:
... The synthesis of pyrylium and pyridinium salts and pyridines with azulene-1-yl moieties in position 4 and two 2-heteroarylvinyl groups in positions 2 and 6 was accomplished. The pyrylium salts were obtained starting from pyranones and pyridines could be prepared from these salts by treating them with ammonium acetate. The general procedures for the synthesis of pyridinium salts, which occur with g ...
DOI:
10.1016/j.tet.2017.03.035

40. 4-Aminoantipyrine in carbohydrate research: Design, synthesis and anticancer activity of thioglycosides of a novel class of 4-aminoantipyrines and their corresponding pyrazolopyrimidine and pyrazolopyridine thioglycosides

Author:
Galal H. Elgemeie; Mamdouh A. Abu-Zaied; Samah A. Loutfy
Source:
Tetrahedron 2017 pp. -
ISSN:
0040-4020
Subject:
antineoplastic activity; antipyrine; breasts; chemical reactions; chemical structure; colon; colorectal neoplasms; cytotoxicity; humans; liver; liver neoplasms; neoplasm cells; nuclear magnetic resonance spectroscopy; sodium; spectral analysis
Abstract:
... A convenient method for the synthesis of antipyrine, pyrazolopyrimidine and pyrazolopyridine thioglycosides was developed. This study reports a novel and efficient method for the synthesis of thioglycosides of a novel class of 4-aminoantipyrines 6a,b; 13a,b and their corresponding pyrazolopyrimidine thioglycosides 7a,b; 9a,b and pyrazolopyridine thioglycosides 14a,b; 16a,b. These series of compoun ...
DOI:
10.1016/j.tet.2017.08.024

41. 4-Diazoisochroman-3-imines: A Class of Metal Carbene Precursors for the Synthesis of Isochromene Derivatives

Author:
Ren Anni; Lang Bo; Lin Jialun; Lu Ping; Wang Yanguang
Source:
Journal of organic chemistry 2017 v.82 no.20 pp. 10953-10959
ISSN:
1520-6904
Subject:
alkenes; alkynes; carbenes; catalytic activity; chemical reactions; chemical structure; imidoesters; organic chemistry; pyrroles
Abstract:
... 4-Diazoisochroman-3-imines were investigated for their synthetic applications as a new class of metal carbene precursors. Under the catalysis from a Rh(II) complex, this class of α-diazo imidates reacted with alkenes and conjugated dienes through a formal [2 + 1] (i.e., cyclopropanation) or [4 + 3] cycloaddition to furnish spiro[cyclopropane-1,4′-isochroman]-3′-imines and tetrahydroisochromeno[3,4 ...
DOI:
10.1021/acs.joc.7b01860

42. 4-Trichloroacetyl-1,2,3-triazoles: A versatile building block for rapid assessment of carbohydrazides and rufinamide derivatives

Author:
Helio G. Bonacorso; Francieli M. Libero; Fábio M. Luz; Maiara C. Moraes; Susiane Cavinatto; Felipe S. Stefanello; Melissa B. Rodrigues; Nilo Zanatta; Marcos A.P. Martins
Source:
Tetrahedron letters 2017 v.58 pp. 3827-3830
ISSN:
0040-4039
Subject:
azides; cycloaddition reactions; bioactive properties; triazoles; rapid methods; chemical structure
Abstract:
... This work reports the synthesis of a series of (1H-1,2,3-triazol-4-yl)carbohydrazides (2), which were obtained from 4-trichloroacetyl-1H-1,2,3-triazoles (1). Triazoles 1 were synthesized by 1,3-dipolar cycloaddition reaction, starting from 4-alkoxy-1,1,1-trichloroalk-3-en-2-ones and benzyl azides and easily (15min) converted to 2 by reaction with hydrazine hydrate (73–82% yield). Carbohydrazides 2 ...
DOI:
10.1016/j.tetlet.2017.08.049

43. 4Z- and 4E-12-deoxydihydrokromycins, two naturally occurring kromycin aglycons of pikromycin from Streptomyces sp

Author:
Inho Yang; Jisoo Yoon; Dayoung Kim; Dongyup Hahn; Sang-Jip Nam; William Fenical
Source:
Tetrahedron letters 2017 pp. -
ISSN:
0040-4039
Subject:
Streptomyces; X-ray diffraction; bacteria; chemical reactions; chemical structure; circular dichroism spectroscopy; culture media; high performance liquid chromatography; macrolides; spectral analysis; stereochemistry
Abstract:
... HPLC-UV guided isolation for the culture broth extract of the marine-derived bacterium Streptomyces sp. has led to the two 14-membered macrolides, 4Z- (1) and 4E-12-dehydroxykromycins (2). The chemical structures of compounds 1 and 2 were elucidated by spectral data, while the absolute stereochemistry of 1 and 2 were determined by application of circular dichroism (CD) and analysis of X-ray crysta ...
DOI:
10.1016/j.tetlet.2017.03.088

44. 5-Nitroso-1,3-diphenyltetrazolium salt as a mediator for the oxidation of alcohols

Author:
Yuta Matsukawa; Tsunehisa Hirashita; Shuki Araki
Source:
Tetrahedron 2017 pp. -
ISSN:
0040-4020
Subject:
X-radiation; acetonitrile; alcohols; carbonyl compounds; chemical structure; nitric acid; oxidation
Abstract:
... We describe the synthesis of a mesoion-derived nitroso compound, 5-nitroso-1,3-diphenyltetrazolium tetrafluoroborate (1), and its application in the oxidation of alcohols. The structure of 1 was fully characterized by X-ray analysis, showing that it exists as a monomer in the solid state. In the cyclic voltammetric analysis of 1, a reversible redox peak was observed at 0.43 V (vs. Ag/Ag+ in MeCN) ...
DOI:
10.1016/j.tet.2017.08.055

45. A 7-Step Formal Asymmetric Total Synthesis of Strictamine via an Asymmetric Propargylation and Metal-Mediated Cyclization

Author:
Smith Myles W.; Zhou Zhiyao; Gao Alison X.; Shimbayashi Takuya; Snyder Scott A.
Source:
Organic letters 2017 v.19 no.5 pp. 1004-1007
ISSN:
1523-7052
Subject:
alkaloids; chemical structure; gold; oxidation
Abstract:
... Herein is shown how a novel catalytic asymmetric propargylation of 3,4-dihydro-β-carboline, followed by a designed Au(I)/Ag(I)-mediated 6-endo-dig cyclization, can directly deliver the indolenine-fused methanoquinolizidine core of the akuammiline alkaloid strictamine in its native oxidation state, ultimately achieving a 7-step formal asymmetric total synthesis. Also demonstrated are how the cycliz ...
DOI:
10.1021/acs.orglett.6b03839

46. 8-Propyldithieno[3,2-b:2′,3′-e]pyridine-3,5-diamine (DITIPIRAM) Derivatives as Neutral Receptors Tailored for Binding of Carboxylates

Author:
Cholewiak Agnieszka; Tycz Agnieszka; Jurczak Janusz
Source:
Organic letters 2017 v.19 no.11 pp. 3001-3004
ISSN:
1523-7052
Subject:
X-radiation; chemical reactions; chemical structure; geometry; hydrogen bonding; nuclear magnetic resonance spectroscopy; receptors; solvents; urea
Abstract:
... The DITIPIRAM (8-propyldithieno[3,2-b:2′,3′-e]pyridine-3,5-diamine)-based receptors 11 and 12 were readily synthesized, and their anion-binding properties were studied both in solution and in the solid-state. ¹H NMR titrations revealed that receptor 12 equipped with two phenyl-urea groups preferentially binds carboxylates, even in the highly competitive DMSO-d₆/CD₃OH solvent mixture. X-ray analysi ...
DOI:
10.1021/acs.orglett.7b01235

47. The AIEE properties and solid state fluorescence of 3-indolyl-4-indazolyl maleimide compounds: Synthesis and fluorescence characteristics

Author:
Bo-ye Zhu; Liang Han; Yu-Jin Li; Jian-rong Gao; Qing Ye
Source:
Tetrahedron 2017 pp. -
ISSN:
0040-4020
Subject:
chemical reactions; chemical structure; fluorescence; toluene
Abstract:
... A range of 3-indolyl-4-indazolyl maleimide fluorescent compounds, including 2a, 2b, 2c, 3a and 3b, were synthesized efficiently. In different organic dissolvents, the photo-physical performance was checked, either in the aggregated state or in the solid state. When being in solid and in solution state, these fluorescent compounds showed high fluorescent intensity, indicating a highest fluorescence ...
DOI:
10.1016/j.tet.2017.02.003

48. ATP Depletion Assay Led to the Isolation of New 36-Membered Polyol Macrolides Deplelides A and B from Streptomyces sp. MM581-NF15

Author:
Takeuchi Toshifumi; Hatano Masaki; Umekita Maya; Hayashi Chigusa; Wada Shun-ichi; Nagayoshi Miho; Sawa Ryuichi; Kubota Yumiko; Kawada Manabu; Igarashi Masayuki; Shibasaki Masakatsu
Source:
Organic letters 2017 v.19 no.16 pp. 4207-4210
ISSN:
1523-7052
Subject:
Streptomyces; adenosine triphosphate; assays; chemical reactions; chemical structure; databases; fractionation; inhibitory concentration 50; macrolides; neoplasm cells; nuclear magnetic resonance spectroscopy; polyols; spectral analysis; stereochemistry
Abstract:
... New 36-membered polyol macrolides deplelides A and B were isolated from the culture of Streptomyces MM581-NF15 by bioassay-guided fractionation using an ATP depletion assay. The planar structures of these novel compounds were identified by interpretation of the spectroscopic data (1D/2D NMR, MS, and IR). The relative stereochemistry was partially established using the universal NMR database method ...
DOI:
10.1021/acs.orglett.7b01807

49. Ab Initio Molecular Dynamic Simulations on Pd Clusters Confined in UiO-66-NH2

Author:
Chen De-Li; Wu Shengnan; Yang Pengyong; He Sihui; Dou Li; Wang Fang-Fang
Source:
The Journal of Physical Chemistry C 2017 v.121 no.16 pp. 8857-8863
ISSN:
1932-7455
Subject:
chemical structure; coordination polymers; deformation; encapsulation; energy; molecular dynamics; simulation models; thermodynamics
Abstract:
... The thermodynamically stable metal organic framework UiO-66-NH₂ has experimentally been demonstrated as an ideal platform to isolate metal clusters within its nanocages; however, the electronic structures and the dynamics of the encapsulated metal clusters are still unclear. Ab initio molecular dynamics simulations combined with density functional theory-based methods were employed to search the s ...
DOI:
10.1021/acs.jpcc.7b00957

50. About Underappreciated Yet Active Conformations of Thiourea Organocatalysts

Author:
Supady Adriana; Hecht Stefan; Baldauf Carsten
Source:
Organic letters 2017 v.19 no.16 pp. 4199-4202
ISSN:
1523-7052
Subject:
catalysts; catalytic activity; chemical reactions; chemical structure; hydrogen bonding; models; thiourea
Abstract:
... Conformational dynamics can define the function of organocatalysts. While the accepted mechanism of Schreiner’s catalyst features a double hydrogen bond to the substrate that only forms with the anti-anti conformation of its central thiourea group, our electronic-structure theory study reveals that binding of the model substrate methyl vinyl ketone prefers syn-anti conformations. We find a new mec ...
DOI:
10.1021/acs.orglett.7b01782