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You searched for: Publication Year 2017 Remove constraint Publication Year: 2017 Subject chemical structure Remove constraint Subject: chemical structure Text availability Citation in PubAg Remove constraint Text availability: Citation in PubAg
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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 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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