PubAg

Main content area

You searched for: Subject "free radicals" Remove constraint Subject: "free radicals"
Start Over

Search

15,422  Search Results

« Previous | 1 - 20 of 15,422 |
Number of results to display per page

Search Results

1. Correction: Alkoxy radicals generation: facile photocatalytic reduction of N-alkoxyazinium or azolium salts

Author:
Capaldo, Luca; Ravelli, Davide
Source:
Chemical communications 2019 v.55 no.24 pp. 3560
ISSN:
1364-548X
Subject:
free radicals,   etc   ; photocatalysis; salts;     Show all 3 Subjects
Abstract:
... Correction for ‘Alkoxy radicals generation: facile photocatalytic reduction of N-alkoxyazinium or azolium salts’ by Luca Capaldo et al., Chem. Commun., 2019, DOI: 10.1039/c9cc00035f. ...
DOI:
10.1039/c9cc90106j

2. Forging C(sp³)–C(sp³) Bonds with Carbon-Centered Radicals in the Synthesis of Complex Molecules

Author:
Pitre, Spencer P.; Weires, Nicholas A.; Overman, Larry E.
Source:
Journal of the American Chemical Society 2018 v.141 no.7 pp. 2800-2813
ISSN:
1520-5126
Subject:
free radicals
Abstract:
... Radical fragment coupling reactions that unite intricate subunits have become an important class of transformations within the arena of complex molecule synthesis. This Perspective highlights some of the early contributions in this area, as well as more modern applications of radical fragment couplings in the preparation of natural products. Additionally, emphasis is placed on contemporary advance ...
DOI:
10.1021/jacs.8b11790

3. Recent advances and trends of molecularly imprinted polymers for specific recognition in aqueous matrix: Preparation and application in sample pretreatment

Author:
Zhou, Tianyu; Ding, Lan; Che, Guangbo; Jiang, Wei; Sang, Lei
Source:
Trends in analytical chemistry 2019 v.114 pp. 11-28
ISSN:
0165-9936
Subject:
free radicals,   etc   ; absorbents; biopolymers; hydrophilicity; polymerization;     Show all 5 Subjects
Abstract:
... Molecularly imprinted polymers (MIPs), as artificially fabricated selective absorbents, have exhibited great potential for selective separation and enrichment of trace targets in complicated matrix. However, preparing MIPs for specific recognition in aqueous matrix often face enormous challenges, which greatly limit the wide application of MIPs for selectively analyzing targets in water-containing ...
DOI:
10.1016/j.trac.2019.02.028

4. Visible-light-induced carbosulfonylation of unactivated alkenes via remote heteroaryl and oximino migration

Author:
Tang, Nana; Yang, Shan; Wu, Xinxin; Zhu, Chen
Source:
Tetrahedron 2019 v.75 no.12 pp. 1639-1646
ISSN:
0040-4020
Subject:
free radicals,   etc   ; alkenes; cleavage (chemistry); moieties; photocatalysis;     Show all 5 Subjects
Abstract:
... An efficient visible-light photocatalytic protocol for the vicinal heteroarylsulfonylation and oximinosulfonylation of unactivated olefins is described. The addition of sulfonyl radicals to alkenes triggers the intramolecular migration of remote heteroaryl and oximino groups via CC bond cleavage. The transformation features a good functional group tolerance and a broad substrate scope. A variety o ...
DOI:
10.1016/j.tet.2018.12.003

5. Multiple-functionalizations of terminal alkynes with sodium sulfinates and tert-butyl nitrite: facile synthesis of 2H-azirines

Author:
He, Xingyi; Yue, Xin; Zhang, Lei; Wu, Shuang; Hu, Ming; Li, Jin-Heng
Source:
Chemical communications 2019 v.55 no.24 pp. 3517-3520
ISSN:
1364-548X
Subject:
free radicals,   etc   ; alkynes; nitric oxide; nitrites;     Show all 4 Subjects
Abstract:
... A new, catalyst-free tandem annulation route to 2,2-disulfonyl-2H-azirines via multiple-functionalizations of terminal alkynes with sodium sulfinates and tert-butyl nitrite is described. The use of sodium sulfinates and tert-butyl nitrite enables the formation of sulfonyl and NO radicals to selectively initiate and terminate the tandem annulation protocol, constituting a straightforward, conceptua ...
DOI:
10.1039/c9cc00625g

6. Alkoxy radicals generation: facile photocatalytic reduction of N-alkoxyazinium or azolium salts

Author:
Capaldo, Luca; Ravelli, Davide
Source:
Chemical communications 2019 v.55 no.21 pp. 3029-3032
ISSN:
1364-548X
Subject:
free radicals,   etc   ; chemical bonding; hydrogen; photocatalysis; salts;     Show all 5 Subjects
Abstract:
... The generation of alkoxy radicals from N-alkoxyazinium or azolium salts, occurring via the facile mono-electronic photocatalytic reduction of the starting compounds, has been recently reported. The photogenerated radicals can be in turn exploited for synthetic applications. These include the possibility to promote inter- or intramolecular hydrogen atom transfer processes to generate P- or C-center ...
DOI:
10.1039/c9cc00035f

7. Experimental study on viscosity reduction of heavy oil by hydrogen donors using a cavitating jet

Author:
Wan, Chunhao; Wang, Ruihe; Zhou, Weidong; Li, Luopeng
Source:
RSC advances 2019 v.9 no.5 pp. 2509-2515
ISSN:
2046-2069
Subject:
free radicals,   etc   ; hydrogen; oils; temperature; viscosity;     Show all 5 Subjects
Abstract:
... Cavitating jet technology is used to change the quality and to reduce the viscosity of heavy oil because bubble collapse can cause extreme conditions such as high pressure and temperature. The experimental study on the viscosity reduction of heavy oil using a cavitating jet was performed through a self-designed experimental system for heavy oil viscosity reduction by a cavitating jet. Tetrahydrona ...
DOI:
10.1039/c8ra08087a

8. Visible-light mediated carbamoyl radical addition to heteroarenes

Author:
Jatoi, Ashique Hussain; Pawar, Govind Goroba; Robert, Frédéric; Landais, Yannick
Source:
Chemical communications 2019 v.55 no.4 pp. 466-469
ISSN:
1364-548X
Subject:
free radicals,   etc   ; acids; amides; decarboxylation; heterocyclic compounds;     Show all 5 Subjects
Abstract:
... The generation of carbamoyl radicals, followed by their addition to heteroarenes, was performed under mild conditions through a metal-free photocatalyzed decarboxylation of oxamic acids. The process has been applied to the carbamoylation of heteroaromatic bases using α-aminoacid-derived oxamic acids, leading to the corresponding amides without racemization. ...
DOI:
10.1039/c8cc08326f

9. Radical polymerization of radical‐labeled monomers: The triarylmethyl‐based radical monomer as an example

Author:
Edeleva, Mariya V.; Marque, Sylvain R. A.; Rogozhnikova, Olga Yu.; Tormyshev, Victor M.; Troitskaya, Tatiana I.; Bagryanskaya, Elena G.
Source:
Journal of polymer science 2018 v.56 no.23 pp. 2656-2664
ISSN:
0887-624X
Subject:
free radicals,   etc   ; polymerization; polymers;     Show all 3 Subjects
Abstract:
... Recent development of spin‐labeled nitroxide‐mediated polymerization (NMP) involving successful polymer preparation with high livingness and narrow dispersity in the presence of persistent trityl‐based stable radicals attached to the initiators (90% recovery of a trityl radical signal after the polymerization) led us to the preparation of stable organic radical polymers based on trityl radical‐sub ...
DOI:
10.1002/pola.29249

10. 2-Azaallyl Anions, 2-Azaallyl Cations, 2-Azaallyl Radicals, and Azomethine Ylides

Author:
Tang, Shaojian; Zhang, Xia; Sun, Jiayue; Niu, Dawen; Chruma, Jason J.
Source:
Chemical reviews 2018 v.118 no.20 pp. 10393-10457
ISSN:
1520-6890
Subject:
free radicals,   etc   ; anions; cations;     Show all 3 Subjects
Abstract:
... This review covers the use of 2-azaallyl anions, 2-azaallyl cations, and 2-azaallyl radicals in organic synthesis up through June 2018. Particular attention is paid to both foundational studies and recent advances over the past decade involving semistabilized and nonstabilized 2-azaallyl anions as key intermediates in various carbon–carbon and carbon–heteroatom bond-forming processes. Both transit ...
DOI:
10.1021/acs.chemrev.8b00349

11. Catalytic Alkene Difunctionalization via Imidate Radicals

Author:
Nakafuku, Kohki M.; Fosu, Stacy C.; Nagib, David A.
Source:
Journal of the American Chemical Society 2018 v.140 no.36 pp. 11202-11205
ISSN:
1520-5126
Subject:
free radicals,   etc   ; imidoesters; photocatalysis;     Show all 3 Subjects
Abstract:
... The first catalytic strategy to harness imidate radicals has been developed. This approach enables alkene difunctionalization of allyl alcohols by photocatalytic reduction of their oxime imidates. The ensuing imidate radicals undergo consecutive intra- and intermolecular reactions to afford (i) hydroamination, (ii) aminoalkylation, or (iii) aminoarylation, via three distinct radical mechanisms. Th ...
DOI:
10.1021/jacs.8b07578

12. Improved dewaterability of anaerobically digested sludge and compositional changes in extracellular polymeric substances by indigenous persulfate activation

Author:
Maqbool, Tahir; Cho, Jinwoo; Hur, Jin
Source:
The Science of the total environment 2019 v.674 pp. 96-104
ISSN:
0048-9697
Subject:
free radicals,   etc   ; biopolymers; fluorescence; humic substances; iron; minerals; oxidation; sludge;     Show all 8 Subjects
Abstract:
... In this study, an indigenous activation of persulfate by iron-bearing minerals was examined using peroxymonosulfate (PMS) and peroxydisulfate (PDS) for the dewaterability and extracellular polymeric substances (EPS) composition of anaerobically digested sludge (ADS). Iron minerals originally present in the ADS seemed to operate as an initiator of the persulfate activation, which was indicated by a ...
DOI:
10.1016/j.scitotenv.2019.04.115

13. Theoretical investigation on atmospheric oxidation of fluorene initiated by OH radical

Author:
Ding, Zhezheng; Yi, Yayi; Zhang, Qingzhu; Zhuang, Tao
Source:
The Science of the total environment 2019 v.669 pp. 920-929
ISSN:
0048-9697
Subject:
free radicals,   etc   ; fluorenes; hydroxyl radicals; oxidation; quantum mechanics; risk; toxicity;     Show all 7 Subjects
Abstract:
... Atmospheric oxidation of fluorene and its derivatives initiated by OH radicals was investigated theoretically with quantum chemical calculation methods [M06-2X/6-311++G(3df,2p)//M06-2X/6-311+G(d,p)]. It revealed that the OH addition pathways form hydroxyfluorene and ring-opening product dialdehyde while the H abstraction pathways lead to the formation of 9-fluorenone. Subsequent oxidation of 9-flu ...
DOI:
10.1016/j.scitotenv.2019.02.400

14. Electron spin resonance studies of coals and coal conversion processes: A review

Author:
Zhou, Bin; Liu, Qingya; Shi, Lei; Liu, Zhenyu
Source:
Fuel processing technology 2019 v.188 pp. 212-227
ISSN:
0378-3820
Subject:
free radicals,   etc   ; biomass; coal; electron paramagnetic resonance spectroscopy; oil shale;     Show all 5 Subjects
Abstract:
... Electron spin resonance (ESR) is a spectroscopic method to detect paramagnetic species, which has been applied in coal and coal conversion research over 60 years. The major advancements made before 1990s were reviewed but the studies and findings reported since then have not been reviewed. The recent studies not only showed new phenomena on ESR radical behaviors associated with coal conversion pro ...
DOI:
10.1016/j.fuproc.2019.01.011

15. A scalable electrochemical dehydrogenative cross-coupling of P(O)H compounds with RSH/ROH

Author:
Li, Yujun; Yang, Qi; Yang, Liquan; Lei, Ning; Zheng, Ke
Source:
Chemical communications 2019 v.55 no.34 pp. 4981-4984
ISSN:
1364-548X
Subject:
free radicals,   etc   ; cross-coupling reactions; dehydrogenation; electrochemistry; phenols; phosphorus; thiols;     Show all 7 Subjects
Abstract:
... A practical, scalable electrochemical dehydrogenative cross-coupling of P(O)H compounds with thiols, phenols and alcohols in both an undivided cell and a continuous-flow setup is disclosed. Its broad substrate scope (>50 examples), good functional-group tolerance and scalability (>10 g) show potential for practical synthesis. A preliminary mechanistic study suggests that the phosphorus radicals ar ...
DOI:
10.1039/c9cc01378d

16. Carbonylation of tertiary carbon radicals: synthesis of lactams

Author:
Yin, Zhiping; Zhang, Zhuan; Zhang, Youcan; Dixneuf, Pierre H.; Wu, Xiao-Feng
Source:
Chemical communications 2019 v.55 no.32 pp. 4655-4658
ISSN:
1364-548X
Subject:
free radicals,   etc   ; carbon; carbon monoxide; chemical reactions; lactams;     Show all 5 Subjects
Abstract:
... Herein, we disclose an interesting iron-catalyzed approach for the carbonylation of a tertiary carbon radical. The tertiary carbon radical generated from a 1,5-hydrogen atom transfer can be captured by CO gas smoothly. Various six-membered lactams were constructed chemo-selectively in high yields. ...
DOI:
10.1039/c9cc02112d

17. A free radical alkylation of quinones with olefins

Author:
Liu, Shuai; Shen, Tong; Luo, Zaigang; Liu, Zhong-Quan
Source:
Chemical communications 2019 v.55 no.28 pp. 4027-4030
ISSN:
1364-548X
Subject:
free radicals,   etc   ; alkylation; ambient temperature; bioactive compounds; iron; quinones;     Show all 6 Subjects
Abstract:
... We demonstrated herein an Fe(iii)-mediated radical alkylation of quinones. A wide range of bioactive molecules with quinone motifs can be rapidly synthesized by using readily available and inexpensive NaBH₄/NaBD₄ with alkenes at room temperature under open flask conditions. ...
DOI:
10.1039/c9cc01704f

18. Reprint of: Recent advances in the functionalization of allenes via radical process

Author:
Qiu, Guanyinsheng; Zhang, Jun; Zhou, Kaida; Wu, Jie
Source:
Tetrahedron 2019 v.75 no.12 pp. 1578-1589
ISSN:
0040-4020
Subject:
free radicals,   etc   ; allene; carbon; chemical reactions; chemical structure; regioselectivity; stereoselectivity;     Show all 7 Subjects
Abstract:
... This review is focused on the recent advances in the functionalization of allenes via radical process. Different radical partners including carbon radicals and heteroatom radicals are discussed in the reactions of allenes. Generally, the radical formed in situ would attack the allene at the central carbon leading to allyl radical intermediate. However, the formation of alkenyl radical intermediate ...
DOI:
10.1016/j.tet.2019.02.046

19. Metal-free desilylative C–C bond formation by visible-light photoredox catalysis

Author:
Uygur, Mustafa; Danelzik, Tobias; García Mancheño, Olga
Source:
Chemical communications 2019 v.55 no.20 pp. 2980-2983
ISSN:
1364-548X
Subject:
free radicals,   etc   ; catalytic activity; chemical bonding; oxidants; redox reactions; silanes;     Show all 6 Subjects
Abstract:
... A newly developed methodology for the use of organosilanes as radical precursors under metal-free and visible-light conditions is presented. The strong oxidant character of the 9-mesityl-10-methylacridinium salt in its excited state enables the transformation of simple silanes to the corresponding carbon-centered radicals, which were trapped by various acceptor molecules. ...
DOI:
10.1039/c8cc10239b

20. Experimental and kinetic study of diisobutylene isomers in laminar flames

Author:
Yin, Geyuan; Hu, Erjiang; Huang, Shihan; Ku, Jinfeng; Li, Xiaojie; Xu, Zhaohua; Huang, Zuohua
Source:
Energy 2019 v.170 pp. 537-545
ISSN:
0360-5442
Subject:
free radicals,   etc   ; isomers; kinetics; model validation; models; prediction; temperature;     Show all 7 Subjects
Abstract:
... Laminar flame speeds of 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene were studied at initial temperatures of 298–453 K, the equivalence ratios of 0.8–1.6 and initial pressure of 0.1 MPa. The comparison between 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene was also performed in this work. Results show that 2,4,4-trimethyl-2-pentene has faster laminar flame speeds than 2,4,4-tri ...
DOI:
10.1016/j.energy.2018.12.194