PubAg

Main content area

You searched for: Subject "esters" Remove constraint Subject: "esters"
Start Over

Search

18,879  Search Results

« Previous | 1 - 20 of 18,879 |
Number of results to display per page

Search Results

1. Flash vacuum pyrolysis of acetylenic esters: A mechanistic study

Author:
Al-Awadi, Nouria A.; Mohamed, Asaad S.; Habib, Osama M.; Al-Awadhi, Fatma H.; Al-Jalal, Nader A.; Ibrahim, Yehia A.
Source:
Journal of analytical and applied pyrolysis 2020 v.146 pp. 104778
ISSN:
0165-2370
Subject:
esters,   etc   ; carbenes; pyrolysis;     Show all 3 Subjects
Abstract:
... Products from flash vacuum pyrolysis of eleven acetylenic esters are reported in this study. The mechanism of their pyrolysis is proposed based on the products isolated. These reveal a combination of two main mechanistic approaches. Esters with β-hydrogens favor a retro-ene reaction via a six-membered transition state, the absence of such β-hydrogen leads to a carbene intermediate followed by inse ...
DOI:
10.1016/j.jaap.2020.104778

2. Correction: Expedient synthesis of eumelanin-inspired 5,6-dihydroxyindole-2-carboxylate ethyl ester derivatives

Author:
Aebly, Andrew H.; Levy, Jeffrey N.; Steger, Benjamin J.; Quirke, Jonathan C.; Belitsky, Jason M.
Source:
RSC advances 2019 v.9 no.48 pp. 27754
ISSN:
2046-2069
Subject:
esters,   etc   ; synthesis;     Show all 2 Subject
Abstract:
... Correction for ‘Expedient synthesis of eumelanin-inspired 5,6-dihydroxyindole-2-carboxylate ethyl ester derivatives’ by Andrew H. Aebly et al., RSC Adv., 2018, 8, 28323–28328. ...
DOI:
10.1039/c9ra90065a

3. Facile access to fluoroalkylated 2-aminopyridines by Cu-catalyzed [3 + 3] couplings of oxime esters with β-CF3 acrylonitrile

Author:
Li, Xueyan; Yu, Yanjiang; Qi, Ruobing; Bai, Dachang
Source:
Tetrahedron letters 2020 v.61 no.20 pp. 151858
ISSN:
0040-4039
Subject:
esters,   etc   ; catalytic activity; chemical reactions; moieties; regioselectivity;     Show all 5 Subjects
Abstract:
... Copper catalyzed the [3 + 3] coupling of the oxime esters with β-CF₃-acrylonitrile toward divergent fluoroalkyl-substituted 2-aminopyridines was described. This redox-neutral coupling conditions with the acrylonitrile affording the trifluoromethylated 2-aminopyridines, respectively, under the reductive conditions, difluoromethylated 2-aminopyridines were obtained. The reactions occurred under mild ...
DOI:
10.1016/j.tetlet.2020.151858

4. Base-induced Sommelet–Hauser rearrangement of N-(α-(2-oxyethyl)branched)benzylic glycine ester-derived ammonium salts via a chelated intermediate

Author:
Tayama, Eiji; Hirano, Kazuki; Baba, Souya
Source:
Tetrahedron 2020 pp. 131064
ISSN:
0040-4020
Subject:
esters,   etc   ; ammonium; ammonium salts; chemical reactions; moieties;     Show all 5 Subjects
Abstract:
... The base-induced Sommelet–Hauser (S–H) rearrangement of N-(α-branched)benzylic glycine ester-derived ammonium salts 1 was investigated. When the α-branched substituent was a simple alkyl, such as a methyl or butyl, desired S–H rearrangement product 2 was obtained in low yield with formation of the [1,2] Stevens rearranged 4 and Hofmann eliminated products 5 and 6. However, when the α-branched subs ...
DOI:
10.1016/j.tet.2020.131064

5. A synthetic route toward α,α-dialkyl α-amino ester derivatives via radical addition to hydrazone derivatives of α-ketoesters under “on-water” conditions

Author:
Nam, Tae Kyu; Jang, Doo Ok
Source:
Tetrahedron letters 2020 v.61 no.3 pp. 151411
ISSN:
0040-4039
Subject:
esters,   etc   ; chemical reactions; chemical structure; hydrazones; solvents;     Show all 5 Subjects
Abstract:
... Herein, radical addition to the CN bond in hydrazone derivatives of α-ketoesters under “on-water” conditions has been described. The present method provides a route to synthesize α,α-dialkyl α-amino esters, which are difficult to obtain using other methods because of their intrinsically low activity. The radical addition reaction is more efficient when performed under “on-water” conditions than wh ...
DOI:
10.1016/j.tetlet.2019.151411

6. On the electron withdrawing nature of ethers in glycosylation chemistry

Author:
Marqvorsen, Mikkel H.S.; Brinkø, Anne; Jensen, Henrik H.
Source:
Carbohydrate research 2020 v.487 pp. 107886
ISSN:
0008-6215
Subject:
esters,   etc   ; alcohols; carbohydrates; ethers; glycosylation; moieties;     Show all 6 Subjects
Abstract:
... The present paper is a commentary on the electronic effects that protecting groups exert on glycosylation chemistry. Specifically, its purpose is to rectify the misguided use of the term electron donating benzyl groups, which hardly makes sense in the context of protecting groups on alcohols in saturated systems such as carbohydrates. It is argued that benzyl ethers (OBn) should rightfully be refe ...
DOI:
10.1016/j.carres.2019.107886

7. Methoxyacetic acid esters: Applications in protecting group and glycosylation chemistry

Author:
Williams, Spencer J.
Source:
Carbohydrate research 2019 v.486 pp. 107848
ISSN:
0008-6215
Subject:
esters,   etc   ; carbohydrates; glycosylation; lanthanides;     Show all 4 Subjects
Abstract:
... The methoxyacetate (MAc) protecting group was introduced over 50 years ago and has proved useful owing to its combination of stability and its ability to be selectively removed in the presence of unactivated esters and a wide variety of other protecting groups. Glycosyl methoxyacetates have been investigated as glycosyl donors under activation by lanthanoids. In this mini-review we highlight a ran ...
DOI:
10.1016/j.carres.2019.107848

8. Copper-catalyzed intra- and intermolecular carbonylative transformation of remote C(sp3)[sbnd]H bonds in N-fluoro-sulfonamides

Author:
Yin, Zhiping; Zhang, Youcan; Zhang, Shuo; Wu, Xiao-Feng
Source:
Journal of catalysis 2019 v.377 pp. 507-510
ISSN:
0021-9517
Subject:
esters,   etc   ; catalytic activity; medicine;     Show all 3 Subjects
Abstract:
... Herein, we developed an interesting copper-catalyzed carbonylation approach for the transformations of the remote C(sp3)H bonds in N-fluoro-sulfonamides. The corresponding δ-lactams and esters were produced selectively. Notably, N-fluoro-carboxamide and medicine Celecoxib-derived substrate can also be transformed under the same conditions. ...
DOI:
10.1016/j.jcat.2019.07.045

9. The rhodium-catalyzed selective oxidative Heck reaction of amides with allylic esters

Author:
Hei, Yu-Yuan; Song, Jian-Lan; Zhan, Xin-Chen; Zhang, Xing-Guo; Deng, Chen-Liang
Source:
Tetrahedron letters 2019 v.60 no.24 pp. 1557-1561
ISSN:
0040-4039
Subject:
esters,   etc   ; benzamides; moieties; oxidation;     Show all 4 Subjects
Abstract:
... The Rh-catalyzed direct selective oxidation Heck reaction of benzamides with allylic esters has been developed for the synthesis of amides and isoquinolin-1-ones. According to the functional groups on N-atom, benzamides or isoquinolin-1-ones were synthesized under optimal reaction conditions. The ambient catalytic system has good functional group tolerance, afforded corresponding products in moder ...
DOI:
10.1016/j.tetlet.2019.05.012

10. Efficient access to chiral dihydrobenzoxazinones via Rh-catalyzed hydrogenation

Author:
Chen, Ziyi; Yin, Xuguang; Dong, Xiu-Qin; Zhang, Xumu
Source:
RSC advances 2019 v.9 no.27 pp. 15466-15469
ISSN:
2046-2069
Subject:
acetate esters,   etc   ; hydrogenation;     Show all 2 Subject
Abstract:
... Rh/(S)-DTBM-SegPhos-catalyzed asymmetric hydrogenation of prochiral (Z)-2-(2-oxo-2H-benzo[b][1,4]oxazin-3(4H)-ylidene)acetate esters was successfully developed. A series of chiral dihydrobenzoxazinones were prepared through this efficient methodology with good to excellent results (up to >99% conversion, 93% yield and >99% ee), which are important motifs in the biologically active molecules. ...
DOI:
10.1039/c9ra02694k

11. Two new phenylpropanoid esters from Bulbophyllum retusiusculum

Author:
Sun, Jing; Chen, Li-Jun; Zhang, Yan; Zhan, Rui; Chen, Ye-Gao
Source:
Journal of Asian natural products research 2019 v.21 no.4 pp. 331-336
ISSN:
1477-2213
Subject:
esters,   etc   ; Bulbophyllum; spectral analysis;     Show all 3 Subjects
Abstract:
... Two new phenylpropanoid esters bobulretulates A (1) and B (2), together with eleven known compounds, were isolated from the whole plants of Bulbophyllum retusiusculum. Their structures were elucidated by means of extensive spectroscopic analysis. ...
DOI:
10.1080/10286020.2018.1425995

12. Stability and performance of gun propellants incorporating 3,6-dihydrazino-s-tetrazine and 5-aminotetrazolium nitrate

Author:
Lavoie, Jonathan; Petre, Catalin-Florin; Durand, Simon; Dubois, Charles
Source:
Journal of hazardous materials 2019 v.363 pp. 457-463
ISSN:
0304-3894
Subject:
esters,   etc   ; burning; nitrates; stabilizers;     Show all 4 Subjects
Abstract:
... The addition of either 3,6-dihydrazino-s-tetrazine (DHT) or 5-aminotetrazolium nitrate (HAT-NO3) to nitrocellulose-based propellants were investigated. At 25% (m/m) concentration, DHT and HAT-NO3 had significant impact on the burning rate of the propellant, up to 80% higher than that of the reference propellant. DHT was found to have very poor compatibility with nitrocellulose and the nitrated est ...
DOI:
10.1016/j.jhazmat.2018.09.088

13. Access to Highly Functionalized Indanes from Arynes and α,γ-Diketo Esters

Author:
Hu, Wanyao; Zhang, Cong; Huang, Jie; Guo, Yingying; Fu, Zhenqian; Huang, Wei
Source:
Organic letters 2019 v.21 no.4 pp. 941-945
ISSN:
1523-7052
Subject:
esters,   etc   ; chemical reactions; moieties;     Show all 3 Subjects
Abstract:
... An unprecedented method for the synthesis of highly functionalized indanes from arynes and α,γ-diketo esters is described. Importantly, mild and nearly pH-neutral conditions ensure excellent functional group tolerance. Theoretical studies indicated that the reaction proceeds through a benzocyclobutane intermediate. ...
DOI:
10.1021/acs.orglett.8b03919

14. Enantioselective synthesis of anti-3-alkenyl-2-amido-3-hydroxy esters: application to the total synthesis of (+)-alexine

Author:
Yu, Lu; Somfai, Peter
Source:
RSC advances 2019 v.9 no.5 pp. 2799-2802
ISSN:
2046-2069
Subject:
esters,   etc   ; enantioselective synthesis; enantioselectivity;     Show all 3 Subjects
Abstract:
... A straightforward synthesis of anti-3-alkenyl-2-amido-3-hydroxy esters from the corresponding racemic α-amino-β-keto esters by using a ATH/DKR protocol has been developed. This method gives moderate to excellent yields with high chemo-, diastereo- and enantioselectivities for a broad range of substrates. In order to highlight the versatility of the methodology it was applied in an efficient asymme ...
DOI:
10.1039/c9ra00173e

15. Oral persistence of esters is affected by wine matrix composition

Author:
Muñoz-González, Carolina; Pérez-Jiménez, María; Pozo-Bayón, María Ángeles
Source:
Food research international 2020 v.135 pp. 109286
ISSN:
0963-9969
Subject:
esters,   etc   ; ethanol; gallic acid; mouth; odors; polyphenols; winemaking; wines;     Show all 8 Subjects
Abstract:
... The present work evaluated for the first time the influence of wine matrix composition on oral ester persistence. To do that, the in mouth behaviour (oral retention and persistence) of six esters was followed in nine individuals after they rinsed their mouths with four rosé wines presenting two levels (low and moderate) of ethanol (0.5% or 10% v/v) and polyphenols (402 ± 10 or 661 ± 33 mg gallic a ...
DOI:
10.1016/j.foodres.2020.109286

16. NFSI/KF mediated mild and chemoselective interconversion of aryl TBDMS ethers to their benzene sulfonate

Author:
Dond, Bharat D.; Thore, Shivaji N.
Source:
Tetrahedron letters 2020 v.61 no.13 pp. 151660
ISSN:
0040-4039
Subject:
esters,   etc   ; benzene; chemical reactions; chemical structure; chemoselectivity; ethers; sulfonates;     Show all 7 Subjects
Abstract:
... A one pot protocol for the transformation of aryl TBDMS ethers to corresponding benzene sulfonate esters using NFSI (N-flurobenzenesulfonimide)/KF is described. In situ generation of benzenesulfonyl fluoride directs chemoselective cleavage of aryl silyl ethers over alkyl silyl ethers. Electron withdrawing substituent’s on aryl ring provided better yield than donating groups. Protecting groups and ...
DOI:
10.1016/j.tetlet.2020.151660

17. Metal-Free Oxidative Esterification of Ketones and Potassium Xanthates: Selective Synthesis of α-Ketoesters and Esters

Author:
Luo, Xianglin; He, Runfa; Liu, Qiang; Gao, Yanping; Li, Jingqing; Chen, Xiuwen; Zhu, Zhongzhi; Huang, Yubing; Li, Yibiao
Source:
Journal of organic chemistry 2020 v.85 no.8 pp. 5220-5230
ISSN:
1520-6904
Subject:
esters,   etc   ; chemical bonding; esterification; ketones; moieties; organic chemistry; potassium;     Show all 7 Subjects
Abstract:
... A novel and efficient oxidative esterification for the selective synthesis of α-ketoesters and esters has been developed under metal-free conditions. In the protocol, various α-ketoesters and esters are available in high yields from commercially available ketones and potassium xanthates. Mechanistic studies have proven that potassium xanthate not only promotes oxidative esterification but also pro ...
DOI:
10.1021/acs.joc.9b03272

18. Access to Fused Pyrroles from Cyclic 1,3-Dienyl Boronic Esters and Arylnitroso Compounds

Author:
François, Benjamin; Eberlin, Ludovic; Berrée, Fabienne; Whiting, Andrew; Carboni, Bertrand
Source:
Journal of organic chemistry 2020 v.85 no.8 pp. 5173-5182
ISSN:
1520-6904
Subject:
esters,   etc   ; chemical reactions; chemical structure; organic chemistry; pyrroles;     Show all 5 Subjects
Abstract:
... Complimentary to classical hydroboration and boron-Wittig reactions, a new, efficient access to cyclic 1,3-dienyl boronic esters has been developed via diene or triene metathesis. Subsequently, fused pyrroles were synthesized with a broad substrate scope from the reaction of cyclic 1,3-dienyl boronic esters with arylnitroso compounds using a one-pot hetero-Diels–Alder/ring contraction sequence. ...
DOI:
10.1021/acs.joc.9b03214

19. Electrochemical synthesis of sulfinic esters from alcohols and thiophenols

Author:
He, Yang; Zhang, Jinli; Xu, Liang; Wei, Yu
Source:
Tetrahedron letters 2020 v.61 no.12 pp. 151631
ISSN:
0040-4039
Subject:
esters,   etc   ; alcohols; catalysts; chemical reactions; chemical structure; electrochemistry; electrosynthesis; oxidants;     Show all 8 Subjects
Abstract:
... Electrochemical oxidative couplings between SH and OH bonds are achieved herein directly from readily-available alcohols and thiophenols, affording a series of diverse sulfinic esters. This strategy can take advantage of 6 equivalents of alcohol, relative to thiophenol, to achieve moderate to good yields, without the assistance of any metallic catalysts, bases, and additional oxidants. ...
DOI:
10.1016/j.tetlet.2020.151631

20. Lewis Acid Catalyzed Ring-Opening 1,3-Aminothiolation of Donor–Acceptor Cyclopropanes Using Sulfenamides

Author:
Guin, Avishek; Rathod, Thukaram; Gaykar, Rahul N.; Roy, Tony; Biju, Akkattu T.
Source:
Organic letters 2020 v.22 no.6 pp. 2276-2280
ISSN:
1523-7052
Subject:
esters,   etc   ; Lewis acids; catalytic activity; chemical reactions; moieties; regioselectivity; stereospecificity;     Show all 7 Subjects
Abstract:
... Yb(OTf)₃ catalyzed mild and regioselective ring-opening 1,3-aminothiolation of donor–acceptor (D–A) cyclopropanes using sulfenamides has been demonstrated. The insertion of the C–C σ-bond of D–A cyclopropanes into the S–N σ-bond of sulfenamides allows the synthesis of diverse γ-aminated α-thiolated malonic diesters in moderate to good yields (up to 87%) with good functional group compatibility. Th ...
DOI:
10.1021/acs.orglett.0c00483