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1. 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

2. 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

3. 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

4. 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

5. 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

6. 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

7. Computational mapping of redox-switchable metal complexes based on ferrocene derivatives

Author:
Lai, Amy; Clifton, Jamie; Diaconescu, Paula L.; Fey, Natalie
Source:
Chemical communications 2019 v.55 no.49 pp. 7021-7024
ISSN:
1364-548X
Subject:
esters,   etc   ; ligands; metals; oxidation; polymerization;     Show all 5 Subjects
Abstract:
... DFT calculations were used to capture the properties of redox-switchable metal complexes relevant to the ring-opening polymerisation of cyclic esters by varying the metals, donors, linkers, and substituents in both accessible ferrocene oxidation states. A map of this chemical space highlights that modifying the ligand architecture and the metal has a larger impact on structural changes than changi ...
DOI:
10.1039/c9cc01977d

8. Synthesis of the Tricyclic Picrotoxane Motif by an Oxidative Cascade Cyclization

Author:
Cao, Jingming; Thor, Waygen; Yang, Shenkun; Zhang, Mengxun; Bao, Wenli; Zhu, Lizhi; Yang, Wei; Cheng, Yuen-Kit; Lee, Chi-Sing
Source:
Organic letters 2019 v.21 no.12 pp. 4896-4899
ISSN:
1523-7052
Subject:
esters,   etc   ; chemical structure; cyclization reactions;     Show all 3 Subjects
Abstract:
... An oxidative cascade cyclization of β-keto esters has been developed for the construction of the tricyclic picrotoxane motif in a single step, and DFT calculations suggested a possible cationic cyclization mechanism. This cascade cyclization can be operated on a 20 g scale to obtain a 77% total yield of the tricyclic products, which in turn can be converted to versatile intermediates for further e ...
DOI:
10.1021/acs.orglett.9b01806

9. Practical Approach for Clean Preparation of Z-β-Thiocyanate Alkenyl Esters

Author:
Wu, Chao; Hong, Lin; Shu, Hui; Zhou, Qun-Huai; Wang, Yi; Su, Neng; Jiang, Si; Cao, Zhong; He, Wei-Min
Source:
ACS sustainable chemistry & engineering 2019 v.7 no.9 pp. 8798-8803
ISSN:
2168-0485
Subject:
esters,   etc   ; biomass; catalysts; lactic acid;     Show all 4 Subjects
Abstract:
... A practical and eco-friendly method for the clean preparation of a variety of Z-β-thiocyanate alkenyl esters via lactic acid-catalyzed multicomponent hydrothiocyanation reaction was established. In the subgram-scale synthesis, Z-β-thiocyanate alkenyl esters were exclusively generated, and the product could be easily isolated in high purity via extraction. In the large-scale synthesis, the pure pro ...
DOI:
10.1021/acssuschemeng.9b00708

10. Prying open a Thiele cage: discovery of an unprecedented extended pinacol rearrangement

Author:
DaoThese authors contributed equally to the preparation of the manuscript., Nathan; Sader, Jonathan K.; Oliver, Allen G.; Wulff, Jeremy E.
Source:
Chemical communications 2019 v.55 no.11 pp. 1600-1603
ISSN:
1364-548X
Subject:
esters,   etc   ; chemical communication; chemical reactions;     Show all 3 Subjects
Abstract:
... The first extended pinacol rearrangement across an sp³–sp³ bond is reported. The reaction appears to be both stereo- and regio-specific, and results in an extremely rare example of cage opening for a 1,3-bishomocubane structure derived from Thiele's ester. ...
DOI:
10.1039/c8cc08862d

11. Combination of fatty acids extraction and enzymatic esterification for biodiesel production using sludge palm oil as a low-cost substrate

Author:
Muanruksa, Papasanee; Kaewkannetra, Pakawadee
Source:
Renewable energy 2020 v.146 pp. 901-906
ISSN:
0960-1481
Subject:
carboxylic ester hydrolases; esters,   etc   ; Rhizopus oryzae; agitation; biocatalysts; biodiesel; catalytic activity; esterification; fatty acids; free fatty acids; fuel production; methanol; palm oils; saponification; sludge; temperature;     Show all 16 Subjects
Abstract:
... The alternative approach to the production of biodiesel from sludge palm oil (SPO) via two steps of extraction and enzymatic esterification was performed. Free fatty acids (FFAs) from SPO were obtained through saponification reaction and subsequent extraction. The FFAs were further converted to biodiesel (fatty acids methyl esters) via esterification reaction catalysed by immobilised Rhizopus oryz ...
DOI:
10.1016/j.renene.2019.07.027

12. Heterogeneous catalyst screening for fatty acid methyl esters production through interesterification reaction

Author:
Simões, S.S.; Ribeiro, J.S.; Celante, D.; Brondani, L.N.; Castilhos, F.
Source:
Renewable energy 2020 v.146 pp. 719-726
ISSN:
0960-1481
Subject:
fatty acid methyl esters,   etc   ; acetates; biodiesel; catalysts; fuel production; magnesium oxide; oils; screening; soybeans; temperature; zeolites;     Show all 11 Subjects
Abstract:
... This study aimed the investigation of a potential heterogeneous catalyst for the interesterification reaction for soybean biodiesel production. Different types of catalysts (Y Zeolite, MgO, Nb2O5 and mixed oxides) were tested in this work. Ca–Mg–Al mixed oxide with 40% wt. Ca was the more suitable catalyst for interesterification reaction. Effects of temperature, catalyst content and methyl acetat ...
DOI:
10.1016/j.renene.2019.07.023

13. Extra hydrogen bonding interactions by peripheral indole groups stabilize benzene-1,3,5-tricarboxamide helical assemblies

Author:
Basuyaux, Gaëtan; Desmarchelier, Alaric; Gontard, Geoffrey; Vanthuyne, Nicolas; Moussa, Jamal; Amouri, Hani; Raynal, Matthieu; Bouteiller, Laurent
Source:
Chemical communications 2019 v.55 no.59 pp. 8548-8551
ISSN:
1364-548X
Subject:
esters,   etc   ; chemical reactions; hydrogen bonding; tryptophan;     Show all 4 Subjects
Abstract:
... Benzene-1,3,5-tricarboxamide monomers derived from alkyl esters of tryptophan (BTA Trp) self-assemble into helices with an inner threefold hydrogen bond network surrounded by a second network involving the indole N–H groups. As a consequence of this extra stabilization of its helical assemblies, BTA Trp forms more viscous solutions than a range of ester and alkyl BTAs. ...
DOI:
10.1039/c9cc03906f

14. Light- and pH-responsive self-healing hydrogel

Author:
Yang, Meng; Wang, Linlin; Cheng, Yongbin; Ma, Ke; Wei, Xinran; Jia, Pengxiang; Gong, Yongkuan; Zhang, Yang; Yang, Jingfa; Zhao, Jiang
Source:
Journal of materials science 2019 v.54 no.13 pp. 9983-9994
ISSN:
0022-2461
Subject:
esters,   etc   ; hydrogels; hysteresis; mechanical properties; phenylboronic acids;     Show all 5 Subjects
Abstract:
... A self-healing hydrogel was synthesized via the multi-component reaction of azobenzene-methacrylamide, β-CD and 3-methacrylamido phenylboronic acid. The orthogonal method was applied to analyze the influence of host–guest inclusion complexation, cross-linker and phenylboronic acid monomers content on mechanical properties and healing efficiency of the hydrogel. The results indicated that hydrogel ...
DOI:
10.1007/s10853-019-03547-z

15. An effective cis-β-octahedral Mn(iii) SALPN catalyst for the Mukaiyama–Isayama hydration of α,β-unsaturated esters

Author:
Donnelly, Paul S.; North, Andrea J.; Radjah, Natalia Caren; Ricca, Michael; Robertson, Angus; White, Jonathan M.; Rizzacasa, Mark A.
Source:
Chemical communications 2019 v.55 no.53 pp. 7699-7702
ISSN:
1364-548X
Subject:
esters,   etc   ; catalysts; catalytic activity; chemical reactions; manganese;     Show all 5 Subjects
Abstract:
... Two cis-β-MnᴵᴵᴵSALPN catalysts were synthesised and tested in the Mukaiyama–Isayama hydration of α,β-unsaturated esters. The MnᴵᴵᴵEtOSALPN(acac) complex 7 is the most active and catalyses hydration with little or no detectable undesired alkene reduction. This catalyst is superior for alkene hydration compared to the originally reported Mn(dpm)₃ catalyst. ...
DOI:
10.1039/c9cc03921j

16. Thioallenoates in catalytic enantioselective [2+2]-cycloadditions with unactivated alkenes

Author:
Conner, Michael L.; Wiest, Johannes M.; Brown, M. Kevin
Source:
Tetrahedron 2019 v.75 no.24 pp. 3265-3271
ISSN:
0040-4020
Subject:
esters,   etc   ; alkenes; chemical structure; cycloaddition reactions; enantioselectivity;     Show all 5 Subjects
Abstract:
... The application of thioallenoates to catalytic enantioselective [2+2]-cycloadditions with unactivated alkenes is reported. In many cases, the thioallenoates examined exhibit superior reactivity and selectivity compared to the allenic esters generally used in these cycloadditions. ...
DOI:
10.1016/j.tet.2019.04.028

17. Site-Selective Mono-Oxidation of 1,2-Bis(boronates)

Author:
Yan, Lu; Morken, James P.
Source:
Organic letters 2019 v.21 no.10 pp. 3760-3763
ISSN:
1523-7052
Subject:
esters,   etc   ; butanol; chemical structure; oxidation; solvents; trimethylamine;     Show all 6 Subjects
Abstract:
... Site-selective oxidation of vicinal bis(boronates) is accomplished through the use of trimethylamine N-oxide in 1-butanol solvent. The reaction occurs with good efficiency and selectivity across a range of substrates, providing 2-hydro-1-boronic esters which are shown to be versatile intermediates in the synthesis of chiral building blocks. ...
DOI:
10.1021/acs.orglett.9b01204

18. Strain Release of Donor–Acceptor Cyclopropyl Boronate Complexes

Author:
Gregson, Charlotte H. U.; Ganesh, Venkataraman; Aggarwal, Varinder K.
Source:
Organic letters 2019 v.21 no.9 pp. 3412-3416
ISSN:
1523-7052
Subject:
esters,   etc   ; Lewis acids; alkylation; chemical structure;     Show all 4 Subjects
Abstract:
... The reactivity of boronate complexes which resemble donor–acceptor cyclopropanes is described. The enantioenriched cyclopropyl boronate complexes were shown to undergo concerted 1,2-metalate rearrangement/ring opening upon activation with a Lewis acid. This method provides atom-efficient access to optically active γ-carbonyl boronic esters in moderate to excellent yields with complete enantiospeci ...
DOI:
10.1021/acs.orglett.9b01152

19. A Sequential Acyl Thiol–Ene and Thiolactonization Approach for the Synthesis of δ-Thiolactones

Author:
McCourt, Ruairí O.; Scanlan, Eoin M.
Source:
Organic letters 2019 v.21 no.9 pp. 3460-3464
ISSN:
1523-7052
Subject:
esters,   etc   ; acids; chemical bonding; chemical reactions; moieties;     Show all 5 Subjects
Abstract:
... A novel strategy for the synthesis of δ-thiolactones from inexpensive and readily available γ-unsaturated esters has been developed. This strategy incorporates a radical acyl thiol–ene reaction as the key C–S bond forming step. Cyclization is achieved via a Steglich-type thiolactonization of 5-mercaptopentanoic acids. We report the facile and scalable synthesis of δ-thiolactones in moderate to goo ...
DOI:
10.1021/acs.orglett.9b01271

20. Iridium-Catalyzed α-Methylation of α-Aryl Esters Using Methanol as the C1 Source

Author:
Tsukamoto, Yuya; Itoh, Satoshi; Kobayashi, Masaki; Obora, Yasushi
Source:
Organic letters 2019 v.21 no.9 pp. 3299-3303
ISSN:
1523-7052
Subject:
esters,   etc   ; biochemistry; chemical structure; methanol; methylation;     Show all 5 Subjects
Abstract:
... IrCl(cod)₂]/dppe-catalyzed α-methylation of aryl esters using methanol as the C1 source was developed. This methylation process is useful in several fields including organic chemistry, biochemistry, and medicinal chemistry. Readily available methanol as methylation reagent was successfully adapted. The reaction processed high atom economy and efficient. By applying the reaction system, the synthes ...
DOI:
10.1021/acs.orglett.9b01025