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1. Simple alkanoyl acylating agents for reversible RNA functionalization and control

Author:
Park, Hyun Shin; Kietrys, Anna M.; Kool, Eric T.
Source:
Chemical communications 2019 v.55 no.35 pp. 5135-5138
ISSN:
1364-548X
Subject:
moieties,   etc   ; RNA; acylation; imidazoles;     Show all 4 Subjects
Abstract:
... We describe the synthesis and RNA acylation activity of a series of minimalist azidoalkanoyl imidazole reagents, with the aim of functionalizing RNA at 2′-hydroxyl groups at stoichiometric to superstoichiometric levels. We find marked effects of small structural changes on their ability to acylate and be reductively removed, and identify reagents and methods that enable efficient RNA functionaliza ...
DOI:
10.1039/c9cc01598a

2. PhI(OAc)2-mediated alkoxyoxygenation of β,γ-unsaturated ketoximes: Preparation of isoxazolines bearing two contiguous tetrasubstituted carbons

Author:
Ye, Chenghao; Kou, Xuezhen; Yang, Guoqiang; Shen, Jiefeng; Zhang, Wanbin
Source:
Tetrahedron letters 2019 v.60 no.16 pp. 1148-1152
ISSN:
0040-4039
Subject:
moieties,   etc   ; oxidation; oximes;     Show all 3 Subjects
Abstract:
... A PhI(OAc)2-promoted dioxygenation of allyl oximes, including one alkoxylation, has been developed. This reaction can give isoxazoline products bearing two contiguous tetrasubstituted carbons. Various oximes substrates bearing different aryl groups and tetrasubstituted-olefin moieties were compatible with the mild reaction conditions. A two-electron oxidation pathway was proposed based on results ...
DOI:
10.1016/j.tetlet.2019.03.046

3. An efficient method for the N-formylation of amines under catalyst- and additive-free conditions

Author:
Xu, Zhuo-Wei; Xu, Wen-Yi; Pei, Xiao-Jun; Tang, Fei; Feng, Yi-Si
Source:
Tetrahedron letters 2019
ISSN:
0040-4039
Subject:
moieties,   etc   ; amines; chemical reactions;     Show all 3 Subjects
Abstract:
... A simple catalyst- and additive-free method for the N-formylation of amines has been developed. The advantages of this protocol include a wide range of functional group tolerance, high efficiency and a lack of required extra promoters under mild conditions. This convenient strategy will provide a facile synthesis towards N-formamide natural products and pharmaceutical derivatives. A mechanism that ...
DOI:
10.1016/j.tetlet.2019.03.071

4. 1-Alkyl-3-alkylindolin-2-imine hydrochlorides as useful building blocks in the copper-catalyzed synthesis of polycyclic indoline scaffolds

Author:
Liu, Can; Yang, Haijun; Zhu, Changjin; Fu, Hua
Source:
RSC advances 2019 v.9 no.15 pp. 8369-8372
ISSN:
2046-2069
Subject:
moieties,   etc   ; catalysts; hydrides; quinoline;     Show all 4 Subjects
Abstract:
... A novel and efficient copper-catalyzed synthesis of dihydro-6H-indolo[2,3-b]quinoline derivatives has been developed by using 3-alkyl-1-alkylindolin-2-imine hydrochlorides as the building blocks. Furthermore, easy reduction of dihydro-6H-indolo[2,3-b]quinolines with diisobutylaluminum hydride provided tetrahydro-6H-indolo[2,3-b]quinoline derivatives in excellent yields. The present method shows so ...
DOI:
10.1039/c9ra00995g

5. Synthesis of C3-Symmetric star-shaped molecules containing 1,3-azoles via hetero-aryl Heck coupling

Author:
Kotha, Sambasivarao; Todeti, Saidulu
Source:
Tetrahedron 2019 v.75 no.10 pp. 1359-1363
ISSN:
0040-4020
Subject:
moieties,   etc   ; benzimidazole; chemical reactions;     Show all 3 Subjects
Abstract:
... We have demonstrated a useful synthetic strategy to assemble star-shaped C3-symmetric molecules containing 1,3-azole moieties at the periphery. To generate these C3-symmetric heterocycles, we have employed the Pd/Cu-based coupling reactions. To this end, we have used benzoxazole, benzothiazole, and benzimidazole as coupling partners to generate the corresponding hetero-aryl Heck coupling products. ...
DOI:
10.1016/j.tet.2019.01.044

6. Synthesis of ertugliflozin from d-glucose

Author:
Triantakonstanti, Virginia V.; Andreou, Thanos; Koftis, Theoharis V.; Gallos, John K.
Source:
Tetrahedron letters 2019
ISSN:
0040-4039
Subject:
moieties,   etc   ; glucose; oxidation;     Show all 3 Subjects
Abstract:
... A new synthesis of ertugliflozin from d-glucose in 7% overall yield is reported. The reaction sequence involves conversion of d-glucose to a fully protected open chain d-glucose aldehyde in 4 steps, further installation of the aglycon group by a Grignard reaction, introduction of the hydroxymethyl group by a sequential oxidation/aldol reaction/Canizzarro reduction, and finally benzylic oxidation a ...
DOI:
10.1016/j.tetlet.2019.03.009

7. Rhodium-catalyzed CH activation/cyclization of enaminones with sulfoxonium ylides toward polysubstituted naphthalenes

Author:
Wang, Zhenlian; Xu, Huang
Source:
Tetrahedron letters 2019 v.60 no.9 pp. 664-667
ISSN:
0040-4039
Subject:
moieties,   etc   ; chemical reactions; naphthalenes;     Show all 3 Subjects
Abstract:
... A rhodium-catalyzed ortho-CH functionalization and annulation between enaminones and sulfoxonium ylides was developed, affording a series of multi-substituted naphthalenes in good to moderate yields with excellent functional group compatibility. The procedure featured with enaminone acting as both a directing and cyclization bifunctional group, and the application of sulfoxonium ylide in CH functi ...
DOI:
10.1016/j.tetlet.2019.01.051

8. Click and release: bioorthogonal approaches to “on-demand” activation of prodrugs

Author:
Ji, Xingyue; Pan, Zhixiang; Yu, Bingchen; De La Cruz, Ladie Kimberly; Zheng, Yueqin; Ke, Bowen; Wang, Binghe
Source:
Chemical Society reviews 2019 v.48 no.4 pp. 1077-1094
ISSN:
1460-4744
Subject:
moieties,   etc   ; derivatization; drugs;     Show all 3 Subjects
Abstract:
... Prodrug approaches represent an excellent solution to certain pharmaceutical issues commonly encountered in the drug discovery and development process. Along this line, the chemistry needed for the bio-reversible derivatization of drug functional groups for on-demand release is critical. In recent years, “click and release” approaches have shown great promise in the design of prodrugs because of t ...
DOI:
10.1039/c8cs00395e

9. Ruthenium(II) as Conductive Promoter To Alleviate Conductance Attenuation in Oligoynyl Chains

Author:
Zhang, Li-Yi; Duan, Ping; Wang, Jin-Yun; Zhang, Qian-Chong; Chen, Zhong-Ning
Source:
Journal of physical chemistry 2019 v.123 no.9 pp. 5282-5288
ISSN:
1932-7455
Subject:
moieties,   etc   ; ethane; models; ruthenium;     Show all 4 Subjects
Abstract:
... To unveil the influence of metal coordination on charge transport and length-dependent conductance attenuation in π-conjugated organic molecules, trans-Ru(dppe)₂ (dppe = 1,2-bis(diphenylphosphino)ethane) was implanted into oligoynyl chains with various number of ethynyl groups to construct Au–molecule–Au junctions using methylthiol (−SMe) as anchoring groups. The single-molecule conductance measur ...
DOI:
10.1021/acs.jpcc.9b00148

10. Synthesis of chiral allene moiety from Morita–Baylis–Hillman adduct of isatin derivatives via Claisen rearrangement

Author:
Vaithiyanathan, Vadivel; Ravichandran, Ganesan; Thirumailavan, Vijayakumar
Source:
Tetrahedron letters 2019 v.60 no.6 pp. 507-510
ISSN:
0040-4039
Subject:
moieties,   etc   ; allene; chemical reactions;     Show all 3 Subjects
Abstract:
... Chiral allenes are synthesized from Morita–Baylis–Hillman adduct of isatin derivatives via Claisen rearrangement for the first time. The chiral 1,3-substituted allene entity is achieved using (R)-but-3-yn-2-ol. The details of the work are elaborately discussed in this letter. ...
DOI:
10.1016/j.tetlet.2019.01.018

11. 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:
moieties,   etc   ; chemical reactions; esters;     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

12. Direct C4-Benzylation of Indoles via Tandem Benzyl Claisen/Cope Rearrangements

Author:
Abe, Takumi; Kosaka, Yuta; Asano, Miku; Harasawa, Natsuki; Mishina, Akane; Nagasue, Misato; Sugimoto, Yuri; Katakawa, Kazuaki; Sueki, Shunsuke; Anada, Masahiro; Yamada, Koji
Source:
Organic letters 2019 v.21 no.3 pp. 826-829
ISSN:
1523-7052
Subject:
moieties,   etc   ; aromatization; benzylation; indoles;     Show all 4 Subjects
Abstract:
... A novel direct C4 benzylation of indoles utilizing 2-benzyloxyindoles has been developed to access 4-benzyl-2-oxindoles. This strategy involves the in situ formation of isotoluene intermediates via benzyl Claisen rearrangements, which undergoes Cope rearrangement and aromatization. The method provides the desired products in moderate to high yields and shows good functional group tolerance. ...
DOI:
10.1021/acs.orglett.8b04120

13. Xylochemical Synthesis of Cytotoxic 2-Aminophenoxazinone-Type Natural Products Through Oxidative Cross Coupling

Author:
Kühlborn, Jonas; Konhäuser, Matthias; Groß, Jonathan; Wich, Peter R.; Opatz, Till
Source:
ACS sustainable chemistry & engineering 2019 v.7 no.4 pp. 4414-4419
ISSN:
2168-0485
Subject:
moieties,   etc   ; cytotoxicity; petroleum;     Show all 3 Subjects
Abstract:
... Today, the total synthesis of natural products mostly relies on the use of petroleum-based starting materials. The commercial availability of building blocks of this type often deflects attention away from lengthy synthetic routes required for the reintroduction of heteroatom substitution patterns lost in the geological process of kerogenesis. Herein, the use of wood-based starting materials, the ...
DOI:
10.1021/acssuschemeng.8b06353

14. New functionalized MIL-53(In) solids: syntheses, characterization, sorption, and structural flexibility

Author:
Wu, Lei; Chaplais, Gérald; Xue, Ming; Qiu, Shilun; Patarin, Joël; Simon-Masseron, Angélique; Chen, Huaxin
Source:
RSC advances 2019 v.9 no.4 pp. 1918-1928
ISSN:
2046-2069
Subject:
moieties,   etc   ; nitrogen; porosity; sorption;     Show all 4 Subjects
Abstract:
... The syntheses and characterization of a series of functionalized MIL-53(In) solids have been reported. Chemical groups with variations in steric hindrance and chemical nature (–(OH)₂, –Br or –NO₂ groups) were introduced through the terephthalate linker to modify the pore surface. Single crystal X-ray diffraction data, N₂ adsorption–desorption isotherms, and infrared spectra were systematically inv ...
DOI:
10.1039/c8ra08522f

15. Synthetic studies towards the penicisulfuranols: Synthesis of an advanced spirocyclic diketopiperazine intermediate

Author:
Gayler, Kevin M.; Lambert, Kyle M.; Wood, John L.
Source:
Tetrahedron 2019
ISSN:
0040-4020
Subject:
moieties,   etc   ; diketopiperazines; oxidation;     Show all 3 Subjects
Abstract:
... The 2,5-diketopiperazine (DKP) moiety is a core feature of many natural products and medicinally relevant scaffolds. As part of our efforts directed towards a total synthesis of penicisulfuranol B, we have developed and report herein: (1) the preparation of an N-hydroxy diketopiperazine intermediate accessible via a molybdenum-mediated oxidation of a parent diketopiperazine, and (2) further synthe ...
DOI:
10.1016/j.tet.2019.01.032

16. Synthesis and odour evaluation of novel sulfur‐containing cyclic acetals

Author:
Miyazawa, Yamato; Masuda, Yui; Ohmori, Yuichiro; Katsuta, Ryo; Nukada, Tomoo; Ishigami, Ken
Source:
Flavour and fragrance journal 2019 v.34 no.1 pp. 43-51
ISSN:
0882-5734
Subject:
moieties,   etc   ; flavor; odors;     Show all 3 Subjects
Abstract:
... Some sulfur‐containing compounds are known as useful flavours, but they have the drawback of instability in flavour composition. Therefore, we decided to develop stable sulfur‐containing compounds. We focused on 3‐mercapto‐2‐butanone (1), which is known for a meat‐like flavour. The carbonyl group of 1 was acetalized to improve the stability and to develop new flavouring compounds. We expected the ...
DOI:
10.1002/ffj.3478

17. Opposite ESIPT characteristic of two AIE-active isomers with different linkage sites

Author:
Dong, Yujie; Shen, Junjie; Li, Weijun; Zhao, Ruiyang; Pan, Yuyu; Song, Qingbao; Zhang, Cheng
Source:
Tetrahedron 2019 v.75 no.18 pp. 2670-2675
ISSN:
0040-4020
Subject:
moieties,   etc   ; chemical reactions; imidazoles; isomers;     Show all 4 Subjects
Abstract:
... In this work, we report two isomers composed of 1-phenyl-1H-phenanthro[9,10-d]imidazole (PI), hydroxyl and tetraphenylethylene (TPE), abbreviated as m-PITPE and p-PITPE. It is found that they exhibit similar aggregation-induced emission (AIE) behavior but totally different excited-state intramolecular proton transfer (ESIPT) characteristic, as a result of the different linkage sites of PI on TPE m ...
DOI:
10.1016/j.tet.2019.03.041

18. Oxidative CH alkylation of naphthoquinones with simple alkenes

Author:
Cao, Liya; Long, Huan; Guan, Honghao; Bi, Yusui; Bi, Gehua; Huang, Haofei; Liu, Lei
Source:
Tetrahedron letters 2019 v.60 no.18 pp. 1268-1271
ISSN:
0040-4039
Subject:
moieties,   etc   ; alkenes; alkylation; ammonium; naphthoquinones;     Show all 5 Subjects
Abstract:
... Direct CH functionalization of naphthoquinones represents a straightforward and attractive approach to prepare substituted naphthoquinones. Current studies predominantly adopted prefunctionalized coupling components that required multiple steps for preparation. In the manuscript, an (NH4)2S2O8 mediated oxidative CH functionalization of naphthoquinones with alkenes has been reported. The three-comp ...
DOI:
10.1016/j.tetlet.2019.04.002

19. Total synthesis of kehokorins A and B

Author:
Fujiwara, Kenshu; Motousu, Ryosuke; Sato, Daisuke; Kondo, Yoshihiko; Akiba, Uichi; Suzuki, Takanori; Tokiwano, Tetsuo
Source:
Tetrahedron letters 2019 v.60 no.18 pp. 1299-1301
ISSN:
0040-4039
Subject:
moieties,   etc   ; Suzuki reaction; bromination; dibenzofuran;     Show all 4 Subjects
Abstract:
... The total synthesis of a dibenzofuran rhamnoside, kehokorin A, and its aglycone, kehokorin B, was achieved via a route including Suzuki-Miyaura cross-coupling followed by Ullmann ether synthesis to form a dibenzofuran, stepwise bromination at C7 of the dibenzofuran, a second Suzuki-Miyaura cross-coupling to install a 4-methoxyphenyl group at C7, and rhamnosylation. ...
DOI:
10.1016/j.tetlet.2019.04.011

20. Copper (II) catalyzed homocoupling and heterocoupling of terminal alkynes

Author:
Holganza, Maria Katrina; Trigoura, Leslie; Elfarra, Suzanne; Seo, Yoona; Oiler, Jeremy; Xing, Yalan
Source:
Tetrahedron letters 2019 v.60 no.17 pp. 1179-1181
ISSN:
0040-4039
Subject:
moieties,   etc   ; alkynes; chemical reactions; copper;     Show all 4 Subjects
Abstract:
... Cu(OTf)2 catalyzed homo– and heterocoupling of aromatic and aliphatic terminal alkynes has been developed. Symmetric and unsymmetric 1,3-diynes have been synthesized in good yields under an aerobic condition in the presence of an organic base DBU. This reaction features mild conditions, a wide substrate scope, and excellent functional group compatibility. ...
DOI:
10.1016/j.tetlet.2019.03.057