intramolecular ring
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Molbank ◽  
10.3390/m1317 ◽  
2022 ◽  
Vol 2022 (1) ◽  
pp. M1317
Author(s):  
Yuliya E. Ryzhkova ◽  
Varvara M. Kalashnikova ◽  
Fedor V. Ryzhkov ◽  
Michail N. Elinson

Michael addition–halogenation–intramolecular ring-closing (MHIRC) reactions are processes in which a halogen atom as a leaving group can attach to substrates or reactants during the reaction, which then undergoes intramolecular ring closure. In this communication the MHIRC transformation of 4-benzylidene-3-phenylisoxazol-5(4H)-one and 1,3-dimethylbarbituric acid in the presence of N-bromosuccinimide and sodium acetate in EtOH at room temperature was carefully investigated to give novel 1,3-dimethyl-3′,5-diphenyl-1,5-dihydro-2H,5′H-spiro[furo[2,3-d]pyrimi- dine-6,4′-isoxazole]-2,4,5′(3H)-trione in a good yield. The structure of the new compound was confirmed by the results of elemental analysis as well as mass, nuclear magnetic resonance, and infrared spectroscopy.


Synthesis ◽  
2021 ◽  
Author(s):  
Angel Ho ◽  
Austin Pounder ◽  
Samuel Koh ◽  
Matthew Macleod ◽  
Emily Carlson ◽  
...  

The present work demonstrates the ability of carboxylic acid-tethered cyclopropanated oxabenzonorbornadienes (CPOBDs) to undergo ring-opening reactions in mild acidic conditions. The optimized reaction conditions involve the use of pTsOH in DCE at 90 °C. Two regioisomers are formed but the reactions are highly regioselective towards type 3 ring-opened products. It was observed that substitution at the C-5 and aryl positions of CPOBD significantly hinders the ring opening reactions leading to decreased yields of ring-opened product, although high regioselectivity for the Type 3 ring-opened product is still maintained. Herein, we report the first examples of acid-catalyzed intramolecular ring-opening reactions of CPOBD with carboxylic acid nucleophiles.


2021 ◽  
Vol 12 (10) ◽  
pp. 1585-1588
Author(s):  
Guoyun Bai ◽  
Thomas N. O’Connell ◽  
Michael A. Brodney ◽  
Christopher R. Butler ◽  
Lara C. Czabaniuk ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 597
Author(s):  
Hosam Choi ◽  
Hanho Jang ◽  
Joohee Choi ◽  
Kiyoun Lee

Herein, we are reporting an efficient approach toward the synthesis of 4,5-disubstituted oxazolidin-2-one scaffolds. The developed approach is based on a combination of an asymmetric aldol and a modified Curtius protocol, which uses an effective intramolecular ring closure to rapidly access a range of oxazolidin-2-one building blocks. This strategy also permits a straightforward and concise asymmetric total synthesis of (−)-cytoxazone. Consisting of three steps, this is one of the shortest syntheses reported to date. Ultimately, this convenient platform would provide a promising method for the early phases of drug discovery.


Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 248
Author(s):  
Vera V. Voinova ◽  
Nikita A. Selivanov ◽  
Ivan V. Plyushchenko ◽  
Mikhail F. Vokuev ◽  
Alexander Yu. Bykov ◽  
...  

The novel members of the 1,2-diboraoxazoles family have been obtained. In the present work, we have carried out the intramolecular ring-closure reaction of borylated iminols of general type [B10H9N=C(OH)R]− (R = Me, Et, nPr, iPr, tBu, Ph, 4-Cl-Ph). This process is conducted in mild conditions with 83–87% yields. The solid-state structures of two salts of 1,2-diboraoxazoles were additionally investigated by X-ray crystallography. In addition, the phenomena of bonding interactions in the 1,2-diboraoxazole cycles have been theoretically studied by the Quantum Theory of Atoms in Molecules analysis. Several local and integral topological properties of the electron density involved in these interactions have been computed.


2021 ◽  
Author(s):  
Fang-Peng Hu ◽  
Xue-Guo Zhang ◽  
meng wang ◽  
hesong wang ◽  
Guosheng Huang

Herein, we have developed a rhodium-catalyzed C−H functionalization and subsequent intramolecular ring-opening/cyclization of vinylene carbonate with 2-pyrrolyl/indolylanilines, leading to oxazolidinones with moderate to good yields. In this transformation, vinylene carbonate...


2021 ◽  
Author(s):  
Tristan J. Keller ◽  
Christopher Sterzenbach ◽  
Joshua Bahr ◽  
Taria L. Schneiders ◽  
Markus Bursch ◽  
...  

Molecular spoked wheels with D3h and Cs symmetry are synthesized by Vollhardt trimerization of C2v-symmetric dumbbell structures with central acetylene units and subsequent intramolecular ring closure. Scanning tunneling microscopy of the D3h-symmetric species at the solid/liquid...


Author(s):  
Jonali Das ◽  
Sajal Kumar Das

Herein, we report that the trifluoroethanol-mediated intramolecular ring opening cyclization of 4-(oxiran-2-ylmethoxy)indoles takes place in diastereoselective and 6-endo fashion to generate pyrano[2,3-e]indol-3-ols in high yields. This regioselective cyclization at indole...


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