Understanding the Ring-Opening Reaction of α-Amino Acid N-Carboxyanhydride in an Amine-Mediated Living Polymerization: A DFT Study

2010 ◽  
Vol 211 (15) ◽  
pp. 1708-1711 ◽  
Author(s):  
Jun Ling ◽  
Yanxin Huang
Keyword(s):  
Amino Acid ◽  
Ring Opening ◽  
Living Polymerization ◽  
Dft Study ◽  
Ring Opening Reaction

How does HOTf/HFIP Cooperative System Catalyze the Ring‐Opening Reaction of Cyclopropanes? A DFT Study

2020 ◽  
Vol 9 (2) ◽  
pp. 311-316 ◽  
Author(s):  
Yongzhu Zhou ◽  
Rong‐Chao Xue ◽  
Yaqing Feng ◽  
Lei Zhang
Keyword(s):  
Ring Opening ◽  
Dft Study ◽  
Cooperative System ◽  
Ring Opening Reaction

scholarly journals Ring Opening of Spiroepoxides Dithianedioxide with Bis-nucleophiles

2011 ◽  
Vol 3 (3) ◽  
pp. 575-586
Author(s):  
R. Ritmaleni ◽  
V. K. Aggarwal
Keyword(s):  
Amino Acid ◽  
Amino Alcohol ◽  
Ring Opening ◽  
Ring Opening Reaction ◽  
The Right ◽  
Morpholine Ring ◽  
Moderate Yield

This research was aimed to apply the spiroepoxide dithianedioxide for the synthesis of amino acid via ring opening of the spiroepoxide by bis-nucleophiles. First attempt was made to synthesize the bis-nucleophiles, amino alcohol, which was eventually used to the ring opening reaction of the spiroepoxide to produce the morpholine ring compound. The reaction was carried out in racemic and asymmetric method with moderate yield and high 99%. The last step produced amino acid that was still remained unsuccessful. However, it cannot be concluded yet whether the spiroepoxide dithianedioxide is the right intermediate for the synthesis of amino acid.Keywords:  Amino alcohol; Morpholine ring; Spiroepoxide dithianedioxide; Amino acid.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: 10.3329/jsr.v3i3.6746               J. Sci. Res. 3 (3), 585-596 (2011)

Ringöffnungsreaktionen an bioreaktiven Lactamsystemen / Ring Opening Reactions of Bioreactive Lactam Systems

1987 ◽  
Vol 42 (5) ◽  
pp. 603-612 ◽  
Author(s):  
Hermann Frister ◽  
Eckhard Schlimme
Keyword(s):  
Amino Acid ◽  
Ring Opening ◽  
Side Chains ◽  
Amino Groups ◽  
Ring Opening Reaction ◽  
Ring Opening Reactions ◽  
Amino Acid Side Chains ◽  
Tin Tetrachloride ◽  
Model Reactions

Abstract 1-β-ᴅ-Ribofuranosylpyrrolidin-2,5-dione (9) was synthesized by ribosylation of N-silylated succinimide (7) with 1,2,3,5-tetra-O-acetyl-β-ᴅ-ribofuranose in acetonitril in the presence of tin tetrachloride. The compounds 9, 1-β-ᴅ-ribofuranosyl-l-H-pyrrol-2,5-dione (5) and N-methyl- maleinimide (2) were converted with ammonia to the ring-opened components 16. 14 and 15. The bioreactivity of the N-maleinimide derivatives 2 and 5 with respect to addition and ring-opening reactions with amino acid side chains containing either thiol or amino groups was shown in model reactions with glutathion (compds. 17,18) and lysine (compds. 19, 20). The ring opening reaction of 3-methyl-3-phenyl-1-β-ᴅ-ribofuranosylpyrrolidin-2,5-dione (11) with lysine yields 21, thus demonstrating the possibility of glycosuccinylation of amino groups in proteins.

On the Conrotatory Ring Opening of 3-Carbomethoxycyclobutene Vis-À-Vis 3-Carbomethoxy-1,2-Benzocyclobutene and the Predominant Inward Opening of 3-Dimethylaminocarbonyl-1,2-Benzocyclobutene

2018 ◽  
Author(s):  
Veejendra Yadav ◽  
Dasari L V K Prasad ◽  
Arpita Yadav ◽  
Maddali L N Rao
Keyword(s):  
Transition State ◽  
Ring Opening ◽  
Electron Process ◽  
Ring Opening Reaction ◽  
Stable Species ◽  
Electron Event

<p>The torquoselectivity of conrotatory ring opening of 3-carbomethoxycyclobutene is controlled by p<sub>C1C2</sub>→s*<sub>C3C4</sub> and s<sub>C3C4</sub>→p*<sub>CO</sub> interactions in the transition state in a 4-electron process as opposed to only s<sub>C3C4</sub>→p*<sub>CO</sub> interaction in an apparently 8-electron event in 3-carbomethoxy-1,2-benzocyclobutene. The ring opening of 3-carbomethoxy-1,2-benzocyclobutene is sufficiently endothermic. We therefore argue that the reverse ring closing reaction is faster than the forward ring opening reaction and, thus, it establishes an equilibrium between the two and subsequently allows formation of the more stable species <i>via</i> outward ring opening reaction. Application of this argument to 3-dimethylaminocarbonyl-1,2-benzocyclobutene explains the predominantly observed inward opening.</p>

scholarly journals Expanding Monomers as Anti-Shrinkage Additives

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 806
Author(s):  
Philipp Marx ◽  
Frank Wiesbrock
Keyword(s):  
Ring Opening ◽  
Covalent Bond ◽  
Volumetric Shrinkage ◽  
Structure Property ◽  
Atomic Packing ◽  
Materials Properties ◽  
Volumetric Expansion ◽  
Structure Property Relationships ◽  
Ring Opening Reaction ◽  
Measuring Techniques

Commonly, volumetric shrinkage occurs during polymerizations due to the shortening of the equilibrium Van der Waals distance of two molecules to the length of a (significantly shorter) covalent bond. This volumetric shrinkage can have severe influence on the materials’ properties. One strategy to overcome this volumetric shrinkage is the use of expanding monomers that show volumetric expansion during polymerization reactions. Such monomers exhibit cyclic or even oligocyclic structural motifs with a correspondingly dense atomic packing. During the ring-opening reaction of such monomers, linear structures with atomic packing of lower density are formed, which results in volumetric expansion or at least reduced volumetric shrinkage. This review provides a concise overview of expanding monomers with a focus on the elucidation of structure-property relationships. Preceded by a brief introduction of measuring techniques for the quantification of volumetric changes, the most prominent classes of expanding monomers will be presented and discussed, namely cycloalkanes and cycloalkenes, oxacycles, benzoxazines, as well as thiocyclic compounds. Spiroorthoesters, spiroorthocarbonates, cyclic carbonates, and benzoxazines are particularly highlighted.

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