Unexpected Ring-opening Reaction of Aziridine with Acetic Anhydride in DMF

2007 ◽  
Vol 36 (5) ◽  
pp. 604-605 ◽  
Author(s):  
Tianning Diao ◽  
Xiaoyu Sun ◽  
Renhua Fan ◽  
Jie Wu
Keyword(s):  
Acetic Anhydride ◽  
Ring Opening ◽  
Ring Opening Reaction

Unexpected Ring-Opening Reaction of Aziridine with Acetic Anhydride in DMF.

ChemInform ◽  
2007 ◽  
Vol 38 (40) ◽  
Author(s):  
Tianning Diao ◽  
Xiaoyu Sun ◽  
Renhua Fan ◽  
Jie Wu
Keyword(s):  
Acetic Anhydride ◽  
Ring Opening ◽  
Ring Opening Reaction

Covalent modification of graphite oxide with acetic anhydride to enhance dispersibility in organic solvents

2016 ◽  
Vol 09 (03) ◽  
pp. 1650044 ◽  
Author(s):  
Jingjing Li ◽  
Anwei Yang ◽  
Chen Zhang ◽  
Lei Zhang ◽  
Feifei Sun ◽  
...  
Keyword(s):  
Acetic Anhydride ◽  
Organic Solvents ◽  
Mild Condition ◽  
Graphite Oxide ◽  
Ring Opening ◽  
Covalent Modification ◽  
Alkyl Aryl ◽  
Aryl Chlorides ◽  
Ring Opening Reaction ◽  
Epoxy Groups

Graphite oxide (GO) was modified by acetic anhydride via a catalyzed ring-opening reaction of the attached epoxy groups at very mild condition. The dispersion of the modified GO is thus largely imporved in many organic solvents and the highest GO concentration reaches 2.0[Formula: see text]mg/mL in alkyl(aryl) chlorides, ethers, alcohols and cyclohexane, which is amongst the highest value for GO in organics.

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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