The role of ring opening reaction chemistry of sultones/lactones in the direct zwitterionization of polyamide nano-filtration membranes

The torquoselectivity of conrotatory ring opening of 3-carbomethoxycyclobutene is controlled by pC1C2→s*C3C4 and sC3C4→p*CO interactions in the transition state in a 4-electron process as opposed to only sC3C4→p*CO 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 via outward ring opening reaction. Application of this argument to 3-dimethylaminocarbonyl-1,2-benzocyclobutene explains the predominantly observed inward opening.

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One-step preparation of cyclen-containing hydrophilic polymeric monolithic materials via epoxy-amine ring-opening reaction and their application in enrichment of N-glycopeptides

Talanta ◽

10.1016/j.talanta.2020.122049 ◽

2021 ◽

Vol 225 ◽

pp. 122049

Author(s):

Chen Ma ◽

Ruizhi Tang ◽

Yan Wang ◽

Shujuan Ma ◽

Shouwan Tang ◽

...

Keyword(s):

Ring Opening ◽

Epoxy Amine ◽

Ring Opening Reaction ◽

One Step

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Expanding Monomers as Anti-Shrinkage Additives

Polymers ◽

10.3390/polym13050806 ◽

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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Design and synthesis of 1,8-Naphthalimide Functionalized Benzothiadiazoles

New Journal of Chemistry ◽

10.1039/d1nj00919b ◽

2021 ◽

Author(s):

Rajneesh Misra ◽

Yogjivan Rout

Keyword(s):

Ring Opening ◽

Coupling Reaction ◽

Cross Coupling ◽

Design And Synthesis ◽

Cross Coupling Reaction ◽

Ring Opening Reaction

A series of multi acceptor based push-pull derivatives BTD2–BTD5 were designed and synthesized via Pd-catalyzed Sonogashira cross-coupling reaction followed by [2+2] cycloaddition–electrocyclic ring-opening reaction in which benzothiadiazole (BTD, A1), naphthalimide...

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N-Chlorinative Ring Contraction of 1,4-Dimethoxyphthalazines via a Bicyclization/Ring-Opening Mechanism

Synthesis ◽

10.1055/s-0040-1706639 ◽

2020 ◽

Author(s):

Jeong Kyun Im ◽

Ilju Jeong ◽

Jun-Ho Choi ◽

Won-jin Chung ◽

ByeongDo Yang ◽

...

Keyword(s):

Ring Opening ◽

Reaction Conditions ◽

Ring Contraction ◽

Silyl Group ◽

Favorskii Rearrangement ◽

Mechanistic Analysis ◽

Group A ◽

Overall Efficiency ◽

Trichloroisocyanuric Acid

AbstractAn unprecedented N-chlorinative ring contraction of 1,2-diazines was discovered and investigated with an electrophilic chlorinating reagent, trichloroisocyanuric acid (TCICA). Through optimization and mechanistic analysis, the assisting role of n-Bu4NCl as an exogenous nucleophile was identified, and the optimized reaction conditions were applied to a range of 1,4-dimethoxyphthalazine derivatives. Also, an improvement of overall efficiency was demonstrated by the use of a labile O-silyl group. A bicyclization/ring-opening mechanism, inspired by the Favorskii rearrangement, was proposed and supported by the DFT calculations. Furthermore, the efforts on scope expansion as well as the evaluation of other electrophilic promoters revealed that the newly developed ring contraction reactivity is a unique characteristic of 1,4-dimethoxyphthalazine scaffold and TCICA.

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Theoretical Study on the Photo-Oxidation and Photoreduction of an Azetidine Derivative as a Model of DNA Repair

Molecules ◽

10.3390/molecules26102911 ◽

2021 ◽

Vol 26 (10) ◽

pp. 2911

Author(s):

Miriam Navarrete-Miguel ◽

Antonio Francés-Monerris ◽

Miguel A. Miranda ◽

Virginie Lhiaubet-Vallet ◽

Daniel Roca-Sanjuán

Keyword(s):

Electron Transfer ◽

Energy Barrier ◽

Ring Opening ◽

Dna Lesions ◽

Barrier Heights ◽

Dna Lesion ◽

Electron Reduction ◽

The Stability ◽

Electron Transfer Processes

Photocycloreversion plays a central role in the study of the repair of DNA lesions, reverting them into the original pyrimidine nucleobases. Particularly, among the proposed mechanisms for the repair of DNA (6-4) photoproducts by photolyases, it has been suggested that it takes place through an intermediate characterized by a four-membered heterocyclic oxetane or azetidine ring, whose opening requires the reduction of the fused nucleobases. The specific role of this electron transfer step and its impact on the ring opening energetics remain to be understood. These processes are studied herein by means of quantum-chemical calculations on the two azetidine stereoisomers obtained from photocycloaddition between 6-azauracil and cyclohexene. First, we analyze the efficiency of the electron-transfer processes by computing the redox properties of the azetidine isomers as well as those of a series of aromatic photosensitizers acting as photoreductants and photo-oxidants. We find certain stereodifferentiation favoring oxidation of the cis-isomer, in agreement with previous experimental data. Second, we determine the reaction profiles of the ring-opening mechanism of the cationic, neutral, and anionic systems and assess their feasibility based on their energy barrier heights and the stability of the reactants and products. Results show that oxidation largely decreases the ring-opening energy barrier for both stereoisomers, even though the process is forecast as too slow to be competitive. Conversely, one-electron reduction dramatically facilitates the ring opening of the azetidine heterocycle. Considering the overall quantum-chemistry findings, N,N-dimethylaniline is proposed as an efficient photosensitizer to trigger the photoinduced cycloreversion of the DNA lesion model.

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(1R,4S,5S)-5-((3-Hydroxypropyl)amino)-4-((1-Methyl-1H-tetrazol-5-yl)thio)Cyclopent-2-en-1-ol

Molbank ◽

10.3390/m1199 ◽

2021 ◽

Vol 2021 (2) ◽

pp. M1199

Author(s):

Milene A. G. Fortunato ◽

Filipa Siopa ◽

Carlos A. M. Afonso

Keyword(s):

Spectral Data ◽

13C Nmr ◽

Ring Opening ◽

Environmentally Friendly ◽

Mass Spectral Data ◽

Mass Spectral ◽

Excellent Yield ◽

Ring Opening Reaction ◽

Nucleophilic Ring Opening

Using environmentally friendly conditions, the nucleophilic ring-opening reaction of 6-azabicyclo[3.1.0]hex-3-en-2-ol with 1-methyl-1H-tetrazole-5-thiol provided a novel thiol-incorporated aminocyclopentitol, (1R,4S,5S)-5-((3-hydroxypropyl)amino)-4-((1-methyl-1H-tetrazol-5-yl)thio)cyclopent-2-en-1-ol, in excellent yield (95%). The newly synthesized compound was analyzed and characterized via 1H, 13C-NMR, HSQC, and mass spectral data.

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