Rapid and Effective Reaction of 2-Methylpyridin-N-oxides with Triphosgene via a [3,3]-Sigmatropic Rearrangement: Mechanism and Applications

2021 ◽  
Author(s):  
Hao Li ◽  
Hong-Cheng Xia ◽  
Fang-Yuan Nie ◽  
Qin-Hua Song
Keyword(s):  
Sigmatropic Rearrangement ◽  
Rearrangement Mechanism ◽  
Effective Reaction

scholarly journals Gold-catalyzed intermolecular coupling of sulfonylacetylene with allyl ethers: [3,3]- and [1,3]-rearrangements

2013 ◽  
Vol 9 ◽  
pp. 1724-1729 ◽  
Author(s):  
Jungho Jun ◽  
Hyu-Suk Yeom ◽  
Jun-Hyun An ◽  
Seunghoon Shin
Keyword(s):  
Gold Catalyst ◽  
Sigmatropic Rearrangement ◽  
Allyl Ethers ◽  
Rearrangement Mechanism ◽  
Intermolecular Coupling

Gold-catalyzed intermolecular couplings of sulfonylacetylenes with allyl ethers are reported. A cooperative polarization of alkynes both by a gold catalyst and a sulfonyl substituent resulted in an efficient intermolecular tandem carboalkoxylation. Reactions of linear allyl ethers are consistent with the [3,3]-sigmatropic rearrangement mechanism, while those of branched allyl ethers provided [3,3]- and [1,3]-rearrangement products through the formation of a tight ion–dipole pair.

Solvent-assisted osmium staining of butyl acrylate and ethylene-propylene-diene in a styrene acrylonitrile matrix

1993 ◽  
Vol 51 ◽  
pp. 900-901 ◽  
Author(s):  
Gudrun A. Hutchins
Keyword(s):  
Butyl Acrylate ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Staining Procedure ◽  
Reactive Site ◽  
Ethylene Propylene ◽  
Minimal Distortion ◽  
Styrene Acrylonitrile ◽  
Engineering Polymers ◽  
Effective Reaction

In order to optimize the toughening effect of elastomers in engineering polymers, it is necessary to characterize the size, morphology and dispersion of the specific elastomer within the polymer matrix. For unsaturated elastomers such as butadiene or isoprene, staining with osmium tetroxide is a well established procedure. The residual carbon-carbon double bond in these materials is the reactive site and forms a 1,2-dilato complex with the OsO4. Incorporation of osmium tetroxide into the elastomer not only produces sufficient contrast for TEM, but also crosslinks the elastomer sufficiently so that ultramicrotomy can be accomplished at room temperature with minimal distortion.Blends containing saturated elastomers such as butyl acrylate (BA) and ethylene propylene diene monomer (EPDM) cannot be stained directly with OsO4 because effective reaction sites such as C=C or -NH2 are not available in sufficient number. If additional reaction sites can be introduced selectively into the elastomer by a chemical reaction or the absorption of a solvent, a modified, two-step osmium staining procedure is possible.

scholarly journals Fusion genes in gynecologic tumors: the occurrence, molecular mechanism and prospect for therapy

2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Bingfeng Lu ◽  
Ruqi Jiang ◽  
Bumin Xie ◽  
Wu Wu ◽  
Yang Zhao
Keyword(s):  
Tumor Progression ◽  
Massively Parallel Sequencing ◽  
Gynecologic Cancer ◽  
Endometrial Stromal Sarcoma ◽  
Driver Mutations ◽  
Fusion Genes ◽  
Stromal Sarcoma ◽  
Uterine Tumors ◽  
Rearrangement Mechanism ◽  
Gynecologic Tumors

AbstractGene fusions are thought to be driver mutations in multiple cancers and are an important factor for poor patient prognosis. Most of them appear in specific cancers, thus satisfactory strategies can be developed for the precise treatment of these types of cancer. Currently, there are few targeted drugs to treat gynecologic tumors, and patients with gynecologic cancer often have a poor prognosis because of tumor progression or recurrence. With the application of massively parallel sequencing, a large number of fusion genes have been discovered in gynecologic tumors, and some fusions have been confirmed to be involved in the biological process of tumor progression. To this end, the present article reviews the current research status of all confirmed fusion genes in gynecologic tumors, including their rearrangement mechanism and frequency in ovarian cancer, endometrial cancer, endometrial stromal sarcoma, and other types of uterine tumors. We also describe the mechanisms by which fusion genes are generated and their oncogenic mechanism. Finally, we discuss the prospect of fusion genes as therapeutic targets in gynecologic tumors.

scholarly journals Copper-Catalyzed Synthesis of Axially Chiral Biaryls with Diaryliodonium Salts as Arylation Reagents

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3223
Author(s):  
Ji-Wei Zhang ◽  
Shao-Hua Xiang ◽  
Shaoyu Li ◽  
Bin Tan
Keyword(s):  
Amino Alcohols ◽  
Sigmatropic Rearrangement ◽  
Synthetic Route ◽  
Mild Conditions ◽  
Good Substrate ◽  
Diaryliodonium Salts ◽  
Axially Chiral

NOBIN and BINAM derivatives harboring biaryl frameworks are recognized as a class of important atropisomers with versatile applications. Here, we present an efficient synthetic route to access such compounds through copper-catalyzed domino arylation of N-arylhydroxylamines or N-arylhydrazines with diaryliodonium salts and [3,3]-sigmatropic rearrangement. This reaction features mild conditions, good substrate compatibility, and excellent efficiency. The practicality of this protocol was further extended by the synthesis of biaryl amino alcohols.

An Umpolung Oxa-[2,3] Sigmatropic Rearrangement Employing Arynes for the Synthesis of Functionalized Enol Ethers

2021 ◽  
Author(s):  
Rahul N. Gaykar ◽  
Malini George ◽  
Avishek Guin ◽  
Subrata Bhattacharjee ◽  
Akkattu T. Biju
Keyword(s):  
Sigmatropic Rearrangement ◽  
Enol Ethers

scholarly journals Effect of ammonia and water molecule on OH + CH3OH reaction under tropospheric condition

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohamad Akbar Ali ◽  
M. Balaganesh ◽  
Faisal A. Al-Odail ◽  
K. C. Lin
Keyword(s):  
Water Molecule ◽  
Energy Surface ◽  
Rate Coefficient ◽  
Water Concentration ◽  
State Theory ◽  
Rate Coefficients ◽  
Hydrogen Atoms ◽  
Experimental And Theoretical Studies ◽  
Effective Reaction ◽  
Effective Reaction Rate

AbstractThe rate coefficients for OH + CH3OH and OH + CH3OH (+ X) (X = NH3, H2O) reactions were calculated using microcanonical, and canonical variational transition state theory (CVT) between 200 and 400 K based on potential energy surface constructed using CCSD(T)//M06-2X/6-311++G(3df,3pd). The results show that OH + CH3OH is dominated by the hydrogen atoms abstraction from CH3 position in both free and ammonia/water catalyzed ones. This result is in consistent with previous experimental and theoretical studies. The calculated rate coefficient for the OH + CH3OH (8.8 × 10−13 cm3 molecule−1 s−1), for OH + CH3OH (+ NH3) [1.9 × 10−21 cm3 molecule−1 s−1] and for OH + CH3OH (+ H2O) [8.1 × 10−16 cm3 molecule−1 s−1] at 300 K. The rate coefficient is at least 8 order magnitude [for OH + CH3OH(+ NH3) reaction] and 3 orders magnitude [OH + CH3OH (+ H2O)] are smaller than free OH + CH3OH reaction. Our calculations predict that the catalytic effect of single ammonia and water molecule on OH + CH3OH reaction has no effect under tropospheric conditions because the dominated ammonia and water-assisted reaction depends on ammonia and water concentration, respectively. As a result, the total effective reaction rate coefficients are smaller. The current study provides a comprehensive example of how basic and neutral catalysts effect the most important atmospheric prototype alcohol reactions.

scholarly journals Imino‐λ 3 ‐iodane and Catalytic Amount of I 2 ‐Mediated Synthesis of N ‐Allylsulfenamides via [2,3]‐Sigmatropic Rearrangement

2020 ◽  
Vol 2020 (41) ◽  
pp. 6433-6439
Author(s):  
Cody L. Makitalo ◽  
Akira Yoshimura ◽  
Gregory T. Rohde ◽  
Irina A. Mironova ◽  
Rosa Y. Yusubova ◽  
...  
Keyword(s):  
Catalytic Amount ◽  
Sigmatropic Rearrangement

Catalyst-Free [2,3]-Sigmatropic Rearrangement Reactions of Photochemically Generated Ammonium Ylides

Synthesis ◽  
2019 ◽  
Vol 51 (23) ◽  
pp. 4348-4358 ◽  
Author(s):  
Fang Li ◽  
Feifei He ◽  
Rene M. Koenigs
Keyword(s):  
Visible Light ◽  
Sigmatropic Rearrangement ◽  
Tertiary Amines ◽  
Amino Esters ◽  
Catalyst Free ◽  
Rearrangement Reaction ◽  
Rearrangement Reactions ◽  
Free Ammonium

The rearrangement reaction of ammonium ylides furnishes valuable α,α-disubstituted amino esters. In this work, we describe the visible-light photolysis reaction of aryldiazoacetates in the presence of tertiary amines that react via a free ammonium ylide in a sigmatropic rearrangement reaction to provide amino esters in moderate to very good yields (33 examples, up to 97% yield).

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