Insight into the Mechanisms of the Ethylbenzene Disproportionation: Transition State Shape Selectivity on Zeolites

2008 ◽  
Vol 130 (38) ◽  
pp. 12642-12644 ◽  
Author(s):  
Jun Huang ◽  
Yijiao Jiang ◽  
V. R. Reddy Marthala ◽  
Michael Hunger
Keyword(s):  
Transition State ◽  
Shape Selectivity ◽  
Insight Into

scholarly journals Single-cell evaluation reveals shifts in the tumor-immune niches that shape and maintain aggressive lesions in the breast

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Vidya C. Sinha ◽  
Amanda L. Rinkenbaugh ◽  
Mingchu Xu ◽  
Xinhui Zhou ◽  
Xiaomei Zhang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
T Cells ◽  
Mouse Model ◽  
Transition State ◽  
Tumor Cell ◽  
Single Cell ◽  
Tumor Cells ◽  
Breast Lesions ◽  
Aggressive Tumor ◽  
Insight Into

AbstractThere is an unmet clinical need for stratification of breast lesions as indolent or aggressive to tailor treatment. Here, single-cell transcriptomics and multiparametric imaging applied to a mouse model of breast cancer reveals that the aggressive tumor niche is characterized by an expanded basal-like population, specialization of tumor subpopulations, and mixed-lineage tumor cells potentially serving as a transition state between luminal and basal phenotypes. Despite vast tumor cell-intrinsic differences, aggressive and indolent tumor cells are functionally indistinguishable once isolated from their local niche, suggesting a role for non-tumor collaborators in determining aggressiveness. Aggressive lesions harbor fewer total but more suppressed-like T cells, and elevated tumor-promoting neutrophils and IL-17 signaling, disruption of which increase tumor latency and reduce the number of aggressive lesions. Our study provides insight into tumor-immune features distinguishing indolent from aggressive lesions, identifies heterogeneous populations comprising these lesions, and supports a role for IL-17 signaling in aggressive progression.

The Structure of the Decalone Obtained From the Oxidation of Guaiol

1992 ◽  
Vol 45 (2) ◽  
pp. 327 ◽  
Author(s):  
RM Carman ◽  
AC Garner ◽  
WT Robinson
Keyword(s):  
Transition State ◽  
Crystallographic Analysis ◽  
Ring System ◽  
X Ray ◽  
Fused Ring ◽  
Fused Ring System ◽  
Insight Into

The structure of the decalone previously reported from the oxidation of guaiol has, after X-ray crystallographic analysis, been revised to structure (3c) which contains a cis -fused ring system. Deuteration studies give insight into the conformation of the transition state during the reaction.

scholarly journals Analysis of transition state mimicry by tight binding aminothiazoline inhibitors provides insight into catalysis by human O-GlcNAcase

2016 ◽  
Vol 7 (6) ◽  
pp. 3742-3750 ◽  
Author(s):  
N. Cekic ◽  
J. E. Heinonen ◽  
K. A. Stubbs ◽  
C. Roth ◽  
Y. He ◽  
...  
Keyword(s):  
Transition State ◽  
Tight Binding ◽  
Insight Into

2′-Aminothiazoline inhibitors of human OGA are tight binding transition state mimics for which binding depends on inhibitor pKa.

scholarly journals Ni/Photoredox-Catalyzed Enantioselective Cross-Electrophile Coupling of Styrene Oxides with Aryl Iodides

2021 ◽  
Author(s):  
Sii Hong Lau ◽  
Meredith Borden ◽  
Talia Steiman ◽  
Lucy Wang ◽  
Marvin Parasram ◽  
...  
Keyword(s):  
Linear Regression ◽  
Transition State ◽  
Cross Coupling ◽  
Reductive Coupling ◽  
Mechanistic Studies ◽  
State Structure ◽  
Transition State Structure ◽  
Aryl Iodides ◽  
Electronic Character ◽  
Insight Into

A Ni/photoredox-catalyzed enantioselective reductive coupling of styrene oxides and aryl iodides is reported. This reaction affords access to enantioenriched 2,2-diarylalcohols from racemic epoxides via a stereoconvergent mechanism. Multivariate linear regression (MVLR) analysis with 29 bioxazoline (BiOx) and biimidazoline (BiIm) ligands revealed that enantioselectivity correlates with electronic properties of the ligands, with more electron-donating ligands affording higher ee’s. Mechanistic studies were conducted, lending support to the hypothesis that the electronic character of the ligands influences the enantioselectivity by altering the position of the transition state structure along the reaction coordinate. This study demonstrates the benefits of utilizing statistical modeling as a platform for mechanistic understanding and provides new insight into an emerging class of chiral ligands for stereoconvergent Ni and Ni/photoredox cross-coupling.

The acidity of β-phosphoglucomutase monofluoromethylenephosphonate ligands probed by NMR spectroscopy and quantum mechanical methods

2016 ◽  
Vol 94 (11) ◽  
pp. 902-908 ◽  
Author(s):  
Stephanie M. Forget ◽  
Eric A.C. Bushnell ◽  
Russell J. Boyd ◽  
David L. Jakeman
Keyword(s):  
Nmr Spectroscopy ◽  
Transition State ◽  
Quantum Mechanical ◽  
Phosphoryl Transfer ◽  
Quantum Mechanical Calculations ◽  
Transition State Analogues ◽  
Mechanical Methods ◽  
Insight Into ◽  
Computational Quantum

We recently described the binding of 1-β-phosphonomethylene-1-deoxy-d-glucopyranose, (S)-1-β-phosphonofluoromethylene-1-deoxy-D-glucopyranose (βG1CFSP), and (R)-1-β-phosphonofluoromethylene-1-deoxy-d-glucopyranose (βG1CFRP) to the enzyme β-phosphoglucomutase as transition state analogues of phosphoryl transfer through formation of stable MgF3− and AlF4− complexes (Proc. Natl. Acad. Sci. U.S.A. 2014, 111, 12384). Herein, we describe in detail the five-fold difference in acidity (pKa2) for the (S)- and (R)-configured diastereomeric fluorophosphonates through a series of NMR spectroscopy experiments. The differences in acidity were corroborated using computational quantum mechanical calculations to determine structures of lowest energy conformers and provide insight into why the (S) isomer is substantially more acidic.

scholarly journals Single-cell evaluation reveals shifts in the tumor-immune niches that shape and maintain aggressive lesions in the breast

2021 ◽  
Author(s):  
Vidya C. Sinha ◽  
Amanda L. Rinkenbaugh ◽  
Mingchu Xu ◽  
Xinhui Zhou ◽  
Xiaomei Zhang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
T Cells ◽  
Mouse Model ◽  
Transition State ◽  
Tumor Cell ◽  
Single Cell ◽  
Tumor Cells ◽  
Breast Lesions ◽  
Aggressive Tumor ◽  
Insight Into

Abstract There is an unmet clinical need for stratification of breast lesions as indolent or aggressive to tailor treatment. Here, single-cell transcriptomics and multiparametric imaging applied to a mouse model of breast cancer revealed that the aggressive tumor niche is characterized by an expanded basal-like population, specialization of tumor subpopulations, and mixed-lineage tumor cells potentially serving as a transition state between luminal and basal phenotypes. Despite vast tumor cell-intrinsic differences, aggressive and indolent tumor cells were functionally indistinguishable once isolated from their local niche, suggesting a role for non-tumor collaborators in determining aggressiveness. Aggressive lesions harbored fewer total but more suppressed-like T cells, and elevated tumor-promoting neutrophils and IL-17 signaling, disruption of which increased tumor latency and reduced the number of aggressive lesions. Our study provides insight into tumor-immune features distinguishing indolent from aggressive lesions, identifies heterogeneous populations comprising these lesions, and supports a role for IL-17 signaling in aggressive progression.

Why do the Togni reagent and some of its derivatives exist in the high-energy hypervalent iodine form? New insight into the origins of their kinetic stability

2017 ◽  
Vol 19 (48) ◽  
pp. 32179-32183 ◽  
Author(s):  
Shungo Koichi ◽  
Benjamin Leuthold ◽  
Hans P. Lüthi
Keyword(s):  
Transition State ◽  
Thermodynamic Stability ◽  
High Energy ◽  
Kinetic Stability ◽  
Hypervalent Iodine ◽  
Insight Into

A scheme for the prediction of the kinetic and thermodynamic stability of Togni-type reagents is presented. The scheme is evaluated based on computations of the isomerization and transition state energies of an array of more than 600 compounds.

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