Asymmetric organocatalytic sequential Michael-cyclization of functionalized nitroalkanes to 2-hydroxycinnamaldehydes: synthesis of benzofused dioxa[3.3.1] and oxa[4.3.1] methylene-bridged compounds

2021 ◽  
Author(s):  
Chen-Jun Peng ◽  
Jun-Ping Pei ◽  
Ying-Han Chen ◽  
Zhi-Yong Wu ◽  
Ming Liu ◽  
...  
Keyword(s):  
Conjugate Addition ◽  
Anion Binding ◽  
Reaction Sequence

An organocatalytic asymmetric conjugate addition-initiated reaction sequence of 2-hydroxycinnamaldehydes with various functionalized nitroalkanes has been described. The combination of iminium catalysis and thiourea anion-binding catalysis was found to be crucial...

An asymmetric multicatalytic reaction sequence of 2-hydroxycinnamaldehydes and enolic 1,3-dicarbonyl compounds to construct bridged bicyclic acetals

2020 ◽  
Vol 7 (2) ◽  
pp. 292-297 ◽  
Author(s):  
Xiao-Qian Zhang ◽  
Xue-Jiao Lv ◽  
Jun-Ping Pei ◽  
Rui Tan ◽  
Yan-Kai Liu
Keyword(s):  
Anion Binding ◽  
Reaction Sequence ◽  
Dicarbonyl Compounds

2-Hydroxycinnamaldehydes and cyclic 1,3-dicarbonyl nucleophiles were used in an asymmetric organocatalyzed reaction sequence to construct bridged bicyclic acetals via a multicatalytic process involving iminium catalysis and anion-binding catalysis.

Lewis Base Promoted, Direct 1,4-Conjugate Addition to Quinone Imine Ketals: Efficient Access to Unsymmetrical Diaryl Sulfones

Synthesis ◽  
2018 ◽  
Vol 51 (06) ◽  
pp. 1365-1376 ◽  
Author(s):  
Teng Liu ◽  
Feixiang Cheng ◽  
Jianjun Liu ◽  
Xianfu Shen ◽  
Jianbin Xu ◽  
...  
Keyword(s):  
High Efficiency ◽  
Conjugate Addition ◽  
Quinone Imine ◽  
Lewis Base ◽  
Elimination Reaction ◽  
Reaction Sequence ◽  
Efficient Approach ◽  
Efficient Access ◽  
Alternative Approach

An alternative approach with eco-friendliness and high efficiency for the preparation of unsymmetrical diaryl sulfones has been developed. The strategy takes advantage of the reaction of sulfonyl hydrazides with quinone imine ketals catalyzed by DABCO (triethylenediamine) in ethanol. This transformation proceeds via a Lewis base promoted, direct 1,4-conjugate addition/sulfonylation/alcohol elimination reaction sequence. The protocol provides an efficient approach to access an array of diverse unsymmetrical diaryl and heterodiaryl sulfones, aryl alkyl sulfones and aryl vinyl sulfones in good to excellent yields.

The Ability of Thrombin Inhibitors to Reduce the Thrombin Activity Generated in Plasma on Extrinsic and Intrinsic Activation

1997 ◽  
Vol 77 (03) ◽  
pp. 498-503 ◽  
Author(s):  
D Prasa ◽  
L Svendsen ◽  
J Stürzebecher
Keyword(s):  
Active Site ◽  
Thrombin Generation ◽  
Anion Binding ◽  
Thrombin Inhibitors ◽  
Coagulation System ◽  
Thrombin Activity ◽  
Continuous Registration ◽  
High Concentrations ◽  
20 Nm ◽  
Generation Test

SummaryIn a thrombin generation test with continuous registration of thrombin activity in plasma we studied the ability of a variety of thrombin inhibitors of different type and mechanism of action to influence the activity of thrombin after activation of the coagulation system. Depending on the inhibitor, the peak of thrombin activity is delayed and/or reduced.By blocking the active site of generated thrombin inhibitors cause a concentration dependent reduction of the thrombin peak and inhibit feed-back reactions of thrombin resulting in a delay of thrombin generation. Highly potent synthetic active-site directed inhibitors (Ki ≤ 20 nM) reduce the thrombin activity formed in plasma after extrinsic or intrinsic activation with the same efficiency (IC50 0.1 - 0.6 μM) as hirudin. The delay and reduction of thrombin generation by inhibitors of the anion-binding exosite 1 of thrombin is only attributed to an inhibition of feed-back reactions of thrombin. For a 50% reduction of thrombin activity in plasma by this type of inhibitors relatively high concentrations were determined.

An Efficient Imine Photocyclization as an Alternative to the Pictet-Spengler Reaction for the Synthesis of AzaBenzannulated Perylenediimide Dyes

2020 ◽  
Author(s):  
Antoine Goujon ◽  
Lou Rocard ◽  
Thomas Cauchy ◽  
Piétrick Hudhomme
Keyword(s):  
Solar Cells ◽  
Visible Light ◽  
Organic Solar Cells ◽  
Reaction Sequence ◽  
Large Scope ◽  
High Yields

AzaBenzannulated PDI (AzaBPDI) dyes were synthesized in high yields via a new reaction sequence involving an imine condensation followed by visible light-induced photocyclization. The large scope and efficiency of this alternative to the Pictet-Spengler reaction is demonstrated, and allows the easy preparation of dimeric AzaBPDI as potential non-fullerene acceptors for organic solar cells.

Cambiarenes: Single-Step Synthesis and Anion Binding of a Clip- Shaped Macrocycle with a Redox-Active Core

2019 ◽  
Author(s):  
Riley J. Petersen ◽  
Brett J. Rozeboom ◽  
Shalisa Oburn ◽  
Nolan Blythe ◽  
Tanner Rathje ◽  
...  
Keyword(s):  
Electron Density ◽  
Single Step ◽  
Anion Binding ◽  
Host Molecule ◽  
Selective Binding ◽  
The Core ◽  
Redox Active ◽  
Active Core ◽  
Guest Binding

<div>We report the synthesis of a novel macrocyclic host molecule that forms in a single step from commercially available starting materials. The core of the macrocycle backbone possesses two quinone rings and, thus, is redox-active. Host-guest binding involving the clip-shaped cavity indicates selective binding of pyridine <i>N</i>-oxides based of the electron density of and steric bulk of the anionic oxygen.</div>

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