scholarly journals Enantioenriched α-substituted glutamates/pyroglutamates via enantioselective cyclopropenimine-catalyzed Michael addition of amino ester imines

2021 ◽  
Vol 17 ◽  
pp. 2077-2084
Author(s):  
Zara M Seibel ◽  
Jeffrey S Bandar ◽  
Tristan H Lambert
Keyword(s):  
Functional Groups ◽  
Michael Addition ◽  
Enantioselective Synthesis ◽  
Amino Ester ◽  
Catalyst Structure ◽  
The Impact

A procedure for the enantioselective synthesis of α-substituted glutamates and pyroglutamates via a cyclopropenimine-catalyzed Michael addition of amino ester imines is described. Enantioselectivities of up to 94% have been achieved, and a variety of functional groups were found to be compatible. The impact of the catalyst structure and imine substitution is discussed. Compared to other methods, this protocol allows for a broader and more enantioselective access to pyroglutamate derivatives.

scholarly journals Synthesis and Biological Activity of Brassinosteroid Analogues with a Nitrogen-Containing Side Chain

2020 ◽  
Vol 22 (1) ◽  
pp. 155
Author(s):  
Mikhail V. Diachkov ◽  
Karoll Ferrer ◽  
Jana Oklestkova ◽  
Lucie Rarova ◽  
Vaclav Bazgier ◽  
...  
Keyword(s):  
Biological Activity ◽  
Functional Groups ◽  
Side Chain ◽  
Biotic And Abiotic Stresses ◽  
Short Side ◽  
Arabidopsis Root ◽  
Physiological Processes ◽  
Growth Promoting ◽  
The Impact ◽  
Brassinosteroid Analogues

Brassinosteroids are a class of plant hormones that regulate a broad range of physiological processes such as plant growth, development and immunity, including the suppression of biotic and abiotic stresses. In this paper, we report the synthesis of new brassinosteroid analogues with a nitrogen-containing side chain and their biological activity on Arabidopis thaliana. Based on molecular docking experiments, two groups of brassinosteroid analogues were prepared with short and long side chains in order to study the impact of side chain length on plants. The derivatives with a short side chain were prepared with amide, amine and ammonium functional groups. The derivatives with a long side chain were synthesized using amide and ammonium functional groups. A total of 25 new brassinosteroid analogues were prepared. All 25 compounds were tested in an Arabidopsis root sensitivity bioassay and cytotoxicity screening. The synthesized substances showed no significant inhibitory activity compared to natural 24-epibrassinolide. In contrast, in low concentration, several compounds (8a, 8b, 8e, 16e, 22a and 22e) showed interesting growth-promoting activity. The cytotoxicity assay showed no toxicity of the prepared compounds on cancer and normal cell lines.

ChemInform Abstract: Highly Enantioselective Synthesis of α-Fluoro-α-nitro Esters via Organocatalyzed Asymmetric Michael Addition.

ChemInform ◽  
2011 ◽  
Vol 42 (16) ◽  
pp. no-no
Author(s):  
Hai-Feng Cui ◽  
Peng Li ◽  
Xiao-Wei Wang ◽  
Zhuo Chai ◽  
Ying-Quan Yang ◽  
...  
Keyword(s):  
Michael Addition ◽  
Enantioselective Synthesis ◽  
Asymmetric Michael Addition ◽  
Nitro Esters

scholarly journals Enantioselective synthesis of seven-membered carbo- and heterocyles by organocatalyzed intramolecular Michael addition

RSC Advances ◽  
2016 ◽  
Vol 6 (36) ◽  
pp. 30166-30169 ◽  
Author(s):  
James O. Guevara-Pulido ◽  
José M. Andrés ◽  
Deisy P. Ávila ◽  
Rafael Pedrosa
Keyword(s):  
Michael Addition ◽  
Enantioselective Synthesis ◽  
High Yields

Enantioenriched seven membered rings have been prepared in high yields and stereoselectivities by intramolecular Michael addition of functionalized enals catalyzed by Jorgensen–Hayashi catalyst.

scholarly journals Interactions, information and emergence: Exploring task allocation in ant colonies using network analysis

2021 ◽  
Author(s):  
Anshuman Swain ◽  
Sara D Williams ◽  
Louisa J Di Felice ◽  
Elizabeth A Hobson
Keyword(s):  
Network Analysis ◽  
Functional Groups ◽  
Task Allocation ◽  
Interaction Networks ◽  
Group Level ◽  
Ant Colonies ◽  
Individual Level ◽  
Network Measures ◽  
Interaction History ◽  
The Impact

In animal societies, individuals may take on different roles to fulfil their own needs and the needs of their groups. Ant colonies display high levels of organisational complexity, with ants fulfilling different roles at different timescales (what is known as task allocation). Factors affecting task allocation can be at the individual level (e.g., physiology), or at the group level (e.g., interaction histories). In this work, we focus on group level processes by exploring the impact of the history of interaction networks on task allocation and task switching using a previously published dataset (Mersch et al., 2013) tracking the behaviour of six Camponotus fellah colonies over 41 days. First, we investigated the architecture of interaction networks using node (individual) level network measures and their relation to the individual's task - foraging, cleaning or nursing - and whether or not the ant switched tasks. We then explored how noisy information propagation is among ants, as a function of the colony composition (how many ants are carrying out which tasks), through the information-theoretic metric of effective information. Our results show that interaction history affected task allocation, with ants more likely to switch to a task if they had interacted with other ants carrying out that task. The degree to which interaction history affected task allocation, as well as the noise in their interactions, depended on which groups of ants are interacting. Overall, we showed that colony cohesion is stable even as ant-level network measures vary more for ants when they switched functional groups; thus ant colonies maintain a high level of information flow as determined by network analysis and ant functional groups play different roles in maintaining colony cohesion.

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