- Design, synthesis, and biological evaluation of structurally constrained hybrid analogues containing ropinirole moiety as a novel class of potent and selective dopamine D3 receptor ligands
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Two series of hybrid analogues were designed, synthesized, and evaluated as a novel class of selective ligands for the dopamine D3 receptor. Binding affinities of target compounds were determined (using the method of radioligand binding assay). Compared to comparator agent BP897, compounds 2a and 2c were found to demonstrate a considerable binding affinity and selectivity for D3 receptor, and especially compound 2h was similarly potent and more selective D3R ligand than BP897, a positive reference. Thus, they may provide valuable information for the discovery and development of highly potent dopamine D3 receptor ligands with outstanding selectivity.
- Zhou, Benhua,Hong, Kwon Ho,Ji, Min,Cai, Jin
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p. 1597 - 1609
(2018/07/31)
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- Charge-transfer-directed radical substitution enables para-selective C-H functionalization
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Efficient C-H functionalization requires selectivity for specific C-H bonds. Progress has been made for directed aromatic substitution reactions to achieve ortho and meta selectivity, but a general strategy for para-selective C-H functionalization has remained elusive. Herein we introduce a previously unappreciated concept that enables nearly complete para selectivity. We propose that radicals with high electron affinity elicit arene-to-radical charge transfer in the transition state of radical addition, which is the factor primarily responsible for high positional selectivity. We demonstrate with a simple theoretical tool that the selectivity is predictable and show the utility of the concept through a direct synthesis of aryl piperazines. Our results contradict the notion, widely held by organic chemists, that radical aromatic substitution reactions are inherently unselective. The concept of radical substitution directed by charge transfer could serve as the basis for the development of new, highly selective C-H functionalization reactions.
- Boursalian, Gregory B.,Ham, Won Seok,Mazzotti, Anthony R.,Ritter, Tobias
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p. 810 - 815
(2016/07/29)
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