- Biphenyl substituted piperazine derivative synthesis method
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The invention discloses a biphenyl substituted piperazine derivative 4-(N-Boc-piperazine-3-yl)biphenyl synthesis method. 4-acetyl biphenyl is taken as a starting material and subjected to oxidation, cyclization and Boc addition to obtain a target product. A biphenyl substituted piperazine derivative which is a compound is an important medical intermediate.
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Paragraph 0023; 0024
(2017/08/29)
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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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- Synthesis and characterization of brain penetrant prodrug of neuroprotective D-264: Potential therapeutic application in the treatment of Parkinson's disease
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Parkinson's disease (PD) is one of the major debilitating neurodegenerative disorders affecting millions of people worldwide. Progressive loss of dopamine neurons resulting in development of motor dysfunction and other related non-motor symptoms is the hallmark of PD. Previously, we have reported on the neuroprotective property of a potent D3 preferring agonist D-264. In our goal to increase the bioavailability of D-264 in the brain, we have synthesized a modified cysteine based prodrug of D-264 and evaluated its potential in crossing the blood-brain barrier. Herein, we report the synthesis of a novel modified cysteine conjugated prodrug of potent neuroprotective D3 preferring agonist D-264 and systematic evaluation of the hydrolysis pattern of the prodrug to yield D-264 at different time intervals in rat plasma and brain homogenates using HPLC analysis. Furthermore, we have also performed in vivo experiments with the prodrug to evaluate its enhanced brain penetration ability.
- Dholkawala, Fahd,Voshavar, Chandrashekhar,Dutta, Aloke K.
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- Structural modifications of neuroprotective anti-parkinsonian (-)-N6-(2-(4-(biphenyl-4-yl)piperazin-1-yl)-ethyl)-N6-propyl-4,5,6, 7-tetrahydrobenzo[d]thiazole-2,6-diamine (D-264): An effort toward the improvement of in vivo efficacy of the parent molecule
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In our overall goal to develop multifunctional dopamine D 2/D3 agonist drugs for the treatment of Parkinson's disease (PD), we previously synthesized potent D3 preferring agonist D-264 (1a), which exhibited neuroprotective properties in two animal models of PD. To enhance the in vivo efficacy of 1a, a structure-activity relationship study was carried out. Competitive binding and [35S]GTPγS functional assays identified compound (-)-9b as one of the lead molecules with preferential D3 agonist activity (EC50(GTPγS); D3 = 0.10 nM; D2/D3 (EC50): 159). Compounds (-)-9b and (-)-8b exhibited high in vivo activity in two PD animal models, reserpinized and 6-hydroxydopamine (OHDA)-induced unilateral lesioned rats. On the other hand, 1a failed to show any in vivo activity in these models unless the compound was dissolved in 5-10% beta-hydroxy propyl cyclodextrin solution. Lead compounds exhibited appreciable radical scavenging activity. In vitro experiments with dopaminergic MN9D cells indicated neuroprotection by both 1a and (-)-9b from toxicity of MPP+.
- Modi, Gyan,Antonio, Tamara,Reith, Maarten,Dutta, Aloke
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p. 1557 - 1572
(2014/03/21)
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- Further delineation of hydrophobic binding sites in dopamine D 2/D3 receptors for N-4 substituents on the piperazine ring of the hybrid template 5/7-{[2-(4-aryl-piperazin-1-yl)-ethyl]-propyl-amino}-5, 6,7,8-tetrahydro-naphthalen-2-ol
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Here we report a structure-activity relationship (SAR) study of analogues of 5/7-{[2-(4-aryl-piperazin-1-yl)-ethyl]-propyl-amino}-5,6,7,8-tetrahydro- naphthalen-2-ol. Our SAR is focused on introduction of various substitutions in the piperazine ring of the hybrid template. The goal behind this study is to delineate the nature of the binding pocket for N-aryl substitution in the piperazine ring by observing the effect of various hydrophobic and other heteroaromatic substitutions on binding affinity (Ki), as measured with tritiated spiperone and HEK-293 cells expressing either D2 or D3 receptors. Functional activity of selected compounds was assessed with the GTPγS binding assay. Compound 8d was the most selective for the D3 receptor in the spiperone binding assay. An interesting similarity in binding affinity was observed between isoquinoline derivative D-301 and the 2-substituted pyridine derivative 8d, suggesting the importance of relative spatial relationships between the N-atom of the ligand and the molecular determinants of the binding pocket in D2/D3 receptors. Functional activity assays demonstrated high potency and selectivity of (+)-8a and (-)-28b (D2/D3 (ratio of EC50): 105 and 202, respectively) for the D3 receptor and both compounds were more selective compared to the reference drug ropinirole (D2/D3 (ratio of EC50): 29.5).
- Ghosh, Balaram,Antonio, Tamara,Gopishetty, Bhaskar,Reith, Maarten,Dutta, Aloke
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experimental part
p. 5661 - 5674
(2010/10/01)
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- SYNTHESIS AND USE OF HETEROCYCLIC ANTIBACTERIAL AGENTS
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This invention relates to compounds of the following Formula (I); or a pharmaceutically acceptable salt, solvate, ester or isomer thereof, which is useful for the treatment of diseases or conditions mediated by LpxC.
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Page/Page column 51; 52
(2010/01/30)
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- Substituted piperazine derivatives, the preparation thereof and their use as medicaments
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The present invention relates to substituted piperazine derivatives of general formula wherein Ra, Rb, RcRf, Rgand m, n and X are defined as in claim 1, the isomers and salts thereof, particularly the
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- Synthesis of potent and selective dopamine D4 antagonists as candidate radioligands
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A series of dopamine D4 antagonists was synthesized and evaluated as potential candidates for development as positron emission tomography (PET) radioligands. All new compounds display high affinity and selectivity for the D4 receptors and compounds 5b, 5d, and 5e were identified as candidates for radioligand development.
- Huang, Yiyun,Kegeles, Lawrence S.,Bae, Sung-A,Hwang, Dah-ren,Roth, Bryan L.,Savage, Jason E.,Laruelle, Marc
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p. 1375 - 1377
(2007/10/03)
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