- Carborane-containing urea-based inhibitors of glutamate carboxypeptidase II: Synthesis and structural characterization
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Glutamate carboxypeptidase II (GCPII) is a zinc metalloprotease on the surface of astrocytes which cleaves N-acetylaspartylglutamate to release N-acetylaspartate and glutamate. GCPII inhibitors can decrease glutamate concentration and play a protective role against apoptosis or degradation of brain neurons. Herein, we report the synthesis and structural analysis of novel carborane-based GCPII inhibitors. We determined the X-ray crystal structure of GCPII in complex with a carborane-containing inhibitor at 1.79 ? resolution. The X-ray analysis revealed that the bulky closo-carborane cluster is located in the spacious entrance funnel region of GCPII, indicating that the carborane cluster can be further structurally modified to identify promising lead structures of novel GCPII inhibitors.
- Youn, Sihyun,Kim, Kyung Im,Ptacek, Jakub,Ok, Kiwon,Novakova, Zora,Kim, YunHye,Koo, JaeHyung,Barinka, Cyril,Byun, Youngjoo
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- Rh-Catalyzed Regioselective Dialkylation of Cage B-H bonds in o-Carboranes: Oxidative Heck Reactions via an Enol Isomerization
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In the presence of a carboxylic acid directing group, Rh-catalyzed regioselective directed dialkylation of B(4,5)-H bonds in o-carboranes and oxidative coupling with allylic alcohols is reported. This strategy constructs a series of 4,5-dialkylated o-carboranes in good yields with excellent regioselectivity. A possible catalytic cycle is proposed that involves a tandem sequence of Rh-catalyzed cage B-H activation, alkene insertion, selective β-H elimination, enol isomerization, and decarboxylation.
- Wang, Qian,Tian, Song,Zhang, Chuyi,Li, Jiangwei,Wang, Zhixuan,Du, Yongmei,Zhou, Ling,Lu, Jian
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supporting information
p. 8018 - 8021
(2019/10/19)
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- Reduction of hydroxy-functionalised carbaboranyl carboxylic acids to tertiary alcohols by organolithium reagents
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Reduction of hydroxy-functionalised carbaboranyl carboxylic acids by organolithium reagents yields the corresponding tertiary alcohols. This is in contrast to exo-polyhedral C-C bond cleavage of unsubstituted carbaboranyl carboxylic acids upon reaction with lithium organyls. The proposed dimeric contact ion pairs may also explain the formation of tertiary alcohols instead of the expected ketones.
- Neumann, Wilma,Hiller, Markus,Loennecke, Peter,Hey-Hawkins, Evamarie
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supporting information
p. 4935 - 4937
(2014/04/03)
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- Synthesis of 3-Amino-1-carboxy-o-carborane and an Improved, General Method for the Synthesis of All Three C-Amino-C-carboxycarboranes
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Amino acids of the polyhedral carboranes have potential applications in boron neutron capture therapy and in other areas of bioorganic chemistry, but simple, general methods for their synthesis are nonexistent. A general method for synthesis of C-amino-C-carboxy derivatives of o-, m-, and p-carborane is reported, starting from their respective monoacids and proceeding through nucleophilic attack by an alcohol on the intermediateC-isocyanates. Deprotection of the resulting carbamates provides a simp le method for access to the C-amines. Alternatively, the C-isocyanates can be isolated for further reactions. Carbonylation of the carbamates atthe remaining carboranyl CH results in high-yield production of the car bamate-protected amino acid. Another related method for the high-yield preparation of the isomeric 3-amino-1-carboxy-o-carborane is also described which makes available for the first time all four reasonably accessible members of the series.
- Kasar, Ramesh A.,Knudsen, Giselle M.,Kahl, Stephen B.
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p. 2936 - 2940
(2008/10/08)
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- Tumour-targetted Boranes. Part 3. Synthesis of Carbamate-linked Nitroimidazolyl Carboranes Designed for Boron Neutron Capture Therapy of Cancer
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Carboranes targetted to specific tumour tissues are important for boron neutron capture therapy of cancer (BNCT).Carbamoylation of 2-ethoxy>ethanol 5 and 1-(chloromethyl-2-(nitroimidazol-1-yl)ethanol 6 with carboran-1-yl isocyanate (generated in situ by a Curtius rearrangement of carborane-1-carbonyl azide) gave the corresponding carbamate-linked nitroimidazolylcarboranes 16 and 17.A similar reaction of 4-carboranylphenyl isocyanate with 6 afforded the corresponding carbamate 24.
- Scobie, Martin,Threadgill, Michael D.
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p. 2059 - 2064
(2007/10/02)
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