- Five-fold-symmetric macrocyclic aromatic pentamers: High-affinity cation recognition, ion-pair-induced columnar stacking, and nanofibrillation
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Described in this study is a conceptually new class of five-fold-symmetric cavity-containing planar pentameric macrocycles with their interior decorated by five convergently aligned, properly spaced carbonyl oxygen atoms. These cation-binding oxygens enclose a hydrophilic lumen of 2.85 A in radius and thus display high-affinity binding toward alkali metal cations, and possibly many other cations, too. Arising from their high-affinity recognition of metal ions, these planar macrocycles form cation- or ion-pair-induced one-dimensional columnar aggregates, and subsequently fascinating fibrillation results.
- Ren, Changliang,Maurizot, Victor,Zhao, Huaiqing,Shen, Jie,Zhou, Feng,Ong, Wei Qiang,Du, Zhiyun,Zhang, Kun,Su, Haibin,Zeng, Huaqiang
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supporting information; experimental part
p. 13930 - 13933
(2011/10/30)
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- BOP-mediated one-pot synthesis of C5-symmetric macrocyclic pyridone pentamers
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We report here, for the first time, the BOP-mediated one-pot macrocyclization that is facilitated and guided by internally placed intramolecular H-bonds to allow for the highly selective formation of five-residue cation-binding macrocycles.
- Du, Zhiyun,Ren, Changliang,Ye, Ruijuan,Shen, Jie,Maurizot, Victor,Lu, Yujin,Wang, Jian,Zeng, Huaqiang
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supporting information; experimental part
p. 12488 - 12490
(2012/02/02)
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- Synthesis of N-modified 4-aminopyridine-3-carboxylates by ring transformation
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3-Methyl-5-nitropyrimidin-4(3H)-one reacted with enaminones to cause the ring transformation leading to functionalized 4-aminopyridines. Various kinds of amino groups can be introduced at the 4-position by modifying the enaminones. The modification of its vicinal positions was also possible. In addition, a bicyclic pyridine could be synthesized by making use of the vicinal functionality of a 4-aminopyridine-3-carboxylic acid. Georg Thieme Verlag Stuttgart.
- Nishiwaki, Nagatoshi,Nishimoto, Toyosato,Tamura, Mina,Ariga, Masahiro
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p. 1437 - 1439
(2007/10/03)
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- Perchloro-2,5,8-triazaphenalenyl radical
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(Chemical Equation Presented) The unusually stable perchloro-2,5,8- triazaphenalenyl radical 1 and its twisted dechlorinated dimer 2 were synthesized and characterized by ESR spectroscopy and X-ray crystallography. The X-ray structure of dimer 2 shows that the double bond connecting the two triazaphenalene systems is strongly twisted. Dimer 2 has a dramatic color shift from the solid state to solution, which may be due to a change of the twisting angle between both states.
- Zheng, Shijun,Thompson, Joe D.,Tontcheva, Ana,Khan, Saeed I.,Rubin, Yves
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p. 1861 - 1863
(2007/10/03)
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- Synthesis and transformations of alkyl 1,5-bis-(dimethylamino)-3-oxopenta-1,4-diene-2,4-dicarboxylates. A simple synthesis of dialkyl 1-substituted 4-oxo-1,4-dihydropyridine-3,5-dicarboxylates
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Dimethyl (2a) and diethyl 1,5-bis(dimethylamino)-3-oxo-penta-1,4-diene-2,4-dicarboxylate (2b), available in good yields from the corresponding dialkyl acetonedicarboxylates (1a, b) and N,N-dimethylformamide dimethyl acetal (DMFDMA), were used as reagents for a one-step preparation of 1-substituted 1,4-dihydropyridin-4-ones (3a-u). Thus, compounds (2) were treated with ammonia, hydrazines, and primary aliphatic, aromatic, or heterocyclic amines to form dialkyl 1-substituted 4-oxo-1,4-dihydropyridine-3,5-dicarboxylates (3a-u).
- Zupancic, Silvo,Svete, Jurij,Stanovnik, Branko
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p. 2033 - 2042
(2007/10/03)
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