- Molecular recognition principles and stationary-phase characteristics of topoisomer-selective chemoaffinity materials for chromatographic separation of circular plasmid DNA topoisomers
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We recently discovered the molecular recognition capability of a quinine carbamate ligand attached to silica as a powerful chemoaffinity material for the chromatographic separation of circular plasmid topoisomers of different linking numbers. In this paper we develop structure-selectivity relationship studies to figure out the essential structural features for topoisomer recognition. By varying different moieties of the original cinchonan-derived selector, it was shown that intercalation by the quinoline moiety of the ligand as assumed initially as the working hypothesis is not an essential feature for topoisomer recognition during chromatography. We found that the key elements for topoisomer selectivity are the presence of a rigid weak anion-exchange site and a H-donor site separated from each other in a defined distance by a 4-atom spacer. Additionally, incorporation of the weak anion-exchange site into a cyclic ring structure provides greater rigidity of the ligand molecule and turned out to be advantageous, if not mandatory, for (close to) baseline separation.
- Mahut, Marek,Lindner, Wolfgang,Laemmerhofer, Michael
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- Direct access of the chiral quinolinyl core of cinchona alkaloids via a br?nsted acid and chiral amine co-catalyzed chemo- and enantioselective α-alkylation of quinolinylmethanols with enals
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A strategy for the facile construction of the chiral quinolinylmethanolic structure, a core featured in cinchona alkaloids, is reported. A new reactivity is harnessed by TfOH-promoted chemoselective activation of α-C-H over O-H bond in quinolinylmethanols. The new reactivity is successfully engineered with an iminium catalysis in a synergistic manner to create a powerful conjugate addition-cyclization cascade process for synthesis of chiral quinoline derived π-butyrolactones in good yields and with good to excellent enantioselectivities. The method enables the first total synthesis of natural product broussonetine in three steps.
- Tong, Mengchao,Wang, Sinan,Zhuang, Jinchen,Qin, Cong,Li, Hao,Wang, Wei
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supporting information
p. 1195 - 1199
(2018/02/23)
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- 4-(1-AMINO-ETHYL)-CYCLOHEXYLAMINE DERIVATIVES
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The invention relates to compounds of formula (I) wherein R0 represents H or OH; R1 represents alkoxy; U and W represent N, V represents CH and R2 represents H or F, or U and V represent CH, W represents N and R2 /su
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Page/Page column 37
(2010/03/02)
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- Practical and highly selective sulfur ylide mediated asymmetric epoxidations and aziridinations using an inexpensive, readily available chiral sulfide. Applications to the synthesis of quinine and quinidine
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(Chemical Presented) Heating one of the most abundant naturally occurring inorganic chemicals (elemental sulfur) with one of the most readily available homochiral molecules (limonene) gives a one-step synthesis of a chiral sulfide which exhibits outstanding selectivities in sulfur ylide mediated asymmetric epoxidations and aziridinations. In particular reactions of benzyl and allylic sulfonium salts with both aromatic and aliphatic aldehydes gave epoxides with perfect enantioselectivities and the highest diastereoselectivities reported to date. In addition reactions with imines gave aziridines again with the highest enantioselectivities and diastereoselectivities reported to date. The reactions are scaleable, and the sulfide can be reisolated in high yield. The epoxidation has been used as the key step in a convergent and stereoselective synthesis of each of the diastereoisomers of the cinchona alkaloids, quinine and quinidine. Copyright
- Illa, Ona,Arshad, Muhammad,Ros, Abel,McGarrigle, Eoghan M.,Aggarwal, Varinder K.
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supporting information; experimental part
p. 1828 - 1830
(2010/04/25)
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- 4-(1-AMINO-ETHYL)-CYCLOHEXYLAMINE DERIVATIVES
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The invention relates to compounds of formula (I) wherein R0 represents H or OH; R1 represents alkoxy; U and W represent N, V represents CH and R2 represents H or F, or U and V represent CH, W represents N and R2/sup
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Page/Page column 95
(2008/12/06)
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- Novel cyclic urea derivatives, preparation thereof and pharmaceutical use thereof as kinase inhibitors
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The present invention relates to a cyclic urea compound of formula I: as defined herein. The invention is also directed to the process for its preparation, pharmaceutical composition comprising it and its pharmaceutical use, as an inhibitor on a protein kinase. Thus, it is useful for preventing or treating a physiological disorder capable of being modulated by inhibiting the activity of a protein kinase, such as a solid tumor.
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- Stereocontrolled synthesis of quinine and quinidine
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Disubstituted cyclopentene was prepared from cyclopentene monoacetate and transferred into disubstituted piperidine via oxidative cleavage of the olefin moiety followed by piperidine ring formation. The piperidine was then condensed at the side chain with a quinoline part to afford the olefin precursor of quinine. Finally, the olefin was converted into quinine through the corresponding epoxide. Quinidine was synthesized in a similar way.
- Igarashi, Junji,Katsukawa, Masahiro,Wang, Yong-Gang,Acharya, Hukum P.,Kobayashi, Yuichi
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p. 3783 - 3786
(2007/10/03)
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- Structure-activity relationships of cyclic enediyned related to dynemicin A-II. Synthesis and antitumor activity of 9- and 12-substituted enediynes equipped with aryl carbamate moietes
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Novel enediyne compounds 4-8, simple analogues of dynemicin A (1) equipped with the phenyl or 4-chlorophenyl carbamate moiety, were synthesized and evaluated for DNA-cleaving ability, in vitro cytotoxicity, and in vivo antitumor activity. As a result of the SAR study, it was revealed that the size and character of the substituents (R1 and R2) at the C9 position critically influenced both the stability and antitumor activity of the enediyne compounds. We found that the 9-deoxy compound 6a, a stable and less bulky enediyne having a hydrogen as the R1 and R2 substituents, showed a significant in vivo activity with a T/C of 215% at a daily dosage of 2.0 mg/kg for 4 days. The incorporation of an oxygen-containing functional group as the R3 substituent on a benzene ring resulted in considerable abolishing of both the in vitro and in vivo potencies. In a series of 9-acyloxy compounds, incorporation of the basic aromatic moiety such as 8e was effective for the in vitro activity, but it was ineffective for the in vivo activity. Furthermore, for the stereochemistry-activity relationships at the C9 position, the (9R(*))-isomers of 8c, 8e, and 8f were found to show]higher both in vitro and in vivo than the corresponding (9S(*))-isomers. For the mechanistic studies, compound 6a underwent Bergman cycloaromatization via a diradical pathway under acidic conditions, whereas it scarcely showed DNA-cleaving activity due to the chemical stability of the aryl carbamate moiety under neutral conditions.
- Unno, Ryoichi,Michishita, Hisashi,Inagaki, Hideaki,Suzuki, Yoko,Baba, Yutaka,Jomori, Takahito,Moku, Masatoshi,Nishikawa, Toshio,Isobe, Minoru
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p. 903 - 919
(2007/10/03)
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