- Borontribromide-mediated C-C bond formation in cyclic ketones: A transition metal free approach
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Borontribromide (BBr3) is a well-known demethylating agent. The current investigation was focused on a new application of borontribromide as a C-C bond forming agent in cyclic ketones. In this study, borontribromide mediated C-C bond formation reactions of tetralones, chromenone, thiochromenone and indanones were explored. A methoxy group containing ketones showed selective C-C bond formation reaction instead of demethylation of the methoxy group. MM2 steric energy calculations for the final products showed that the reaction favored the formation of exo- or endo-cyclic double bond containing products, depending upon their low MM2 steric energy in a specific frame structure, as observed in X-ray crystallography. A comprehensive crystallographic and pi-stacking analysis of product 10a demonstrated the formation of 10a as an enantiomeric mixture, and its centre of inversion was stabilized by a set of three unique pi-pi interactions.
- Ahmad, Imran,Pathak, Vinay,Vasudev, Prema G.,Maurya, Hardesh K.,Gupta, Atul
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p. 24619 - 24634
(2014/07/07)
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- Simple synthesis and biological evaluation of flocoumafen and its structural isomers
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Simple synthesis and biological properties of flocoumafen 1 and its structural isomers are described. The key synthetic strategies involve Knoevenagel condensation, Grignard reaction, intramolecular ring cyclization and coupling reaction. Flocoumafen 1 was easily separated into cis and trans forms using flash column chromatography. They were then evaluated for suppression of LPS-induced NO generation and anti-excitotoxicity in vitro. It was found that the trans-flocoumafen was potent suppressor of NO generation with the concentration of 10 μM in vitro, while no significant effect for neurotoxicity in cultured cortical neurons. Indian Academy of Sciences.
- Jung, Jae-Chul,Jang, Soyong,Oh, Seikwan,Park, Oee-Sook
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scheme or table
p. 833 - 838
(2011/10/04)
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- Synthesis and antitumor activity of 4-hydroxycoumarin derivatives
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A series of 4-hydroxycoumarin derivatives was prepared and evaluated for antitumor activity against five human tumor cell lines. A series of 4-hydroxycoumarin derivatives was prepared and evaluated for antitumor activity. The key fragments were 2a-c, 5c, 12b, 13b, 17, and 18 which were prepared via dianion ring cyclization, Friedel-Crafts acylation, and Reformatsky reaction. Compound 20b showed the most potent antitumor activity among the total 12 derivatives and compounds 19a and 19b exhibited efficacy comparable to etoposide in vitro antitumor activity.
- Jung, Jae-Chul,Lee, Ji-Ho,Oh, Seikwan,Lee, Jae-Gon,Park, Oee-Sook
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p. 5527 - 5531
(2007/10/03)
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- Anti-coagulants of the 4-hydroxycoumarin type and rodenticidal compositions (baits) comprising such anti-coagulants
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Compounds having blood-anticoagulant properties of the general molecular formula: STR1 in which Z represents a halogen atom, preferably a chlorine atom, and n is 0, 1 or 2 and R4 represents either (1) a grouping which comprises a phenylene radical attached directly or indirectly to the tetralin ring and having in the para position (with respect to such attachment) an electron-withdrawing atom or group whose rotational volume substantially does not exceed that of a phenyl group and which forms together with said phenylene radical a polarizable structure, or (2) a grouping selected from: STR2 or (3) a grouping which comprises a phenylene radical attached directly to the tetralin ring and having in the para position (with respect to such attachment) a substituted furanyl or thiophenyl radical attached thereto directly or through oxygen and/or methylene, said furanyl or thiophenyl radical having such an electron-withdrawing atom or group as a substituent in a position forming with the furanyl or thiophenyl radical a polarizable structure, compounds of the type (1) in which R4 contains two phenylene radicals linked essentially linearly by an aliphatic chain comprising a methylene radical or radicals and optionally at least one oxygen or sulphur atom being preferred. Also included are the processes for the preparation of such compound; rodenticidal compositions containing them; and a method for controlling rodents by applying such a composition.
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