- Design and synthesis of a new polymer-supported Evans-type oxazolidinone: An efficient chiral auxiliary in the solid-ph ase asymmetric alkylation reactions
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Wang resin-supported Evans' chiral auxiliary (23) was designed based on a novel polymer-anchoring strategy, which utilizes the 5-position of the oxazolidinone ring, and its new synthetic route applicable to multi-gram preparation in just a day was developed. Solid-phase Evans' asymmetric alkylation on 23-derived N-acylimide resin and following lithium hydroperoxide-mediated chemoselective hydrolysis afforded the corresponding α-branched carboxylic acids in desired high stereoselectivities (up to 97% ee) and moderate to good overall yield (up to 70%, for 3 steps), which were comparable to those of the conventional solution-phase methods. Furthermore, recovery and recycling of the polymer-supported chiral auxiliary were successfully achieved without decreasing the stereoselectivity of the product. Therefore, this is the first successful example that the solid-phase Evans' asymmetric enolate-alkylation was efficiently performed on the solid-support, and it is concluded that the connection to the solid-support via the 5-position of the oxazolidinone ring is an ideal strategy in the solid-phase Evans' chiral auxiliary.
- Kotake, Tomoya,Hayashi, Yoshio,Rajesh,Mukai, Yoshie,Takiguchi, Yuka,Kimura, Tooru,Kiso, Yoshiaki
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p. 3819 - 3833
(2007/10/03)
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- Indanylidenes. 2. Design and synthesis of (E)-2-(4-chloro-6-fluoro-1-indanylidene)-N-methylacetamide, a potent antiinflammatory and analgesic agent without centrally acting muscle relaxant activity
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Extension of the structure-activity relationship studies that led to the discovery of the nonsedating potent muscle relaxant, antiinflammatory, and analgesic agent (E)-2-(4,6-difluoro-1-indanylidene)acetamide, 1, has given rise to (E)-2-(4-chloro-6-fluoro
- Musso, David L.,Orr, G. Faye,Cochran, Felicia R.,Kelley, James L.,Selph, Jeffrey L.,Rigdon, Greg C.,Cooper, Barrett R.,Jones, Michael L.
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p. 409 - 416
(2007/10/03)
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- Amide derivatives and their therapeutic use
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A compound of formula (I), wherein R1 and R2 are independently selected from chloro, fluoro, bromo, C1-6 alkyl, C1-6 alkoxy or C1-6 haloalkyl provided that both R1 and R2 are not
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