- Synthesis and analgesic evaluation of a series of proline-typed spiro cyclic quaternary ammoniums
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A series of proline derivated spirocyclic quaternary ammoniums were synthesized and evaluated via in vivo analgesic activities. Compounds 9a showed the best analgesic effect with 84 % inhibition in mice. These compounds showed only micromolar Ki value by in vitro α7 nAChR binding test, which may indicate the form of active metabolite play a role in their in vitro analgesic activities.
- Lin, Songwen,Wang, Na,Zhao, Shuo,Sun, Qi,Zhang, Weiwei,Ye, Jia,Cheng, Tieming,Li, Runtao
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p. 862 - 869
(2014/03/21)
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- The stability of imidazolidinones is the primary influence on the catalytic activity of proline amides and proline sulfonamides in enamine catalysis using alkyl aldehyde substrates
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Some N-substituted proline derivatives catalyse the reactions of alkyl aldehydes with electrophilic partners, and others give negligible amounts of product. The key reaction between the aldehyde and the proline derivative has been studied, and a rationale for the reactivity observed is presented. Simple proline amides derived from aromatic amines (poor catalysts) form stable imidazolidinones quite rapidly at the expense of enamines, the latter being detected, if at all, for less than an hour. Less basic proline amides form a kinetic diastereomer of an imidazolidinone that very slowly inverts its stereochemistry to give a final thermodynamic product. The stereochemistry of these diastereomers was fully assigned by 1H NMR, NOE, and TOCSY experiments. A proline amide derived from an alkylamine (good catalyst) forms high concentrations of enamine that is only slowly (days) converted into a single diastereomer of an inert imidazolidinone. In contrast, another good catalyst, a proline sulfonamide, immediately forms a reactive imidazolidinone, that rapidly ring-opens and exchanges with other aldehydes. This presumably drip-feeds iminium ions and enamines into the catalytic cycle. Thus, there are two quite different mechanistic regimes that lead to efficient catalysis. These mechanistic insights should now allow some element of rational design of prolinamides for enamine reactions using aldehydes. Some proline amides are poor catalysts when aldehydes are used as substrates since the catalysts irreversibly form imidazolidinones. Proline amides with more basic amide groups form long-lived enamines, which allows catalysis to proceed. Proline sulfonamides only form imidazolidones, but these are unstable. Copyright
- Tin, Sergey,Fuentes, Jose A.,Lebl, Tomas,Clarke, Matthew L.
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p. 141 - 147
(2013/02/22)
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- AlMe3-promoted formation of amides from acids and amines
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In the presence of AlMe3, amines can be directly coupled with acids through dimethylaluminum amide intermediates to form the corresponding amides. A wide range of amines and acids including less nucleophilic amines, bulky amines, unprotected se
- Li, Jianqing,Subramaniam, Krishnananthan,Smith, Daniel,Qiao, Jennifer X.,Li, Jie Jack,Qian-Cutrone, Jingfang,Kadow, John F.,Vite, Gregory D.,Chen, Bang-Chi
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supporting information; experimental part
p. 214 - 217
(2012/02/16)
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- Chiral lewis base catalyzed highly enantioselective reduction of N-alkyl β-enamino esters with trichlorosilane and water
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First, test the water! In the presence of a chiral Lewis base catalyst 2, the supposedly moisture-unfriendly reduction system with trichlorosilane was found to be highly efficient and enantioselective when using water as an additive. For the first time, this method enables the reduction of a broad range of N-alkyl β-enamino esters 1 to give N-alkyl β-amino esters 3 in good to high yields and with excellent enantioselectivities (see scheme).
- Wu, Xinjun,Li, Yang,Wang, Chao,Zhou, Li,Lu, Xiaoxia,Sun, Jian
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supporting information; experimental part
p. 2846 - 2848
(2011/04/24)
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- Use of amino amides derived from proline as chiral ligands in the ruthenium(II)-catalyzed transfer hydrogenation reaction of ketones
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We developed an efficient, easily available, and easy to use proline amide-based ruthenium(II) catalysts for the asymmetric hydride transfer reduction of prochiral ketones and e.e.s up to 98.8% have been measured.
- Rhyoo, Hae Yoon,Yoon, Young-Ae,Park, Hee-Jung,Chung, Young Keun
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p. 5045 - 5048
(2007/10/03)
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