- Flexible synthesis of planar chiral azoninones and optically active indolizidinones
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The flexible synthesis of defined substituted optically active indolizidinones starting from chiral pool (S)-proline and trans 4-hydroxy-(S)-proline is described. Several defined 2-vinylpyrrolidines were generated in short sequences. The aza-Claisen rearr
- Bohland, Frank,Erlin, Irina,Platte, Lukas,Schr?der, Maike,Schollmeyer, Dieter,Nubbemeyer, Udo
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supporting information
p. 6272 - 6284
(2015/03/30)
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- NHC-Catalyzed intramolecular redox amidation for the synthesis of functionalized lactams
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A very efficient NHC-catalyzed lactamization reaction is reported. For most cases, the ring expansion reaction proceeds to cleanly furnish five- and six-membered N-Ts and N-Bn lactams, without the need for further purification. Evidence is presented suggesting a dual role for the stoichiometric base: (1) deprotonation of the triazolium precatalyst and (2) activation of the nitrogen leaving group through hydrogen bonding.
- Thai, Karen,Wang, Li,Dudding, Travis,Bilodeau, Francois,Gravel, Michel
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p. 5708 - 5711
(2011/03/19)
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- Synthesis and antibacterial activity of novel 4-pyrrolidinylthio carbapanems. Part III: Novel 2-alkyl substituents containing cationic heteroaromatics linked via a C-N bond
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The synthesis and biological activity of a novel series of 2-alkyl-4-pyrrolidinylthio-β-methylcarbapenems containing a variety of cationic heteroaromatic substituents is described. As a result of these studies, we uncovered a relationship between in vitro antibacterial activity and the length of the alkyl spacer part, and discovered FR20950 (1c), containing a two methylene spacer moiety and an imidazolio group, which possesses a balanced spectrum of antibacterial activity, including Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus (MRSA). Furthermore, FR20950 exhibited excellent urinary recovery, and com- parable stability against renal dehydropeptidase-I (DHP-I) to Biapenem. DHP-I stability could be improved by introduction of a substituent on to the imidazole ring. (C) 1999 Elsevier Science Ltd. All rights reserved.
- Azami, Hidenori,Barrett, David,Matsuda, Keiji,Tsutsumi, Hideo,Washizuka, Kenichi,Sakurai, Minoru,Kuroda, Satoru,Shirai, Fumiyuki,Chiba, Toshiyuki,Kamimura, Toshiaki,Murata, Masayoshi
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p. 1665 - 1682
(2007/10/03)
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- Unusual diastereoselection in the synthesis of nine-membered ring lactams and conformation-controlled transannular reactions to generate optically active indolizidinones
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The aza-Claisen rearrangement of vinylpyrrolidines 1 yielded almost exclusively the trans-3,8-disubstituted nine-membered ring lactams 2 (TBS = tBuMe2Si), independent of whether cis or trans isomers were used as starting materials. The conforma
- Sudau, Alexander,Nubbemeyer, Udo
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p. 1140 - 1143
(2007/10/03)
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