- An operationally simple and efficient synthesis of orthogonally protected L-threo-β-hydroxyasparagine
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A synthesis of orthogonally protected L-threo-β-hydroxyasparagine from L-aspartic acid is reported. Iodocyclization of 3-benzoylaminoaspartic acid provided an intermediate oxazoline dicarboxylate that was efficiently hydrolyzed to L-threo-β-hydroxyasparti
- Guzmán-Martínez, Aikomari,VanNieuwenhze, Michael S.
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- Structure and total synthesis of lysobactin (katanosin B)
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(Chemical Equation Presented) Tackle-resistant bacteria: Determination of the 3D structure of the antibiotic lysobactin has led to its total synthesis and resulted in a high-yielding macrolactamization step. The minimal use of protecting groups allowed pr
- Von Nussbaum, Franz,Anlauf, Sonja,Benet-Buchholz, Jordi,Haebich, Dieter,Koebberling, Johannes,Musza, Laszlo,Telser, Joachim,Ruebsamen-Waigmann, Helga,Brunner, Nina A.
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p. 2039 - 2042
(2008/03/11)
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- MONOCYCLIC BETA-LACTAMS AND PROCESS FOR THE PREPARATION THEREOF
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Monocyclic beta-lactam compounds represented by the formula STR1 wherein R 1 is H, NH 2, acylamino, C 1 -C 4 alkyl, etc.; R 2 is e.g. C 1 -C 4 alkyl, hydroxyalkyl, aminoalkyl, carboxy, esterified carboxy, esterified carboxyalkyl, or carboxyalkyl; and R 3 is hydrogen, benzyl, substituted benzyl, pivaloyl, --SO 3 M, or --P(C-O)(OM')2; are obtained by the cyclization of an O-substituted hydroxamate of a beta-substituted alkylcarboxylic acid. For example, alpha-ethylmalic acid monobenzyl ester is reacted with O-benzylhydroxylamine to form the O-benzylhydroxamate of the free carboxy group, and the hydroxamate is cyclized with diethyl diazodicarboxylate and triphenylphosphine to form the beta-lactam of the above formula wherein R 1 is ethyl, R 2 is benzyloxycarbonyl and R 3 is benzyl. The beta-lactam compounds are useful intermediates for preparing beta-lactamase inhibitors and monocyclic beta-lactam antibiotics and, when R 3 is --SO 3 M or -P(C-O)(OM')2 the compounds and salts thereof are antibacterial agents.
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