- Nitrone protecting groups for enantiopure N-hydroxyamino acids: Synthesis of N-terminal peptide hydroxylamines for chemoselective ligations
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The synthesis of enantiopure N-benzylidene nitrones of N-hydroxy-α- amino acids and their incorporation using standard Fmoc-based peptide chemistry into solid-supported peptide chains is described. Deprotection and resin cleavage affords N-terminal peptid
- Medina, S. Irene,Wu, Jian,Bode, Jeffrey W.
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supporting information; experimental part
p. 3405 - 3417
(2010/08/21)
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- 5-Hydroxy[1,2]oxazinan-3-ones as potential carbapenem and D-ala-D-ala surrogates
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The title compounds are amino acids whose nitrogen atom is enclosed in a six-membered cyclic hydroxamate bearing a C5-hydroxyl group. They belong to a proposed new family of antibacterial agents targeted to the penicillin receptor. The glycine and alanine members of the family have been synthesized, as racemates, in seven steps from the four-carbon synthon diketene and the tert-butyl esters of N-hydroxyglycine and N-hydroxyalanine. Numerous alternatives to diketene have also been examined, but these lead mainly to five-membered cyclic hydroxamates. The theoretical considerations that have led to this synthetic programme are discussed in some detail. They include analysis of the structures of natural and unnatural penicillin surrogates, analysis of the penicillin pharmacophore, and a treatment of the chemical reaction with which penicillin blocks bacterial cell wall synthesis. The glycine derivative exhibits marginal but real activity vs. Micrococcus luteus. The alanine derivative, which more closely resembles D-ala-D-ala, is fifty times more active. Two five-membered structural isomers of the glycine derivative are inactive.
- Wolfe, Saul,Akuche, Christiana,Ro, Stephen,Wilson, Marie-Claire,Kim, Chan-Kyung,Shi, Zheng
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p. 915 - 936
(2007/10/03)
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- Oxazinones having antibacterial activity
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The invention relates to novel oxazinones designed to bind to the penicillin receptor, methods of synthesizing the compounds, and the use of the compounds as antibacterial agents. The compounds have the general formula (I) Preferably the compounds have a carboxyethyl or a substituted carboxymethyl substituent at the 2-position and a hydroxyl group at the 5-position and have a molecular shape suitable for binding to and reacting with the active site of a pencillin-recognizing enzyme. The compounds are synthesized by condensing a carboxyl-protected N-hydroxy amino acid with a 3-hydroxyprotected-4-bromobutanoic acid to form a a doubly protected N-hydroxy N-acylamino acid, which is cyclized with an organic base to yield a doubly protected 1,2-oxazin-3-one. The protecting groups are then removed to provide an antibacterial agent.
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