Studies directed toward the synthesis of glycopeptide antibiotic teicoplanin: first synthesis of the N-terminal 14-membered ring
摘要:
The N-terminal 14-membered ring formed by an ether linkage between the phenyl moieties of amino acids 1 and 3 of glycopeptide antibiotic teicoplanin 1 plays a crucial role in binding of C-terminal D-Ala-D-Ala residues of the peptidoglycan precursor, thereby inhibiting bacterial cell wall biosynthesis. Herein, the first stereocontrolled synthesis of this very important cyclic peptide 2 is described. The two alpha-arylglycines present in this segment are constructed in optically pure form by diastereoselective Strecker synthesis using alpha-phenylglycinol as chiral auxiliary. Finally, the coupling between the acid function of amino acid 1 and the amino function of amino acid 2 leads to the desired macrocyclization. Optical purity of the synthetic product is determined by NMR studies.
A general synthetic route towards bastadins. Part 1: Synthesis of the eastern part of bastadins 4–16
作者:Elias A. Couladouros、Vassilios I. Moutsos
DOI:10.1016/s0040-4039(99)01429-x
日期:1999.9
A general syntheticroute for the construction of the eastern part of the macrocyclic bastadins 4–16 is presented. The brominated biaryl ethers are synthesized using the iodonium salt method. The synthesis is accomplished within 18 steps in 15.5% overall yield.
A general synthetic route towards bastadins. Part 2: Synthesis of the western part of bastadins 4–16, and fully functionalized macrocycle of bastadin 12
作者:Elias A. Couladouros、Vassilios I. Moutsos
DOI:10.1016/s0040-4039(99)01430-6
日期:1999.9
A general synthetic route for the construction of the western part of the macrocyclic bastadins 4–16 is presented. The western and the eastern segements were coupled using the imidazolide of the corresponding acid. The bromine at position Y2 may be added at this advanced step regiospecifically, strengthening the convergence of the presented approach. Finally, the fully functionalized α,ω-aminoacid