Schmidt U, Schumacher A, Mittendorf J, Riedl B. Contribution to the synthesis of aureobasidin A. Synthesis of cyclopeptolides containing the sequence leucyl-N-methyl-beta-hydroxyvalyl-(2R)-oxy-(3R)-methyl-pentanoi c acid.
THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1998;
52:143-54. [PMID:
9727871 DOI:
10.1111/j.1399-3011.1998.tb01369.x]
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Abstract
The efficient antimycotic agent aureobasidin A, isolated from the culture broth of Aureobasidium pullulans R 106, and the [(R)-Pro9]-aureobasidin A were prepared starting from benzyl N-Boc-N-methyl-(S)-beta-triethylsiloxyvalinate, the synthesis of which is described here. The easy accessibility of the tripeptolide benzyl Boc-leucyl-N-methyl-beta-hydroxyvalyl-(2R)-oxy-(3R)-methylpentanoa te [Boc-Leu-HOMeVal-(R)-HMP-OBn] facilitates the construction of the cyclopeptolides 28, 34, 45 and 47. The peptide bonds of the N-methylamino acids were formed with the help of O-(7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophophate. The rings of [(R)-Pro9]-aureobasidin A and of cyclopeptolides 28, 34, 45 and 47 were closed by way of pentafluorophenyl esters. The ring of aureobasidin A could only be formed with bromo-tris-pyrrolidinophosphonium hexafluorophosphate.
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