Synthesis of Cyclopentapeptides with Three to Five Aib Units |
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Authors: | Anthony Linden Heinz Heimgartner |
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Institution: | Institut für Chemie der Universit?t Zürich, Winterthurerstrasse 190, CH‐8057 Zürich, (phone: +41?44?635?4282) |
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Abstract: | Four new Aib‐containing cyclopentapeptides have been synthesized by cyclization of the corresponding linear pentapeptides using the diethyl phosphorocyanidate (DEPC)/EtN(iPr)2 method. The linear precursors were prepared via the ‘azirine/oxazolone method’, i.e., the Aib units were introduced by the reaction of amino acids or peptide acids with a 2,2‐dimethyl‐2H‐azirin‐3‐amine, followed by selective hydrolysis of the terminal amide function. Most remarkably, cyclo(Aib)5] exists in CDCl3 solution in a symmetrical conformation, i.e., no intramolecular H‐bonds are detectable. |
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Keywords: | Cyclopentapeptides Peptides ‘ Azirine/oxazolone’ method 2‐Aminoisobutyric acid (Aib) X‐Ray crystallography |
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