Neue Cyclopeptide aus <i>Trichoderma polysporum</i> (L<scp>INK EX</scp> P<scp>ERS</scp>.) R<scp>IFAI</scp>: Die Cyclosporine B, D und E

Abstract

New Cyclopeptides from Trichoderma polysporum (L INK EX P ERS .) R IFAI : Cyclosporins B, D and E Cyclosporins represent a new group of biologically active metabolites produced by Trichoderma polysporum (L INK EX P ERS .) R IFAI and other fungi imperfecti. The structures of the main components, cyclosporins A ( 1 ) and C( 3 ) have been determined as neutral cyclic oligopeptides composed of 11 amino acids, among them a new C 9 ‐amino acid [2–4]. In addition, three minor metabolites, cyclosporins B, D and E, have now been isolated and characterized. Chemical investigation, spectroscopic evidence and X‐ray analysis led to the structural formulae of cyclosporins B (2) and D (4) . Both compounds have the same sequence of amino acids as cyclosporin A (1) , with the exception of L ‐α‐aminobutyric acid, replaced in cyclosporin B (2) by L ‐alanine and in cyclosporin D (4) by L ‐valine, respectively. Cyclosporins undergo a characteristic intramolecular N , O ‐acyl migration to furnish the corresponding basic isocompounds. The antifungal activities of cyclosporins are reported.