Ampullosporin Analogs: Solid Phase Synthesis, Conformational Studies, and Biological Activities

Ampullosporin A (Amp A) Ac-Trp-Ala-Aib-Aib-Leu-Aib-Gln-Aib-Aib-Aib-Gln-Leu-Aib-Gln-Leuol, extracted from fungus Sepedonium ampullosporum surface culture belongs to the class of peptaibols rich in Aib, with an acetylated N-terminus and an alcohol at C-terminus [1]. Besides antimicrobial effects, Amp A induces the formation of black pigment on fungus Phoma destructiva, as do cyclosporin A, chrysospermin, and also neuroleptic drugs, including haloperidol, chlorpromazine, clozapine, and sertindol. Moreover, Amp A was found to cause the hypothermia in mice suggesting a neuroleptic activity [1]. Recently, peptides containing adjacent sterically hindered Aib-residues have been synthesized without difficulties via Fmoc amino acid fluorides, which can be generated in situ by using tetramethylfluoroformamidium hexafluorophosphate (TFFH) as coupling reagent [2].