Abstract: A cyclopentenone derivative represented by the following formula [I] or an optically active substance or a salt thereof. ##STR1## (In the formula, R.sub.1 and R.sub.2 are same or different and each of them is straight or branched alkyl group, straight or branched alkenyl group, aromatic group, aromatic-aliphatic group or H with a proviso that the case where R.sub.1 =R.sub.2 =H, or R.sub.1 =benzyl group and R.sub.2 =H is excluded.

Abstract: This invention relates to Aureobasidins useful as an antifungal agent having broader spectrum. The compound according to this invention includes a cyclic depsipeptide consisting of one hydroxy acid residue having A.sup.1, 3 amino acid residues having C.sup.1, F.sup.1 and H.sup.1, respectively, 4 N-methylamino acid residues having B.sup.1, D.sup.1, G.sup.1 and I.sup.1, respectively, and 1 cyclic amino acid residue having E.sup.1. The typical compound includes one wherein A.sup.1 is CH.sub.3 CH.sub.2 CH(CH.sub.3)--, B.sup.1 is (CH.sub.3).sub.2 CH--, C.sup.1 is benzyl, cyclohexylmethyl, p-fluorobenzyl, benzyloxymethyl, benzyloxybenzyl, methoxybenzyl, cyclohexylmethyloxybenzyl or the like, D.sup.1 is methyl, benzyl, hydroxymethyl or the like, E.sup.1 is --(CH.sub.2).sub.3 --, F.sup.1 is CH.sub.3 CH.sub.2 CH(CH.sub.3)--, G.sup.1 is (CH.sub.3).sub.2 CH--, H.sup.1 is (CH.sub.3).sub.2 CHCH.sub.2 -- and I.sup.1 is (CH.sub.3).sub.2 C(OH)--.

Abstract: To provide a process for the total synthesis of a cyclic peptide, which is useful as antifungal drug, and novel compounds prepared by the synthesis method. A process for synthesizing a cyclic peptide represented by the following formula (I): ##STR1## wherein X1, X2, X4 and X7 are independently N-methyl-.alpha.-amino acid or .alpha.-hydroxy acid,provided that at least one of X1, X2, X4 and X7 is a .alpha.-hydroxy acid;X3, X6 and X8 are independently .alpha.-amino acid;X5 is a cyclic amino acid;X9 is a N-methyl-.alpha.-amino acid or .alpha.-hydroxy acid substituted by a hydroxy group;and the dotted lines represent intramolecular hydrogen bonds;which process comprises cyclizing a corresponding linear peptide between X5 and X6 via a peptide bond, and a novel compound represented by the formula (I).

Abstract: A process is provided for the total synthesis of a cyclic peptide, which is useful as antifungal drug, and novel compounds prepared by the synthesis method. The cyclic peptide is represented by the following formula (I): ##STR1## wherein X1, X2, X4 and X7 are independently N-methyl-.alpha.-amino acid or .alpha.-hydroxy acid,provided that at least one of X1, X2, X4 and X7 is an .alpha.-hydroxy acid;X3, X6 and X8 are independently .alpha.-amino acid;X5 is a cyclic amino acid;X9 is an N-methyl-.alpha.-amino acid or .alpha.-hydroxy acid substituted by a hydroxy group;and the dotted lines represent intramolecular hydrogen bonds.The process includes cyclizing a corresponding linear peptide between X5 and X6 via a peptide bond.