Structures and Antifungal Activities of New Aureobasidins.

(Ab's) are a group of antifungal antibiotics produced by a black yeast, Aureobasidium pullulans R106.1 ~4) Besides its main product AbA, there are over 20 congeners of Ab's and their structures characterized as a cyclic depsipeptide consisted of eight amino acids, three or four of which are TV-methylated, and one hydroxy acid. In the course of our search for new Ab's, we discovered six new congeners designated