Physico-chemical properties of new acyl derivatives of tylosin produced by microbial transformation.

Abstract
By microbial [Streptomyces thermotolerans] transformation of tylosin (I), the following 8 new acyl derivatives were obtained: 3-acetyltylosin (II), 3-propionyltylosin (III), 4"-butyryltylosin (IV), 4"-isovaleryltylosin (V), 3-acetyl-4"-butyryltylosin (VI), 3-acetyl-4"-isovaleryltylosin (VII), 3-propionyl-4"-butyryltylosin (VIII) and 3-propionyl-4"-isovaleryltylosin (IX).