Isolation of decomposition products of tylosin using liquid chromatography

Decomposition products of tylosin A were isolated using open column chromatography and preparative liquid chromatography. Two decomposition products, formed in slightly alkaline medium, were identified as epimers of tylosin A aldol, one of which has been described previously. Another decomposition product was formed on exposure of a tylosin A solution toght. Isomerization of the double bond between C 12−C 13 takes place, resulting in the formation of the hitherto unreported isotylosin A.