de(N-methyl)-11-deoxy-N-isopropyl-12-O-methyl-11-oxo-8,9-anhydroerythromycin A 6,9-hemiacetal fumaric acid
de(n-methyl)-11-deoxy-n-isopropyl-12-o-methyl-11-oxo-8,9-anhydroerythromycin a 6,9-hemiacetal fumaric acid