D. R = CH₂-O-CH₂-CH₂-O-CH₃, R¹ = H, R² = OH, R³ = H: (9S)-9,11-{imino[(1RS)-2-(2-methoxyethoxy)ethyliden]oxy}-3՛-O-demethyl-9-deoxo-11-deoxyerythromycin (dirithro-mycin C),