6-O-Methylerythromycin A (I) was protected as the 2'-acetate (II) and subsequently treated with chlorotrimethylsilane and pyridine to afford the 4''-O-silyl ether (III). Condensation of (III) with 1,1'-carbonyldiimidazole yielded the 12-O-acylimidazole derivative (IV), which was subsequently reacted with 3,4-dichlorophenethyl amine (V) to form the 11,12-cyclic carbamate (VI). Deprotection of the acetate ester of (VI) on heating with methanol, followed by desilylation with tetrabutylammonium fluoride in THF yielded (VII).

N-Demethylation by treatment with iodine and sodium acetate under irradiation of a halogen lamp produced secondary amine (VIII). Finally, reductive condensation of (VIII) with cyclopentanone (IX) in the presence of sodium cyanoborohydride yielded the title cyclopentylamino compound.