CHEMICAL MODIFICATION OF ERYTHROMYCINS

V. CYCLIC CARBONATES OF 8-HYDROXYERYTHROMYCIN A

Abstract

By treatment of 8-hydroxyerythromycin A in an aprotic solvent with ethylene carbonate in the presence of K₂CO₃, two cyclic carbonates of 8-hydroxyerythromycin A with molecular formulae of C₃₈H₆₅NO₁₅ and C₃₉H₆₃NO₁₆, respectively, were obtained. Analytical, spectral and chemical data indicated their structures to be the 11, 12-cyclic carbonate of 8-hydroxyerythromycin A and the 8, 9; 11, 12-dicyclic dicarbonate of 8-hydroxyerythromycin A 6⁹-hemiketal, respectively. The respective compounds have antibacterial activities against Bacillus pumilus (in erythromycin A units) corresponding to 500μg/mg and 1, 250μg/mg. Similar treatment of the methyl⁹ 6-ketal of 8-hydroxyerythromycin A yields the 11, 12-cyclic carbonate. Acid hydrolysis of the latter is another route providing the 11, 12-cyclic carbonate of 8-hydroxyerythrornycin A, mentioned above.