Sporeamicins A

Previous work investigated the FAB mass spectra of aspacochiosides A and B in different solvents (methanol and acetonitrile) with the matrix (glycerol+NaCl) and the intact [M+na]⁺ ions was successfully observedHowever, it was found that aspacochioside B apparently converted into aspacochioside A when dissolved in acetonitrile.Detailed investigations of the interconversion between aspacochiosides A and B by FAB-MS were conducted and the results are reported here.Interconversion between aspacochiosides A and B easily occurs in different solvent systems and these solvent effects should be taken into consideration in isolation and anal. procedures of natural products within reactive groups.

The conversion of 6-deoxyerythromycin A (I) to 6-deoxysporeamicin A (II) is described.The antibacterial spectrum of II was similar to those of I, erythromycin, and sporeamicin A, but it had better potency against susceptible streptococci than I.II also had better activity than sporeamicin A against most susceptible organisms and an overall potency similar to that of erythromycin.