ANTIBIOTIC SB22484 - A NOVEL COMPLEX OF THE AURODOX GROUP .2. STRUCTURE ELUCIDATION OF THE 4 FACTORS

SB22484, active against Neisseriae gonorrhoeae and Neisseriae meningitidis, is a complex of four factors, designated 1 through 4, which from two pairs of isomers, 1 and 3, and 2 and 4. Facotrs 1 and 3 account for 65% of the complex, factor 3 being the predominant one. On the basis of the existing and implemented correlations between structure and physico-chemical characteristics (UV and IR spectroscopies, ionization properties, MS as FAB and as negative and positive CI, H-1 NMR spectroscopy as 2D COSY and NOESY) in the aurodox field, the complete structures were assigned. Factor 3 can be described as N-[7-[5(R)-[7-[1,2-dihydro-4-hydroxy-1H-2-oxo-3-pyridinyl] -6-methyl-7-oxo-1(E),3(E),5(E)-heptatrienyl]tetrahydro-3(S), 4(R)-dihydroxyfuran-2(S)-yl]-6(S)-methoxy-5,7(R)-dimethyl-2(E), 4(E)-heptadienyl]-alpha-(S)-methyl-5(S)-methyltetrahydro-2(S), 4(S or R)-dihydroxy-6(S)-[1(E),3(Z)-pentadienyl]2H-pyran-2-acetamide. Factor 1 is an epimer of factor 3 with the opposite configuration at the anomeric center. Factors 2 and 4 have an ethyl group instead of the methyl group-alpha to the acetamide moiety and are in the same stereochemical relationship as the pair 1 and 3.