ANTIBIOTIC SB22484: A NOVEL COMPLEX OF THE AURODOX GROUP

II. STR UCTURE ELUCIDATION OF THE FOUR FACTORS

Abstract

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. Factors 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, ¹H 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]-α(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 a to the acetamide moiety and are in the same stereochemical relationship as the pair 1 and 3.