Oximidines I and II:  Novel Antitumor Macrolides from Pseudomonas sp.

Our screening for cell-cycle inhibitors in transformed cells resulted in the isolation of novel active compounds, oximidines I (1) and II (2), from Pseudomonas sp. Q52002. The molecular formulas of 1 and 2 were established as C(23)H(24)N(2)O(7) and C(23)H(24)N(2)O(6), respectively, by high-resolution FABMS. The structures of the oximidines were elucidated by NMR spectral analysis, including a variety of two-dimensional techniques. The absolute stereochemistry of 1 was determined by using the modified Mosher method. The oximidines are novel 12-membered macrolides containing an O-methyloxime moiety. Oximidines I and II selectively inhibited the growth of rat 3Y1 cells transformed with E1A, ras, or src oncogenes.