Absolute configuration of hypothemycin and 5′-O-methylhypothemycin from Phoma sp.—a test case for solid state CD/TDDFT approach

Two metabolites, the known antitumor macrolide hypothemycin 1 and its new 5′-O-methyl ether, 5′-O-methylhypothemycin 2, and the known steroid ergosterol 3, were isolated from a Phoma sp. The structures were elucidated by means of spectroscopic data analysis, and the absolute configuration of hypothemycin 1 was confirmed by single crystal X-ray analysis in combination with the new solid-state CD/TDDFT methodology. Since the solid-state CD spectrum shows contributions from intermolecular interactions in the crystal, 1 represents a critical test case for our solid-state CD/TDDFT approach.

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HypothemycinC19H22O8[α]D20=+18 (c 0.50, CHCl3)

5′-O-Methylhypothemycin 2C20H24O8[α]D20=+21.0 (c 0.50, CHCl3, 5% CH3OH)