Goniodomic Acid, a Transient Oxirane Intermediate in the Conversion of the Macrolide Algal Toxin Goniodomin A to Seco Acids.

ABSTRACT: The algal macrolide goniodomin A (GDA) undergoes ring-cleavage under unusually mild, alkaline conditions to form mixtures of stereoisomers of seco acids GDA-sa and iso-GDA-sa. In the primary fragmentation pathway, opening of the macrolide ring occurs by displacement of the carboxyl group by a base-catalyzed attack of the C32 hemiketal hydroxy group on C31, yielding an oxirane-carboxylic acid, named goniodomic acid. The oxirane ring is unstable, undergoing solvolytic opening to form mainly GDA-sa. Experimental support for this pathway obtained by carrying out the ring-opening reaction in H₂¹⁸O resulted in incorporation of the isotopic label at C32 of the seco acid. Collision-induced dissociation (CID) mass spectrometry of Na⁺ and NH₄⁺ i

SUBMITTER: Harris CM 

PROVIDER: S-EPMC11752514 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature