Actinoplanic acids structure

Actinoplanic acids A and B (Figure 15) are structurally complex polyketide-derived polycarboxylic acids isolated from the unicellular organism Actinoplanes sp. These compounds were efficiently isolated [86,87] by two-step processes employing gel filtration and reverse phase HPLC. The structure elucidation of these complex molecules required the use of a battery of 2D NMR methods. The HMBC correlations of the methyl groups to the respective carbons were most helpful in delineation of the carbon framework. 

Structurally, both compounds contain a 30-carbon straight chain tri and tetrahydroxy carboxylic acid. The alkyl chain in each compound is substituted with an ethyl and a number of methyl groups and two of the hydroxy groups are esterified with two units of tricarballylic acid. One of the methyl groups in actinoplanic acid A is oxidized to an hydroxy methyl group that, in turn, forms a 20-membered 6w-lactone ring with the free carboxy group of one of the tricarballylic acids [86,87]. 

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