The molecule is the conjugate base of ketomycolic acid type-1 (X). A class of mycolic acids characterized by the presence of a proximal cis-cyclopropyl group followed by a distal oxo group and a (CH-CH3) fragment of (S) stereochemistry in the meromycolic chain.
(2R,3R)-2-ethyl-3-hydroxy-4-[2-[(3S)-3-methyl-2-oxopentyl]cyclopropyl]butanoate