The molecule is the conjugate base of ketomycolic acid type-1 (XI). A class of mycolic acids characterized by the presence of a proximal trans-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-[(5S)-5-methyl-4-oxoheptan-2-yl]cyclopropyl]butanoate