The molecule is a phenolate anion obtained by deprotonation of 5-hydroxy group of aklaviketone. It is the major microspecies at pH 7.3 (according to Marvin v 6.2.0.). It is a conjugate base of an aklaviketone.
(1R,2R)-2-ethyl-2,7-dihydroxy-1-methoxycarbonyl-4,6,11-trioxo-1,3-dihydrotetracen-5-olate