The molecule is a zwitterion obtained by transfer of a proton from the 2-hydroxy group to the 1-amino group of 11a-hydroxytetracycline. It is the major microspecies at pH 7.3 (according to Marvin v 6.2.0.). It is a zwitterion and an an 11a-hydroxytetracyline zwitterion. It is a tautomer of an 11a-hydroxytetracycline.
(4S,4aS,5aR,6S,11aS,12aR)-2-carbamoyl-4-(dimethylazaniumyl)-6,10,11a,12a-tetrahydroxy-6-methyl-3,11,12-trioxo-4,4a,5,5a-tetrahydrotetracen-1-olate