2,3,5,6,8,9,11,12-Octahydrobenzo[b][1,4,7,10,13]pentaoxacyclopentadecine-14,17-dicarboxylic acid

1,?4,?7,?10,?13-?Benzopentaoxacyclope?ntadecin-?14,?17-?dicarboxylic acid, 2,?3,?5,?6,?8,?9,?11,?12-?octahydro-