4,6-propano-1H-cyclopent[c]oxepin-5,5a(3H)-dicarboxylic acid, hexahydro-9-oxo-, dimethyl ester InChI=1/C16H22O6/c1-20-14(18)13-9-3-6-12(17)11-5-4-10(8-22-7-9)16(11,13)15(19)21-2/h9-11,13H,3-8H2,1-2H dimethyl 4-oxooctahydro-1,7-(methanooxymethano)azulene-8,8a(1H)-dicarboxylate