5-22-04-00432 (Beilstein Handbook Reference) 982-12-7 9aH-quinolizine-1,2,3,4-tetracarboxylic acid, 9-methyl-, tetramethyl ester BRN 0061310 Tetramethyl 9-methyl-9aH-quinolizine-1,2,3,4-tetracarboxylate