Start with a benzene ring fused to a seven-membered ring (N1-C2-C3-N4-C5-C6-C7). The nitrogen at position N1 carries a carbonyl group (-C=O), with the carbonyl carbon substituted by a methoxy group (-O-CH3). Carbons C6 and C7 are shared with the benzene ring, while C3 and N4 are shared to an adjacent pyrrole ring (a five-membered aromatic ring featuring one nitrogen and four carbon atoms). In the pyrrole ring, the carbon adjacent to the nitrogen (not the shared carbon) is substituted with a carboxyl group (-COOH).