Pyrimido[4,5-c]pyridazine-5,7(6H,8H)-dione

Pyrimido[4,5-c]pyridazine-5,7(6H,8H)-dione corresponds to CAS 20886-77-5, molecular formula C6H4N4O2, and molecular weight 164.12. PubChem resolves this registry number to one compound, CID 21817447. Its verified connectivity is SMILES C1=CN=NC2=C1C(=O)NC(=O)N2, while InChIKey ZIMDKZKMFQILPB-UHFFFAOYSA-N identifies the same graph. The representation is one neutral molecular component with no defined stereochemical layer.

The framework fuses a pyrimidinedione ring to a pyridazine ring according to the [4,5-c] junction descriptor. Four nitrogens belong to the fused bicyclic system, and the two oxygens are the carbonyl atoms at positions 5 and 7. PubChem gives 8H-pyrimido[4,5-c]pyridazine-5,7-dione as its IUPAC name and also records the alternate hydrogen-locant wording Pyrimido[4,5-c]pyridazine-5,7(1H,6H)-dione as a synonym for this same CID. The preferred H1 above follows PubChem's Title, avoiding an unsupported choice beyond the verified entry.

For an identity-specific inquiry, provide Rlavie with the preferred full name, CAS 20886-77-5, and the requested quantity. Include a MOL or SDF structure file so the fused-ring junction, two carbonyl positions, and four ring nitrogens can be compared with PubChem CID 21817447, the stated SMILES, and InChIKey ZIMDKZKMFQILPB-UHFFFAOYSA-N. Rlavie can reconcile those references before request-specific information is considered. Because shorthand hydrogen-locant descriptions may differ among naming sources, the CAS, CID, and submitted molecular graph should remain the controlling identity set.