{"doi":"10.1107/s2414314622012238","title":"1<i>H</i>-Benzo[<i>g</i>]pteridine-2,4-dione","abstract":"The structure of the title compound, C 10 H 6 N 4 O 2 , reported by Smalley et al. [(2021). Cryst. Growth Des. 22 , 524–534] from powder diffraction data and 15 N NMR spectroscopy, is confirmed using low-temperature data from a twinned crystal. The tautomer in the solid state is alloxazine (1 H -benzo[ g ]pteridine-2,4-dione) rather than isoalloxazine (10 H -benzo[ g ]pteridine-2,4-dione). In the extended structure, the molecules form hydrogen-bonded chains propagating in the [0\\overline{1}1] direction through alternating centrosymmetric R 2 2 (8) rings with pairwise N—H...O interactions and centrosymmetric R 2 2 (8) rings with pairwise N—H...N interactions. The crystal chosen for data collection was found to be a non-merohedral twin (180° rotation about [001]) in a 0.446 (4):0.554 (6) domain ratio.","journal":"IUCrData","year":2023,"id":402274,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9509,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":537827,"name":"Frank R. Fronczek","orcid":"0000-0001-5544-2779","position":1,"is_corresponding":false},{"id":1179580,"name":"Rao M. Uppu","orcid":"0000-0003-1940-7161","position":0,"is_corresponding":true}],"reference_count":16,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-19T01:20:23.920156Z","pmid":"36794048","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}