{
  "meta": {
    "disclaimer": "Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated. We may limit or otherwise restrict your access to the API in line with our Terms of Service.",
    "terms": "https://open.fda.gov/terms/",
    "license": "https://open.fda.gov/license/",
    "last_updated": "2025-09-19",
    "results": {
      "skip": 0,
      "limit": 1,
      "total": 1
    }
  },
  "results": [
    {
      "codes": [
        {
          "uuid": "e8b42602-f08a-4eab-9c16-22050676f2f4",
          "code": "497-23-4",
          "type": "PRIMARY",
          "url": "https://commonchemistry.cas.org/detail?cas_rn=497-23-4",
          "code_system": "CAS",
          "references": [
            "2e913df4-950c-4645-8606-7361463afc37",
            "bcc73b5a-57d4-4b92-8194-c04e079406d1"
          ]
        },
        {
          "uuid": "0f083945-ff3a-4082-b001-507852001299",
          "code": "C004511",
          "type": "PRIMARY",
          "url": "http://www.ncbi.nlm.nih.gov/mesh/67004511",
          "code_system": "MESH",
          "references": [
            "2e913df4-950c-4645-8606-7361463afc37"
          ]
        },
        {
          "uuid": "c672a733-583b-43a8-96eb-810e52d10ea5",
          "code": "207-839-3",
          "type": "PRIMARY",
          "url": "https://echa.europa.eu/substance-information/-/substanceinfo/100.007.128",
          "code_system": "ECHA (EC/EINECS)",
          "references": [
            "2e913df4-950c-4645-8606-7361463afc37"
          ]
        },
        {
          "uuid": "ed0e1a70-8191-499b-8768-131a8521b786",
          "code": "10341",
          "type": "PRIMARY",
          "url": "https://pubchem.ncbi.nlm.nih.gov/compound/10341",
          "code_system": "PUBCHEM",
          "references": [
            "2e913df4-950c-4645-8606-7361463afc37"
          ]
        },
        {
          "uuid": "a654b73a-973a-bf38-a7a4-348e29166ff9",
          "code": "8151",
          "type": "PRIMARY",
          "url": "https://pubchem.ncbi.nlm.nih.gov/source/hsdb/8151",
          "code_system": "HSDB",
          "references": [
            "ea439843-a7e0-506a-9b27-4befd93d038f"
          ]
        },
        {
          "uuid": "b97bc013-b49d-7034-1054-8ff449e28361",
          "code": "DTXSID7075422",
          "type": "PRIMARY",
          "url": "https://comptox.epa.gov/dashboard/chemical/details/DTXSID7075422",
          "code_system": "EPA CompTox",
          "references": [
            "a66409c1-4590-ab0f-96d8-9739f3a83d7e"
          ]
        },
        {
          "uuid": "a8926af3-eee1-4483-9b17-3d9517d6628c",
          "code": "8KXK25H388",
          "type": "PRIMARY",
          "code_system": "FDA UNII"
        },
        {
          "uuid": "c59a2af8-549b-1ba7-afe8-e49f1b7973de",
          "code": "38118",
          "type": "PRIMARY",
          "url": "https://www.ebi.ac.uk/chebi/chebiOntology.do?chebiId=CHEBI:38118",
          "code_system": "CHEBI",
          "references": [
            "05f6a1bf-a841-1ebf-cb77-14aa54ea11f1"
          ]
        },
        {
          "uuid": "0c23ea46-96e5-068d-b933-a9ced4f6a714",
          "code": "2-Furanone",
          "type": "PRIMARY",
          "url": "https://en.wikipedia.org/wiki/2-Furanone",
          "code_system": "WIKIPEDIA",
          "references": [
            "24e444d8-31b6-909b-6d0a-a7e6617c8d39"
          ]
        },
        {
          "uuid": "7f257584-20f7-6b99-105d-bceca479ef70",
          "code": "197009",
          "type": "PRIMARY",
          "url": "https://dtp.cancer.gov/dtpstandard/servlet/dwindex?searchtype=NSC&outputformat=html&searchlist=197009",
          "code_system": "NSC",
          "references": [
            "6ea07ce3-8e22-6edf-0451-ed274c3b3f9f"
          ]
        },
        {
          "uuid": "ffdd2a07-d885-8767-2cc8-c2fc797245f9",
          "code": "1978",
          "type": "PRIMARY",
          "url": "https://www.fao.org/food/food-safety-quality/scientific-advice/jecfa/jecfa-flav/details/en/c/1978/",
          "code_system": "JECFA MONOGRAPH",
          "references": [
            "e1742670-819f-9508-43ef-35a2e0b21e98"
          ]
        }
      ],
      "substance_class": "chemical",
      "names": [
        {
          "uuid": "125ad187-0e9f-4d63-af29-525709d58809",
          "name": ".BETA.-CROTONOLACTONE",
          "stdName": ".BETA.-CROTONOLACTONE",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "9e6eeac1-1de8-4ecd-a61b-72525fa47eac",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        },
        {
          "uuid": "f07c72c3-b854-409a-ba67-3107eab51c4b",
          "name": ".DELTA.,.ALPHA.,.BETA.-BUTENOLIDE",
          "stdName": ".DELTA.,.ALPHA.,.BETA.-BUTENOLIDE",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "eab6c78c-5668-4aad-8502-6960202ce9ee",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        },
        {
          "uuid": "adcc01fa-928b-429e-8028-b66fd38719b7",
          "name": "2(5H)-FURANONE",
          "stdName": "2(5H)-FURANONE",
          "type": "sys",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "9e6eeac1-1de8-4ecd-a61b-72525fa47eac",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": true
        },
        {
          "uuid": "04490f66-cb03-4e4c-9134-c92d71aeb6aa",
          "name": "2,5-DIHYDROFURANONE",
          "stdName": "2,5-DIHYDROFURANONE",
          "type": "sys",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "9e6eeac1-1de8-4ecd-a61b-72525fa47eac",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        },
        {
          "uuid": "897f0254-75d6-4c59-b124-4b9baef87465",
          "name": "2-BUTEN-4-OLIDE",
          "stdName": "2-BUTEN-4-OLIDE",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "9e6eeac1-1de8-4ecd-a61b-72525fa47eac",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        },
        {
          "uuid": "93a78094-06d0-49fa-8e25-38dbd6351d52",
          "name": "2-BUTENOIC ACID, 4-HYDROXY-, .GAMMA.-LACTONE",
          "stdName": "2-BUTENOIC ACID, 4-HYDROXY-, .GAMMA.-LACTONE",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "9e6eeac1-1de8-4ecd-a61b-72525fa47eac",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        },
        {
          "uuid": "0609ecb5-d2c4-4aab-b193-b7d7b95d086c",
          "name": "2-OXO-2,5-DIHYDROFURAN",
          "stdName": "2-OXO-2,5-DIHYDROFURAN",
          "type": "sys",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "9e6eeac1-1de8-4ecd-a61b-72525fa47eac",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        },
        {
          "uuid": "0939563f-0179-4562-9aa6-99125d1d6a6d",
          "name": "4-HYDROXY-2-BUTENOIC ACID .GAMMA.-LACTONE [FHFI]",
          "stdName": "4-HYDROXY-2-BUTENOIC ACID .GAMMA.-LACTONE [FHFI]",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "8d245a6b-2a13-4bd4-8199-f228c706d566",
            "fb6dde0b-bae2-47c8-bf78-c6e66f55d6ef"
          ],
          "display_name": false
        },
        {
          "uuid": "24ac746d-fe75-416f-9487-a83d0d36a397",
          "name": "4-HYDROXY-2-BUTENOIC ACID LACTONE",
          "stdName": "4-HYDROXY-2-BUTENOIC ACID LACTONE",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "9e6eeac1-1de8-4ecd-a61b-72525fa47eac",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        },
        {
          "uuid": "462a12d1-b50d-47a1-b8fc-88d95b35f46b",
          "name": "5-OXO-2,5-DIHYDROFURAN-3-YL ESTER",
          "stdName": "5-OXO-2,5-DIHYDROFURAN-3-YL ESTER",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "9e6eeac1-1de8-4ecd-a61b-72525fa47eac",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        },
        {
          "uuid": "052f86a8-0516-4b5e-aa56-ee446026dd75",
          "name": "CRATONE",
          "stdName": "CRATONE",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "9e6eeac1-1de8-4ecd-a61b-72525fa47eac",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        },
        {
          "uuid": "54603906-8b3a-482d-9b64-a28538f88681",
          "name": "CROTONIC ACID, 4-HYDROXY-, .GAMMA.-LACTONE",
          "stdName": "CROTONIC ACID, 4-HYDROXY-, .GAMMA.-LACTONE",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "9e6eeac1-1de8-4ecd-a61b-72525fa47eac",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        },
        {
          "uuid": "75534a1c-ea67-4a39-9728-2656b9c59fd9",
          "name": "FEMA NO. 4138",
          "stdName": "FEMA NO. 4138",
          "type": "cd",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "eab6c78c-5668-4aad-8502-6960202ce9ee",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        },
        {
          "uuid": "b76e14fd-9577-4c6c-876f-e46a4c2eb8c1",
          "name": "ISOCROTONOLACTONE",
          "stdName": "ISOCROTONOLACTONE",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "0b95698b-e118-4b78-84fb-deba9220e990"
          ],
          "display_name": false
        },
        {
          "uuid": "80793b3f-5a0d-4b7f-be39-3c743c2d0fb6",
          "name": "NSC-197009",
          "stdName": "NSC-197009",
          "type": "cd",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "eab6c78c-5668-4aad-8502-6960202ce9ee",
            "8d245a6b-2a13-4bd4-8199-f228c706d566"
          ],
          "display_name": false
        }
      ],
      "references": [
        {
          "uuid": "0b95698b-e118-4b78-84fb-deba9220e990",
          "citation": "ICSAS BATCH 2010",
          "doc_type": "SRS",
          "public_domain": true,
          "tags": [
            "NOMEN",
            "PUBLIC_DOMAIN_RELEASE",
            "AUTO_SELECTED"
          ]
        },
        {
          "uuid": "9e6eeac1-1de8-4ecd-a61b-72525fa47eac",
          "citation": "STN",
          "doc_type": "SRS",
          "public_domain": true,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "8d245a6b-2a13-4bd4-8199-f228c706d566",
          "citation": "STN (SCIFINDER)",
          "doc_type": "STN (SCIFINDER)",
          "public_domain": true,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "eab6c78c-5668-4aad-8502-6960202ce9ee",
          "citation": "CHEMID",
          "doc_type": "SRS",
          "public_domain": true,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "fb6dde0b-bae2-47c8-bf78-c6e66f55d6ef",
          "citation": "FHFI",
          "doc_type": "SRS",
          "public_domain": true,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "2e913df4-950c-4645-8606-7361463afc37",
          "citation": "SRS CODE IMPORT",
          "doc_type": "SRS",
          "public_domain": true,
          "document_date": 1493390950000,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "1567b27e-78b7-4490-acd0-d58d1a92879a",
          "citation": "SRS import [8KXK25H388]",
          "url": "http://fdasis.nlm.nih.gov/srs/srsdirect.jsp?regno=8KXK25H388",
          "doc_type": "SRS",
          "public_domain": true,
          "document_date": 1493390950000,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "50968246-2a57-45e4-bdd7-8d90b9e3073f",
          "citation": "CHEMID 2010",
          "doc_type": "SRS",
          "public_domain": true,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "ea439843-a7e0-506a-9b27-4befd93d038f",
          "citation": "WEBSITE",
          "url": "https://toxnet.nlm.nih.gov/cgi-bin/sis/search2/r?dbs+hsdb:@term+@rn+@rel+497-23-4",
          "doc_type": "WEBSITE",
          "public_domain": true,
          "tags": [
            "NOMEN",
            "PUBLIC_DOMAIN_RELEASE"
          ]
        },
        {
          "uuid": "a66409c1-4590-ab0f-96d8-9739f3a83d7e",
          "citation": "WEBSITE",
          "url": "https://comptox.epa.gov/dashboard/dsstoxdb/results?utf8=%E2%9C%93&search=497-23-4",
          "doc_type": "WEBSITE",
          "public_domain": true,
          "tags": [
            "NOMEN",
            "PUBLIC_DOMAIN_RELEASE"
          ]
        },
        {
          "uuid": "24e444d8-31b6-909b-6d0a-a7e6617c8d39",
          "citation": "WIKI",
          "doc_type": "WIKI",
          "public_domain": true
        },
        {
          "uuid": "05f6a1bf-a841-1ebf-cb77-14aa54ea11f1",
          "doc_type": "SYSTEM",
          "public_domain": true
        },
        {
          "uuid": "bcc73b5a-57d4-4b92-8194-c04e079406d1",
          "citation": "STN",
          "doc_type": "STN (SCIFINDER)",
          "public_domain": true
        },
        {
          "uuid": "6ea07ce3-8e22-6edf-0451-ed274c3b3f9f",
          "citation": "NCI",
          "doc_type": "NCI DRUG DICTIONARY",
          "public_domain": true
        },
        {
          "uuid": "e1742670-819f-9508-43ef-35a2e0b21e98",
          "citation": "JECFA",
          "doc_type": "JECFA",
          "public_domain": true
        }
      ],
      "definition_type": "PRIMARY",
      "moieties": [
        {
          "uuid": "327886b0-b626-454c-abc1-f04afb6c8f6b",
          "id": "327886b0-b626-454c-abc1-f04afb6c8f6b",
          "molfile": "\n  Marvin  01132102422D          \n\n  6  6  0  0  0  0            999 V2000\n    7.9253   -4.7446    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n    7.1342   -5.0065    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n    6.4662   -4.5178    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n    5.7992   -5.0065    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n    6.0536   -5.7910    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n    6.8789   -5.7910    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n  2  1  2  0  0  0  0\n  2  3  1  0  0  0  0\n  6  2  1  0  0  0  0\n  3  4  1  0  0  0  0\n  4  5  1  0  0  0  0\n  5  6  2  0  0  0  0\nM  END",
          "smiles": "C1=CC(=O)OC1",
          "formula": "C4H4O2",
          "atropisomerism": "No",
          "charge": 0,
          "count": 1,
          "stereochemistry": "ACHIRAL",
          "count_amount": {
            "type": "MOL RATIO",
            "average": 1,
            "units": "MOL RATIO",
            "uuid": "9bc11052-d1cd-4262-b320-075eca8f9383"
          },
          "defined_stereo": 0,
          "ez_centers": 0,
          "molecular_weight": "84.0735",
          "optical_activity": "NONE",
          "stereo_centers": 0
        }
      ],
      "definition_level": "COMPLETE",
      "uuid": "8303742e-dcf6-4e59-a3bc-a5019807bf4b",
      "version": "8",
      "structure": {
        "id": "72241af1-134a-4786-9616-a88c2b70184d",
        "molfile": "\n  Marvin  01132105552D          \n\n  6  6  0  0  0  0            999 V2000\n    6.0536   -5.7910    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n    5.7992   -5.0065    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n    6.4662   -4.5178    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n    7.1342   -5.0065    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n    6.8789   -5.7910    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n    7.9253   -4.7446    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n  2  1  1  0  0  0  0\n  3  2  1  0  0  0  0\n  4  3  1  0  0  0  0\n  5  4  1  0  0  0  0\n  1  5  2  0  0  0  0\n  4  6  2  0  0  0  0\nM  END",
        "smiles": "C1=CC(=O)OC1",
        "formula": "C4H4O2",
        "atropisomerism": "No",
        "charge": 0,
        "count": 1,
        "stereochemistry": "ACHIRAL",
        "defined_stereo": 0,
        "ez_centers": 0,
        "molecular_weight": "84.0735",
        "optical_activity": "NONE",
        "references": [
          "50968246-2a57-45e4-bdd7-8d90b9e3073f",
          "1567b27e-78b7-4490-acd0-d58d1a92879a"
        ],
        "stereo_centers": 0
      },
      "unii": "8KXK25H388"
    }
  ]
}