{
  "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": "4311230f-8c4e-48c8-8b18-36a4ecf0344d",
          "code": "623-91-6",
          "type": "PRIMARY",
          "url": "https://commonchemistry.cas.org/detail?cas_rn=623-91-6",
          "code_system": "CAS",
          "references": [
            "b702688d-3b21-4bdf-8d66-bdfaa2a6fa0f",
            "3b4864f8-ab87-4c63-acad-82a5b5a570b7"
          ]
        },
        {
          "uuid": "b8a28886-e375-4f98-8069-b45c6eaf5ae9",
          "code": "C035088",
          "type": "PRIMARY",
          "url": "http://www.ncbi.nlm.nih.gov/mesh/67035088",
          "code_system": "MESH",
          "references": [
            "b702688d-3b21-4bdf-8d66-bdfaa2a6fa0f"
          ]
        },
        {
          "uuid": "cf530af3-26cc-48af-8d98-99ffbaafcd0a",
          "code": "210-819-7",
          "type": "PRIMARY",
          "url": "https://echa.europa.eu/substance-information/-/substanceinfo/100.009.836",
          "code_system": "ECHA (EC/EINECS)",
          "references": [
            "b702688d-3b21-4bdf-8d66-bdfaa2a6fa0f"
          ]
        },
        {
          "uuid": "2f46e1da-2aee-4622-8ca0-0f4b6372291d",
          "code": "638144",
          "type": "PRIMARY",
          "url": "https://pubchem.ncbi.nlm.nih.gov/compound/638144",
          "code_system": "PUBCHEM",
          "references": [
            "b702688d-3b21-4bdf-8d66-bdfaa2a6fa0f"
          ]
        },
        {
          "uuid": "68119c71-f3ff-8b65-2aee-54f39a2336df",
          "code": "5722",
          "type": "PRIMARY",
          "url": "https://pubchem.ncbi.nlm.nih.gov/source/hsdb/5722",
          "code_system": "HSDB",
          "references": [
            "2610e691-f342-2c78-fdd0-7bed03a329ee"
          ]
        },
        {
          "uuid": "fdafc723-db8b-ef4f-ade1-c7fe173038bb",
          "code": "DTXSID7027253",
          "type": "PRIMARY",
          "url": "https://comptox.epa.gov/dashboard/chemical/details/DTXSID7027253",
          "code_system": "EPA CompTox",
          "references": [
            "b0843690-20e7-54de-fed6-f4bd253ef8fb"
          ]
        },
        {
          "uuid": "72f7ffbd-d1f0-4721-bdc4-a3e7b6cca2dd",
          "code": "5WBU5A3E8A",
          "type": "PRIMARY",
          "code_system": "FDA UNII"
        },
        {
          "uuid": "965125b7-6a31-a49c-c49c-99e00a89cf40",
          "code": "20954",
          "type": "PRIMARY",
          "url": "https://dtp.cancer.gov/dtpstandard/servlet/dwindex?searchtype=NSC&outputformat=html&searchlist=20954",
          "code_system": "NSC",
          "references": [
            "a3ab25b1-5afb-b242-91ef-d478c784cefe"
          ]
        }
      ],
      "substance_class": "chemical",
      "names": [
        {
          "uuid": "22ed171e-4021-4c31-854f-ca3854b2db26",
          "name": "2-BUTENEDIOIC ACID (2E)-, DIETHYL ESTER",
          "stdName": "2-BUTENEDIOIC ACID (2E)-, DIETHYL ESTER",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "2cbad86c-6356-45b1-b969-cd165197a489",
            "2e3b6030-6261-479f-8b50-2642ed431ffe"
          ],
          "display_name": false
        },
        {
          "uuid": "7c8a1bb9-4ef2-4729-ba68-2fb8c63df145",
          "name": "2-BUTENEDIOIC ACID (E)-, DIETHYL ESTER",
          "stdName": "2-BUTENEDIOIC ACID (E)-, DIETHYL ESTER",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "2cbad86c-6356-45b1-b969-cd165197a489",
            "2e3b6030-6261-479f-8b50-2642ed431ffe"
          ],
          "display_name": false
        },
        {
          "uuid": "fa2a95b0-5de6-48cf-babf-e7d2ed40392e",
          "name": "2-BUTENEDIOIC ACID, DIETHYL ESTER, (E)-",
          "stdName": "2-BUTENEDIOIC ACID, DIETHYL ESTER, (E)-",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "2cbad86c-6356-45b1-b969-cd165197a489",
            "2e3b6030-6261-479f-8b50-2642ed431ffe"
          ],
          "display_name": false
        },
        {
          "uuid": "cf072d15-3515-4a14-b5ca-fb16f95c4eb6",
          "name": "DIETHYL FUMARATE",
          "stdName": "DIETHYL FUMARATE",
          "type": "sys",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "2cbad86c-6356-45b1-b969-cd165197a489",
            "8a362d91-3f2c-4132-8081-125db072f17f",
            "ee0f4f39-0826-4fb9-a36a-08d619deb18c",
            "a6078f9c-797d-4c15-9ead-83f147f4778b"
          ],
          "display_name": true
        },
        {
          "uuid": "31bbcca3-6abe-4f0d-9bda-df660fbfd43b",
          "name": "DIETHYL FUMARATE [HSDB]",
          "stdName": "DIETHYL FUMARATE [HSDB]",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "2cbad86c-6356-45b1-b969-cd165197a489",
            "ee0f4f39-0826-4fb9-a36a-08d619deb18c"
          ],
          "display_name": false
        },
        {
          "uuid": "7b7fcaa5-512d-40b4-933d-040b6afaccf1",
          "name": "FUMARIC ACID, DIETHYL ESTER",
          "stdName": "FUMARIC ACID, DIETHYL ESTER",
          "type": "cn",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "2cbad86c-6356-45b1-b969-cd165197a489",
            "2e3b6030-6261-479f-8b50-2642ed431ffe"
          ],
          "display_name": false
        },
        {
          "uuid": "8dc08e6d-5820-423e-8ac2-cb37e306cbed",
          "name": "NSC-20954",
          "stdName": "NSC-20954",
          "type": "cd",
          "languages": [
            "en"
          ],
          "preferred": false,
          "references": [
            "2cbad86c-6356-45b1-b969-cd165197a489",
            "2e3b6030-6261-479f-8b50-2642ed431ffe"
          ],
          "display_name": false
        }
      ],
      "references": [
        {
          "uuid": "8a362d91-3f2c-4132-8081-125db072f17f",
          "citation": "SA",
          "doc_type": "SRS",
          "public_domain": true,
          "tags": [
            "NOMEN",
            "PUBLIC_DOMAIN_RELEASE",
            "AUTO_SELECTED"
          ]
        },
        {
          "uuid": "2cbad86c-6356-45b1-b969-cd165197a489",
          "citation": "SIGMA-ALDRICH",
          "doc_type": "SIGMA-ALDRICH",
          "public_domain": true,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "2e3b6030-6261-479f-8b50-2642ed431ffe",
          "citation": "ChemID",
          "doc_type": "SRS",
          "public_domain": true,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "ee0f4f39-0826-4fb9-a36a-08d619deb18c",
          "citation": "HSDB",
          "doc_type": "SRS",
          "public_domain": true,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "b702688d-3b21-4bdf-8d66-bdfaa2a6fa0f",
          "citation": "SRS CODE IMPORT",
          "doc_type": "SRS",
          "public_domain": true,
          "document_date": 1493390868000,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "7648f16c-8411-43ac-a86d-a5851c50c390",
          "citation": "SRS import [5WBU5A3E8A]",
          "url": "http://fdasis.nlm.nih.gov/srs/srsdirect.jsp?regno=5WBU5A3E8A",
          "doc_type": "SRS",
          "public_domain": true,
          "document_date": 1493390868000,
          "tags": [
            "NOMEN"
          ]
        },
        {
          "uuid": "a6078f9c-797d-4c15-9ead-83f147f4778b",
          "citation": "DIETHYL FUMARATE [HSDB]",
          "doc_type": "SRS_LOCATOR",
          "public_domain": true
        },
        {
          "uuid": "2610e691-f342-2c78-fdd0-7bed03a329ee",
          "citation": "WEBSITE",
          "url": "https://toxnet.nlm.nih.gov/cgi-bin/sis/search2/r?dbs+hsdb:@term+@rn+@rel+623-91-6",
          "doc_type": "WEBSITE",
          "public_domain": true,
          "tags": [
            "NOMEN",
            "PUBLIC_DOMAIN_RELEASE"
          ]
        },
        {
          "uuid": "b0843690-20e7-54de-fed6-f4bd253ef8fb",
          "citation": "WEBSITE",
          "url": "https://comptox.epa.gov/dashboard/dsstoxdb/results?utf8=%E2%9C%93&search=623-91-6",
          "doc_type": "WEBSITE",
          "public_domain": true,
          "tags": [
            "NOMEN",
            "PUBLIC_DOMAIN_RELEASE"
          ]
        },
        {
          "uuid": "a3ab25b1-5afb-b242-91ef-d478c784cefe",
          "citation": "NCI",
          "doc_type": "NCI DRUG DICTIONARY",
          "public_domain": true
        },
        {
          "uuid": "3b4864f8-ab87-4c63-acad-82a5b5a570b7",
          "citation": "STN",
          "doc_type": "STN (SCIFINDER)",
          "public_domain": true
        }
      ],
      "definition_type": "PRIMARY",
      "moieties": [
        {
          "uuid": "4864c98f-af51-4434-a210-f581120e13d2",
          "id": "4864c98f-af51-4434-a210-f581120e13d2",
          "molfile": "\n  Marvin  01132103482D          \n\n 12 11  0  0  0  0            999 V2000\n    8.1453   -7.3318    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n    8.8598   -6.9193    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n    9.5744   -7.3318    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n   10.2890   -6.9193    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n   10.2890   -6.0942    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n   11.0035   -7.3318    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n   11.7181   -6.9193    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n   12.4326   -7.3318    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n   12.4326   -8.1569    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n   13.1472   -6.9193    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n   13.8618   -7.3318    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n   14.5763   -6.9193    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n  1  2  1  0  0  0  0\n  2  3  1  0  0  0  0\n  3  4  1  0  0  0  0\n  5  4  2  0  0  0  0\n  4  6  1  0  0  0  0\n  6  7  2  0  0  0  0\n  7  8  1  0  0  0  0\n  9  8  2  0  0  0  0\n 10  8  1  0  0  0  0\n 10 11  1  0  0  0  0\n 11 12  1  0  0  0  0\nM  END",
          "smiles": "CCOC(=O)/C=C/C(=O)OCC",
          "formula": "C8H12O4",
          "atropisomerism": "No",
          "charge": 0,
          "count": 1,
          "stereochemistry": "ACHIRAL",
          "count_amount": {
            "type": "MOL RATIO",
            "average": 1,
            "units": "MOL RATIO",
            "uuid": "20cb148e-3a54-4224-8685-b7b6eab3fe05"
          },
          "defined_stereo": 0,
          "ez_centers": 1,
          "molecular_weight": "172.1788",
          "optical_activity": "NONE",
          "stereo_centers": 0
        }
      ],
      "definition_level": "COMPLETE",
      "uuid": "8fe0f945-c1d3-414a-be27-d0d3df751315",
      "version": "6",
      "structure": {
        "id": "511a64f2-808f-4343-a09b-8d3d0c1478cc",
        "molfile": "\n  Marvin  01132104132D          \n\n 12 11  0  0  0  0            999 V2000\n   12.4326   -7.3318    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n   11.7181   -6.9193    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n   11.0035   -7.3318    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n   10.2890   -6.9193    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n   10.2890   -6.0942    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n    9.5744   -7.3318    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n    8.8598   -6.9193    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n    8.1453   -7.3318    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n   13.1472   -6.9193    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n   12.4326   -8.1569    0.0000 O   0  0  0  0  0  0  0  0  0  0  0  0\n   13.8618   -7.3318    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n   14.5763   -6.9193    0.0000 C   0  0  0  0  0  0  0  0  0  0  0  0\n  2  1  1  0  0  0  0\n  3  2  2  0  0  0  0\n  4  3  1  0  0  0  0\n  5  4  2  0  0  0  0\n  6  4  1  0  0  0  0\n  7  6  1  0  0  0  0\n  8  7  1  0  0  0  0\n  9  1  1  0  0  0  0\n 10  1  2  0  0  0  0\n  9 11  1  0  0  0  0\n 11 12  1  0  0  0  0\nM  END",
        "smiles": "CCOC(=O)/C=C/C(=O)OCC",
        "formula": "C8H12O4",
        "atropisomerism": "No",
        "charge": 0,
        "count": 1,
        "stereochemistry": "ACHIRAL",
        "defined_stereo": 0,
        "ez_centers": 1,
        "molecular_weight": "172.1788",
        "optical_activity": "NONE",
        "references": [
          "8a362d91-3f2c-4132-8081-125db072f17f",
          "7648f16c-8411-43ac-a86d-a5851c50c390"
        ],
        "stereo_centers": 0
      },
      "unii": "5WBU5A3E8A"
    }
  ]
}