S6821
{{cs1 config|name-list-style=vanc|display-authors=6}}
{{Drugbox
| IUPAC_name = 3-[1-[(3,5-dimethyl-1,2-oxazol-4-yl)methyl]pyrazol-4-yl]-1-[(3-hydroxyphenyl)methyl]imidazolidine-2,4-dione
| image = S6821_structure.png
| width =
| tradename =
| routes_of_administration =
| CAS_number = 1119831-25-2
| UNII = 1P43YY1KO2
| ATC_prefix =
| PubChem = 57422431
| IUPHAR_ligand =
| ChemSpiderID = 26233877
| ChEMBL = 3924866
| C=19 | H=19 | N=5 | O=4
| smiles = CC1=C(C(=NO1)C)CN2C=C(C=N2)N3C(=O)CN(C3=O)CC4=CC(=CC=C4)O
| StdInChI = 1S/C19H19N5O4/c1-12-17(13(2)28-21-12)10-23-9-15(7-20-23)24-18(26)11-22(19(24)27)8-14-4-3-5-16(25)6-14/h3-7,9,25H,8,10-11H2,1-2H3
| StdInChIKey = LLJBKECMPVCSDS-UHFFFAOYSA-N
}}
S6821 is a food additive that acts as a potent and selective antagonist of the bitter taste receptor TAS2R8. It has been approved as a food additive to block the bitter taste of certain active pharmaceutical ingredients, excipients, and nutraceuticals which primarily produce their bitter taste through binding to TAS2R8.{{cite journal | vauthors = Karanewsky DS, Arthur AJ, Liu H, Chi B, Ida L, Markison S | title = Toxicological evaluation of two novel bitter modifying flavour compounds: 3-(1-((3,5-dimethylisoxazol-4-yl)methyl)-1H-pyrazol-4-yl)-1-(3-hydroxybenzyl)imidazolidine-2,4-dione and 3-(1-((3,5-dimethylisoxazol-4-yl)methyl)-1H-pyrazol-4-yl)-1-(3-hydroxybenzyl)-5,5-dimethylimidazolidine-2,4-dione | journal = Toxicology Reports | date = 2016 | volume = 3 | pages = 310–327 | pmid = 28959552 | pmc = 5615838 | doi = 10.1016/j.toxrep.2016.02.007 | bibcode = 2016ToxR....3..310K }}{{cite journal | vauthors = Fotsing JR, Darmohusodo V, Patron AP, Ching BW, Brady T, Arellano M, Chen Q, Davis TJ, Liu H, Servant G, Zhang L, Williams M, Saganich M, Ditschun T, Tachdjian C, Karanewsky DS | title = Discovery and Development of S6821 and S7958 as Potent TAS2R8 Antagonists | journal = Journal of Medicinal Chemistry | volume = 63 | issue = 9 | pages = 4957–4977 | date = May 2020 | pmid = 32330040 | doi = 10.1021/acs.jmedchem.0c00388 }}