chlormezanone chlormezanone chlormezanone (marketed under the brandname trancopal or fenaprim) is a drug used as an anxiolytic and a muscle relaxant. "trancopal" redirects here. for trancopal dolo, see flupirtine. chlormezanoneclinical dataahfs/drugs.cominternational drug namesroutes ofadministrationoralatc codem03bb02 (who) legal statuslegal status in general: ℞ (prescription only) pharmacokinetic dataelimination half-life40.5 hoursidentifiers iupac name 2-(4-chlorophenyl)-3-methyl-1,1-dioxo-1,3-thiazinan-4-one cas number80-77-3 ypubchem cid2717iuphar/bps7323drugbankdb01178 ychemspider2616 yuniigp568v9g19keggd00268 ychebichebi:3619 ychemblchembl1200714 ncomptox dashboard (epa)dtxsid3022798 echa infocard100.001.190 chemical and physical dataformulac11h12clno3smolar mass273.73 g·mol−13d model (jsmol)interactive image smiles o=s1(ccc(n(c)c1c2=cc=c(c=c2)cl)=o)=o inchi inchi=1s/c11h12clno3s/c1-13-10(14)6-7-17(15,16)11(13)8-2-4-9(12)5-3-8/h2-5,11h,6-7h2,1h3 ykey:weqayvwkmwhejo-uhfffaoysa-n y ny (what is this?) (verify) its use was discontinued in many countries from 1996 on, due to rare but serious cases of toxic epidermal necrolysis. synthesis chlormezanone synthesis sterling drug inc., us 3082209 (1958). surrey, a. r.; webb, w. g.; gesler, r. m. (1958). "central nervous system depressants. the preparation of some 2-aryl-4-metathiazanones". journal of the american chemical society. 80 (13): 3469. doi:10.1021/ja01546a065.