Chlormezanone
Chlormezanone (marketed under the brandname Trancopal or Fenaprim) is a drug used as an anxiolytic and a muscle relaxant.
Its use was discontinued in many countries from 1996 on, due to rare but serious cases of toxic epidermal necrolysis.
Chemistry

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.
References
Wollina U, Hipler U, Seeling A, Oelschlager H (2005). "Investigations of interactions of chlormezanone racemate and its enantiomers on human keratinocytes and human leucoytes in vitro". Skin Pharmacol Physiol 18 (3): 132–138. doi:10.1159/000084910. PMID 15897685.
Seeling A, Oelschläger H, Rothley D (2000). "Important pharmaceutical-chemical characteristics of the central muscle relaxant chlormezanone". Pharmazie 55 (4): 293–6. PMID 10798243.
Oelschläger H, Klinger W, Rothley D, Seeling A, Bockhard H, Hofmann B, Machts H, Riederer H, Rackur H (1998). "[Cleavage and biotransformation of the central muscle relaxant chlormezanone]". Pharmazie 53 (9): 620–4. PMID 9770210.