text: The thalidomide molecule is a synthetic derivative of glutamic acid and consists of a glutarimide ring and a phthaloyl ring (Figure 5). Its IUPAC name is 2-(2,6-dioxopiperidin-3-yl)isoindole-1,3-dione and it has one chiral center
  After thalidomides selective inhibition of TNF-α had been reported, a renewed effort was put in thalidomides clinical development. The clinical development led to the discovery of new analogs which strived to have improved activities and decreased side effects.
  Clinically, thalidomide has always been used as a racemate. Generally the S-isomer is associated with the infamous teratogenic effects of thalidomide and the R-isomer is devoid of the teratogenic properties but conveys the sedative effects, however this view is highly debated and it has been argued that the animal model that these different R- and S-effects were seen in was not sensitive to the thalidomide teratogenic effects. Later reports in rabbits, which is a sensitive species, unveiled teratogenic effects from both isomers. Moreover, thalidomide enantiomers have been shown to be interconversed in vivo due to the acidic chiral hydrogen in the asymmetric center (shown, for the EM-12 analog, in Figure 3), so the plan to administer a purified single enantiomer to avoid the teratogenic effects will most likely be in vain.