The two enantiomers of<unk> :Left: (S)-(−)-thalidomideRight: (R)-(+)-thalidomide<unk>  is racemic; while S-thalidomide is the bioactive form of the molecule, the individual enantiomers can racemize to each other due to the acidic hydrogen at the chiral centre, which is the carbon of the glutarimide ring bonded to the phthalimide substituent. The racemization process can occur in vivo. Celgene Corporation originally synthesized<unk>  using a three-step sequence starting with L-glutamic acid treatment, but this has since been reformed by the use of L-glutamine. As shown in the image below, N-carbethoxyphthalimide (1) can react with L-glutamine to yield N-phthaloyl-L-glutamine (2). Cyclization of N-phthaloyl-L-glutamine occurs using carbonyldiimidazole, which then yields<unk>  (3). Celgene Corporation's original method resulted in a 31% yield of S-thalidomide, whereas the two-step synthesis yields 85–93% product that is 99% pure. Muller et al.'s two-step<unk>  synthesis
Thalidomide
Pomalidomide
Vincristine
Lenalidomide
Mercaptopurine
Febuxostat
Ifosfamide
Ixazomib