(S)-Thalidomide is the S-enantiomer of thalidomide, which is an immunomodulatory agent and the model drug of the thalidomide class of medications. It is primarily used to treat certain cancers (such as multiple myeloma) and a leprosy complication. The German pharmaceutical company Grunenthal first introduced it as a sedative and immunomodulatory agent in the 1950s. It is also being studied for its potential to treat the symptoms of numerous cancers. Thalidomide is now frequently used as a building block for PROTACs (Proteolysis Targeting Chimeras), which serve as ligands for the E3 ubiquitin ligase cereblon. The PROTAC technology makes use of hetero-bifunctional small molecules, one end of which attracts an E3 ubiquitin ligase and the other of which interacts with the target protein. A CRBN-DDB1-Cul4A complex is an E3 ubiquitin ligase that is inhibited by thalidomide. Thalidomide is an effective costimulator of primary human T cells in vitro. When combined with stimulation through the T cell receptor complex, it promotes the proliferation of T cells through interleukin 2 and the production of interferon gamma.

Physicochemical Properties

Molecular Formula	C13H10N2O4
Molecular Weight	258.23
Exact Mass	258.064
Elemental Analysis	C, 60.47; H, 3.90; N, 10.85; O, 24.78
CAS #	841-67-8
Related CAS #	Thalidomide;50-35-1;Thalidomide-d4;1219177-18-0;(R)-Thalidomide;2614-06-4
PubChem CID	92142
Appearance	Off-white to light brown solid powder
Density	1.503g/cm3
Boiling Point	509.7ºC at 760 mmHg
Melting Point	269-271ºC
Flash Point	262.1ºC
Index of Refraction	1.646
LogP	0.354
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	1
Heavy Atom Count	19
Complexity	449
Defined Atom Stereocenter Count	1
SMILES	C1CC(=O)NC(=O)C1N2C(=O)C3=CC=CC=C3C2=O
InChi Key	UEJJHQNACJXSKW-VIFPVBQESA-N
InChi Code	InChI=1S/C13H10N2O4/c16-10-6-5-9(11(17)14-10)15-12(18)7-3-1-2-4-8(7)13(15)19/h1-4,9H,5-6H2,(H,14,16,17)/t9-/m0/s1
Chemical Name	2-[(3S)-2,6-dioxopiperidin-3-yl]isoindole-1,3-dione
Synonyms	(S)-Thalidomide; NSC91730; NSC 91730; (S)-Thalidomide; (-)-Thalidomide; 841-67-8; (S)-(-)-thalidomide; l-Thalidomide; S-(-)-Thalidomide; S-Thalidomide; Thalidomide, (-)-; NSC-91730; l-Thalidomide
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: This product requires protection from light (avoid light exposure) during transportation and storage.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	Cereblon; Apoptosis; E3 ligase
ln Vitro	(S)-Thalidomide treatment results in a reduction in cell viability in U266 cells with an IC50 of 362 μM[1]. (S)-Thalidomide treatment increased apoptosis in a dose-dependent manner in U266 cells[1]. Genes involved in apoptosis and angiogenesis have altered expression profiles, but the apoptotic genes have undergone the most significant changes. In particular, there is a two-fold reduction in I-B kinase expression, which is accompanied by a four-fold reduction in NF-B expression. The Bax:Bcl-2 ratio is raised by (S)-thalidomide, which also raises I-kB protein levels and lowers NF-kB activity. When combined with other cytotoxic agents, (S)-Thalidomide dramatically reduces Bcl-2 expression, which raises the possibility of enhancing the cytotoxic effect[1].
ln Vivo	Early in the history of the thalidomide disaster, chick embryos were "eliminated" as useful in the study of thalidomide. One reason for that conclusion was that many of the early experiments were flawed. We employed a number of experiments to expose chick embryos to thalidomide. Our data show that thalidomide does cause limb reduction defects in chick embryos as long as the embryos are directly exposed to the drug. The most useful techniques are implanting thalidomide-soaked beads into the embryo immediately adjacent to the limb territory or soaking presumptive chick limb territories in thalidomide and then grafting the explants to a host embryo celom. Thalidomide affects the chick limb grafted to a host embryo in a dose response fashion. Furthermore, S-thalidomide and S-EM12 are more teratogenic than R-thalidomide and R-EM12.[2] As long as chick embryos are directly exposed to the drug, thalidomide does result in limb reduction defects. The best methods involve implanting Thalidomide-soaked beads into the embryo next to the limb territory or sowing Thalidomide into presumptive chick limb territories before grafting the explants to a host embryo celom. Thalidomide has dose-dependent effects on the chick limb transplanted into the host embryo. The teratogenicity of (S)-thalidomide is also higher than that of (R)-thalidomide[1].
Cell Assay	s-Thalidomide has proven efficacy in multiple myeloma. Although it has both antiangiogenic and pro-apoptotic effects, its primary mode of therapeutic action remains unclear. We have investigated the changes to the expression of genes involved with these cellular processes following culture with s-thalidomide in the U266 MM cell line. Cells were cultured with s-thalidomide (0-1000 microM), and cell parameters, including apoptosis, were assessed on day 3. RNA was extracted from cells cultured for 24 h at the IC(50) concentration of s-thalidomide, and changes to gene expression were investigated by microarray methodologies. A reduction in cell viability was observed in U266 cells cultured with s-thalidomide (IC(50): 362 microM), which were mirrored by significant increases in apoptosis (for example, 200 microM on day 3: 40.3+/-3.1% vs. 3.2+/-0.4% on day 0; P<0.001). There were changes in the expression profile of genes involved in angiogenesis and apoptosis, but the changes were most dramatic in the apoptotic genes. In particular, the expression of I-kappaB kinase was decreased by two-fold, which was associated with a four-fold decrease in NF-kappaB expression. These data correlated with immunoblotting analyses, which showed significant increases in I-kappaB protein levels and decreased NF-kappaB activity. Additionally, the Bax : Bcl-2 ratio was significantly increased. Our data suggest that both angiogenic and apoptotic genes and proteins are affected by s-thalidomide. Additionally, a dramatic decrease in Bcl-2 expression with s-thalidomide suggests a possible enhancement of cytotoxic effect if combined with other cytotoxic agents[1].
Animal Protocol	Thalidomide is currently under evaluation as an anti-angiogenic agent in cancer treatment, alone and in combination with cytotoxic agents. Thalidomide is a racemate with known pharmacologic and pharmacokinetic enantioselectivity. In a previous study with thalidomide combination chemotherapy, we found evidence of anti-tumour synergy. In this study, we examined whether the synergy involved altered pharmacokinetics of thalidomide enantiomers. Adult female F344 rats were implanted with 9L gliosarcoma tumours intracranially, subcutaneously (flank), or both. Effectiveness of oral thalidomide alone, and with intraperitoneal BCNU or cisplatin combination chemotherapy, was assessed after several weeks treatment. Presumed pseudo steady-state serum, tumour and other tissues, collected after treatment, were assayed for R- and S-thalidomide by chiral HPLC. Both serum and tissue concentrations of R-thalidomide were 40-50% greater than those of S-thalidomide. Co-administration of BCNU or cisplatin with thalidomide did not alter the concentration enantioselectivity. Poor correlation of concentration with subcutaneous anti-tumour effect was found for individual treatments, and with all treatments for intracranial tumours. The consistency of the enantiomer concentration ratios across treatments strongly suggests that the favourable antitumour outcomes from interactions between thalidomide and the cytotoxic agents BCNU and cisplatin did not have altered enantioselectivity of thalidomide pharmacokinetics as their basis.[3] 100 mg/kg, p.o. C57BL/6 mice
ADME/Pharmacokinetics	Metabolism / Metabolites (-)-thalidomide has known human metabolites that include 5-hydroxy-thalidomide, 5'-Hydroxythalidomide, and (-)-thalidomide arene oxide.
Toxicity/Toxicokinetics	mouse LD50 oral 700 mg/kg BEHAVIORAL: SOMNOLENCE (GENERAL DEPRESSED ACTIVITY) Nature., 215(296), 1967 [PMID:6059519]
References	[1]. s-thalidomide has a greater effect on apoptosis than angiogenesis in a multiple myeloma cell line. Hematol J. 2004;5(3):247-54. [2]. The effect of thalidomide in chicken embryos. Birth Defects Res A Clin Mol Teratol. 2009 Aug;85(8):725-31. [3]. Enantioselectivity of thalidomide serum and tissue concentrations in a rat glioma model and effects of combination treatment with cisplatin and BCNU. J Pharm Pharmacol. 2007 Jan;59(1):105-14. [4]. Understanding the Thalidomide Chirality in Biological Processes by the Self-disproportionation of Enantiomers. Sci Rep. 2018 Nov 20;8(1):17131.
Additional Infomation	(S)-thalidomide is a 2-(2,6-dioxopiperidin-3-yl)-1H-isoindole-1,3(2H)-dione that has S-configuration at the chiral centre. It has a role as a teratogenic agent. It is an enantiomer of a (R)-thalidomide. Twenty years after the thalidomide disaster in the late 1950s, Blaschke et al. reported that only the (S)-enantiomer of thalidomide is teratogenic. However, other work has shown that the enantiomers of thalidomide interconvert in vivo, which begs the question: why is teratogen activity not observed in animal experiments that use (R)-thalidomide given the ready in vivo racemization ("thalidomide paradox")? Herein, we disclose a hypothesis to explain this "thalidomide paradox" through the in-vivo self-disproportionation of enantiomers. Upon stirring a 20% ee solution of thalidomide in a given solvent, significant enantiomeric enrichment of up to 98% ee was observed reproducibly in solution. We hypothesize that a fraction of thalidomide enantiomers epimerizes in vivo, followed by precipitation of racemic thalidomide in (R/S)-heterodimeric form. Thus, racemic thalidomide is most likely removed from biological processes upon racemic precipitation in (R/S)-heterodimeric form. On the other hand, enantiomerically pure thalidomide remains in solution, affording the observed biological experimental results: the (S)-enantiomer is teratogenic, while the (R)-enantiomer is not.[4]

Solubility Data

Solubility (In Vitro)	DMSO: ~52 mg/mL (~201.4 mM) Water: <1 mg/mL (slightly soluble or insoluble) Ethanol: ~2 mg/mL (~7.7 mM)
Solubility (In Vivo)	30% PEG400+0.5% Tween80+5%Propylene glycol: 5 mg/mL  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	3.8725 mL	19.3626 mL	38.7252 mL
	5 mM	0.7745 mL	3.8725 mL	7.7450 mL
	10 mM	0.3873 mL	1.9363 mL	3.8725 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.