SB-743921 HCl

    WARNING: This product is for research use only, not for human or veterinary use.

MedKoo CAT#: 205790

CAS#: 940929-33-9

Description: SB-743921 is a synthetic small molecule with potential antineoplastic properties. SB-743921 selectively inhibits kinesin spindle protein (KSP), an important protein involved in the early stages of mitosis that is expressed in proliferating cells. Inhibition of KSP results in inhibition of mitotic spindle assembly and interrupts cell division, thereby causing cell cycle arrest and induction of apoptosis.

Price and Availability


USD 150
USD 650
Ask price

USD 265
Ask price
Ask price

USD 420
Ask price
Ask price

SB-743921 HCl, purity > 98%, is in stock. The same day shipping out after order is received. Delivery time: overnight (USA/Canada); 3-5 days (worldwide). Shipping fee: $30.00 (USA); from $45.00 (Canada); from $70.00 (international).

Chemical Structure


Theoretical Analysis

MedKoo Cat#: 205790
Name: SB-743921 HCl
CAS#: 940929-33-9
Chemical Formula: C31H34Cl2N2O3
Exact Mass:
Molecular Weight: 553.52
Elemental Analysis: C, 67.27; H, 6.19; Cl, 12.81; N, 5.06; O, 8.67

Synonym: SB743921; SB 743921; SB743921.

IUPAC/Chemical Name: (S)-N-(3-aminopropyl)-N-(1-(3-benzyl-7-chloro-4-oxo-4H-chromen-2-yl)-2-methylpropyl)-4-methylbenzamide hydrochloride

SMILES Code: O=C(N(CCCN)[C@H](C1=C(CC2=CC=CC=C2)C(C3=C(O1)C=C(Cl)C=C3)=O)C(C)C)C4=CC=C(C)C=C4.[H]Cl

Technical Data

white solid powder

>98% (or refer to the Certificate of Analysis)

Certificate of Analysis:

Safety Data Sheet (MSDS):

Shipping Condition:
Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition:
Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Soluble in DMSO, not in water

Shelf Life:
>2 years if stored properly

Drug Formulation:
This drug may be formulated in DMSO

Stock Solution Storage:
0 - 4 C for short term (days to weeks), or -20 C for long term (months).

Harmonized System Code:

Additional Information

SB-743921, Cytokinetics's second KSP inhibitor to enter clinical trials, is structurally distinct from ispinesib, Cytokinetics' most advanced anti-cancer drug candidate. SB-743921 was the subject of a Phase I/II clinical trial in Hodgkin and non-Hodgkin Lymphoma that has been completed  


1: Viswanath AN, Pae AN. Resistance by allostery: a novel perspective for eg5-targeted drug design. J Med Chem. 2013 Aug 22;56(16):6314-6. doi: 10.1021/jm401071u. Epub 2013 Jul 30. PubMed PMID: 23899248.

2: Talapatra SK, Anthony NG, Mackay SP, Kozielski F. Mitotic kinesin Eg5 overcomes inhibition to the phase I/II clinical candidate SB743921 by an allosteric resistance mechanism. J Med Chem. 2013 Aug 22;56(16):6317-29. doi: 10.1021/jm4006274. PubMed PMID: 23875972.

3: Good JA, Wang F, Rath O, Kaan HY, Talapatra SK, Podgórski D, MacKay SP, Kozielski F. Optimized S-trityl-L-cysteine-based inhibitors of kinesin spindle protein with potent in vivo antitumor activity in lung cancer xenograft models. J Med Chem. 2013 Mar 14;56(5):1878-93. doi: 10.1021/jm3014597. Epub 2013 Feb 27. PubMed PMID: 23394180; PubMed Central PMCID: PMC3759169.

4: Holen KD, Belani CP, Wilding G, Ramalingam S, Volkman JL, Ramanathan RK, Vasist LS, Bowen CJ, Hodge JP, Dar MM, Ho PT. A first in human study of SB-743921, a kinesin spindle protein inhibitor, to determine pharmacokinetics, biologic effects and establish a recommended phase II dose. Cancer Chemother Pharmacol. 2011 Feb;67(2):447-54. doi: 10.1007/s00280-010-1346-5. Epub 2010 May 12. PubMed PMID: 20461380.

5: Tomillero A, Moral MA. Gateways to clinical trials. Methods Find Exp Clin Pharmacol. 2009 Jan-Feb;31(1):47-57. PubMed PMID: 19357798.

6: Bayés M, Rabasseda X, Prous JR. Gateways to clinical trials. Methods Find Exp Clin Pharmacol. 2006 Oct;28(8):533-91. PubMed PMID: 17136234.