RI-2 is an optimized RAD51 inhibitor with an IC50 of 44.17 μM in the standard DNA binding assay; specifically inhibits HR(Homologous recombination) repair in human cells.

Rigosertib (ON-01910) is a non-ATP-competitive inhibitor of PLK1 with IC50 of 9 nM; shows 30-fold greater selectivity against PLK2 and no activity to PLK3.

RKI-1313 is the negative control for RKI-1447 which is a potent inhibitor of the Rho-associated ROCK kinases with anti-invasive and antitumor activities in breast cancer

RKI-1447 is a potent small molecule inhibitor of ROCK1 and ROCK2.

Ro-3306 is a potent and selective inhibitor of CDK1 with Ki value of 35 nM for CDK1/cyclin B1, 10-fold selectivity relative to CDK2/cyclin E and >50-fold relative to CDK4/cyclin D.

Roniciclib is an orally bioavailable pan-cyclin dependent kinase (CDK) inhibitor, with IC50s of 5-25 nM for CDK1, CDK2, CDK3, CDK4, CDK7 and CDK9.

Roscovitine (Seliciclib, CYC202, R-roscovitine) is a potent and selective CDK inhibitor for Cdc2/cyclin B, CDK2/cyclin A, CDK2/cyclin E and CDK5/p53 with IC50 of 0.65 μM, 0.7 μM, 0.7 μM and 0.16 μM, respectively.

Rucaparib (AG-014699, PF-01367338) is an inhibitor of PARP with Ki of 1.4 nM with binding affinity to nine PARP domains. Phase 1/2.

Rucaparib inactivates PARP activity in cells with homologous recombination DNA repair pathway mutations at LC50 values ranging from 1.3-5.5 μM.

RX-3117 is an orally available and potent DNA synthesis inhibitor with potential antineoplastic activity.

Sapacitabine is an orally bioavailable pyrimidine analogue prodrug with potential antineoplastic activity.

SAR-020106 is an ATP-competitive, potent, and selective CHK1 inhibitor with an IC(50) of 13.3 nmol/L on the isolated human enzyme.

SAR407899 Hcl is a potent, ATP-competitive ROCK inhibitor woth Ki value of 36 nM/41 nM for human ROCK/Rat ROCK respectively.

SAR407899 is a potent, ATP-competitive ROCK inhibitor woth Ki value of 36 nM/41 nM for human ROCK/Rat ROCK respectively.

SB218078 is an inhibitor of checkpoint kinase 1 (Chk1) that displays selectivity over other protein kinases (IC50 values are 15, 250 and 1000 nM for Chk1, cdc2 and PKC respectively).

SCH 900776 is a selective Chk1 inhibitor with IC50 of 3 nM. It shows 50-fold selectivity against Chk2. Phase 2.

SCH900776 (S-isomer) is the S-isomer form of SCH900776, which is a potent, selective and orally bioavailable inhibitor of checkpoint kinase Chk1 (IC50 = 3 nM), highly selective against Chk2 (IC50 = 1500 nM) and cyclin-dependent kinase CDK2 (IC50

Senexin A is a potent and selective inhibitor of CDK8 and its nearest relative, CDK19 with Kd values of 0.83 μM and 0.31 μM for CDK8 and CDK19 ATP site binding, respectively.

SLx-2119(KD-025) is a small molecule and selective inhibitor of ROCK2 with IC50 of 105 nM; > 200 fold selecivity over ROCK1(IC50 =24 uM)

SN-38(NK-012) is an active metabolite of CPT-11, inhibits DNA topoisomerase I, DNA synthesis and causes frequent DNA single-strand breaks.

SNS-032(BMS-387032) is a potent inhibitor of cyclin-dependent kinases (cdks) 9, 2 and 7 (IC50 values are 4, 38 and 62 nM respectively).

SR-3677 is a new potent and selective ROCK-II inhibitor with an IC50 of ~3 nM in enzyme and cell based assays; IC50 for ROCK-I is 56 ± 12 nM.