Novel CDKs inhibitors for the treatment of solid tumour by simultaneously regulating the cell cycle and transcription control

Abstract A novel series of cyclin-dependent kinases (CDKs) inhibitors, which play critical roles in the cell cycle control and regulation of cell transcription, were synthesised. A systematic study of enzymatic and cellular assays led to the identification of compound X22 with a nanomolar potency against CDK4 and CDK9 and potent antiproliferative activities against a panel of tumour cell lines. X22 could induce cell cycle arrest and cell apoptosis in cancer cell lines. X22 dose-dependently inhibits signalling pathways downstream of CDKs in cancer cells. In vivo antitumor activity assays, oral administration of X22 led to significant tumour regression in mouse model without obvious toxicity. Superior anti-cancer efficacy in vitro and in vivo of X22 demonstrated combined depletion of cell cycle and transcriptional CDK all contributed to antitumor activity. Taken together, concomitant inhibition of cell cycle and transcriptional CDK activities provided valuable guide for further structural optimisation.


General method E for preparation of 12a~12e
Potassium carbonate (2.0 eq) was added slowly to solution of 5a~5e (9 mmol, 1.0 eq) in 20 mL DMF and the mixture was stirred for 10 min.
When the addition was finished, the mixture was warm to room temperature and stirred for 2 h. After completion of reaction, the reaction was quenched with saturated Na2SO3 solution and stirred for a while. The organic phase was washed with brine, dried with anhydrous Na2SO4. After filtered, the product was concentrated with rotary evaporator to give the intermediates 8a~8e or 13a~13e as white solid.  3,144.5,134.5,131.9,129.9,127.4,124.7,123.6,54.0,36.3, 5,147.4,134.2,134.1,132.0,126.4,124.1,123.4,37.3,31.4,27.7, Method E1: To a stirred solution of the yellow solid 7a, 7c, 7f~7h, 8a~8e or 13a~13e (1.0 eq) in AcOH (reaction concentration: 0.1 mmol/mL), Fe powder (11 eq) was added in portion, and the mixture was refluxed at 65°C. After the completion of the reaction, the reaction mixture was absorbed onto celite, washed with dichloromethane, concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to afford intermediates 9a~10e or 15a~15e as yellow oil.
Method E2: To a stirred solution of the yellow solid 12a~13e (1.0 eq) and ammonium chloride (9.0 eq) in MeOH (reaction concentration: 0.1 mmol/mL), Zn powder (7.0 eq) was added in several portion, and the mixture was stirred at RT for 1.5h. After the completion of the reaction, the reaction mixture was absorbed onto celite, concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to afford intermediates 14a~14e as yellow oil.
Method G2: A solution of compounds X1 or X4 (1.0 eq) in dichloromethane (5 mL) were cooled to -10°C. A solution of 85% m-CPBA (1.5 eq) of DCM (5 mL) was added dropwise over 10 min keeping the temperature below 0°C. When the addition was finished, the mixture was warm to 0°C and stirred for 2 h. After completion of reaction, the reaction was quenched with saturated Na2SO3 solution and stirred for a while. The organic phase was washed with brine, dried with anhydrous Na2SO4. The crude product was concentrated with rotary evaporator and purified through silica gel column chromatography to give the target compounds X5 or X7 as white solid.
Method G3: A solution of compounds X4 (1.0 eq) in dichloromethane (5 mL) were cooled to 0°C. A solution of 85% m-CPBA (4.5 eq) of DCM (5 mL) was added dropwise over 10 min keeping the temperature at 0°C. Then stirred at room temperature for 2 h. The reaction was quenched with saturated Na2SO3 solution and stirred for a while. The organic phase was washed with brine, dried with anhydrous Na2SO4. The crude product was concentrated with rotary evaporator and purified through silica gel column chromatography to give the target compounds X6 as white solid.