Design,Synthesis And Biological Evaluation Of Urea-based ROCK 2 Inhibitors

Rho-associated protein kinase(ROCK)is the first discovered downstream effector of small GTPase-binding protein RhoA,belongs to serine-threonine protein kinases of AGC kinases family.ROCK contains two isomers of ROCK1 and ROCK2.Rho/ROCK signal pathway could induce cell contraction,cell migration,cytoskeletal remodeling,promote the elongation of axons and the division of cytoplasm.Pharmacological studies have shown that the high expression of ROCK is closely related to the occurrence of various diseases such as glaucoma,nerve damage,hypertension,diabetic nephropathy,cancer,etc.ROCK has become an important therapeutic target for diseases such as ocular diseases,cardiovascular diseases,neurological diseases,and cancer.CID5056270,a pyridinethiazolyl amide compound,has high ROCK 2 inhibitory activity,but has the disadvantage of poor selectivity.SR6846 is a new type of selective urea-based inhibitor with excellent enzyme activity and cell activity.The aminoalkyl side chain enhances its selectivity and activity.In this thesis,compounds CID5056270 and SR6846 are used as lead compounds.Based on the design idea of combination principles,the aminoalkyl side chain was introduced at the 5-position on the thiazole ring of compound CID5056270,and the amide structure at the 2-position on the thiazole ring was replaced with a urea structure.A new class of small molecular urea derivatives were designed.At the same time,after extensive literature research,it was found that ROCK inhibitors containing 7-azaindole structural fragment also have a good inhibitory activity,Therefore,the 7-azaindole structure was introduced into the compound design instead of the pyridine group.Thus we obtained another series of urea derivatives.Futher biological studies were then conducted to the two series urea-based synthesized derivatives.A total of 25 compounds in two series were synthesized by chemical methods.The structures were confirmed by 1H-NMR,13C-NMR,and HR-MS,and they are all new chemical entities that have not been reported in the past literature.The inhibitory activity of the synthesized compounds on ROCK2 were screened by enzyme-linked immunoassay(ELISA).The experimental results showed that both types of urea derivatives exhibited certain ROCK2 inhibitory activity.Among them,compound 6K shows the most inhibitory activity on ROCK2 with the IC50 value of 26 nM.The two types of urea derivatives showed similar inhibitory activities.The electron-donating substitution on the benzene ring is better than the electron-withdrawing substitution.In addition,in the series A,4-position nitrogen substituted in the pyridine ring is better than the 3-position.As for the aminoalkyl side chain at the 5-position of the thiazole ring,pyrrole is better than morpholine and piperidine.A preliminary summary of the structure-activity relationships of above ROCK2 small molecular inhibitors has laid a solid foundation for the future research of urea-based ROCK2 inhibitors.