Design,Synthesis And Anti-inflammatory Of Novel 5,7-substituted Dihydrothieno [3,2-d] Pyrimidine Derivtives

Inducible nitric oxide synthase（iNOS）is expressed as a pro-inflammatory stimulus,producing low concentrations of nitric oxide（NO）with cell protection.However,over-expression of iNOS induces excessive NO production,and abnormally increased NO levels are associated with various diseases such as Parkinson’s disease,Alzheimer’s dis-ease,multiple sclerosis,rheumatoid arthritis and inflammatory bowel disease Patho-physiology.Therefore,selective inhibition of iNOS is one of the effective methods for treating such diseases.Based on the previous research results of the pyrazolopyrimidine skeleton deriva-tives of the research group and related literature investigations,we found.First,the dihydrothiophene ring can be used as a group to anchor iNOS and has a certain affinity for iNOS;second,the dihydrothiophene ring is a bioelectronic isostere of the pyrazole ring.We replaced the pyrazolopyrimidine core with The dihydrothienopyrimidine core nucleus extends the research direction.Third,molecular docking shows that the1,3-alkyl substitution of the pyrazole ring in the pyrazolopyrimidine core nucleus has no decisive effect on anti-inflammatory activity.It is planned to replace the pyrazole ring with a bioelectronic isostere dihydrothiophene ring.The 1,3 alkyl substitution will not be included in this design synthesis.The styryl group,2-furan vinyl group,and3,4,5-trimethoxystyryl group are respectively connected at the carbon 5 position.In the carbon 7 position,different aniline and substituted aniline,benzylamine and substituted benzylamine,phenethylamine and substituted phenethylamine,alkylamine and hetero-cyclic amine are used for substitution.Three series of dihydrothieno[3,2-d]pyrimidine derivatives of A,B and C were obtained.Most compounds were confirmed by ¹H-NMR,¹³C-NMR and HR-MS.Preliminary structure-activity relationship studies have shown that A series substituted by styryl groups at the 5-position of carbon have no significant difference in NO inhibition rate and generally weaker activity.It shows that the A series is not suitable for continued optimization.Among them,the inhibition rate of NO re-lease by C series compounds is much higher than that of A series and B series com-pounds.Studies on the structure-activity relationship of substitution of C7 have shown that the introduction of hydrogen bond donors at the carbon 7 position significantly en-hances the inhibitory activity;the substitution of electron withdrawing groups at the carbon 7 position can significantly enhance the activity;No significant improvement in activity.It shows that the connecting shaft is NH is very important for activity.After optimization,we obtained the most active compounds C7 and C20 in the C series.Western blot experiments show that compound C20 can inhibit the formation of iNOS dimer and has a concentration-dependent characteristic.Through the anti-inflammatory activity test on adjuvant arthritis rats,the degree of paw swelling,body weight changes,joint pathological sections and changes in serum inflammatory factors were recorded.It shows that C20 has good anti-inflammatory activity in vivo.Through the NO release inhibition rate experiment and Western blot experiment,the best performing compound C20 was selected.A variety of experimental methods were used to verify the target and determine the mechanism of action.Provides the most effective compound structure.C20 is used as a lead compound for subsequent modifica-tion to rationally design new and effective iNOS inhibitors.