Design,Synthesis And Activity Evaluation Of Novel Thienopyrimidone Carboxylic Acids As Potent URAT1 Inhibitors

Gout is a metabolic disease caused by the deposited in joint tissue of monosodium urate crystals,which formed by overproduction or under-excretion of uric acid,a product of purine catabolism physiologically excreted in the urine,hyperuricemia is its main clinical manifestation.In recent decades,the number of patients with gout and hyperuricemia has been increasing worldwide,which seriously affects the quality of human life and places a heavy burden on society.China is a country with a high incidence of gout.The number of patients with gout is about 1%-3%,and the number of patients with hyperuricemia has reached 5.0%-23.4%.At present,the drugs used clinically for the treatment of gout and hyperuricemia mainly include anti-inflammatory drugs,uric acid production inhibitors and promote uric acid excretion drugs.There are serious toxic and side effects,which greatly limit the clinical use.Therefore,it is of great significance to develop safe and effective anti-gout drugs.With an in-depth understanding of the pathogenesis of gout,about 90%of gout patients are caused by uric acid excretion disorders,of which uric acid transporter 1(URAT1)can reabsorb large amounts of uric acid and play an important role in uric acid excretion process.Lesinurad as the first drug for this target was launched in the United States at the end of 2015.It can be used in combination with a xanthine oxidase inhibitor(XOI)to improve the therapeutic effects.This opens up a new field for the research of anti-gout drugs.The successful approval of Dotinurad(FYU-981)in 2020 proves that further exploitation of URAT1 inhibitors has bright prospects.As the first approved URAT1 inhibitor,it was found that Lesinurad has liver and kidney toxicity to some extend,so there is a need for further optimization to improve its efficacy.In this paper,based on the structure-activity relationship of our preliminary modification of Lesinurad and the pharmacophore model of URAT1 inhibitors,two series of novel thienopyrimidone compounds were designed and synthesized by using pharmacophore-guided scaffold hopping to seek more potent back-up derivatives of Lesinurad.The resulting compounds were evaluated by URAT1 inhibition activity test in vitro,blood uric acid lowering test in mice,acute toxicity experiment and pharmacokinetic test.In the inhibitory activity test of URAT1 in vitro,we use cell transfection and radioactive detection methods to test the target compounds.Since the ester compounds were difficult to dissolve in the activity test medium,only the carboxylic acid compounds were tested.The results showed that almost all target compounds have target inhibition activity,and most of the compounds have comparable activity to the positive compound(Lesinurad),especially the inhibition activity of series ?compounds is generally higher than compounds of series I.Among them,a total of 11 compounds have IC50 values that are better than Lesinurad,especially compounds ?-3a(IC50=3.27 ?M)and ?-3b(IC50=2.69 ?M)are 4.7 times and 5.7 times as potent as Lesinurad(IC50=15.34 ?M)respectively.In rescreening test the results showed that the activity of compounds ?-3a and ?-3b are comparable to T7 and were basically consistent with the results of the initial screening.When there are no substitution on the thiophene ring,the inhibition activity is the best,and the introduction of cyclohexane structure was also beneficial in increasing the activity.In addition,nine carboxylic acid derivatives with remarkable URAT1-inhibitory potency were selected for further investigation.A total of 18 compounds(carboxylic acids and their corresponding esters)were tested in mice for reducing uric acid activity.It was found that almost all compounds demonstrated potency in lowering blood uric acid.Among them,the most potent compounds were ?-3a(decrease rate of uric acid concentration:90.2%)and ?-3o(96.2%),which obviously better than Lesinuard(31.4%).The acid or ester form of most compounds displayed similar activity in lowering uric acid activity,and the acid is slightly stronger than the ester.Further,the selected compound II-3a has a lower acute toxicity in mice and good pharmacokinetic properties.In summary,in this study,inspired by the insights from our previous optimization of Lesinurad,a total of 48 novel thienopyrimidinone URAT1 inhibitors in two series were designed and synthesized by using pharmacophore-guided scaffold hopping principle.Through URAT1-inhibition activity screening and uric acid lowering experiments in mice,several derivatives were selected as new lead compounds with great potential for further study,as exemplified by ?-3a.