Molecular Design,Synthesis And Anti-HIV Activity Research Of 2-thiomethylpyrimidine Derivatives

AIDS,is also known as Acquired Immune Deficiency Syndrome.It is a kind of disease accompanied with a variety of clinical symptoms caused by human immune deficiency virus（HIV）retrovirus infection.And it can be spread through maternal infant,blood and sexual contact.The virus attacks the body’s T lymphocytes,causing the body’s immune system to gradually collapse,even causing the infection to die.HIV replicates in host cells through these processes:receptor recognition and membrane fusion,reverse transcription,integration,transcription and translation,virus assembly and mature release.Thus,stopping any of these links can inhibit viral replication.By inhibiting the reverse transcription process of HIV,there is an effective way to prevent the virus from further replicating and damaging the immune system.HIV reverse transcriptase has become an important target for anti-HIV drug design because of its key role in the catalytic transformation of viral RNA into DNA.In the early stage of our research group,the effective non-nucleoside HIV reverse transcriptase inhibitor DB02 was synthesized,but its resistance and oral utilization were poor.Based on the analysis of the mechanism of DB02,skeleton transition and biological electron,the C-2 side chain acetyl pharmacophore of DB02 was replaced with pyrazole ring to enhance the binding force of the molecule and target protein and improve the resistance of these compounds.As the introduction of the weak acid group,pyrazole ring can improve the pharmacokinetic properties of these compounds and further increase the solubility of salt.Through the above molecular design strategies,we hope to obtain a new anti-HIV drug with high efficiency,low toxicity,good oral utilization and anti-resistance.Firstly,β-ketone ester was synthesized by method of Clay.Then,β-ketone ester reacted with thiourea in the catalysis of sodium alcohol and got condensation products2-sulfur pyrimidine ketones.Finally,2-sulfur pyrimidine ketones can interact-t with intermediate of 3-（bromomethyl）pyrazole or 3-（bromomethyl）-4-choprazole derivatives in K₂CO₃ and DMF conditions,obtaining target compounds of2-thiomethylpyrimidine by thialkylation reaction.Meanwhile,the synthesis method of3-（bromomethyl）pyrazole or 3-（bromomethyl）-4-cloprazole derivatives is as follows.Initially,ketoesters were prepared when various substituents of methyl ketones reacted with diethyl malonate in alkaline conditions.Then,the intermediate pyrazolate derivatives were derived from the recombination of ketonesters and hydrazine.Through LiAlH₄ reduction of pyrazolate derivatives,the intermediate pyrazolol was obtained.Finaly,the final intermediates were obtained by bromination.A total of 34 target compounds were synthesized by chemical reaction steps of 9or 10.The structure of target compounds was identified by ¹H NMR,¹³C NMR,even the structure of some target compounds was identified by IR and MS spectral.In this paper,we selecteded the novel 2-methyl ketone compounds to evaluate their in vitro toxicity test（MTT）and anti-HIV activity（CPE）against human cells according to procedures described in the literature.As shown in results,34 compounds exhibited different degree of anti-HIV activity against the human cells.7 samples have lower poisonous to the cells of C8166 in vitro,CC₅₀>200μM(CC₅₀ value,defined as the concentration corresponding to 50%growthinhibition).Surprisely,9 samples（I01,I07-I10,I14,I17,I23,I25）have relatively strong anti-HIV-1 activity in vitro,and the therapeutic index（TI）excesses 3000.The remaining samples shows moderate anti-HIV-1 activity in vitro and TI maintains between 50³000.The EC₅₀0 of all samples is range from 0.0030μM to 0.7678μM.The EC₅₀ of the two samples of I01and I17 is 0.0068±0.0017μM,0.0038±0.0011μM respectively.We have carried on enzyme inhibition and the anti-resistance test to compound I17.The results show that the inhibitory rate of I17 to extracorporeal reverse transcriptase was 73.42%.The EC₅₀value of I17 for drug-resistant strains is generally at the nM level,showing the ideal resistance and specificity.At the same time,we analyzed the main pharmacokinetic parameters of I17,Oral utilization:10.4±2.79%,drug clearance rate（CL/F）:3.83±1.01L/hr/kg,Half-life(T_1/2):2.50±1.63hr,the compound shows the basic oral exploitation degree,metabolic pharmacokinetic properties of stability and more powerful,and can be used as a new drug research and development of lead compounds or candidate that deserving further research.