Study On Ligustrazine Derivatives For Antiplatelet Aggregation

Cardiovascular Vascule Disease?CVDs?threatens human health seriously,Statistics show that the number of deaths from cardiovascular and cerebrovascular diseases worldwide is about 17.65 million,Far higher than the number of cancer deaths?8.93 million?.At present,the treatment of cardiovascular and cerebr ovascular diseases caused by platelet aggregation lacks effective drug treatment Screening safe and effective candidate compounds for anti-platelet aggregation is of great significance for the development of drugs for cardiovascular and cer ebrovascular diseases.In this study,lead compounds of natural ligustrazine were studied.Design,synthesis and structure confirmation of ligustrazine derivatives based on bio-electronic isosteric and assembling principles,study on the anti-platelet aggregatio n effect,the following results were obtained:1.The optimum preparation method of key intermediates for synthesis of Ligustrazine derivatives was established.Ligustrazine was selected as raw material,oxidation reaction with hydrogen peroxide,boekelheide rearrangement reaction with anhydride,hydrolysis of 2-h ydroxymethyl-3,5,6-trimethylpyrazine,halogenation of phosphorus tribromide as affinity reagent,a Method for obtaining the key intermediate 2-Bromomethyl-3,5,6-Trimethylpyrazine.Structural confirmation by mass spectrometry and nuclear magnetic resonance,orthogonal experiment was designed to optimize the proce ss,The optimum experimental conditions for the synthesis were determined:The reaction solvent is tetrahydrofuran,The prescription time is 12 hours,Raw mat erial ratio is 1:3.5,2-bromomethyl-3,5,6-trimethylpyrazine 2.12g was obtained,The yield was 91%.2.The design,synthesis,structure confirmation and process optimization of Ligustrazine derivatives were completed.1)The principle of equal arrangement and combination of bioelectrons in pharmaceutical chemistry,ligustrazine as a leading compound,the compounds containing phenolic hydroxyl group,amino group and morpholine group were screened,a series of ester Ligustrazine derivatives were synthesized by Williamson etherification in alkaline environment,synthesis of ligustrazine derivatives con taining carboxyl groups by hydrolysis,eight new ligustrazine derivatives were prepared by this method.2)Spectroscopic methods such as mass spectrometry and nuclear magneticr esonance,structural popper analysis of 8 new ligustrazine derivatives,It is conf irmed that their structures are respectively:4-??3,5,6-trimethylpyrazine-2-yl?meth oxy?benzoic acid?3a?,2-?4-?3,5,6-trimethylpyrazine-2-yl?methoxy?phenyl)aceti c acid?3b?,3-?4-??3,5,6-trimethylpyrazine-2-yl?methoxy?phenyl?propionic acid?3c?,4-??3,5,6-trimethylpyrazine-2-methyl?amino?benzoic acid?3d?,2-?4-??3,5,6-tri methylpyrazine-2-methyl?amino?phenyl?acetic acid?3e?,2,6-dimethyl-4-??3,5,6-t rimethylpyrazine-2-methyl?methyl?morpholine?3f?,4-??3,5,6-trimethylpyrazine-2-yl?methyl?thiomorph?3g?,?E?-3-?4-?3,5,6-trimethylpyrazine-2-methoxy?phenyl?a crylic acid?3h?.3)Process optimization of Ligustrazine derivatives by single factor and ort hogonal experiments,The optimum synthetic conditions were selected,including:Time,Temperature,Proportion,Solvent and Environment,Three main factors were screened by single factor experiment:Reaction Time,Reaction Temperatur e and Raw Material Ratio,Design 3-factor 3-level orthogonal experiment,The o ptimum synthetic conditions of compound 3d,compound 3F and compound 3H were determined as follows:10h,65?,1:1.2.8h,85?,1:1.4.10h,90?,1:1.3.The structure-activity relationship of Ligustrazine derivatives against plat elet aggregation was clarified,It was found that the anti-platelet aggregation effe ct of compound 3h was better than aspirin.The anti-platelet aggregation effect of Ligustrazine derivatives was studied,Aspirin was selected as a positive control drug,The effect of candidate compo unds on platelet aggregation was determined by Microenzyme labeling.The ex perimental results show that:The anti-platelet aggregation effect of some comp ounds was higher than that of aspirin positive control drugs,Compounds 3a,3d,3f,3h have better activity,The best activity of IC₅₀ for 3 hours was 3.8 times that of aspirin.The structure-activity relationship of the activity was studie d.The anti-platelet aggregation effect decreases with the increase of the numbe r of carbon atoms connected at 15 sites,The inhibition of double bonds in 15-position side chains increases,The inhibition of ammonia derivatives is weaker than that of ether derivatives,The activity of morpholine ring at 11 position decreases,carboxyl group is an important group in anti-platelet aggregation.