Synthesis And Preliminary Bioactive Evaluation Of Naftopidil Metabolitic Enantiomers And Its Derivatives

Naftopidil, a novel phenylpiperazine derivatives developed by BoehringerMannheim, Germany. Studies have shown that it is a new selective aryloxy piperazineα1A/D-AR antagonists, one of the main drug as a treatment for benign prostatichyperplasia(BPH). Naftopidil structure contains the structure of chiral secondaryalcohols, with a pair of optical isomers,and this drug often used therapeutically as aracemate.Our lab have used HPLC/MS Determination of plasma samples in rats afteroral administration Naftopidil to study Naftopidil metabolic behaviour and itsmetabolites in animals,we found its can be transformed into three activemetabolites:O-desmethyl-naftopidil, DMN; phenylhydroxy-naftopidi, PHN;naphthyl-naftopidi, NHN.In view of our lab’s preparatory work in the aryloxy piperazine the selectiveα1A/D-receptor antagonists,in order to study the chiral pharmacokinetics and chiralpharmacology of Naftopidil enantiomers and its active chiral metabolites.As the basisof the method of synthesis Naftopidil enantiomers, the study of chiral pharmacologyand pharmacokinetics and the pharmacophore model,this thesis plan to synthesis theactive metabolites of Naftopidil.And make them as the leading compounds withtransformating their chemical structures to sythesis more derivatives.With thebioactive evaluation we can find the new candidate objects of high activity,lowtoxicity,specificity and good pharmacological effects in these derivatives.Research content1. Synthesis active racimic and enantiomeric metabolites of Naftopidil,using HPLC, ESI-MS,1HNMR to determine their purity and identify their structures.2. Design and synthesis4pairs of Naftopidl metabolitic derivatives after the study ofdrug metabolic stabilities and α1-AR antagonist pharmacophore model.3. Based on Dual-luciferase reporter gene detection method,combining the adrenergicreceptor gene and reporter gene to transfect in PC12cell lines and establishing astable expression of adrenergic receptors step somaticstrains for the screening of21target compounds. From Promega dual luciferase reporter gene assay kit technicalmanual operation,we recorded the values of firefly luciferase and renilla luciferaserespectively.using the raw ratios to evaluate the bioacitivity of the targetcompounds.Research results1. This project successfully synthesis active racimic and enantiomeric metabolites ofNaftopidil and establish the content determination of Naftopidil metabolicenantiomers to help the Naftopidil chiral pharmacokinetic and chiral pharmacologystudy.2. After the study of drug metabolic stabilities and α1-AR antagonist pharmacophoremodel,we have modified the chemical structure of Naftopidil active metabolites andsuccessfully synthesis4pairs of Naftopidl metabolitic derivatives.3. This project use Dual-luciferase reporter gene detection method to preliminary testthe biological activity of Naftopidil metabolites and their derivatives. The resultsshow that all the21target compounds have α1A-AR antagonistic activities invarying degrees. Many of these compounds’ α1A-AR antagonistic coefficients arelarger than prazosin’s. Implying that there may be potential antagonists of α1-ARreceptor. Preliminary analysis from the data of fluorescence detection, most of thetarget compounds’(except in BH2,BH4R> S) S–enantiomers have more bioactivethan R-enantiomers, implying that the further verification of the target compounds’chiral pharmacology,chiral pharmacokinetic and the other two α1-AR subtypesselectivity studies are still needed.