Synthesis And Antitumor Activity Evaluation Of Highly Functionalized 2,3,4-trisubstituted Pyrroles

Nitrogen-containing heterocyclic structures are widely found in natural products and physiologically active molecules,and they have important applications in various fields such as medicine,food,chemical industry,and polymer materials.Among them,the five-membered heterocyclic pyrrole is an especially significant member.At present,pyrrole based moities are crucial components of many listed drugs,including atorvastatin and sunitinib.Therefore,the synthesis and application of pyrrole derivatives has become a recent research hotspot,receiving increasing attention.Isocyanoacetate plays a crucial role as a synthetic building block in organic chemistry and has been widely used in cyclization reactions.The present study focuses on investigating the synthetic methodology of highly functionalized 2,3,4-trisubstituted pyrroles utilizing isocyanoacetate,3-phenylpropynylpentanedione and 3-phenylpropynylaldehyde as starting materials.The synthesized compounds were evaluated for their inhibitory activities against glioma cell line U251,and further structural optimization was carried out according to the activity results.The specific research contents are listed as follows:1.Study on the synthesis of polysubstituted alkenylated pyrroles involving 3-phenylpropargyl pentanedione and isocyanoacetate:The synthesis of multi-substituted alkenylated pyrroles with 3-phenylpropargyl pentanedione compounds and isocyanoacetate as substrates.The reaction conditions were optimized by single factor control method,and the substrate expansion study was carried out under the optimal conditions.Finally,20 pyrrole compounds containing different alkenyl substituents were synthesized,and the yield was up to 84%.2.Study on the synthesis of polysubstituted alkynylated pyrroles involving 3-phenylpropargylaldehyde and isocyanoacetate:Substituted alkynyl pyrrole compounds were synthesized by using3-phenylpropynaldehyde and isocyanoacetate as reaction substrates.Based on the screening of reaction conditions such as different solvents and catalytic bases,22pyrrole compounds containing different alkynyl substituents were synthesized.The synthesis of alkynyl pyrrole compounds by this method has the advantages of rapid reaction（5 minutes）,simple and convenient post-processing method and simple reagents.Moreover,the presence of alkynyl groups in the target compounds provides ample scope for subsequent modifications,thereby paving the way for developing a diverse range of drug-like compound libraries.3.Evaluation of anti-proliferation activities against human glioma U251 cell line and optimization of lead compound:Structural analysis of the synthesized compounds revealed that they possess a low relative molecular weight,goodlipophilic solubility,and exhibit typical characteristics of penetrating the blood-brain barrier.Therefore,the above-mentioned substituted pyrrole compounds were selected and evaluated for their anti-proliferation activities against human glioma U251 cell line.The preliminary screening results showed that compound 3t displayed potent inhibitory activity against human glioma U251 cell line(IC₅₀=5.45μM).Building upon the promising results,the current study conducted further structural optimization,resulting in compounds with improved anti-proliferation activities of human glioma cell U251,which is expected to be further studied and developed.In summary,20 pyrrole derivatives containing different alkenyl groups and 22 pyrrole compounds containing different alkynyl groups were synthesized through the reaction of ethyl isocyanoacetate with 3-phenylpropargyl pentanedione and 3-phenylpropargyl aldehyde,respectively.The screening of these analogues against human glioma U251cell line indicated that compound 3t displayed potent anti-proliferation activity.Subsequently,30 compounds were designed and synthesized with 3t as the lead compound.Among these compounds,RC-07(IC₅₀=3.23μM),RC-08(IC₅₀=3.10μM)and RC-09(IC₅₀=2.29μM)were proved with potent inhibitory activities.This study provides a new lead molecule for the development of pyrrole derivatives for the treatment of glioma.