New N- and O-arylpiperazinylalkyl pyrimidines and 2-methylquinazolines derivatives as 5-HT7 and 5-HT1A receptor ligands: Synthesis, structure-activity relationships, and molecular modeling studies

Sebastiano Intagliata, Maria N Modica, Valeria Pittalà, Loredana Salerno, Maria A Siracusa, Alfredo Cagnotto, Mario Salmona, Rafał Kurczab, Giuseppe Romeo

Research output: Contribution to journalArticle

Abstract

Based on our earlier studies of structure activity relationships on 4-substituted piperazine derivatives, in this work we synthesized a novel set of long-chain arylpiperazines with the purpose of elucidating if some structural modifications in the terminal fragment could affect the binding affinity for the 5-HT7 and 5-HT1A receptors. In this new series, the quinazolinone system of the previous derivatives was replaced by a 6-phenylpyrimidine or a 2-methylquinazoline, which were used as versatile building blocks for the preparation of new compounds. A 4-arylpiperazine moiety through a five methylene chain was anchored at the nitrogen or oxygen atom of the heterocyclic scaffolds. The substituents borne by the piperazine nucleus were phenyl, phenylmethyl, 3- or 4-chlorophenyl, and 2-ethoxyphenyl. Binding tests, performed on human cloned 5-HT7 and 5-HT1A receptors, showed that, among the newly synthesized derivatives, 4-[5-[4-(2-ethoxyphenyl)-1-piperazinyl]pentoxy]-6-phenyl-pyrimidine (13) and 3-[5-[4-(2-ethoxyphenyl)-1-piperazinyl]pentyl]-2-methyl-4(3H)-quinazolinone (20) displayed the best affinity values, Ki=23.5 and 8.42nM for 5-HT7 and 6.96 and 2.99nM for 5-HT1A receptors, respectively. Moreover, the functional properties for both compounds were further evaluated using the cAMP assay. Finally, a molecular modeling study has been performed for 5-HT7 and 5-HT1A receptor homology models to investigate the binding mode of N- and O-alkylated pyrimidinones/pyrimidines 4-13, 2-methylquinazolinones/quinazolines 17-22, and previously reported 2- and 3-substituted quinazolinones 23-30.

Original languageEnglish
Pages (from-to)1250-1259
Number of pages10
JournalBioorganic and Medicinal Chemistry
Volume25
Issue number3
DOIs
Publication statusPublished - Feb 1 2017

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Keywords

  • Dose-Response Relationship, Drug
  • HEK293 Cells
  • Humans
  • Ligands
  • Models, Molecular
  • Molecular Structure
  • Pyrimidines
  • Quinazolines
  • Receptor, Serotonin, 5-HT1A
  • Receptors, Serotonin
  • Structure-Activity Relationship
  • Journal Article
  • Research Support, Non-U.S. Gov't

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