Synthesis and bioactivity of novel bis(heteroaryl)piperazine (BHAP) reverse transcriptase inhibitors: structure-activity relationships and increased metabolic stability of novel substituted pyridine analogs

J Med Chem. 1996 Dec 20;39(26):5267-75. doi: 10.1021/jm960269m.

Abstract

The major route of metabolism of the bis(heteroaryl)piperazine (BHAP) class of reverse transcriptase inhibitors (RTIs), atevirdine and delavirdine, is via oxidative N-dealkylation of the 3-ethyl- or 3-isopropylamino substituent on the pyridine ring. This metabolic pathway is also the predominant mode of metabolism of (alkylamino)piperidine BHAP analogs (AAP-BHAPs), compounds wherein a 4-(alkylamino)piperidine replaces the piperazine ring of the BHAPs. The novel AAP-BHAPs possess the ability to inhibit non-nucleoside reverse transcriptase inhibitor (NNRTI) resistant recombinant HIV-1 RT and NNRTI resistant variants of HIV-1. This report describes an approach to preventing this degradation which involves the replacement of the 3-ethyl- or 3-isopropylamino substituent with either a 3-tert-butylamino substituent or a 3-alkoxy substituent. The synthesis, bioactivity and metabolic stability of these analogs is described. The majority of analogs retain inhibitory activities in enzyme and cell culture assays. In general, a 3-ethoxy or 3-isopropoxy substituent on the pyridine ring, as in compounds 10, 20, or 21, resulted in enhanced stabilities. The 3-tert-butylamino substituent was somewhat beneficial in the AAP-BHAP series of analogs, but did not exert a significant effect in the BHAP series. Lastly, the nature of the indole substitution sometimes plays a significant role in metabolic stability, particularly in the BHAP series of analogs.

MeSH terms

  • Anti-HIV Agents / chemical synthesis
  • Anti-HIV Agents / metabolism
  • Anti-HIV Agents / pharmacology
  • Cytochrome P-450 Enzyme System / pharmacology
  • HIV-1 / enzymology
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Microsomes, Liver / enzymology
  • Piperazines / chemical synthesis*
  • Piperazines / metabolism
  • Piperazines / pharmacology*
  • Reverse Transcriptase Inhibitors / chemical synthesis*
  • Reverse Transcriptase Inhibitors / metabolism
  • Reverse Transcriptase Inhibitors / pharmacology*
  • Structure-Activity Relationship

Substances

  • Anti-HIV Agents
  • Piperazines
  • Reverse Transcriptase Inhibitors
  • Cytochrome P-450 Enzyme System