2beta-Substituted analogues of 4'-iodococaine: synthesis and dopamine transporter binding potencies

J Med Chem. 1998 Jun 18;41(13):2380-9. doi: 10.1021/jm980061w.

Abstract

A series of 2beta-substituted analogues of 4'-iodococaine (3) was synthesized and evaluated in an in vitro dopamine transporter (DAT) binding assay. Selective hydrolysis at the 2beta-position of 3 gave the carboxylic acid 15 that served as the intermediate for the synthesis of compounds 4, 5, and 6-11. The 2beta-alkyl derivatives were obtained from ecgonine methyl ester (17) through a series of reactions leading to the aldehyde 20. Wittig reaction of 20 with methyltriphenylphosphorane followed by hydrogenation and benzoylation gave the products 12 and 13. The binding affinity of 4'-iodococaine (3) was 10-fold less than that of cocaine. The hydroxymethane, acetate, amide, benzyl ester, oxidazole, and ethane derivatives of 3 exhibited decreased binding while the vinyl, phenyl, and ethyl esters showed a moderate increase in binding affinity. Only the isopropyl derivative 8 exhibited a 2-fold increase in binding affinity compared with 4'-iodococaine (3). Hydroxylation of 8 at the 2'-position gave 14 which enhanced not only the binding potency at the DAT by another 2-fold but also the selectivity at the DAT over the norepinephrine and serotonin transporters. Compound 14 failed to stimulate locomotor activity in C57BL/6J mice over a wide dose range and blocked cocaine-induced locomotor stimulant action.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Brain / metabolism
  • Carrier Proteins / metabolism*
  • Central Nervous System Stimulants / metabolism
  • Central Nervous System Stimulants / pharmacology
  • Cocaine / analogs & derivatives*
  • Cocaine / chemical synthesis
  • Cocaine / metabolism
  • Cocaine / pharmacology
  • Dopamine Plasma Membrane Transport Proteins
  • Male
  • Membrane Glycoproteins*
  • Membrane Transport Proteins*
  • Mice
  • Mice, Inbred C57BL
  • Motor Activity / drug effects
  • Nerve Tissue Proteins*
  • Protein Binding / drug effects
  • Rats
  • Rats, Sprague-Dawley

Substances

  • 3-((2'-hydroxy-4'-iodobenzoyl)oxy)-8-methyl-8-azabicyclo(3.2.1)octane-2-carboxylic acid isopropyl ester
  • 4'-iodococaine
  • Carrier Proteins
  • Central Nervous System Stimulants
  • Dopamine Plasma Membrane Transport Proteins
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Nerve Tissue Proteins
  • Slc6a3 protein, mouse
  • Slc6a3 protein, rat
  • Cocaine