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Cannabimimetic Indoles, Pyrroles, and Indenes: Structure–Activity Relationships and Receptor Interactions

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The Cannabinoid Receptors

Part of the book series: The Receptors ((REC))

Abstract

A number of years ago it was found that 1-aminoalkyl-3-aroylindoles have affinity for the canabinoid receptor that is expressed in the central nervous system (CB1 receptor). More than 100 of these aminoalkylindoles were prepared and structure–activity relationships (SARs) were developed for these compounds. Subsequently it was found that the aminoalkyl substituent could be replaced by a straight chain alkyl group of four to six carbon atoms without loss of affinity for the CB1 receptor. One of these indoles, 1-propyl-3-(1-naphthoyl)indole was found to have relatively high affinity for the cannabinoid receptor that is expressed in the periphery (CB2 receptor), but with little affinity for the CB1 receptor. In order to explore the SAR for these cannabimimetic 3-(1-naphthoyl)alkylindoles a number of compounds have been synthesized, some of which have very high affinity for the CB1 receptor and others which are highly selective for the CB2 receptor.

On the basis of a suggested pharmacophore for the cannabimimetic indoles, a series of 1-alkyl-3-(1-naphthoyl)pyrroles was prepared, one of which had modest affinity for the CB1 receptor and was active in vivo. Subsequent work led to the development of a series of 1-alkyl-2-aryl-4-(1-naphthoyl)pyrroles, some of which have high affinity for the CB1 and/or CB2 receptor. Two groups have reported the synthesis of cannabimimetic indenes, which serve as rigid models for the CB1 receptor. Through a combination of molecular modeling and studies of mutant receptors a body of evidence has been acquired, which indicates that cannabimimetic indoles, and by extension pyrroles and indenes, interact with the CB1 and CB2 receptors primarily by aromatic stacking.

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References

  1. Mechoulam R. The pharmacohistory of Cannabis sativa. In: Mechoulam R, editor. Cannabinoids as therapeutic agents. Boca Raton: CRC Press, 1986. pp. 1–19.

    Google Scholar 

  2. Gaoni Y, Mechoulam R. Isolation, structure and partial synthesis of an active constituent of hashish. J Am Chem Soc. 1964;86:1646–7.

    Article  CAS  Google Scholar 

  3. Razdan RK. Structure-activity relationships in cannabinoids. Pharmacol Rev. 1986;38:75–149.

    CAS  PubMed  Google Scholar 

  4. Rapaka RS, Makriyanis A. Structure-activity relationships of the cannabinoids. NIDA Research Monograph 79. Rockville: National Institute on Drug Abuse; 1987.

    Google Scholar 

  5. Mechoulam R, Devane WA, Glaser R. Cannabinoid geometry and biological behavior. In: Murphy L, Bartke A, editors. Marijuana/cannabinoids: neurobiology and neurophysiology. Boca Raton: CRC Press; 1992. pp. 1–33.

    Google Scholar 

  6. Melvin LS, Johnson MR, Herbert, CA, et. al. A cannabinoid derived prototypical analgesic. J Med Chem. 1984;27:67–71.

    Article  CAS  PubMed  Google Scholar 

  7. Johnson MR, Melvin, LS, Milne GM. Prototype cannabinoid analgetics, prostaglandins and opiates-a search for points of mechanistic interaction. Life Sci. 1982;31:1703–6.

    Article  CAS  PubMed  Google Scholar 

  8. Johnson MR, Melvin LS. The discovery of nonclassical cannabinoid anagetics. In: Mechoulam R, editor. Cannabinoids as therapeutic agents. Boca Raton: CRC Press; 1986. pp. 121–45.

    Google Scholar 

  9. Melvin LS, Milne GM, Johnson MR, et. al. Structure activity relationships for cannabinoid receptor-binding and analgesic activity: studies of bicyclic cannabinoid analogs. Mol Pharmacol. 1993;44:1008–15.

    CAS  PubMed  Google Scholar 

  10. Bell MR, D’Ambra TE, Kumar V, et. al. Antinociceptive (aminoalkyl)indoles. J Med Chem. 1991;34:1099–110.

    Article  CAS  PubMed  Google Scholar 

  11. D’Ambra TE, Estep KG, Bell MR, et. al. Conformationally restrained analogues of pravadoline: nanomolar potent enantioselective, (aminoalkyl)indole agonists of the cannabinoid receptor. J Med Chem. 1992;35:124–35.

    Article  PubMed  Google Scholar 

  12. Huffman JW, Dai D, Martin BR, et. al. Design, synthesis and pharmacology of cannabimimetic indoles. Bioorg Med Chem Lett. 1994;4:563–6.

    Article  Google Scholar 

  13. Wiley JL, Compton DR, Dai D, et. al. Structure-activity relationships of indole- and pyrrole-derived cannabinoids. J Pharmacol Exp Ther. 1998;285:995–1004.

    CAS  PubMed  Google Scholar 

  14. Showalter VM, Compton DR, Martin BR, et. al. Evaluation of binding in a transfected cell line expressing a peripheral cannabinoid receptor (CB2): identification of cannabinoid receptor subtype selective ligands. J Pharmacol Exp Ther. 1996;278:989–99.

    CAS  PubMed  Google Scholar 

  15. Lainton JAH, Huffman JW, Martin BR, et. al. 1-Alkyl-3-(1-naphthoyl)pyrroles: a new class of cannabinoid. Tetrahedron Lett. 1995;36:1401–4.

    Article  CAS  Google Scholar 

  16. Kumar V, Alexander MD, Bell MR, et. al. Morpholinoaminoalkylindenes as antinociceptive agents: novel cannabinoid receptor agonists. Bioorg Med Chem Lett. 1995;5:381–6.

    Article  CAS  Google Scholar 

  17. Reggio PH, Basu-Dutt S, Barnett-Norris J, et. al. The bioactive conformation of aminoalkylindoles at the cannabinoid CB1 and CB2 receptors: Insights gained from E and Z naphthylidene indenes. J Med Chem. 1998;41:5177–87.

    Article  CAS  PubMed  Google Scholar 

  18. Devane WA, Dysarz FA, Johnson MR, et. al. Determination of a cannabinoid receptor in rat brain. Mol Pharmacol. 1988;34:605–13.

    CAS  PubMed  Google Scholar 

  19. Matsuda LA, Lolait SJ, Brownstein MJ, et. al. Structure of a cannabinoid receptor and functional expression of the cloned cDNA. Nature. 1990;346:561–4.

    Article  CAS  PubMed  Google Scholar 

  20. Gèrard C, Mollereau C, Vassart G, et. al. Molecular cloning of a human cannabinoid receptor which is also expressed in testis. Biochem J. 1991;279:129–34.

    PubMed  Google Scholar 

  21. Compton DR, Rice KC, De Costa BR, et. al. Cannabinoid structure-activity relationships: Correlation of receptor binding and in vivo activities. J Pharmacol Exp Ther. 1993;265:218–26.

    CAS  PubMed  Google Scholar 

  22. Little PJ, Compton DR, Johnson MR, et. al. Pharmacology and stereoselectivity of structurally novel cannabinoids in mice. J Pharmacol Exp Ther. 1988; 247: 1046–51.

    CAS  PubMed  Google Scholar 

  23. Munro S, Thomas KL, Abu-Shaar M. Molecular characterization of a peripheral receptor for cannabinoids. Nature. 1993;365:61–5.

    Article  CAS  PubMed  Google Scholar 

  24. Pertwee RG. Pharmacology of cannabinoid CB1 and CB2 receptors. Pharmacol Ther. 1997;74:129–80.

    Article  CAS  PubMed  Google Scholar 

  25. Felder CF, Joyce KE, Briley EM, et. al. Comparison of the pharmacology and signal transduction of the human cannabinoid CB1 and CB2 receptors. Mol Pharmacol. 1995;48: 443–50.

    CAS  PubMed  Google Scholar 

  26. Busch-Petersen J, Hill WA, Fan P, et. al. Unsaturated side chain β-11-hydroxyhexahydrocannabinol analogs. J Med Chem. 1996;39:3790–6.

    Article  CAS  PubMed  Google Scholar 

  27. Pertwee RG. The evidence for the existence of cannabinoid receptors. Gen Pharmacol. 1993;24:811–24.

    CAS  PubMed  Google Scholar 

  28. Selley DE, Stark S, Sim LJ, et. al. Cannabinoid receptor stimulation of guanosine-5′-O-(3-[35S]thio)triphosphate binding in rat brain membranes. Life Sci. 1996;59:659–68.

    Article  CAS  PubMed  Google Scholar 

  29. Howlett AC, Barth F, Bonner TI, et. al. International Union of Pharmacology. XXVII. Classification of cannabinoid receptors. Pharmacol Rev. 2002;54:161–202.

    Article  CAS  PubMed  Google Scholar 

  30. Kuster JE, Stevenson JI, Ward SJ, et. al. Aminoalkylindole binding in rat cerebellum: selective displacement by natural and synthetic cannabinoids. J Pharmacol Exp Ther. 1993;264:1352–63.

    CAS  PubMed  Google Scholar 

  31. Compton DR, Gold LH, Ward SJ, et. al. Aminoalkylindole analogs: cannabimimetic activity of a class of compounds structurally distinct from Δ9-tetrahydrocannabinol. J Pharmacol Exp Ther. 1992;263:1118–26.

    CAS  PubMed  Google Scholar 

  32. Eissenstat MA, Bell MR, D’Ambra TE, et. al. Aminoalkylindoles: Structure-activity relationships of novel cannabinoid mimetics. J Med Chem. 1995;38:3094–105.

    Article  CAS  PubMed  Google Scholar 

  33. Pertwee R, Griffin G, Fernando S, et. al. AM630, a competitive cannabinoid receptor antagonist. Life Sci. 1995;56:1949–55.

    Article  CAS  PubMed  Google Scholar 

  34. Landsman RS, Makriyannis A, Deng H, et. al. AM630 is an inverse agonist at the human cannabinoid CB1 receptor. Life Sci. 1998;62:PL109–13.

    Article  Google Scholar 

  35. Hosohata K, Quock RM, Hosohata Y, et. al. AM630 is a competitive cannabinoid receptor antagonist in the guinea pig brain. Life Sci. 1997;61:PL115–8.

    Article  Google Scholar 

  36. Ross RA, Brockie HC, Stevenson LA, et. al. Agonist-inverse agonist characterization at CB1 and CB2 cannabinoid receptors of L759633, L759656 and AM630. Br J Pharmacol. 1999;126:665–72.

    Article  CAS  PubMed  Google Scholar 

  37. D’Ambra TE, Eissenstat MA, Abt J, et. al. C-attached aminoalkylindoles: potent cannabinoid mimetics. Bioorg Med Chem Lett. 1996;6:17–21.

    Article  Google Scholar 

  38. Shim J-Y, Collantes ER, Welsh WJ, et. al. Three-dimensional quantitative structure-activity relationship study of the cannabimimetic (aminoalkyl)indoles using comparative molecular field analysis. J Med Chem. 1998;41:4521–32.

    Article  CAS  PubMed  Google Scholar 

  39. Song ZH, Bonner TH. A lysine residue of the cannabinoid receptor is critical for receptor recognition by several agonists but not WIN-55,212. Mol Pharmacol. 1996;49:891–6.

    CAS  PubMed  Google Scholar 

  40. Ibrahim MM, Deng H, Zvonok A, et. al. Activation of CB2 cannabinoid receptors by AM1241 inhibits experimental neuropathic pain: pain inhibition by receptors not present in the CNS. Proc Natl Acad Sci U S A. 2003;100:10529–33.

    Article  CAS  PubMed  Google Scholar 

  41. Deng H. Design and Synthesis of Selective Cannabinoid Receptor Ligands: Aminoalkylindoles and Other Heterocyclic Analogs. Doctoral dissertation, University of Connecticut; 2000.

    Google Scholar 

  42. Nackley AG, Makriyannis A, Hohmann AG. Selective activation of cannabinoid CB2 receptors suppresses spinal fos protein expression and pain behavior in a rat model of inflammation. Neurosci. 2003;119:747–57.

    Article  CAS  Google Scholar 

  43. Malan TP, Ibrahim MM, Deng H, et. al. CB2 cannabinoid receptor-mediated peripheral antinociception. Pain. 2001;93:239–45.

    Article  CAS  PubMed  Google Scholar 

  44. Hohmann AG, Farthing JN, Zvonok AM, et. al. Selective activation of cannabinoid CB2 receptors suppresses hyperalgesia evoked by intradermal capsaicin. J Pharmacol Exp Ther. 2004;308:446–53.

    Article  CAS  PubMed  Google Scholar 

  45. Ibrahim MM, Porreca F, Lai J, et. al. CB2 cannabinoid receptor activation produces antinociception by stimulating peripheral release of endogenous opiods. Proc Natl Acad Sci USA. 2005;102:3093–8.

    Article  CAS  PubMed  Google Scholar 

  46. Van Sickle MD, Duncan M, Kingsley PJ, et. al. Identification and functional characterization of brainstem cannabinoid CB2 receptors. Science. 2005;310:329–32.

    Article  PubMed  Google Scholar 

  47. Willis PG, Pavlova OA, Chefer SI, et. al. Synthesis and structure-activity relationships of a novel series of aminoalkylindoles with potential for imaging the neuronal cannabinoid receptor by positron emission tomography. J Med Chem. 2005;48:5813–22.

    Article  CAS  PubMed  Google Scholar 

  48. Deng H, Gifford AN, Zvonok AM, et. al. Potent cannabinoid indole analogues as radioiodinatable brain imaging agents for the CB1 cannabinoid receptor. J Med Chem. 2005;48:6386–92.

    Article  CAS  PubMed  Google Scholar 

  49. Hynes J, Leftheris K, Wu H, et. al. C-3 amido-indole cannabinoid receptor modulators. Bioorg Med Chem Lett. 2002;12:2399–402.

    Article  CAS  PubMed  Google Scholar 

  50. Wrobleski ST, Chen P, Hynes J, et. al. Rational design and synthesis of an orally active indolopyridone as a novel conformationally constrained cannabinoid ligand possessing antiinflammatory properties. J Med Chem. 2003;46:2110–6.

    Article  CAS  PubMed  Google Scholar 

  51. Shim J-Y, Collantes ER, Welsh WJ, et. al. Unified pharmacophoric model for cannabinoids and aminoalkylindoles derived from molecular superimposition of CB1 cannabinoid receptor agonists CP55244 and Win55212-2. In: Parrill AL, Reddy MR, editors. Rational drug design: novel methodology and practical applications. Washington: American Chemical Society; 1999. pp. 165–84.

    Chapter  Google Scholar 

  52. Wiley JL, Huffman JW, Balster RL, et. al. Pharmacological specificity of the discriminative stimulus effects of Δ9-tetrahydrocannabinol in rhesus monkeys. Drug Alcohol Depend. 1995;40:81–6.

    Article  CAS  PubMed  Google Scholar 

  53. Pertwee RG, Griffin G, Lainton JAH, et. al. Pharmacological characterization of three novel cannabinoid receptor agonists in the mouse isolated vas deferens. Eur J Pharmacol. 1995;284:241–7.

    Article  CAS  PubMed  Google Scholar 

  54. Griffin G, Fernando SR, Ross RA, et. al. Evidence for the presence of CB2-like cannabinoid receptors on peripheral nerve terminals. Eur J Pharmacol. 1997;339:53–61.

    Article  CAS  PubMed  Google Scholar 

  55. Huffman JW, Zengin G, Wu M-J, et. al. Structure–activity relationships for 1-alkyl-3-(1-naphthoyl)indoles at the cannabinoid CB1 and CB2 receptors: steric and electronic effects of naphthoyl substituents. New highly selective CB2 receptor agonists. Bioorg Med Chem. 2005;13:89–112.

    Article  CAS  PubMed  Google Scholar 

  56. Aung MM, Griffin G, Huffman JW, et. al. Influence of the N-1 alkyl chain length of cannabimimetic indoles upon CB1 and CB2 receptor binding. Drug Alcohol Depend. 2000;60:133–40.

    Article  CAS  PubMed  Google Scholar 

  57. Huffman JW, Mabon R, Wu M-J, et. al. 3-Indolyl-1-naphthylmethanes: New cannabimimetic indoles provide evidence for aromatic stacking interactions with the CB1 cannabinoid receptor. Bioorg Med Chem. 2003;11:539–49.

    Article  CAS  PubMed  Google Scholar 

  58. Smith V, Huffman JW, Wiley JL, et. al. Effects of halogen substituents in the 1-alkyl-3-(1-naphthoyl)indole series on CB1 and CB2 receptor affinities. 2005 Symposium on the Cannabinoids, International Cannabinoid Research Society; Burlington, VT; 2005. p. 87.

    Google Scholar 

  59. Huffman JW, Szklennik, PV, Almond A, et. al. 1-Pentyl-3-phenylacetylindoles, a new class of cannabimimetic indoles. Bioorg Med Chem Lett. 2005;15:4110–3.

    Article  CAS  PubMed  Google Scholar 

  60. Knight LW, Huffman JW, Isherwood ML, et. al. Synthesis and pharmacology of pyrrole based cannabinoids. 2004 Symposium on the Cannabinoids, International Cannabinoid Research Society; Burlington, VT; 2005. p. 97.

    Google Scholar 

  61. Padgett LW. Pyrrole-Based Cannabinoids. Doctoral Dissertation, Clemson University, 2005.

    Google Scholar 

  62. Tarzia G, Duranti A, Tontini A, et. al. Synthesis and structure-activity relationships of a series of pyrrole cannabinoid receptor agonists. Bioorg Med Chem. 2003;11:3965–73.

    Article  CAS  PubMed  Google Scholar 

  63. Bramblett RD, Reggio PH. An exploration of possible binding sites for cannabinoid ligands at the CB1 receptor: a hypothesized aminoalkylindole binding site. In 1995 Symposium on the Cannabinoids, International Cannabinoid Research Society; Burlington, VT; 1995. p. 16.

    Google Scholar 

  64. Reggio PH, Hurst DP, Norris JB, et. al. Computational studies on helix 5 residues of the CB receptors that are important for ligand interaction, sub-type selectivity and activation. 1998 Symposium on the Cannabinoids, International Cannabinoid Research Society; Burlington, VT; 1998. p. 4.

    Google Scholar 

  65. Reggio PH. Ligand-ligand and ligand-receptor approaches to modeling the cannabinoid CB1 and CB2 receptors: achievements and challenges. Curr Med Chem. 1999;6:665–84.

    CAS  PubMed  Google Scholar 

  66. Dutta AK, Ryan W, Thomas BF, et. al. Synthesis, pharmacology, and molecular modeling of novel 4-alkyloxy indole derivatives related to cannabimimetic aminoalkyl indoles (AAIs). Bioorg Med Chem. 1997;8:1591–600.

    Article  Google Scholar 

  67. Xie X-Q, Eissenstat M, Makriyannis A. Common cannabimimetic pharmacophoric requirements between aminoalkyl indoles and classical cannabinoids. Life Sci. 1995;56:1963–70.

    Article  CAS  PubMed  Google Scholar 

  68. Fichera M, Cruciani G, Bianchi A, et. al. A 3D-QSAR study on the structural requirements for binding to CB1 and CB2 cannabinoid receptors. J Med Chem. 2000;43:2300–9.

    Article  CAS  PubMed  Google Scholar 

  69. Chin C, Lucas-Lenard J, Abadji V, et. al. Ligand binding and modulation of cyclic AMP levels depend on the chemical nature of residue 192 of the human cannabinoid receptor 1. J Neurochem. 1998;70:366–73.

    Article  CAS  PubMed  Google Scholar 

  70. Song ZH, Slowey C-A, Hurst DP, et. al. The difference between the CB1 and CB2 cannabinoid receptors at position 5.46 is crucial for the selectivity of WIN55212-2 for CB2. Mol Pharmacol. 1999;56:834.

    CAS  PubMed  Google Scholar 

  71. Bramblett RD, Reggio PH. An exploration of possible binding sites for cannabinoid ligands at the CB1 receptor: A hypothesized binding site for classical cannabinoids, non-classical cannabinoids and anandamides. In 1995 Symposium on the Cannabinoids, International Cannabinoid Research Society; Burlington, VT; 1995. p. 17.

    Google Scholar 

  72. Bramblett RD, Panu AM, Ballesteros JA, et. al. Construction of a 3D model of the cannabinoid CB1 receptor: Determination of helix ends and helix orientation. Life Sci. 1995;56:1971–82.

    Article  CAS  PubMed  Google Scholar 

  73. McAllister SD, Rizvi G, Anavi-Goffer S, et. al. An aromatic microdomain at the cannabinoid CB1 receptor constitutes an agonist/inverse agonist binding region. J Med Chem. 2003;46:5139–52.

    Article  CAS  PubMed  Google Scholar 

  74. Tao Q, Abood ME. Mutation of a highly conserved aspartate residue in the second transmembrane domain of the cannabinoid receptors, CB1 and CB2, disrupts G-protein coupling. J Pharmacol Exp Ther. 1998;285:651–8.

    CAS  PubMed  Google Scholar 

  75. Tao Q, McAllister SD, Andreassi J, et. al. Role of a conserved lysine residue in the peripheral cannabinoid receptor (CB2): evidence for subtype specificity. Mol Pharmacol. 1999;55:605–13.

    CAS  PubMed  Google Scholar 

  76. Rhee M-H, Nevo I, Bayewitch ML, et. al. Functional role of tryptophan residues in the fourth transmembrane domain of the CB2 cannabinoid receptor. J Neurochem. 2000;75:2485–91.

    Article  CAS  PubMed  Google Scholar 

  77. Salo OMH, Raitio KH, Savinainen JR, et. al. Virtual screening of novel CB2 ligands using a comparative model of the human cannabinoid CB2 receptor. J Med Chem. 2005;48:7166–71.

    Article  CAS  PubMed  Google Scholar 

  78. Montero C, Campillo NE, Goya P, et. al. Homology models of the cannabinoid CB1 and CB2 receptors. A docking analysis study. Eur J Med Chem 2005;40:75–83.

    Article  CAS  PubMed  Google Scholar 

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Acknowledgments

The work described in this chapter, carried out at Clemson University and included in the review, was supported by grants DA 03590 and DA15340 from the National Institute on Drug Abuse. The author thanks Drs. Billy R. Martin and Jenny L. Wiley of Virginia Commonwealth University for the pharmacological evaluation of the compounds prepared in our laboratory. The author also thanks Dr. Patricia H. Reggio of the University of North Carolina at Greensboro for the molecular modeling studies of the compounds prepared by our group. Special thanks are extended to the graduate students and postdoctorals at Clemson University who carried out the work from our group described in this chapter. These studies could not have been carried out without their contributions.

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Huffman, J.W. (2009). Cannabimimetic Indoles, Pyrroles, and Indenes: Structure–Activity Relationships and Receptor Interactions. In: Reggio, P.H. (eds) The Cannabinoid Receptors. The Receptors. Humana Press. https://doi.org/10.1007/978-1-59745-503-9_3

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