3-indolyl-1-naphthylmethanes: New cannabimimetic Indoles provide evidence for aromatic stacking interactions with the CB1 cannabinoid receptor
Huffman, J. W., Mabon, R., Wu, M. J., Lu, J. Z., Hart, R., Hurst, D. P., ... Martin, B. R. (2003). 3-indolyl-1-naphthylmethanes: New cannabimimetic Indoles provide evidence for aromatic stacking interactions with the CB1 cannabinoid receptor. Bioorganic and Medicinal Chemistry, 11(4), 539-549.
A series of 1-pentyl-1H-indol-3-yl-(1-naphthyl)methanes (9 11) and 2-methyl-1-pentyl-1H-indol-3-yl-(1-naphthyl)methanes (12-14) have been synthesized to investigate the hypothesis that cannabimimetic 3-(1-naphthoyl)indoles interact with the CB I receptor by hydrogen bonding to the carbonyl group. Indoles 9-11 have significant (K-i 17-23 nM) receptor affinity, somewhat less than that of the corresponding naphthoylindoles (5, 15, 16). 2-Methyl-1-indoles 12-14 have little affinity for the CB1 receptor, in contrast to 2-methyl-3-(1-naphthoyl)indoles 17-19, which have affinities comparable to those of 5, 15, 16. A cannabimimetic indene hydrocarbon (26) was synthesized and found to have K-i = 26 +/- 4 nM. Molecular modeling and receptor docking studies of naphthoylindole 16, its 2-methyl congener (19) and indolyl-1-naphthylmethanes 11 and 14, combined with the receptor affinities of these cannabimimetic indoles, strongly suggest that these cannabinoid receptor ligands bind primarily by aromatic stacking interactions in the transmembrane helix 3-4-5-6 region of the CB1 receptor. (C) 2002 Elsevier Science Ltd. All rights reserved