Is adamantane a suitable substituent to pre-organize the acid orientation in E-selectin antagonists?
The selectins play a key role in the inflammatory process, that is, the recruitment of leukocytes from blood vessels into inflamed tissue. Because excessive infiltration of leukocytes can induce acute or chronic reactions, the control of leukocyte extravasation is of great pharmaceutical interest. All physiological ligands of the selectins contain the tetrasaccharide epitope sialyl Lewis(x), which therefore became the lead structure in selectin antagonist research. Previous studies indicated that an important factor for the affinity of sLe(x) is the fact that in solution its pharmacophores are already conformationally pre-organized in the bioactive orientation. In mimics where the GlcNAc- and the NeuNAc-moieties of sLe(x) were replaced by (R,R)-cyclohexane-1,2-diol and (S)-cyclohexyllactic acid, respectively, an optimized pre-organization of the pharmacophores could be realized, leading to antagonists with improved affinities. To further optimize the pre-organization of the carboxylic acid, a pharmacophore essential for binding, the replacement of NeuNAc by bulky (R)- and (S)-adamantyl-lactic acid was studied. Although antagonist (S)-7 showed a slightly reduced affinity, the expected beneficial effect of the (S)-configuration at C-2 of the lactate could be confirmed.
Titz
Alexander
A
Institute of Molecular Pharmacy, University of Basel, CH-4056 Basel, Switzerland.
Patton
John
J
Alker
André M
AM
Porro
Michele
M
Schwardt
Oliver
O
Hennig
Michael
M
Francotte
Eric
E
Magnani
John
J
Ernst
Beat
B
D000218:Adamantane / Q000494:pharmacology*; D019040:E-Selectin / Q000502:physiology*; D007983:Lewis Blood Group Antigens / Q000737:chemistry* / Q000378:metabolism*; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry* / Q000378:metabolism*; D000080506:Sialyl Lewis X Antigen; D013237:Stereoisomerism
D019040:E-Selectin; D007983:Lewis Blood Group Antigens; D009844:Oligosaccharides; D000080506:Sialyl Lewis X Antigen; D000218:Adamantane