Introduction of ring restrictions to a linear aminobutyramide CC chemokine receptor 2 (CCR2) antagonist lead (2) led to the discovery of a 1, 3-disubstituted cyclopentane scaffold with enhanced hCCR2 receptor binding and antagonist activity.(1 S, 3 R)-N-[3, 5-Bis (trifluoromethyl) benzyl]-1-methyl-3-[(1 R, 3'R)-methyl-1'H-spiro [indene-1, 4'-piperidin]-1'-yl] cyclopentanecarboxamide (16) had IC50 of 1.3 nM (binding) and 0.45 nM (functional ...