BMS-639623

Conformational analysis of the 3-benzylpiperidine in CCR3 antagonist clinical candidate 1 (BMS-639623) predicts that the benzylpiperidine may be replaced by acyclic, conformationally stabilized, anti-1,2-disubstituted phenethyl- and phenpropylamines. Ab initio calculations, enantioselective syntheses, and evaluation in CCR3 binding and chemotaxis assays of anti-1-methyl-2-hydroxyphenethyl- and phenpropylamine-containing CCR3 antagonists support this conformational correlation.

Conformational analysis of trans-1,2-disubstituted cyclohexane CCR3 antagonist 2 revealed that the cyclohexane linker could be replaced by an acyclic syn-alpha-methyl-beta-hydroxypropyl linker. Synthesis and biological evaluation of mono- and disubstituted propyl linkers support this conformational correlation. It was also found that the alpha-methyl group to the urea lowered protein binding and that the beta-hydroxyl group lowered affinity for CYP2D6. Ab initio calculations show that the alpha-methyl group governs the spatial orientation of three key functionalities within the molecule. alpha-Methyl-beta-hydroxypropyl urea 31 with a chemotaxis IC(50)=38 pM for eosinophils was chosen to enter clinical development for the treatment of asthma.