Discovery of novel (S)-alpha-phenyl-gamma-amino butanamide containing CCR5 antagonists via functionality inversion approach.

By using functionality inversion approach, we identified a new scaffold containing (S)-alpha-phenyl-gamma-amino butanamide as CCR5 antagonists derived from the 1,3-propanediamine carboxamide pharmacophore protocol. The (2S)-2-phenyl-4-(8-aza-bicyclo[3.2.1]octan-8-yl)-butanamide derivatives display significantly high potency to antagonize CCR5 receptor with nanomolar IC(50) values.

Forward- and reverse-synthesis of piperazinopiperidine amide analogs: a general access to structurally diverse 4-piperazinopiperidine-based CCR5 antagonists.

Piperazinopiperidine amide analogs are among the most promising CCR5 antagonists. As an effective extension of a previously-reported methodology to synthesize such compounds, forward- and reverse-syntheses were successfully developed in which the convergent synthesis of the piperazinopiperidine nucleus, with a building block of 4-substituent-4-aminopiperidine, served as a common key step. The two-way approach affords a comprehensive access to the piperazinopiperidine templated library with variation on the pharmacophore sites. Thus, a SAR study of our synthesized piperazinopiperidine-based CCR5 antagonists was conducted with respect to the structure and configuration of the substituent on the piperazine ring. The S-configuration of the benzylic-substituent is vital for the CCR5 binding, and the bulky or aryl substituent on the 2-position in the piperazine ring is detrimental to the activity. By using the forward-synthesis approach, the best compound in the chiral piperazine-based CCR5 antagonist series, Sch-D (Vicriviroc), was conveniently synthesized in an excellent yield.