A series of benzoylpiperidine analogs related to 4a was prepared, and their ability to inhibit the uptake of [14C]-glycine in COS7 cells transfected with human glycine transporter type-2 (GlyT-2) was evaluated. Small structural changes to the benzoylpiperidine region of the molecule led to a significant decrease in GlyT-2 inhibitory activity. In contrast, the distal aryl ring was more tolerant to functional group modifications and could accommodate a variety ...