Isosteric ramatroban analogs: selective and potent CRTH-2 antagonists

The chemoattractant receptor-homologous molecule expressed on TH2 cells (CRTH-2), also found on eosinophils and basophils, is a prostaglandin D2 receptor involved in the recruitment of these cell types during an inflammatory response. In this report, we describe the synthesis and optimization of a ramatroban isostere that is a selective and potent antagonist of CRTH-2 which may be useful in the treatment of certain diseases.