The invention is concerned with the compounds of formula I: and pharmaceutically acceptable salts and esters thereof, wherein W, X, Y, and R1-R7 are defined in the detailed description and claims. In addition, the present invention relates to methods of manufacturing and using the compounds of formula I as well as pharmaceutical compositions containing such compounds. The compounds of formula I are antagonists or partial agonists at the CRTH2 receptor and may be useful in treating diseases and disorders associated with that receptor such as asthma.本發明係關於式I化合物:;I;及其藥學上可接受之鹽類與酯類,其中W、X、Y及R1-R7係被定義於詳細說明文與請求項中。此外,本發明係關於製造與使用式I化合物之方法,以及含有此種化合物之醫藥組合物。式I化合物係為對CRTH2受體之拮抗劑或部份催動劑,且可用於治療與該受體有關聯之疾病與病症,譬如氣喘。