Abstract: Compounds of formula (I) are ligands of the CRTH2 receptor and are useful in the treatment of respiratory disease: Formula (I) wherein R1, R2, R3 and R4 each independently are hydrogen, C1C6alkyl, fully or partially fluorinated C1C6alkyl, halo, —S(O)nR10, —SO2N(R10)2, —N(R10)2, —C(O)N(R10)2, —NR10C(O)R9, —CO2R10, —C(O)R9, —NO2, —CN or —OR11; wherein each R9 is independently C1C6alkyl, aryl, heteroaryl; R10 is independently hydrogen, C1C6alkyl, aryl, or heteroaryl; R11 is hydrogen, C1C6alkyl, fully or partially fluorinated C1C6alkyl or a group —SO2R9; n is 0, 1 or 2; R5 is C1C6alkyl, fully or partially fluorinated C1C6alkyl. C1C6alkenyl, C1C6alkynyl, optionally substituted aryl, or optionally substituted heteroaryl; R6 is hydrogen, C1C6alkyl or fully or partially fluorinated C1C6alkyl; R7 and R5 are independently hydrogen or C1C6alkyl, or R7 and R5 together with the atom to which they are attached form a cycloalkyl group; and X is —CHR6—, —S(O)n—, —NR6SO2— or —SO2NR6— wherein n is 0, 1 or 2.