Indole derivatives as CRTH2 receptor antagonists

1. A method of treating a prostaglandin mediated disease selected from the group consisting of nasal congestion and pulmonary congestion, comprising administering a therapeutically effective amount of a compound of formula (I)

wherein:

 represents either

Y 1 is selected from optionally substituted aryl and —C(R 2 )(R 3 )(R 4 );

Y 2 is selected from H and —C 1-6 alkyl;

Z is selected from H and —C 1-6 alkyl;

R 1a and R 1b are independently selected from H, halogen, —OC 1-6 alkyl, —O-haloC 1-6 alkyl, —C 1-6 alkyl, haloC 1-6 alkyl, optionally substituted aryl and —(C 1-3 alkylene)-optionally substituted aryl;

R 2 is selected from H, —C 1-6 alkyl optionally substituted with halogen, —OH or —NHSO 2 CH 3 , —OH, —OC 1-6 alkyl, —S(O) n C 1-6 alkyl, —CN, optionally substituted aryl, optionally substituted —O-aryl and optionally substituted heteroaryl, wherein n is 0, 1 or 2;

R 3 is selected from H, —C 1-6 alkyl, C 1-6 haloalkyl, optionally substituted aryl and optionally substituted heteroaryl; and

R 4 is selected from H, —C 1-6 alkyl, C 1-6 haloalkyl, optionally substituted aryl and optionally substituted heteroaryl; or

R 3 , R 4 and the carbon atom to which they are attached together form —C 3- 6 cycloalkyl, fluorenyl or —C 3-6 heterocyclyl having a ring heteroatom selected from —N(R a )—, —O—and —S—; or

R 3 , R 4 together represent C 1-6 alkylidene;

R a is H, C 1-6 alkyl or —C(O)C 1-6 alkyl; and

the optional substituent for aryl and heteroaryl is 1 to 4 groups independently selected from halogen, —C 1-3 alkoxy, —C 1-3 haloalkyl, hydroxy-C 1-3 alkyl, —S (O)n-C 1-3 alkyl, amino, and mono- and di-(C 1-3 alkyl)amino;

or a pharmaceutically acceptable salt thereof to a mammalian patient in need thereof.

2. The method of claim 1 , wherein the compound of the formula (I) has formula Ib

wherein Y 1 and R 1a are as defined in claim 1 .

3. The method of claim 2 wherein Y 1 is —C(R 3 )(R 4 )-optionally substituted phenyl or —CH 2 O-optionally substituted phenyl; and

(i) one of R 3 and R 4 is H or OH, and the other is H, —C 1-3 alkyl or optionally substituted phenyl; or (ii) R 3 , R 4 and the carbon atom to which they are attached together form —C 3-6 cycloalkyl; or (iii) R 3 and R 4 together represent —C 1-3 alkylidene.

4. The method of claim 3 wherein Y 1 is —C(R 3 )(R 4 )-phenyl optionally substituted with 1 or 2 halogen atoms.

5. The method of claim 1 , wherein the compound is {4-fluoro-7-[5-(4-fluorobenzyl)-1H-[1,2,3]triazol-1-yl]-6,7,8,9-tetrahydropyrido[1,2-a]indol-10-yl}-acetic acid.

6. The method of claim 1 , wherein the compound is {(7R)-4-fluoro-7-[5-(4-fluorobenzyl)-1H-[1,2,3]triazol-1-yl]-6,7,8,9-tetrahydropyrido[1,2-a]indol-10-yl}-acetic acid or a pharmaceutically acceptable salt thereof.

7. The method of claim 1 , wherein the prostaglandin-mediated disease is nasal congestion.

8. The method of claim 6 , wherein the prostaglandin-mediated disease is nasal congestion.

9. The method of claim 7 , wherein the mammalian patient is a human patient.

10. The method of claim 8 , wherein the mammalian patient is a human patient.