Pyrrolopyridine derivatives and their use as CRTH2 antagonists

1. A process for the preparation of compounds of formula (I)

wherein

Q is a bond;

R 1 and R 2 are, independently, H, halogen or C 1 -C 8 -alkyl, or

R 1 and R 2 , together with the carbon atom to which the are attached form a divalent C 3 -C 8 -cycloaliphatic group;

R 3 is C 1 -C 8 -alkyl, a C 3 -C 15 -carbocyclic group, C 1 -C 8 -haloalkyl, alkoxy C 1 -C 8 alkyl, C 1 -C 8 -hydroxyalkyl;

R 4 and R 5 are, independently, halogen, C 1 -C 8 -alkyl, C 1 -C 8 -haloalkyl, C 3 -C 15 -carbocyclic group, nitro, cyano, C 1 -C 8 -alkylsulfonyl, C 1 -C 8 -alkylsulfinyl, C 1 -C 8 -alkylcarbonyl, C 1 -C 8 -alkoxycarbonyl, C 1 -C 8 -alkoxy, C 1 -C 8 -haloalkoxy, carboxy, carboxy-C 1 -C 8 -alkyl, amino, C 1 -C 8 -alkylamino, di(C 1 -C 8 -alkyl)amino, SO 2 NH 2 , (C 1 -C 8 -alkylamino)sulfonyl, di(C 1 -C 8 -alkyl)aminosulfonyl, aminocarbonyl, C 1 -C 8 -alkylaminocarbonyl, di(C 1 -C 8 -alkyl)aminocarbonyl or a 4- to 10-membered heterocyclic group having one or more heteroatoms selected from the group consisting of oxygen, nitrogen and sulphur;

R 6 is H or C 1 -C 8 -alkyl;

W is a C 6 -C 15 -aromatic carbocyclic group or a 4- to 10-membered heterocyclic group containing at least one ring heteroatom selected from the group consisting of nitrogen, oxygen and sulphur;

X is —SO 2 —, —CH 2 —, —CON(C 1 -C 8 -alkyl)-, —CH(C 1 -C 8 -alkyl)- or a bond;

m and n are each, independently, an integer from 0-3; and

p is 1;

in free or salt form, comprising:

(i) (A) for the preparation of compounds of formula I where R 6 is H, cleaving the ester group —COOR 6 in a compound of formula (I),

wherein

R 6 is C 1 -C 8 -alkyl; and

Q, R 1 , R 2 , R 3 , R 4 , R 5 , W, X, m, n and p are as hereinbefore defined; or

(B) for the preparation of compounds of formula (I), wherein R 6 is C 1 -C 8 -alkyl, reacting a compound of formula (II)

wherein

R 6 is C 1 -C 8 -alkyl; and

Q, R 1 , R 2 , R 3 , R 4 , m, n and p are as hereinbefore defined with a compound of formula (III)

G-X—W—(R 5 ) n   (III)

wherein

G is a leaving moiety; and

R 5 , W, X and n are as hereinbefore defined; or

(C) for the preparation of compounds of formula (I),

wherein

R 6 is C 1 -C 8 -alkyl;

R 1 is H or C 1 -C 8 -alkyl;

R 2 is C 1 -C 8 -alkyl; and

p is 1, reacting a compound of formula (I),

where

R 1 is H or C 1 -C 8 -alkyl; and

R 2 is H, with a compound of formula R A G,

where

 R A is C 1 -C 8 -alkyl; and

 G is as hereinbefore defined; and

(ii) recovering the resultant compound of formula I in free or salt form.