Indolylpiperidine derivatives as potent antihistaminic and antiallergic agents

1. A compound of formula I

wherein:

R 1 represents an alkyl, alkenyl, alkoxyalkyl or cycloalkylalkyl group;

R 2 represents a hydrogen or halogen atom; and

wherein the methoxy group substituting the benzoic acid is in position ortho with respect to the carboxy groups and in position para with respect to the carbon atom that is bound to the indolylpiperidine moiety;

or a pharmaceutically acceptable salt thereof.

2. A compound according to claim 1 , wherein R 1 is chosen from ethyl, n-propyl, n-butyl, methoxymethyl, methoxyethyl, ethoxyethyl, cyclopropylmethyl, cyclopentylmethyl, cyclohexylmethyl, cyclopropylethyl, allyl, 2-propenyl, 2-propoxyethyl and 3-methoxypropyl.

3. A compound according to claim 2 , wherein R 1 is methoxyethyl, ethoxyethyl, butyl, cyclopropylmethyl or allyl.

4. A compound according to claim 1 , wherein R 2 is hydrogen, fluorine or chlorine.

5. A compound according to claim 4 , wherein R 2 is hydrogen, fluorine or chlorine.

6. A compound according to claim 1 , chosen from:

5-{4-[1-(2-ethoxyethyl)-1H-indol-3-yl]piperidin-1-ylmethyl}-2-methoxybenzoic acid;

2-methoxy-5-{4-[1-(2-methoxyethyl)-1H-indol-3-yl]piperidin-1-ylmethyl}-benzoic acid;

5-[4-(1-butyl-1H-indol-3-yl)-piperidin-1-ylmethyl]-2-methoxybenzoic acid;

5-{4-[1-(2-ethoxyethyl)-6-fluoro-1H-indol-3-yl]piperidin-1-ylmethyl}-2-methoxybenzoic acid;

5-{4-[6-fluoro-1-(2-methoxyethyl)-1H-indol-3-yl]piperidin-1-ylmethyl}-2-methoxybenzoic acid;

5-[4-(1-butyl-6-fluoro-1H-indol-3-yl)-piperidin-1-ylmethyl]-2-methoxybenzoic acid;

5-[4-(5-bromo-1-propyl-1H-indol-3-yl)-piperidin-1-ylmethyl]-2-methoxybenzoic acid;

3-[4-(5-chloro-1-ethyl-1H-indol-3-yl)-piperidin-1-ylmethyl]-2-methoxybenzoic acid;

3-[4-(1-cyclopropylmethyl-5-fluoro-1H-indol-3-yl)-piperidin-1-ylmethyl]-2-methoxybenzoic acid;

5-[4-(5-chloro-1-cyclohexylmethyl-1H-indol-3-yl)-piperidin-1-ylmethyl]-2-methoxybenzoic acid;

2-methoxy-5-{4-[1-(2-propoxyethyl)-1H-indol-3-yl]-piperidin-1-ylmethyl}-benzoic acid;

3-{4-[5-bromo-1-(3-methoxypropyl)-1H-indol-3-yl]-piperidin-1-ylmethyl}-2-methoxybenzoic acid;

3-[4-(1-allyl-1H-indol-3-yl)-piperidin-1-ylmethyl]-2-methoxybenzoic acid;

3-[4-(1-allyl-6-fluoro-1H-indol-3-yl)-piperidin-1-ylmethyl]-2-methoxybenzoic acid;

5-{4-[5-chloro-1-(2-propenyl)-1H-indol-3-yl]-piperidin-1-ylmethyl}-2-methoxybenzoic acid;

5-[4-(1-cyclopentylmethyl-6-fluoro-1H-indol-3-yl)-piperidin-1-ylmethyl]-2-methoxybenzoic acid;

3-{4-[6-fluoro-1-methoxymethyl-1H-indol-3-yl]-piperidin-1-ylmethyl}-2-methoxybenzoic acid;

3-{4-[1-cyclopropylethyl-1H-indol-3-yl]-piperidin-1-ylmethyl}-2-methoxybenzoic acid;

3-{4-[5-chloro-1-(2-methoxyethyl)-1H-indol-3-yl]-piperidin-1-ylmethyl}-2-methoxybenzoic acid; and

3-{4-[1-(2-ethoxyethyl)-5-fluoro-1H-indol-3-yl]-piperidin-1-ylmethyl}-2-methoxybenzoic acid.

7. A compound according to claim 6 , chosen from:

5-{4-[1-(2-ethoxyethyl)-1H-indol-3-yl]piperidin-1-ylmethyl}-2-methoxybenzoic acid;

2-methoxy-5-{4-[1-(2-methoxyethyl)-1H-indol-3-yl]piperidin-1-ylmethyl}-benzoic acid;

5-[4-(1-butyl-1H-indol-3-yl)-piperidin-1-ylmethyl]-2-methoxybenzoic acid;

5-{4-[1-(2-ethoxyethyl)-6-fluoro-1H-indol-3-yl]piperidin-1-ylmethyl}-2-methoxybenzoic acid;

5-{4-[6-fluoro-1-(2-methoxyethyl)-1H-indol-3-yl]piperidin-1-ylmethyl}-2-methoxybenzoic acid; and

5-[4-(1-butyl-6-fluoro-1H-indol-3-yl)-piperidin-1-ylmethyl]-2-methoxybenzoic acid.

8. A pharmaceutical composition comprising an effective amount of at least one compound as defined in claim 1 , and at least one pharmaceutically acceptable diluent or carrier.

9. A method for treating a subject afflicted with a pathological condition or disease is chosen from bronchial asthma, allergic rhinitis, conjunctivitis, dermatitis, and urticaria comprising administering to said subject an effective amount of at least one compound as defined in claim 1 .