Azaindolylpiperidine derivatives as antihistaminic and antiallergic agents

A compound of formula I

• wherein:
• each of A, B, D and E independently represents a nitrogen atom or a —CR1-group, with the proviso that only one of A, B, D or E is a nitrogen atom;
• R1 represents a hydrogen or a halogen atom, or a hydroxy, alkyl, alkenyl, alkynyl, alkoxy, alkylthio, amino, monalkyalmino, dialkylamino, nitro, cyano or acylamino group,
• wherein a hydrocarbon chain in R1 is optionally substituted by one or more further substituents chosen from halogen, hydroxy, oxo, alkoxy, alkylthio, acylamino, phenyl, alkoxycarbonyl, amino, monoalkylamino, dialkylamino and hydroxycarbonyl groups;
• R2 represents a group of formula L3—(W2)p;
• L1, L2 and L3 each independently represents a single bond or an acyclic, straight or branched, saturated or unsaturated hydrocarbon chain having from 1 to 10 carbon atoms, optionally containing 1 to 3 groups independently chosen from —S—, —O— and —NR3—, which replace a corresponding number of non-adjacent carbon atoms,
• wherein
• p represents 0 or 1;
• when L3 is a single bond, p is 1;
• R3 is chosen from hydrogen and an alkyl group;
• and
• wherein a hydrocarbon chain in L1, L2 or L3 is optionally substituted by one or more substituents chosen from halogen, hydroxy, oxo, acylamino, phenyl, alkoxycarbonyl and hydroxycarbonyl groups;
• R4 and R5 each independently represents a hydrogen or halogen atom, a hydroxy group, or a group chosen from alkyl, alkoxy, alkenyl, alkynyl and phenyl, wherein each of said alkyl, alkoxy, alkenyl, alkynyl or phenyl groups is independently optionally substituted by one or more substituents chosen from halogen, hydroxy, oxo, alkoxy, alkylthio, acylamino, phenyl, alkoxycarbonyl, amino, monoalkylamino, dialkylamino and hydroxycarbonyl groups;
• X represents —O— or —NR6—;
• R6 and R7 each independently represents a hydrogen atom, a group of formula —(CH2)m—W3 or a group chosen from alkyl, alkenyl and alkynyl, wherein each of said alkyl, alkenyl or alkynyl groups is independently optionally substituted by one or more substituents chosen from —(CH2)m—W3, —O—(CH2)m—W3, S—(CH2)m—W3, —NR3—(CH2)m—W3, hydroxy, oxo, halogen, alkoxy, alkylthio, amino, monoalkylamino, and dialkylamino;
• wherein each of the alkyl chains in the alkoxy, alkylthio, monoalkylamino and dialkylamino substituents is independently optionally substituted by one or more further substituents chosen from —(CH2)m—W3, hydroxy, oxo, halogen, alkoxy, alkylthio, amino, monoalkylamino and dialkylamino groups;
• W1, W2 and W3 each independently represents a 3- to 7-membered aromatic or nonaromatic cyclic group containing from 0 to 4 heteroatoms chosen from N, O and S, wherein the 3- to 7-membered aromatic or nonaromatic cyclic group is independently optionally fused to another 3- to 7-membered aromatic or non-aromatic cyclic group containing from 0 to 4 heteroatoms chosen from N, O and S;
• wherein each cyclic group is independently optionally substituted by one or more substituents chosen from halogen, alkyl, alkenyl, alkynyl, aryl, cycloalkyl, heteroaryl, heterocyclic, hydroxy, alkylenedioxy, alkoxy, alkylthio, amino, monoalkylamino, dialkylamino, nitro, cyano, oxo, hydroxycarbonyl, alkylcarbonyl, alkoxycarbonyl, acylamino, carbamoyl, and alkylcarbamoyl groups;
• wherein each of the hydrocarbon chains and the cyclic moieties of these substituents is independently optionally substituted by one or more further substituents chosen from halogen, hydroxy, oxo, alkoxy, alkylthio, acylamino, carbamoyl, alkylcarbamoyl, hydroxyalkoxy, phenyl, alkoxycarbonyl, amino, monoalkylamino, dialkylamino and hydroxycarbonyl groups;
• m is an integer from 0 to 4;
• n represents 0 or 1;
• q is an integer from 1 to 9;
• or a N-oxide or a pharmaceutically acceptable salt thereof,
• with the proviso that the compound of formula I is not the tert-butyl ester of 4-(5-amino-1H-pyrrolo[3,2-b]pyridin-3-yl)-piperidine-1-carboxylic acid.