Novel amines as histamine-3 receptor ligands and their therapeutic applications

A compound of formula (I)

• 18
• or a pharmaceutically acceptable salt or prodrug thereof, wherein
• A is selected from the group consisting of carbonyl and a covalent bond;
• D is selected from the group consisting of O and S;
• L is selected from the group consisting of —CH2CH2— and —CH2CH2CH2—;
• P and Q taken together form a covalent bond or are both hydrogen;
• R1 and R2 are each independently selected from the group consisting of hydrogen, alkyl, aryl, arylalkyl, cycloalkyl, cycloalkylalkyl, heterocycle, heterocyclealkyl, hydroxyalkyl, alkenyl, and alkynyl;
• or
• R1 and R2 taken together with the nitrogen atom to which they are attached, together form a heterocycle;
• R3, R4 and R5 are each independently selected from the group consisting of hydrogen, alkoxy, alkoxycarbonyl, alkyl, alkylcarbonyl, alkylcarbonyloxy, alkylsulfinyl, alkylsulfonyl, alkylthio, carboxy, carboxyalkyl, cyano, cyanoalkyl, formyl, halogen, haloalkoxy, haloalkyl, hydroxy, hydroxyalkyl, mercapto, nitro, —NRARB, (NRARB)alkyl, (NRARB)carbonyl and (NRARB)sulfonyl;
• R6 and R7 are each independently selected from the group consisting of hydrogen, alkoxy, alkoxycarbonyl, alkyl, alkylcarbonyl, alkylcarbonyloxy, alkylsulfinyl, alkylsulfonyl, alkylthio, aryl, carboxy, carboxyalkyl, cyano, cyanoalkyl, cycloalkyl, formyl, halogen, haloalkoxy, haloalkyl, heterocycle, hydroxy, hydroxyalkyl, mercapto, nitro, —NRARB, (NRARB)alkyl, (NRARB)carbonyl and (NRARB)sulfonyl;
• and
• RA and RB are each independently selected from the group consisting of hydrogen, alkyl, alkylcarbonyl and formyl;
• provided that at least one, but not both, of R6 or R7 is aryl, heterocycle or cycloalkyl.