Anti-obesity 1,2,3,4,10,10a-hexahydropyrazino[1,2-a] indoles

A compound of formula (I):

• wherein
• R1, R2, R3 and R4 are independently hydrogen, halogen, hydroxy, alkyl, cycloalkyl, aralkyl, aryl, alkoxy, alkoxy alkyl, hydroxy alkyl, alkoxy alkoxy alkyl, hydroxyalkoxy alkyl, halo alkyl, halo alkoxy, aryloxy, alkylcarbonyl, arylcarbonyl, alkylthio, arylthio, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, amino, nitro, cyano, alkoxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, alkylcarbonylamino, carboxy, heterocyclyl or R3 and R4 form together with the carbon atoms to which they are attached form a 5- to 7-membered carbocyclic ring which ring is unsubstituted or alkyl substituted;
• R5 is hydrogen, alkyl or cycloalkyl;
• R6 is hydrogen, alkyl, hydroxy alkyl, carbamoyl alkyl, alkoxycarbonyl alkyl, aryloxycarbonyl alkyl or —(CH2)n-A;
• R7 is hydrogen, alkyl, cycloalkyl, hydroxyalkyl or alkoxyalkyl, whereby R7 is not hydrogen when R6 is hydrogen, alkyl, cycloalkyl or 1H-pyrrolo(2,3-b)pyridin-3-ylmethyl;
• R8 is hydrogen, alkyl or cycloalkyl;
• A is a heterocyclyl or cycloalkyl ring which ring can be unsubstituted or substituted on a ring carbon atom with a hydroxy, carboxy, oxo, alkanoyloxy alkyl, aryloxycarbonyl or alkylcarbamoyl substituent;
• n is 0, 1, 2 or 3;
• or pharmaceutically acceptable salts, solvates or esters thereof.