Pyridazines as 11b-HSD1 inhibitors

A compound of the formula:

• wherein
• R1 and R2 together with the carbon atoms Ca and Cb to which they are attached form
• R3 is hydrogen, alkyl, cycloalkyl or trifluoromethyl;
• R4 is benzyl, cycloalkyl, arylcycloalkyl, adamantyl, aryl or heterocyclyl, wherein benzyl, cycloalkyl, arylcycloalkyl, aryl and heterocyclyl are optionally substituted with one to three substituents independently selected from alkyl, cycloalkyl, alkoxy, hydroxy, halogen, trifluormethyl, trifluoromethoxy, benzyl, phenyl and phenyl substituted with one to three substituents independently selected from alkyl, alkoxy, hydroxy, cycloalkyl, halogen and trifluoromethyl;
• or pharmaceutically acceptable salts and esters thereof.