The object of the present invention is benzothiazine derivatives having thecapability of inhibiting 11.beta.-HSD1 notonly at an enzymatic level but also at a cell level. The compounds of thepresent invention are of general formula (I). Wherein notablyR1 represents a hydrogen or OR1 represents an ester or an ether. R2 representsa naphthyl or a 1, 2, 3, 4-tetrahydro-naphthaleneor a biphenyl or phenyl pyridine or a substituted phenyl. R3 represents amethyl or ethyl; R4 and R'4 represent a hydrogen.