Phthalazinone-piperidino-derivatives as PDE4 inhibitors

1. A method of treating a dermatose in a patient comprising administering to a patient in need thereof a therapeutically effective amount of a compound of formula I

in which

R1 and R2 are both hydrogen or together form an additional bond,

R3 represents a benzene derivative of formula (a)

wherein

R4 is 1-4C-alkoxy,

R5 is 1-8C-alkoxy,

R9 is (CH 2 ) m —C(O)—R15,

wherein

R15 is —N(R16)R17,

R16 and R17 are independent from each other and are hydrogen or 1-7C-alkyl, and

m is an integer from 1 to 4,

or a pharmaceutically acceptable hydrate, salt or hydrate of a salt thereof, wherein the dermatose is selected from the group consisting of psoriasis and atopic eczema.

2. The method according to claim 1 , wherein the hydrogen atoms in the compounds of formula I in the positions 4a and 8a are cis-configurated.

3. The method according to claim 1 , wherein the absolute configuration of the compounds of formula I is S in the position 4a and R in the position 8a.

4. A method of treating a dermatose in a patient comprising administering to a patient in need thereof a therapeutically effective amount of 2-{4-[(4aS,8aR)-4-(3,4-dimethoxyphenyl)-1-oxo-4a,5,8,8a-tetrahydro-1H-phthalazin-2-yl]-piperidin-1-yl}-acetamide or a pharmaceutically acceptable hydrate, salt or hydrate of a salt thereof, wherein the dermatose is selected from the group consisting of psoriasis and atopic eczema.

5. A method of treating a dermatose in a patient comprising administering to a patient in need thereof a therapeutically effective amount of 2-{4-[(4aS,8aR)-4-(3,4-dimethoxyphenyl)-1-oxo-4a,5,8,8a-tetrahydro-1H-phthalazin-2-yl]-piperidin-1-yl}-acetamide hydrochloride or a hydrate thereof, wherein the dermatose is selected from the group consisting of psoriasis and atopic eczema.