Coumarin derivatives with comt inhibiting activity

A compound of formula I

• 13
• wherein the two OH— substituents in the phenyl moiety are in a position ortho to one another and R1 in a position ortho to one of the hydroxy groups;
• X is O or NR7;
• wherein R7 is H, (C1-C6)alkyl or —(C1-C6)alkyl-COOH;
• R1 is NO2, CN, CHO, CF3 or (C1-C6)alkyl-CO—;
• R2 and R3 are each selected independently from H, OH, halogen, NO2, SH, NH2, (C1-C6)alkyl, (C2-C6)alkenyl, (C1-C6)alkoxy, OH—(C1-C6)alkyl, halo-(C1-C6)alkyl, mono- or di(C1-C6)alkylamino, SO2R10, —CO—(C1-C9)alkyl, —(Y)n—(B)m—COOH and —(Y)n—(B)m—R8;
• wherein
• m is 0 or 1;
• n is 0 or 1;
• Y is —CO— or —CHOH—;
• B is (C1-C6)alkylene or (C2-C6)alkenylene;
• R8 is phenyl, naphthyl, (C3-C7)cycloalkyl or 5- or 6-membered heterocyclyl with one to four heteroatoms each selected independently from N, O and S, wherein the said phenyl, naphthyl, (C3-C7)cycloalkyl or 5- or 6-membered heterocyclyl is optionally substituted with one to five substituents R9 each selected independently from OH, halogen, COOH, 5-tetrazolyl, NO2, SH, NH2, CN, CHO, ═O, (C1-C6)alkyl, (C1-C6)alkoxy, halo-(C1-C6)alkyl, mono- or di(C1-C6)alkylamino, CO—(C1-C6)alkyl, CO—NH2, mono- or di(C1-C6)alkylamino-CO—, NHOH, CONHOH or SO2R10;
• or R8 is
• 14
• or R2 and R3 form together —(CH2)r—;
• wherein r is 3, 4 or 5;
• R4 and R5 are independently H or (C1-C6)alkyl;
• or R4 and R5 form together ═O, ═S or ═NR11, wherein R11 is H or (C1-C6)alkyl;
• R6 is H, NO2, CN, CHO, halogen, CF3 or (C1-C6)alkyl;
• and
• R10 is (C1-C6)alkyl, NH2, OH or mono- or di(C1-C6)alkylamino;
• with the provisos that (a) when X is O, R2 is methyl, R3 is H, R4 and R5 form together ═O, R6 is H and the two hydroxy substituents are at 7- and 8-positions, then R1 is not CHO, (b) when X is O, R2 is H or methyl, R3 is H, R4 and R5 form together ═O, R6 is H and the two hydroxy substituents are at 6- and 7-positions, then R1 is not 8-CO—CH3, (c) when X is O, R2 and R3 are H, R4 and R5 are both methyl, R6 is H and the two hydroxy substituents are at 7- and 8-positions, then R1 is not —CO—CH3,
• or pharmaceutically acceptable salts or pharmaceutically acceptable esters thereof.