Substituted pyrido[3,4-b]indoles for the treatment of cartilage disorders

An intermediate compound of formula II

• wherein:
• R1, R3, R4 and R6 are independently selected from the group consisting of hydrogen, halogen and (C1-C4)-alkyl;
• R2 is selected from the group consisting of hydrogen, halogen, (C1-C4)-alkyl and (C1-C4)-alkyl-O—C(O)—;
• R5 is selected from the group consisting of hydrogen, halogen, (C1-C4)-alkyl, (C1-C4)-alkyl-O—, cyano, R7—O—C(O)— and R8—N(R9)—C(O)—;
• R7, R8 and R9 are independently selected from the group consisting of hydrogen and (C1-C4)-alkyl;
• R10 is selected from the group consisting of hydrogen, (C1-C6)-alkyl, (C2-C6)-alkenyl, (C2-C6)-alkynyl and (C3-C7)-cycloalkyl,
• wherein the (C1-C6)-alkyl group is unsubstituted or substituted by 1 or 2 identical or different substituents selected from the group consisting of (C3-C7)-cycloalkyl, Het, cyano and (C1-C4)-alkyl-O—, and
• wherein each (C3-C7)-cycloalkyl group is unsubstituted or substituted by one or more identical or different substituents selected from the group consisting of fluorine and (C1-C4)-alkyl;
• and
• X is a halogen leaving group;
• wherein Het is a monocyclic, 4-membered to 7-membered, saturated heterocyclic group comprising 1 or 2 identical or different hetero ring members selected from the group consisting of N, N(R40), O and S(O)m, and which is unsubstituted or substituted on ring carbon atoms by one or more identical or different substituents selected from the group consisting of fluorine and (C1-C4)-alkyl;
• R40 is selected from the group consisting of hydrogen and (C1-C4)-alkyl;
• m is selected from the series consisting of 0, 1 and 2, wherein all numbers m are independent of each other and can be identical or different;
• and
• wherein each alkyl group, independently of any other substituents which can be present on an alkyl group, is optionally substituted by one or more fluorine substituents.