9,10-dihydro-5,8-dimethoxy-9,10-dioxoantracene-2-yls and salts or esters thereof and pharmaceutical composition containing same

PURPOSE: To provide novel compounds effective in treating connective-tissue ground substance diseases such as osteo-arthritis and treating cancers. CONSTITUTION: 9,10-Dihydro-5,8-dimethoxy-9,10-dioxoanthracene-2-yls are represented by formula I [wherein R 1 and R 3 are each 1-4C alkyl or 1-4C alkylcarbonyl; R 2 is carboxy, tetrazolyl, 1-4C alkylsulfonamido or CR 4 R 5 CO 2 H (wherein R 4 and R 5 are each H or 1-4C alkyl); and provided that when R 1 and R 3 are both methyl or methylcarbonyl, R 2 is not carboxy] and salts or esters thereof and include, e.g. 5-(9,10-dihydro-5,8-dimethoxy-9,10-dioxo-antracene-2-yl) tetrazole. The compound is obtained, e.g. by reacting a compound of formula II with a 1-4C alkylating agent or acylating agent. COPYRIGHT: (C)1995,JPO