Patent ID: 6593476
Filing Date: 2003-07-15
Classification: A61K,A61Q,C07D

Abstract:
A method for the preparation of 2-arylbenzimidazolesulfonic acid of the formula: wherein Ar is a substituted or unsubstituted phenyl or naphthyl radical and R is a C1-8-alkyl radical or a C1-8-alkoxy radical n is 1, 2, 3 or 4, in is 2 or 3 and o is 0, 1 or 2, comprising reacting an o-phenylenediamine according in the formula II with a second compound having the formula III: in the presence of sulphuric acid activated with oleum, and at a temperature of 20Â° C. to 200Â° C., wherein R1, R2, R3, R4 and R5 are each independently of one another a radical selected from H, C1-8-alkyl, C1-8-alkoxy, hydroxyl, nitro, F, Cl, Br, I, COOH, COORâ€², COCl, COBr or CN, R1 and R2 together or R2 and R3 together are optionally a fused-on, optionally substituted phenylene unit, and Râ€² is a C1-20-alkyl radical, and X is a radical selected from â€”COOH, â€”COORâ€², â€”COCl, â€”COBr, or â€”CN.