Method of preparing 4-(imidazol-1-yl)benzenesulphonamide derivatives

A process for the preparation of a compound of formula I,

• wherein:
• R1 represents aryl or heteroaryl optionally substituted with one or more groups independently selected from halogen, C1-8 alkyl, C1-8 haloalkyl, R2OC0-8 alkyl, R2SC0-8 alkyl, cyano, nitro, —NR2R4, —NR2SO2R3, —SOR3, —SO2R3, —SO2NR2R4 or —CONR2R4;
• R2 represents hydrogen, C1-8 alkyl or arylC0-8 alkyl (wherein the aryl group can be optionally substituted with one or more groups selected from C1-8 alkyl, halogen, C1-8 haloalkyl, cyano, nitro, R5OC0-8 alkyl, R5SC0-8 alkyl, —NR5R6, —NR5COR3, —COR5 or —COOR5);
• R3 represents C1-8 alkyl or C1-8 haloalkyl;
• R4 represents hydrogen, C1-8 alkyl, arylC1-8 alkyl (wherein the aryl group can be optionally substituted with one or more groups selected from C1-8 alkyl, halogen, C1-8 haloalkyl, cyano, nitro, R5OC0-8 alkyl, R5SC0-8 alkyl, —NR5R6, —NR5COR3, —COR5, or —COOR5), —COR6 or —COOR6;
• R5 represents hydrogen, C1-8 alkyl or benzyl;
• R6 represents C1-8 alkyl or C1-8 haloalkyl;
• aryl represents phenyl or naphthyl;
• and
• heteroaryl represents pyridine, pyrazine, pyrimidine or pyridazine, which can be optionally fused to a benzene ring;
• which comprises treating a compound of formula II
• wherein R1 has the meaning defined above in relation to the formula I and But represents tert-butyl, with an acid.