Patent ID: 7411074

Claim:
A process for preparing a compound of formula (I) wherein R 4 and R 5 are independently selected from hydrogen, halo, nitro, cyano, hydroxy, fluoromethyl, difluoromethyl, trifluoromethyl, trifluoromethoxy, amino, carboxy, carbamoyl, mercapto, sulphamoyl, ureido, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 1-6 alkoxy, C 1-6 alkanoyl, C 1-6 alkanoyloxy, N—(C 1-6 alkyl)amino, N,N—(C 1-6 alkyl) 2 amino, C 1-6 alkanoylamino, N—(C 1-6 alkyl)carbamoyl, N,N—(C 1-6 alkyl) 2 carbamoyl, C 1-6 alkylS(O) a wherein a is 0 to 2, C 1-6 alkoxycarbonyl, C 1-6 alkoxycarbonylamino, N—(C 1-6 alkyl)sulphamoyl, N,N,—(C 1-6 alkyl) 2 sulphamoyl, C 1-6 alkylsulphonylamino, and C 1-6 alkylsulphonyl-N—(C 1-6 alkyl)amino; and R 6 is hydrogen or a protecting group, which process comprises cyclisation of a compound of formula (II) wherein R 4 , R 5 , and R 6 are as defined in relation to formula (I); and R 7 is a nitrogen protecting group; and removing protecting group R 7 , and thereafter if desired or necessary, removing any protecting group R 6 to obtain the corresponding carboxylic acid.