Process and intermediates for the preparation of the thienopyrrole derivatives

A process for preparing a compound of formula (I)

• wherein
• R4 and R5 are independently selected from hydrogen, halo, nitro, cyano, hydroxy, fluoromethyl, difluoromethyl, trifluoromethyl, trifluoromethoxy, amino, carboxy, carbamoyl, mercapto, sulphamoyl, ureido, C1-6alkyl, C2-6alkenyl, C2-6alkynyl, C1-6alkoxy, C1-6alkanoyl, C1-6alkanoyloxy, N—(C1-6alkyl)amino, N,N—(C1-6alkyl)2amino, C1-6alkanoylamino, N—(C1-6alkyl)carbamoyl, N,N—(C1-6alkyl)2carbamoyl, C1-6alkylS(O)a wherein a is 0 to 2, C1-6alkoxycarbonyl, C1-6alkoxycarbonylamino, N—(C1-6alkyl)sulphamoyl, N,N,—(C1-6alkyl)2sulphamoyl, C1-6alkylsulphonylamino, and C1-6alkylsulphonyl-N—(C1-6alkyl)amino;
• and
• R6 is hydrogen or a protecting group,
• which process comprises cyclisation of a compound of formula (II)
• wherein
• R4, R5, and R6 are as defined in relation to formula (I);
• and
• R7 is a nitrogen protecting group;
• and
• removing protecting group R7, and thereafter if desired or necessary, removing any protecting group R6 to obtain the corresponding carboxylic acid.