Process for the preparation of sulfamoylbenzoic acid derivatives

A method for the preparation of a compound of formula (I) or its salts, pharmaceutically acceptable stereoisomers, enantiomers, diastereoisomers, tautomers, geometric zwitterions:

• wherein:
• R1 and R2 are, independently, H, substituted or unsubstituted, linear or branched C1-10-alkyl optionally comprising one or more unsaturations;
• substituted or unsubstituted C3-8-cycloalkyl;
• substituted or unsubstituted, linear or branched C4-10-cycloalkyl-alkyl;
• C3-8-heterocycle;
• or, together with the nitrogen atom to which they are bound, R1 and R2 form a substituted or unsubstituted saturated heterocycle;
• R3 and R4 are, independently, hydrogen;
• substituted or unsubstituted C1-10-alkyl optionally comprising one or more unsaturations;
• C3-10-cycloalkyl;
• C4-10-cycloalkyl-alkyl;
• C2-8-haloalkyl;
• substituted or unsubstituted, linear or branched C2-8-heteroalkyl;
• optionally substituted phenyl;
• provided that at least one of R3 and R4 is other than hydrogen;
• R5 is hydrogen;
• halogen;
• hydroxyl;
• thiophenol;
• —NO2;
• R6 is —COOH;
• including the steps of:
• a) reacting, in aqueous solution, a compound of formula (II) with an amine of formula (III) to obtain a compound of formula (IV):
• wherein X and Y are independently a halogen;
• b) reacting, in aqueous solution and in the presence of a base, the compound of formula (IV) with a compound of formula (V) to obtain a compound of formula (I)