Benzothiazine and benzothiadiazine compounds

A compound selected from those of formula (I):

• wherein:
• R1 represents a heterocyclic group,
• R2 represents hydrogen, halogen, or hydroxy,
• A represents NR4, and R3 and R4, together with the carbon and nitrogen atoms to which they are attached, form a ring
• wherein m represents 1, 2, or 3,
• its enantiomers and diastereoisomers, and addition salts thereof with a pharmaceutically-acceptable acid or base,
• it being understood that a heterocyclic group may be a monocyclic or bicyclic, aromatic or non-aromatic group containing from one to four identical or different hetero atoms selected from nitrogen, oxygen, and sulphur, optionally substituted by one or more identical or different groups selected from halogen, linear or branched (C1-C6)alkyl, linear or branched (C1-C6)alkoxy, linear or branched (C1-C6)polyhaloalkyl, linear or branched (C1-C6)alkoxy-carbonyl, oxo, thioxo, carboxy, linear or branched (C1-C6)acyl, linear or branched (C1-C6)polyhaloalkoxy, hydroxy, cyano, nitro, amino optionally substituted by one or more linear or branched (C1-C6)alkyl groups, aminosulphonyl optionally substituted by one or more linear or branched (C1-C6)alkyl groups, and (C1-C6)alkylsulphonylamino.