Chromene derivatives

A compound of formula I:

• or a salt thereof, where:
• each R1 and R3 independently represent hydrogen, C1-4alkyl, C2-4alkenyl, C2-4alkynyl, hydroxyl, C1-4alkoxyl, C1-4alkoxyC1-4alkyl, haloC1-4alkyl, hydroxyC1-4alkyl, cyanoC1-4alkyl, halogen, —CN, —NO2 or Cy2;
• R2 represents hydrogen, C1-4alkyl or Cy2, where C1-4alkyl is optionally substituted by Cy2;
• Cy1 represents a monocyclic heterocycle of 3 to 7 members or bicyclic from 6 to 11 members, saturated or partially unsaturated which can be joined to the rest of the molecule by any available C or N atom, where Cy1 can be optionally merged to a ring of 5 or 6 members carbocyclic or heterocyclic saturated, partly unsaturated or aromatic, where Cy1 can contain from 1 to 4 heteroatoms selected from N, O and S, where one or more atoms of C or S of the ring may be oxidized to form groups CO, SO or SO2, and where Cy1 is optionally replaced by one or more R4;
• each Cy2 independently represents an aromatic ring of 5-7 members which can be joined to the rest of the molecule by any C or N available atom, where Cy2 can be optionally merged to a ring of 5 or 6 members carbocyclic or heterocyclic saturated, partly unsaturated or aromatic, where Cy2 can contain from 1 to 4 heteroatoms in total selected from N, O and S, where one or more atoms of C or S of the ring may be oxidized to form groups CO, SO or SO2, and where Cy2 is optionally replaced by one or more R4;
• each R4 independently represent, C1-4alkyl, C2-4alkenyl, C2-4alkynyl, hydroxyl, C1-4alkoxyl, C1-4alkoxyC1-4alkyl, haloC1-4alkyl, hydroxiC1-4alkyl, cyanoC1-4alkyl, halogen, —CN or —NO2;
• n represents from 0 to 4;
• and
• m represents from 0 to 5.