Derivatives of 7-alkynyl-1,8-naphthyridones, preparation method thereof and use of same in therapeutics

A compound of formula (I):

• wherein:
• R1 and R2
• (1) are, independently of one another:
• a hydrogen atom,
• or a C1-C7 alkyl group, a —CO—(C1-C7) alkyl group or a C3-C8 cycloalkyl group, where said alkyl and cycloalkyl groups are optionally substituted with one or more groups selected from halogen atoms and hydroxyl and alkoxy groups,
• or a phenyl group optionally substituted with one or more groups selected from halogen atoms, and C1-C4 alkyl, C1-C4 alkoxy, hydroxyl, haloalkoxy, haloalkyl, —CN or —NRR′ groups, where R and R′ are as defined below,
• or a heteroaryl group optionally substituted in any position, including on a nitrogen atom of said heteroaryl, with one or more groups selected from halogen atoms, C1-C4 alkyl groups and —NRR′ groups, where R and R′ are as defined below;
• (2) or R1 and R2 form, together with the carbon atom that bears them:
• a C4-C8 cycloalkyl group,
• or a 4- to 8-membered saturated heterocyclic group comprising a heteroatom selected from N, O and S atoms,
• and it being possible for said heterocyclic group to be fused with a phenyl group;
• R3 is:
• a linear or branched C1-C7 alkyl group or a C3-C7 alkyl group in which at least 3 carbon atoms are cyclized, said alkyl group being optionally substituted with one or more groups selected from halogen atoms and hydroxyl, alkoxy, —NRR′, -haloalkyl and —SO2—(C1-C4)alkyl groups, where R and R′ are as defined hereinafter,
• or a —(CH2)n-heterocyclic group, where n=0, 1, 2 or 3 and where the heterocyclic group comprises between 4 and 8 members and comprises at least one heteroatom selected from N, O and S atoms, where said heterocyclic group is optionally substituted with an oxo group,
• or a —(CH2)n-heteroaryl group, where n=0, 1, 2 or 3 and where the heteroaryl group comprises 5 or 6 members and comprises one or more heteroatoms selected from nitrogen, oxygen and sulphur;
• R4 is a hydrogen atom, a C1-C4 alkyl group or a C1-C4 alkoxy group;
• R and R′ are, independently of one another, a hydrogen atom or a C1-C4 alkyl group,
• or an acid addition salt thereof, or an enantiomer or diastereoisomer thereof, or a mixture thereof.