The present invention relates to compounds of formula I, or pharmaceutically acceptable salts or esters thereof, (Formula I) wherein R1 is selected from: aryl heteroaryl -NHR3 fused aryl-C4_7-heterocycloalkyl -CONR4R5 - NHCOR6 -C3-7-cycloalkyl,-NR3R6 -OR3 OH NR4R5 and alkyl optionally substituted with a substituent selected from R11 and a group A wherein said aryl, heteroaryl, fused aryl-C4-7-heterocycloalkyl and C4-7- heterocycloalkyi are each optionally substituted with one or more substituents selected from C1-6-alkyl, C3-7-cycloalkyl, heteroaryl, C4-7-heterocycloalkyl, aryl and a group A, and said C1-6-alkyl, C3-7-cycloalkyl, heteroaryl, C4-7-heterocycloalkyl, and aryl substituents are in turn each optionally substituted with one or more groups selected from R11 and a group A R2 is selected from hydrogen, aryl, C1-6-alkyl, C2-6-alkenyl, C3-7-cycloalkyl, heteroaryl, heterocycloalkyi, fused aryl-C4-7-rheterocycloalkyl and halogen, wherein said C1-6-alkyl, C2-6-alkenyl, aryl, heteroaryl, fused aryl-C4-7-heterocycloalkyl and C4-7-heterocycloalkyl are each optionally substituted with one or more substituents selected from R11 and A. Further aspects relate to pharmaceutical compositions and therapeutic uses of said compounds.La présente invention porte sur des composés de formule I, ou des sels ou esters pharmaceutiquement acceptables de ceux-ci, (Formule I) dans laquelle R1 est choisi parmi : aryle hétéroaryle -NHR3 aryl-(hétérocycloalkyle en C4-7) condensé -CONR4R5 - NHCOR6 -cycloalkyle en C3-7,-NR3R6 -OR3 OH NR4R5 et alkyle éventuellement substitué par un substituant choisi entre R11 et un groupe A lesdits aryle, hétéroaryle, aryl-(hétérocycloalkyle en C4-7) condensé et hétérocycloalkyle en C4-7 étant chacun éventuellement substitués par un ou plusieurs substituants choisis parmi alkyle en C1-6, cycloalkyle en C3-7, hétéroaryle, hétérocycloalkyle en C4-7, aryle et un groupe A et lesdits substituants alkyle en C1-6, cycloalkyle en C3-7, hétéroaryle, hétér
