Compounds 7- (1H-pyrazol-4-yl) -1,6-naphthyridine as inhibitors of Syk

A compound of formula (I): ** ** Formula wherein: X is O or NH; R1 is C2-4 alkyl, cicloalquiloC3-7, hidroxialquiloC2-4, alcoxiC1-2alquiloC1-4, trifluorometilalquiloC1-2 or benzyl; or a salt thereof.