A compound of formula, an N -oxide form, an addition salt or a stereo-chemically isomeric form thereof, wherein n is 0, 1 or 2; X is N or CR 7, wherein R 7 is hydrogen or taken together with R 1 may form a bivalent radical of formula -CH=CH-CH=CH-; R 1 is C 1-6 alkyl; R 2 is hydrogen, hydroxy, C 1-6 alkyl, C 3-6 alkynyl or taken together with R 3 may form =O; R 3 is a radical selected from -(CH 2) S -NR 8 R 9 (a-1), or -C≡N (a-5), wherein s is 1 or 2; R 8 and R 10 are each independently selected from -CHO, C 1-6 alkyl, hydroxyC 1-6 alkyl, di(C 1-6 alkyl)aminoC 1-6 alkyl, C 1-6 alkylcarbonylaminoC 1-6 alkyl, piperidinylC 1-6 alkyl, piperidinylC 1-6 alkylaminocarbonyl, C 1-6 alkyloxy, thiophenylC 1 - 6 alkyl, pyrrolylC 1-6 alkyl, arylC 1-6 alkylpiperidinyl, arylcarbonylC 1-6 alkyl, arylcarbonylpiperidinylC 1-6 alkyl, haloindozolylpiperidinylC 1-6 alkyl, or arylC 1-6 alkyl(C 1-6 alkyl)aminoC 1-6 alkyl; and R 9 is hydrogen or C 1-6 alkyl; or R 3 is a group of formula -(CH 2) t -Z (b-1), wherein t is 2; -Z is a heterocyclic ring system selected from wherein R 12 is hydrogen, C 1-6 alkyl, aminocarbonyl, C 1-6 alkyloxyC 1-6 alkylamino, di(phenylC 2-6 alkenyl), piperidinylC 1-6 alkyl, C 3-10 ocycloalkyl, C 3-10 cycloalkylC 1-6 alkyl, haloindazolyl, or arylC 2-6 alkenyl; and R 13 is hydrogen, piperidinyl or aryl; R 4, R 5 and R 6 are each independently selected from hydrogen, halo, trihalomethyl, trihalomethoxy, C 1-6 alkyl, C 1-6 alkyloxy, di(C 1-6 alkyl)amino, di(C 1-6 alkyl)aminoC 1 - 6 alkyloxy or C 1-6 alkyloxycarbonyl; or when R 5 and R 6 are on adjacent positions they may taken together form a bivalent radical of formula -O-CH 2 -O (d-1), or -O-(CH 2) 2 -O- (d-2), aryl is phenyl, phenyl substituted with halo, C 1-6 alkyl or C 1-6 alkyloxy; with the proviso that 6-benzoyl-3-methyl-2 -quinoxalinone is excluded. n is 0, 1 or 2; X is N or CR 7, wherein R 7 is hydrogen or taken together with R 1 may form a bivalent radical of formula -CH=CH-CH=CH-; R 1 is C 1-6 alkyl; R 2 is hydrogen, hydroxy, C 1-6 alkyl, C 3-6 alkynyl or taken together with R 3 may form =O; R 3 is a radical selected from -(CH 2) S -NR 8 R 9 (a-1), or -C≡N (a-5), wherein s is 1 or 2; R 8 and R 10 are each independently selected from -CHO, C 1-6 alkyl, hydroxyC 1-6 alkyl, di(C 1-6 alkyl)aminoC 1-6 alkyl, C 1-6 alkylcarbonylaminoC 1-6 alkyl, piperidinylC 1-6 alkyl, piperidinylC 1-6 alkylaminocarbonyl, C 1-6 alkyloxy, thiophenylC 1 - 6 alkyl, pyrrolylC 1-6 alkyl, arylC 1-6 alkylpiperidinyl, arylcarbonylC 1-6 alkyl, arylcarbonylpiperidinylC 1-6 alkyl, haloindozolylpiperidinylC 1-6 alkyl, or arylC 1-6 alkyl(C 1-6 alkyl)aminoC 1-6 alkyl; and R 9 is hydrogen or C 1-6 alkyl; or R 3 is a group of formula -(CH 2) t -Z (b-1), wherein t is 2; -Z is a heterocyclic ring system selected from s is 1 or 2; R 8 and R 10 are each independently selected from -CHO, C 1-6 alkyl, hydroxyC 1-6 alkyl, di(C 1-6 alkyl)aminoC 1-6 alkyl, C 1-6 alkylcarbonylaminoC 1-6 alkyl, piperidinylC 1-6 alkyl, piperidinylC 1-6 alkylaminocarbonyl, C 1-6 alkyloxy, thiophenylC 1 - 6 alkyl, pyrrolylC 1-6 alkyl, arylC 1-6 alkylpiperidinyl, arylcarbonylC 1-6 alkyl, arylcarbonylpiperidinylC 1-6 alkyl, haloindozolylpiperidinylC 1-6 alkyl, or arylC 1-6 alkyl(C 1-6 alkyl)aminoC 1-6 alkyl; and R 9 is hydrogen or C 1-6 alkyl; t is 2; -Z is a heterocyclic ring system selected from wherein R 12 is hydrogen, C 1-6 alkyl, aminocarbonyl, C 1-6 alkyloxyC 1-6 alkylamino, di(phenylC 2-6 alkenyl), piperidinylC 1-6 alkyl, C 3-10 ocycloalkyl, C 3-10 cycloalkylC 1-6 alkyl, haloindazolyl, or arylC 2-6 alkenyl; and R 13 is hydrogen, piperidinyl or aryl; R 4, R 5 and R 6 are each independently selected from hydrogen, halo, trihalomethyl, trihalomethoxy, C 1-6 alkyl, C 1-6 alkyloxy, di(C 1-6 alkyl)amino, di(C 1-6 alkyl)aminoC 1 - 6 alkyloxy or C 1-6 alkyloxycarbonyl; or when R 5 and R 6 are on adjacent positions they may taken together form a bivalent radical of formula -O-CH 2 -O (d-1), or -O-(CH 2) 2 -O- (d-2), aryl is phenyl, phenyl substituted with halo, C 1-6 alkyl or C 1-6 alkyloxy; with the proviso that 6-benzoyl-3-methyl-2 -quinoxalinone is excluded.