A compound having the formula I: or a pharmaceutically acceptable salt or an isotopic compound thereof, wherein X is NR 7; R 1 is hydrogen, -C OC 1-6 alkyl, or -C OH, or together with R 2, forms =O; R 2 is hydrogen, or together with R 1, forms =O; R 3 and R 4 are independently -C 1-6 alkyl, -C 1-6 alkylene-OH, -C 1-6 alkylene-C OH, -C 1-6 alkylene-O-C C 1-6 alkyl, -C 1-6 alkylene-aryl, or -CH 2 CH=CH 2, or, together with the nitrogen atom to which they are attached, form a 4- to 7-membered heterocyclic ring containing one nitrogen atom and 0 or 1 oxygen atoms, wherein said ring is unsubstituted or mono-, di- or tri-substituted with halogen, -C 1-6 alkyl or C 1-6 alkyl-OH; R5 and R 6, which are attached to any available carbon ring atom, are independently hydrogen, -C 1-6 alkyl, -C OC 1-6 alkyl, -C OH, aryl, or R 5 and R 6, when they are attached to the same carbon atom, together form =O; R 7 is hydrogen, -C 1-6 alkyl, -C 1-6 alkylene-aryl, -C 1-6 alkyleneC O-C 1-6 alkyl, -C 1-6 alkyleneC OH, -C 1-6 alkyleneCF 3, -CN, -C O-C 1-6 alkyl, -C C 1-6 alkyl, -C OC 3-6 carbocycle, -C CHF 2, -C CHF 3, -C CH 2 OH, -C aryl, -C C 1-6 alkyleneOHC C 3-6 carbocycle, -C NH 2, -C NHC 1-6 alkyl, -C NH-aryl, -C heterocycle, -C NHC 3-6 carbocycle, -C N(C 1-6 alkyl)C 1-6 alkyl, -C NHSO 2 aryl, -SOC 1-6 alkyl, -SO 2 C 1-6 alkyl, -SO 2 CF 3, -SO 2 aryl, -SO 2 heteroaryl, aryl, heteroaryl, heterocycle, -C 3-6 carbocycle; or wherein aryl, alkyl, carbocycle, heteroaryl, and heterocycle are unsubstituted or substituted with 1, 2, 3 or 4 groups independently selected from R 8, where R 8 is independently -CN, halogen, CF 3, =O, -C OC 1-6 alkyl, -O-C 1-6 alkyl, -OCF3, -C 1-6 alkyl, heteroaryl, -C NH 2, or -O-N=N + (O -)N(CH 3)(C(CH 3) 3) and wherein 'aryl' denotes a phenyl, naphthyl or indanyl group; 'heteroaryl' denotes an unsaturated ring having 5 or 6 atom ring members including 1, 2, 3 or 4 heteroatoms independently selected from N, O and S and 'heterocycle' denotes a 4- to 8-membered saturated monocyclic ring or a stable 7-to 12-membered bicyclic ring system which consist of carbon atoms and one or more heteroatoms selected from N, O and S. X is NR 7; R 1 is hydrogen, -C OC 1-6 alkyl, or -C OH, or together with R 2, forms =O; R 2 is hydrogen, or together with R 1, forms =O; R 3 and R 4 are independently -C 1-6 alkyl, -C 1-6 alkylene-OH, -C 1-6 alkylene-C OH, -C 1-6 alkylene-O-C C 1-6 alkyl, -C 1-6 alkylene-aryl, or -CH 2 CH=CH 2, or, together with the nitrogen atom to which they are attached, form a 4- to 7-membered heterocyclic ring containing one nitrogen atom and 0 or 1 oxygen atoms, wherein said ring is unsubstituted or mono-, di- or tri-substituted with halogen, -C 1-6 alkyl or C 1-6 alkyl-OH; -C 1-6 alkyl, -C 1-6 alkylene-OH, -C 1-6 alkylene-C OH, -C 1-6 alkylene-O-C C 1-6 alkyl, -C 1-6 alkylene-aryl, or -CH 2 CH=CH 2, or, together with the nitrogen atom to which they are attached, form a 4- to 7-membered heterocyclic ring containing one nitrogen atom and 0 or 1 oxygen atoms, wherein said ring is unsubstituted or mono-, di- or tri-substituted with halogen, -C 1-6 alkyl or C 1-6 alkyl-OH; R5 and R 6, which are attached to any available carbon ring atom, are independently hydrogen, -C 1-6 alkyl, -C OC 1-6 alkyl, -C OH, aryl, or R 5 and R 6, when they are attached to the same carbon atom, together form =O; hydrogen, -C 1-6 alkyl, -C OC 1-6 alkyl, -C OH, aryl, R 7 is hydrogen, -C 1-6 alkyl, -C 1-6 alkylene-aryl, -C 1-6 alkyleneC O-C 1-6 alkyl, -C 1-6 alkyleneC OH, -C 1-6 alkyleneCF 3, -CN, -C O-C 1-6 alkyl, -C C 1-6 alkyl, -C OC 3-6 carbocycle, -C CHF 2, -C CHF 3, -C CH 2 OH, -C aryl, -C C 1-6 alkyleneOHC C 3-6 carbocycle, -C NH 2, -C NHC 1-6 alkyl, -C NH-aryl, -C heterocycle, -C NHC 3-6 carbocycle, -C N(C 1-6 alkyl)C 1-6 alkyl, -C NHSO 2 aryl, -SOC 1-6 alkyl, -SO 2 C 1-6 alkyl, -SO 2 CF 3, -SO 2 aryl, -SO 2 heteroaryl, aryl, heteroaryl, heterocycle, -C 3-6 carbocycle; or wherein aryl, alkyl, carbocycle, heteroaryl, and heterocycle are unsubstituted or substituted with 1, 2, 3 or 4 groups independently selected from R 8, where R 8 is independently -CN, halogen, CF 3, =O, -C OC 1-6 alkyl, -O-C 1-6 alkyl, -OCF3, -C 1-6 alkyl, heteroaryl, -C NH 2, or -O-N=N + (O -)N(CH 3)(C(CH 3) 3) and wherein 'aryl' denotes a phenyl, naphthyl or indanyl group; 'heteroaryl' denotes an unsaturated ring having 5 or 6 atom ring members including 1, 2, 3 or 4 heteroatoms independently selected from N, O and S and 'heterocycle' denotes a 4- to 8-membered saturated monocyclic ring or a stable 7-to 12-membered bicyclic ring system which consist of carbon atoms and one or more heteroatoms selected from N, O and S. hydrogen, -C 1-6 alkyl, -C 1-6 alkylene-aryl, -C 1-6 alkyleneC O-C 1-6 alkyl, -C 1-6 alkyleneC OH, -C 1-6 alkyleneCF 3, -CN, -C O-C 1-6 alkyl, -C C 1-6 alkyl, -C OC 3-6 carbocycle, -C CHF 2, -C CHF 3, -C CH 2 OH, -C aryl, -C C 1-6 alkyleneOHC C 3-6 carbocycle, -C NH 2, -C NHC 1-6 alkyl, -C NH-aryl, -C heterocycle, -C NHC 3-6 carbocycle, -C N(C 1-6 alkyl)C 1-6 alkyl, -C NHSO 2 aryl, -SOC 1-6 alkyl, -SO 2 C 1-6 alkyl, -SO 2 CF 3, -SO 2 aryl, -SO 2 heteroaryl, aryl, heteroaryl, heterocycle, -C 3-6 carbocycle; or