Heterocyclic antiviral compounds

A compound according to formula I wherein:

• R1 is 2-oxo-2H-pyrazin-1-yl-said 2-oxo-2H-pyrazin-1-yl moiety optionally independently substituted with one or two halogen or C1-3 alkyl substitutents;
• R2 is (a) —CR2a═CR2aAr, (b) —(C(R2b)2)nAr, (c) 1-oxo-1H-isochromen-7-yl or 2H-isoquinolin-1-one either optionally substituted by NRaRb, or, (d) benzooxazol-2-yl or benzothiazol-2-yl either optionally substituted by NRaRb;
• R2a is independently in each occurrence hydrogen, C1-3 alkyl, cyano, carboxyl or halogen;
• R2b is independently in each occurrence hydrogen or C1-3 alkyl, cyano, carboxyl, C1-3 hydroxyalkyl or C1-3 alkoxy-C1-3 alkyl;
• R3 is hydrogen, C1-6 alkoxy, C1-6 alkyl, C1-6 haloalkyl, C1-6 haloalkoxy or halogen or R3 and R4a together are CH2—O or (CH2)2 and together with atoms to which they are attached form a 2,3-dihydrobenzofuran or an indane;
• Ar is (a) aryl or (b) heteroaryl wherein said heteroaryl is pyridin-2-yl, pyridin-3-yl pyrazin-2-yl or pyridizin-3-yl and said aryl or said heteroaryl are optionally independently substituted with one to three substitutents selected from the group consisting of hydroxy, C1-6 alkoxy, C1-6 alkyl, C1-6 hydroxyalkyl, C1-3 alkoxy-C1-6 alkyl, halogen, (CH2)nNRaRb, cyano, C1-6 alkoxycarbonyl, carbamoyl, N-alkylcarbamoyl, N,N-dialkylcarbamoyl, (CH2)nCO2H, SO2NH2, C1-6 alkylsulfinyl and C1-6 alkylsulfonyl;
• Ra and Rb are independently hydrogen, C1-6 alkyl, C1-6 haloalkyl, C1-6 acyl, C1-6 alkylsulfonyl, C1-6 haloalkylsulfonyl, C3-7 cycloalkylsulfonyl, C3-7 cycloalkyl-C1-3 alkyl-sulfonyl, C1-6 alkoxy-C1-6 alkylsulfonyl, —SO2—NRcRd, C1-3 alkylcarbamoyl or C1-3 dialkylcarbamoyl;
• Rc and Rd are (i) independently hydrogen, C1-3 alkyl or (CH2)2-6NReRf or (ii) together with the nitrogen to which they are attached are (CH2)2X5(CH2)2 wherein X5 is O or NRi and Ri is hydrogen, C1-3 alkyl, C1-3 acyl or C1-3 alkylsulfonyl;
• Re and Rf are independently in each occurrence hydrogen or C1-3 alkyl;
• R4 is hydrogen, C1-6 alkyl, C1-6 haloalkyl, C3-5 cycloalkyl, halogen, C1-6 alkoxy, C1-3 haloalkoxy or CR4aR4bR4c wherein:
• (i) R4a, R4b and R4c are independently selected from C1-3 alkyl, C1-2 alkoxy, C1-2 fluoroalkyl, C1-3 hydroxyalkyl, cyano or hydroxy;
• or,
• (ii) when taken together, R4a and R4b together are C2-4 alkylene and R4c is hydrogen, C1-3 alkyl, C1-2 alkoxy, halogen, C1-3 hydroxyalkyl, cyano or C1-2 fluoroalkyl, or R4a and R4b together with the carbon to which they are attached are 3-oxetanyl, or tetrahydrofuran-2-yl;
• or,
• (iii) either R5 or R3 and R4a together are CH2—O or (CH2)2 and together with atoms to which they are attached form a 2,3-dihydro-benzofuran or an indane and R4b and R4c are C1-3 alkyl;
• R5 is hydrogen or halogen or R5 and R4a together are CH2—O or (CH2)2 and together with atoms to which they are attached form a 2,3-dihydrobenzofuran or an indane;
• n is independently in each occurrence zero to three;
• or,
• a pharmaceutically acceptable salt thereof.