Compounds for treating respiratory syncytial virus infections

The disclosure relates to a family of compounds of formula (I) wherein X1, X2, R1, R2, and R3 are as defined in the specification. The disclosure further relates to a method of forming these compounds by synthetic means and chiral resolution. The disclosure also relates to the use of these compounds for treating respiratory syncytial virus (RSV) infections and diseases relating to the infection. Examples of the compounds include: (5aS)-5a-(4-chlorophenyl)-6-[(3-methyl-1,2-oxazol-4-yl)carbonyl]-5a,6,7,8-tetrahydroimidazo[1',2':1,6]pyrido[3,4-b]pyrazin-10(5H)-one; (10aS)-10a-(4-chlorophenyl)-1-[(3-methyl-1,2-oxazol-4-yl)carbonyl]-2,3,10,10a-tetrahydroimidazo[2,1-g][1,7]naphthyridin-5(1H)-one; (10aS)-10a-(4-fluorophenyl)-1-[(3-methyl-1,2-oxazol-4-yl)carbonyl]-2,3,10,10a-tetrahydroimidazo[2,1-g][1,7]naphthyridin-5(1H)-one; (5aS)-5a-(4-fluorophenyl)-6-[(3-methyl-1,2-oxazol-4-yl)carbonyl]-5a,6,7,8-tetrahydroimidazo[1',2':1,6]pyrido[3,4-b]pyrazin-10(5H)-one; (10aS)-10a-(4-fluoro-3-methylphenyl)-1-[(3-methyl-1,2-oxazol-4-yl)carbonyl]-2,3,10,10a-tetrahydroimidazo[2,1-g][1,7]naphthyridin-5(1H)-one.