Preparation of oxalamido-​substituted tricyclic inhibitors of hepatitis B virus

The present invention relates to compds. I [Cy = aryl or heteroaryl; A = CR3 or N; X = O, S, NH, SO, SO2 or a single bond; Y, Y1-​Y3 = (independently) (un)​substituted alkanediyl or alkenediyl, or a single bond; R1 = H or alkyl; R2 = H, OH, halo and alkyl; R3 = H, alkyl, cycloalkyl, haloalkyl, halo; R5 = H or alkyl; or R2 and R5 taken together form alkanediyl bridge; R6 = H, alkyl, cycloalkyl, heterocycloalkyl, etc.; each of R7 and R8 = (independently) H, (un)​substituted alkyl, aryl, heteroaryl, etc.; or R7 and R8 form together with the nitrogen atom to which they are attached a cyclic amine selected from aziridine, azetidine, pyrrolidine, etc.; R, Ra, Rb, Rc = (independently) H, halo, CN, alkyl, etc.] or pharmaceutically acceptable salts, tautomers, solvates or stereoisomers thereof, that are inhibitors of hepatitis B virus (HBV)​. For example, reacting cis-​7-​methyl-​N-​(3,​4,​5-​trifluorophenyl)​-​2,​3,​3a,​4,​10,​10a-​hexahydro-​1H,​7H-​dipyrrolo[3,​4-​b:3',​4'-​f]​[1,​4,​5]​oxathiazocine-​8-​carboxamide 5,​5-​dioxide hydroiodide with N,​N-​dimethyloxamic acid afforded cis-​II. The exemplified compds. I were tested for HBV inhibition (data given)​. Compds. I are useful alone or in combination with other agents for treating, ameliorating, preventing or curing HBV infection and related conditions. The present invention also relates to pharmaceutical compns. contg. said compds. I.