Abstract: Processes are provided which create an aldehyde methylene, or hydrated or hemiacetal methylene attached to a heteroatom of a 6 membered ring without going through an olefinic group and without the necessity of using an osmium reagent. In particular, a compound of formula (I) can be produced from (II) and avoid the use of an allyl amine: (formulae I and II) where R, P1 P3, R3 and Rx are as described herein.

Abstract: The present Invention relates to pharmaceutical compositions of (3S,11aR)-N-[(2,4-difluorophenyl)methyl]-2,3,5,7,11,11a-hexahydro-6-hydroxy-3-methyl-5,7-dioxo-oxazolo[3,2-a]pyrido[1,2-d]pyrazine-8-carboxamide, useful in the treatment or prevention of Human Immunodeficiency Virus (HIV) infections.

Abstract: The present invention is to provide a novel compound (I) shown below, having the anti-virus activity, particularly the HIV integrase inhibitory activity, and a drug containing the same, particularly an anti-HIV drug, as well as a process and an intermediate thereof. (wherein Z1 is NR4; R1 is hydrogen or lower alkyl; X is a single bond, a hetero atom group selected from O, S, SO, SO2 and NH, or lower alkylene or lower alkenylene in which the hetero atom group may intervene; R2 is optionally substituted aryl; R3 is hydrogen, a halogen, hydroxy, optionally substituted lower alkyl etc; and R4 and Z2 part taken together forms a ring, to form a polycyclic compound, including e.g., a tricyclic or tetracyclic compound.

Abstract: The present invention is directed to a substituted 2,3,5,7,11,11a-hexahydro[1,3]oxazolo[3,2 -a]pyrido[1,2-d]pyrazine-5,7-dione useful as an anti-HIV agent, which has the formula: as well as pharmaceutically acceptable salts thereof, compostions thereof, and methods of use thereof.