Provided are a compound represented by general formula (I), or the pharmaceutically acceptable salt thereof,
(wherein R
a
represents a hydrogen atom or the like, R
1
and R
2
may be the same or different, and each represents a hydrogen atom, optionally substituted lower alkyl or cycloalkyl, or R
1
and R
2
are combined together with the adjacent nitrogen atom thereto to form nitrogen-containing heterocyclic group, and Z represents a bicyclic heterocyclic group in which optionally substituted two six-membered rings are fused to each other, or the like) and the like.
This invention relates to novel compounds that are azapeptides, and pharmaceutically acceptable salts thereof. More specifically, the invention relates to novel azapeptide compounds that are derivatives of the HIV protease inhibitor atazanavir sulfate. This invention also provides pyrogen-free compositions comprising one or more compounds of the invention and a carrier, and the use of the disclosed compounds and compositions in methods of treating diseases and conditions that are treated by administering HIV protease inhibitors. The invention also relates to the use of one or more of the disclosed compounds as reagents in analytical studies involving atazanavir.