Different intra- and inter­molecular hydrogen-bonding patterns in (3S,4aS,8aS)-2-[(2R,3S)-3-(2,5-X (2)-benzamido)-2-(2,5-X (2)-benzo­yloxy)-4-phenyl­butyl]-N-tert-butyldeca­hydro­iso­quinoline-3-carboxamides (X = H or Cl): compounds with moderate aspartyl protease inhibition activity

The crystal structures of (3S,4aS,8aS)-2-[(2R,3S)-3-benzamido-2-benzo­yloxy-4-phenyl­but­yl]-N-tert-butyldeca­hydro­iso­quinoline-3-carboxamide, C(38)H(47)N(3)O(4), (I), and (3S,4aS,8aS)-2-[(2R,3S)-3-(2,5-di­chloro­benzamido)-2-(2,5-di­chloro­benzo­yloxy)-4-phenyl­but­yl]-N-tert-butyldeca­hydro­iso­quinoline-3-carboxamide, C(38)H(43)Cl(4)N(3)O(4), (II), are described. Despite their chemical similarity, they adopt different conformations in the solid state: (I) features a bifurcated intra­molecular N—H⋯(N,O) hydrogen bond from the tert-butylamide NH group to the piperidine N atom and the benzoate O atom, whereas (II) has an intra­molecular N—H⋯O link from the benzamide NH group to the tert-butyl­amide O atom. In the crystal of (I), mol­ecules are linked by C(4) amide N—H⋯O hydrogen bonds into chains propagating in the [010] direction, with both donor and acceptor parts of the benzamide group. In the extended structure of (II), C(11) N—H⋯O chains propagating in the [010] direction arise, with the donor being the tert-butylamide NH group and the acceptor being the O atom of the benzamide group.