The effect of hydrogen bonding on the conformations of 2-(1H-indol-3-yl)-2-oxoacetamide and 2-(1H-indol-3-yl)-N,N-dimethyl-2-oxoacetamide

In the title compounds, C₁₀H₈N₂O₂, (I), and C₁₂H₁₂N₂O₂, (II), the two carbonyl groups are oriented with torsion angles of -149.3 (3) and -88.55 (15)°, respectively. The single-bond distances linking the two carbonyl groups are 1.528 (4) and 1.5298 (17) Å, respectively. In (I), the mol­ecules are linked by an elaborate system of N-H...O hydrogen bonds, which form adjacent R²₂(8) and R⁴₂(8) ring motifs to generate a ladder-like construct. Adjacent ladders are further linked by N-H...O hydrogen bonds to build a three-dimensional network. The hydrogen bonding in (II) is far simpler, consisting of helical chains of N-H...O-linked mol­ecules that follow the 2₁ screw of the b axis. It is the presence of an elaborate hydrogen-bonding system in the crystal structure of (I) that leads to the different torsion angle for the orientation of the two adjacent carbonyl groups from that in (II).

Oxycodone N-oxide

The title compound, (5R,9R,13S,14S,17R)-14-hy­droxy-3-meth­oxy-17-methyl-4,5-ep­oxy­morphinan-6-one N-oxide, C₁₈H₂₁NO₅, has been prepared in a diastereomerically pure form by the reaction of oxycodone with 3-chloro­perbenzoic acid and subsequent crystallization of the product from chloro­form. The crystal packing shows that the mol­ecule exhibits intra­molecular O-H...O [D...A = 2.482 (2) Å] hydrogen bonding. In addition, there are weak inter­molecular C-H...O inter­actions which, along with van der Waals forces, stabilize the structure. The new chiral center at the 17-position is demonstrated to be R.