2-[(3R,6R)-6-Methyl-2,5-dioxomorpholin-3-yl]-N-(propan-2-yl)acetamide

The molecular conformation of the title compound, C10H16N2O4, is determined by an intramolecular N—H⋯O hydrogen bond involving the morpholine NH group and the amide O atom. In the crystal, molecules are linked by N—H⋯O hydrogen bonds into chains along the a-axis direction.

The molecular conformation of the title compound, C 10 H 16 N 2 O 4 , is determined by an intramolecular N-HÁ Á ÁO hydrogen bond involving the morpholine NH group and the amide O atom. In the crystal, molecules are linked by N-HÁ Á ÁO hydrogen bonds into chains along the a-axis direction.

Related literature
For the synthesis of polydepsipeptides, see: Feng et al. (2002); Hughes & Sleebs (2005); In 't Veld et al. (1992't Veld et al. ( ,1994; Jö rres et al. (1998). For the synthesis of title compound, see: Wang & Feng (1997 Table 1 Hydrogen-bond geometry (Å , ).  Polydepsipeptides, copolymers of α-hydroxy acids and α-amino acids, are the most important representatives of biodegradable polyesteramides. Morpholine-2,5-dione derivatives are a series of monomers which were used to synthesize polydepsipeptides via ring-opening polymerization. (In't Veld et al., 1992,1994. In recent years, all kinds of functional groups are introduced into these monomers in order to synthesize functional polydepsipeptides (Feng et al., 2002;Jörres et al., 1998;Hughes & Sleebs, 2005). In our current research, related to this topic, we have designed and synthesized the title compound, which includes the isopropyl amide functional group (Fig. 1). In the crystal structure of the title compound, C 10 H 16 N 2 O 4 , there are two kinds of hydrogen bonds, one is intramolecular N-H···O [H···O = 2.09 (3) Å] hydrogen bond, the other is intermolecular N-H···O [H···O = 2.11 (3) Å] hydrogen bond which links molecules into the one-dimensional chains along the a-axis direction (Fig. 2).

Experimental
All reagents used in the syntheses were of analytical grade and used without further purification. The title compound was prepared according to the literature method (Wang & Feng, 1997). Single crystals were grown from ethyl acetate solution by slow evaporation at room temperature.

Refinement
All H atoms were placed in calculated positions, with C-H distances ranging from 0.96 to 0.98 Å, and N-H distances ranging from 0.82 to 0.85 Å. They were refined in the riding-model approximation, with U iso (H) = 1.2U eq (carrier C, N) or U iso (H) = 1.5U eq (C of methyl group).

Figure 2
The hydrogen-bonded chain in the structure of title compound. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.13 e Å −3 Δρ min = −0.13 e Å −3 Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.