3-Chloroazepan-2-one

In the title compound, C6H10ClNO, an intermediate for the production of lysine, there are intramolecular C—H⋯Cl hydrogen bonds.

In the title compound, C 6 H 10 ClNO, an intermediate for the production of lysine, there are intramolecular C-HÁ Á ÁCl hydrogen bonds.
The molecular structure of (I) is shown in Fig. 1. A packing diagram of (I) is shown in Fig. 2, where the dash line indicates C-H···Cl hydrogen bond.
Experimental 18.2 g (100 mmol) 3,3-dichloro-2-oxohexamethyleneimine, 2 g. 5% palladium-on-charcoal and 18 g. (220 mmol) sodium acetate were added into 100 ml glacial acetic acid. The mixture was placed in in a shaker under hydrogen (2 atm. initial pressure) until one equivalent of hydrogen was absorbed. The catalyst and sodium chloride were removed by filtration. The filtrate was neutralized and extracted with chloroform and concentrated, and then recrystallized by n-hexane to give 18.1g white solid (87.4%). (Wineman et al., 1958) Pure compound (I) was obstained by crystallizing from acetic acid. Crystals of (I) suitable for X-ray diffraction were obstained by slow evaporation of an ethanol solution.

Refinement
All H atoms bonded to the C atoms were placed geometrically at the distances of 0.93-0.97 Å, and included in the refinement in riding motion approximation with U iso (H) = 1.2 or 1.5U eq of the carrier atom. Fig. 1. The molecular structure of (I), showing the atom-numbering scheme and displacement ellipsoids at the 30% probability level.

Figures
supplementary materials sup-2  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 Rfactors(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.