(RS/SR)-2-Oxo-4-phenylazetidin-3-yl acetate

In the title compound, C11H11NO3, a modified synthetic acetate derivative, the four memebered β-lactam ring is roughly planar, with a maximum deviation of 0.21 (3) Å, and makes a dihedral angle of 81.46 (14)° with the phenyl ring. In the crystal, a single N—H⋯O hydrogen bond links molecules into a chain parallel to the a axis and thus stabilizes the structure. Although the absolute configuration could not be reliably determined, the compound corresponds to the diasteroisomer (RS/SR)

In the title compound, C 11 H 11 NO 3 , a modified synthetic acetate derivative, the four memebered -lactam ring is roughly planar, with a maximum deviation of 0.21 (3) Å , and makes a dihedral angle of 81.46 (14) with the phenyl ring. In the crystal, a single N-HÁ Á ÁO hydrogen bond links molecules into a chain parallel to the a axis and thus stabilizes the structure. Although the absolute configuration could not be reliably determined, the compound corresponds to the diasteroisomer (RS/SR)

Comment
Recently, lactams have attracted much attention because they are convenient intermediates for semi-synthesis of the antitumour drug Taxol and other bioactive analogues (Kanazawa et al., 1993). Furthermore, the lactam ring (azetidin-2-one) is considered a general 'lead structure' for the design of new inhibitors of enzymes containing a serine nucleophile in the active site (Deschamps et al., 2003). In an attempt to form a Zn(II) complex with title compound, we adventitiously formed the title compound (I) and its crystal structure is determined herein.
The molecular structure of (I) is illustrated in Fig. 1. It is very similar to the related 4-(4-Nitrophenyl)-3-phenoxyazetidin-2-one (Akkurt et al., 2007). The geometry of the β-lactam ring is is planar, with a maximum deviation of 0.21 (3)° for atom N1. It makes dihedral angles of 81.46 (14)° with its phenyl substituent. The lactam ting is also comparable with a related reported structure (Selvanayagam et al., 2005). Although the absolute configuration couldn't be reliably determined, the compound correspond to the diasteroisomer (RS/SR).
Intermolecular N-H···O hydrogen bonds form a zig-zag like chain parallel to the a axis and thus stabilize the structure.

Refinement
In the absence of significant anomalous scattering, the absolute configuration could not be reliably determined and then the Friedel pairs were merged and any references to the Flack parameter were removed.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.