Methyl 11-hydroxy-9-[1-(4-methoxyphenyl)-4-oxo-3-phenoxyazetidin-2-yl]-18-oxo-10-oxa-2-azapentacyclo[9.7.0.01,8.02,6.012,17]octadeca-12(17),13,15-triene-8-carboxylate

In the title compound, C34H32N2O8, one of the pyrrolidine rings in the pyrrolizidine ring system adopts a twist conformation, whereas the other ring adopts an envelope conformation (C atom as flap). The five-membered ring in the indene ring system and the fused furan ring also adopt envelope conformations (C and O atoms as flaps, respectively). The β-lactam ring makes dihedral angles of 23.41 (2) and 25.98 (2)°, respectively, with the attached methoxyphenyl and phenoxy rings. The molecular conformation is stabilized by an intramolecular O—H⋯N hydrogen bond, generating an S(5) motif. In the crystal, molecules are linked into C(12) chains running along the a axis by C—H⋯O hydrogen bonds. The structure is further consolidated by weak intermolecular C—H⋯π and π–π interactions [centroid–centroid distance = 3.7987 (14) Å].

In the title compound, C 34 H 32 N 2 O 8 , one of the pyrrolidine rings in the pyrrolizidine ring system adopts a twist conformation, whereas the other ring adopts an envelope conformation (C atom as flap). The five-membered ring in the indene ring system and the fused furan ring also adopt envelope conformations (C and O atoms as flaps, respectively). The -lactam ring makes dihedral angles of 23.41 (2) and 25.98 (2) , respectively, with the attached methoxyphenyl and phenoxy rings. The molecular conformation is stabilized by an intramolecular O-HÁ Á ÁN hydrogen bond, generating an S(5) motif. In the crystal, molecules are linked into C(12) chains running along the a axis by C-HÁ Á ÁO hydrogen bonds. The structure is further consolidated by weak intermolecular C-HÁ Á Á andinteractions [centroid-centroid distance = 3.7987 (14) Å ].
The molecular structure of the title compound is stabilized by a strong O5-H5A···N2 hydrogen bond, generating an S(5) motif (Bernstein et al., 1995). The H-atom bonded to C15 is involved in hydrogen bonding with atom O6 forming a C(12) chain running along the a axis (Tab. 1 & Fig. 2). A weak intermolecular C-H···π interaction involving the C12-H12 group and the C1-C16 phenoxy ring is also observed.

Experimental
To a reaction mixture of 2-(hydroxy(1-(4-methoxyphenyl)-4-oxo-3-phenoxyazetidin -2-yl)methyl)acrylate (1 mmol), ninhydrine (1.1 mmol) and proline (1.1 mmol) were refluxed in methanol until completion of the reaction was evidenced by TLC analysis. After completion of the reaction the solvent was evaporated under reduced pressure. The crude reaction mixture was dissolved in dichloromethane and washed with water followed by brine solution. The organic layer was separated and dried over sodium sulfate. Filtering and evaporation of the organic solvent under reduced pressure were carried out. The product was separated by column chromatography using hexane and ethyl acetate (3: 7) as an eluent to give colorless solid. The product was dissolved in chloroform and heated for two minutes. The resulting solution was subjected to crystallization by slow evaporation of the solvent resulting in single crystals of the title compound suitable for XRD studies.

Refinement
The H atoms were positioned geometrically with O-H = 0.82 Å and C-H = 0.93, 0.96, 0.97 and 0.98 Å for aryl, methyl, methylene and methyne H atoms, respectively, and constrained to ride on their parent atoms, with U iso (H) = 1.5U eq (methyl C/O) or 1.2U eq (non-methyl C).

Computing details
Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).    Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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.