Methyl 11-hydroxy-9-[1-(4-methoxyphenyl)-4-oxo-3-phenylazetidin-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, C34H32N2O7, the furan ring adopts a twist conformation and both the pyrrolidine rings adopt envelope conformations with O and C as flap atoms. The β-lactam ring makes a dihedral angles of 80.20 (10)° with the furan ring, of 75.55 (10)° with the pyrrolidine ring, of 12.26 (10)° with the methoxyphenyl ring and of 73.77 (13)° with the phenyl ring. The O atom attached to the β-lactam ring deviates by 0.0385 (13) Å from the ring plane. The molecular conformation is stabilized by intramolecular O—H⋯N and C—H⋯O hydrogen bonds. The packing of the crystal is stabilized by intermolecular C—H⋯O hydrogen bonds, which form a chain running along the b axis.

In the title compound, C 34 H 32 N 2 O 7 , the furan ring adopts a twist conformation and both the pyrrolidine rings adopt envelope conformations with O and C as flap atoms. Thelactam ring makes a dihedral angles of 80.20 (10) with the furan ring, of 75.55 (10) with the pyrrolidine ring, of 12.26 (10) with the methoxyphenyl ring and of 73.77 (13) with the phenyl ring. The O atom attached to the -lactam ring deviates by 0.0385 (13) Å from the ring plane. The molecular conformation is stabilized by intramolecular O-HÁ Á ÁN and C-HÁ Á ÁO hydrogen bonds. The packing of the crystal is stabilized by intermolecular C-HÁ Á ÁO hydrogen bonds, which form a chain running along the b axis.

Crystal data
Both the pyrrolidine rings adopt an envelope conformation and the furan ring adopts a twist conformation. The furan ring makes a dihedral angle of 81.29 (8)° with the pyrrolidine ring, a dihedral angle of 72.61 (9)° with the other pyrrolidine ring(N2/C29/C30/C31/C32). The furan ring makes a dihedral angle of 72.26 (8)° with the cyclopentane ring(C19/C20/C21/C26/C27) system. The oxygen atom (O1) attached with the β lactam ring deviates by 0.0385 (13)Å from the ring plane. The hydroxyl oxygen atom (O4) attached with the furan ring deviates by -0.6644 (11)Å from the ring plane. The oxygen atom (O5) attached to the cyclopentane ring deviates by 0.2042 (13)Å from the ring plane. The molecular conformation is stabilized by an intramolecular O-H···N and C-H···O hydrogen bonds. The packing of the crystal is stabilized by intermolecular C-H···O hydrogen bonds (Fig. 2).

Experimental
A mixture of methyl 2-(hydroxy(1-(4-methoxyphenyl)-4-oxo-3-phenylazetidin-2-yl) methyl)acrylate (1.0 equiv.), ninhydrin (1.1 equiv.) and proline (1.1 equiv.) was refluxed in methanol. Completion of the reaction was evidenced by TLC analysis. After completion of the reaction the solvent was evaporated under reduced pressure. The reaction mixture was dissolved in dichloromethane and with water followed by brine solution. The organic layer was separated and evaporated under reduced pressure. The crude mixture was purified by column chromatography using ethyl acetate and hexane as eluent (3: 7). The product was dissolved in chloroform and heated for two minutes. The resulting solution was subjected to crystallization by slow evaporation of the solvent for 48 hours resulting in the formation of single crystals.

Refinement
The hydrogen atoms bonded to carbon atoms were placed in calculated positions with C-H = 0.93 Å to 0.97 Å. They were refined using a riding model with fixed isotropic displacement parameters: U iso (H) = 1.5U eq (C) for methyl groups and U iso (H) = 1.2U eq (C) for other H atoms. The hydroxyl H atom was freely refined.

Figure 1
The molecular structure of the title compound, showing displacement ellipsoids drawn at the 30% probability level. H atoms are presented as a small spheres of arbitrary radius.

Figure 2
The crystal packing of the title compound viewed down b axis. H-atoms not involved in H-bonds have been excluded for clarity.

Methyl 11-hydroxy-9-[1-(4-methoxyphenyl)-4-oxo-3-phenylazetidin-2-yl]-18-oxo
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.