Methyl 3-(4-bromophenyl)-2-(1H-indol-3-ylmethyl)-5-[1-(4-methoxyphenyl)-4-oxo-2-phenylazetidin-2-yl]-4-nitropyrrolidine-2-carboxylate

In the title compound, C37H33BrN4O6, the pyrrolidine ring adopts an envelope conformation. The β-lactam ring is planar and makes dihedral angles of 70.16 (13) and 28.32 (13)° with the phenyl and 4-methoxyphenyl rings, respectively. The molecular packing is stabilized by intramolecular C—H⋯O interactions and the crystal packing is determined by intermolecular N—H⋯O hydrogen bonds, and C—H⋯O and C—H⋯π interactions.

The bond lengths and angles in I are agree with those observed in a similar structure (Sundari Bhaskaran et al., 2006;Kamala et al., 2008). The β-lactam ring is planar with its internal angles in the range 84.4 (2) to 95.5 (2)°. The C-C-C bond angle in the β-lactam ring is comparable to the values in related reported structures (Ulku et al., 1997). The bond N4?C16, is shorter than the bond lengths, N4-C14 and N4-C17 and is close to the length of a double bond, a feature observed in β-propiolactam (Yang et al., 1987) and where C and N are sp 2 hybridized.
In the crystal structure of I (Fig.2), adjacent molecules are linked by N-H···O and C-H···O hydrogen bonds into chains.

Experimental
The β-lactam aldehyde (1 mol) was treated with tryptophanmethylester hydrochloride (1 mol) in the presence of Et 3 N (2.5 mol) and anhydrous MgSO 4 (2 g) in dry dichloromethane (10 ml) at room temperature for 12 h to give the imine. The imine was washed with water and dried over Na 2 SO 4 . The solvent was evaporated under vacuum. The imine (1 mol) was then strirred with silver(I) acetate and p-bromo nitrostyrene (1 mol) in the presence of Et 3 N (1.2 mol) and molecular sieves in dry toluene (30 ml) at room temperature for 12 h. The reaction mixture was filtered through a plug celite. The solvent was supplementary materials sup-2 evaporated under reduced pressure and the residue was subjected to column chromatography on silica gel (100-200 mesh), with hexane-ethyl acetate (7:3) as eluent to give the product. The compound was recrystallized from ethyl acetate.

Refinement
H atoms were placed in idealized positions and allowed to ride on their parent atoms, with C-H = 0.93, 0.98, 0.97 and 0.96 Å for aromatic, methine, methylene and methyl H respectively, and N-H = 0.86 Å, and with U iso (H) = 1.5i>U eq (C) for methyl and U iso (H) = 1.2i>U eq (parent C, N) for all other H atoms.     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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C1