Crystal structure of ethyl 2-(2-{1-[N-(4-bromophenyl)-2-oxo-2-phenylacetamido]-2-tert-butylamino-2-oxoethyl}-1H-pyrrol-1-yl)acetate

In the title compound, C28H30BrN3O5, there is an intramolecular N—H⋯O hydrogen bond and an intramolecular C—H⋯O hydrogen bond, both forming S(9) ring motifs. The planes of the 4-bromophenyl ring and the phenyl ring are inclined to that of the pyrrole ring by 48.05 (12) and 77.45 (14)°, respectively, and to one another by 56.25 (12)°. In the crystal, molecules are linked via C—H⋯O hydrogen bonds and C—H⋯π interactions, forming slabs parallel to (10-1).

Tetsuji Moriguchi, Venkataprasad Jalli, Suvratha Krishnamurthy, Akihiko Tsuge and Kenji Yoza S1. Comments Pyrrole and its derivatives are important classes of heterocyclic compounds because of their important biological and pharmacological properties. They have been shown to have important biological properties, such as antibacterial (Daidone et al., 1990), anti inflammatory (Kaiser & Glenn, 1972), antitumor (Meshram et al., 2010), and immune suppressant activities (Davis et al., 2008). Pyrrole analogs are important components in naturally occurring bio molecules such as heme, chlorophyll, vitamin B12 and pyrrole alkaloids isolated from marine sources. Highly functionalised pyrroles are found in drug molecules such as Atorvastatin, Ketorolac and Sunitinib. Thus, the elucidation of the crystal structures of pyrrole derivatives has attracted much attention. Here, we report on the crystal structure of the racemic title compound, synthesized by a four component one pot reaction, involving pyrrole-1-acetic acid-2-formyl ethyl ester, 4bromo aniline, phenyl glyoxylic acid and tert-butyl isocyanide.
In the title compound, Fig. 1, there is an intramolecular N-H···O hydrogen bonding forming an S(9) ring motif. There is also intramolecular C-H···O hydrogen bonding which also forms an S(9) ring motif. The 4-bromophenyl ring and the phenyl ring are inclined to the pyrrole ring by 48.05 (12) and 77.45 (14) °, respectively, and to one another by 56.25 (12) °.
In the crystal, molecules are linked via C-H···O hydrogen bonds and C-H···π interactions forming slabs parallel to (101); see Table 1 and Fig. 2.

S2. Synthesis and crystallization
The reaction scheme for the synthesis of the title compound is illustrated in Fig. 3. A mixture of pyrrole-1-acetic acid-2formyl ethylester (2 mmol), 4-bromoaniline (2 mmol), phenylglyoxylic acid (2.2 mmol) and τ-butyl-isocyanide (2 mmol) were taken in 10 ml of MeOH and stirred at room temperature for 18 h. The volatiles were removed under reduced pressure and the pure product was isolated by column chromatography, using 30% EtOAc/Hexane, as a white coloured solid. Colourless prismatic crystals of the title compound suitable for X-ray analysis were obtained by slow evaporation of a methanol solution at room temperature. The compound crystalized in the racemic form.

S3. Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2    Crystal packing of the title compound, viewed along the b axis, with the hydrogen bonds shown as dashed lines (see Table 1). H atoms not involved in these reactions have been omitted for clarity.

Figure 3
Reaction scheme for the synthesis of the title compound.

Ethyl 2-(2-{1-[N-(4-bromophenyl)-2-oxo-2-phenylacetamido]-2-tert-butylamino-2-oxoethyl]-1H-pyrrol-1yl)acetate
Crystal data where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.56 e Å −3 Δρ min = −0.38 e Å −3 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.