Crystal and Molecular Structure of N-[ 2-( 6-Methoxy-2-oxo-2 H-Chromen-4-yl-Benzofuran-3-yl ]-Benzamide

The crystal structure of the potential active N-[2-(6-Methoxy-2-oxo-2H-chromen-4-yl)-benzofuran-3-yl]-benzamide (C25H17NO5) (I) has been determined from single crystal X-ray diffraction data. The title compound crystallizes in the monoclinic space group P 21/n, with a = 12.0551(11), b = 9.7853(8), c = 16.6517(16) Å, β = 90.092(4) ̊, V = 1964.28(3) Å, Dcalc = 1.391 Mg/m, Z = 4. In the structure, intermolecular H-bonds lead to the formation of a centrosymmetric dimer of the molecule. There is an intramolecular C7—H7...N1 hydrogen bond forming a closed seven membered ring. There are also intramolecular π-π interactions presented between the 3,6-Dihydro-2H-pyran ring of the chromen moiety [Cg2...Cg2 distance = 3.5812(13) Å]. The packing structure is stabilized by these C—H...N, N—H...O hydrogen bonds, C—H... π and π...π interactions.


Introduction
The amide and sulfonamide moieties are the constituents of many biologically important compounds [1].Coumarin derivatives are known to be an interesting class of natural or synthetic compounds, whose biological activity varies according to the substitutes on the benzopyran ring.Their antibacterial, antifungal, antitumor, anti-HIV and anti-inflammatory and analgesic activities have been published [2].Benzamide derivatives, known for their anti-inflammatory and immunomodulatory, anti-tumoral, antipsychotic and antiallergic activities, are drugs widely used in medicine [3].Benzanilides and benzamides exhibit wide range of biological activity and are extensively used in organic synthesis.Various N-substituted benzamides exhibit potent antiemetic activity [4].The benzanilide core is presented in compounds with such a wide range of biological activities that it has been called a privileged structure.Benzanilides have established their efficacy as centroid elements of ligands that bind to a wide variety of receptor types.Thus benzanilides containing aminoalkyl groups originally designed as a peptidomimetic, have been incorporated in an Arg-Gly-Asp cyclic peptide yielding a high affinity GΠIb/IIIa ligand.Imatinib is an ATP-site binding kinase inhibitor and platelet-derived growth factor receptor kinases.Pyridylmethyl containing benzanilide are vascular endothelial growth factor receptor and tyrosine kinase inhibitor.Furthermore, benzamides have been reported to have activities as acetyl-CoA carboxylase and farnesyl transferase inhibitors [5].N-substituted benzamides are well known anticancer compounds and the mechanism of action for N-substituted benzamide-induced apoptosis has been studied, using declopramide as a lead compound.N-substituted benzamides inhibit the activity of nuclear factor-B and nuclear factor of activated T cells activity while inducing activator protein 1 activity in T lymphocytes.Various N-substituted benzamides exhibit potent antiemetic activity, while heterocyclic analogs of benzanilide derivatives are potassium channel activators.O-Aryloxylation of N-substituted benzamides induced by the copper (II)/trimethylamine N-oxide system has been studied.N-Alkylated 2-nitrobenzamides are intermediates in the synthesis of dibenzo[b,e] [1,4] diazepines and N-Acyl-2-nitrobenzamides are precursors of 2,3-disubstitued 3Hquinazoline-4-ones.A one-pot conversion of 2-nitro-narylbenzamides to 2,3-dihydro-1H-quinazoline-4-ones has also been reported [6].As a part of studying the ring and side-chain substitutions on the crystal structures of chemically and biologically important class of compounds such as benzanilides, we report herein the crystal struc-G.ANURADHA ET AL. 108 ture of the title compound (I).

Synthesis of the Title Compound
A suspension of 0.01 mole of 4-(3'-amino-2'-benzo (b) furanyl) coumarin and 8ml of benzoyl chloride was heated and stirred at 80˚C for about 45 minutes.The mixture was cooled and solid separated was washed thoroughly with cold water and then with ethyl acetate to give sufficiently pure product.The compound is crystallised in alcohol, yield 93%, melting point 204˚C.The compound is recrystallized from ethanol to get good quality single crystals.

X-Ray Crystallography
For the crystal structure determination, the single crystal of the compound C 25 H 17 NO 5 was used for data collection on a Bruker Kappa APEXII CCD diffractometer [7].The MoKα radiation of wavelength, (λ = 0.71073 Å) and multi-scan technique for absorption correction were used for data collection.The lattice parameters were determined by the least-squares methods on the basis of all reflections with F 2 > 2σ (F 2 ).The structures were solved by direct methods using SHELXS-97 and refined by a full-matrix least-squares procedure using the program SHELXL-97 [8,9].H atoms were positioned geometrically and refined using a riding model, fixing the aromatic C-H distances at 0.93 Å [U iso (H) = 1.2 U eq (C)].The softwares used for Molecular graphics are ORTEP-3 for Windows [10] and PLATON [11].The software used to prepare material for publication is WinGX publication routines [12].Chemical structure of the title compound is shown in

Conclusion
The N-substituted benzamide derivatives have been reviewed for antibacterial, anti-inflammatory, analgesic and antiulcer actions.Pharmaceutical compositions of amide derivatives are used as, therapeutic agents for hypertension, angina, pectoris, asthma, renal and peripheral circulatory disturbances and inhibitors of vasospasm.The compounds are useful where cell death is due to trauma, viral infection, neurodegenerative disorder, cardiovascular disease, immune deficiency disorder, autoimmune disorder, renal disease, syndromes or pancreatitis.Substituted benzamides are acting as inhibitors of HIV protease [13].These reported points are very useful to understand the benefit functions of the substituted benzamides in general.The title compound belongs to a class of 4-2'-benzofuranyl coumarins, the methoxy derivatives of which have exhibited potential anti inflammatory activity [14].Further the 6-methoxy group is well known to undergo biotransformation to the corresponding 6-hydroxy coumarin possessing a phenolic group which enhances its ability of binding with biomolecules which is the basis of its pharmacological activity.The N-benzoyl moiety will also undergo cleavage to generate  investigation carried out was quite interesting by the zigzag packing of the dimers formed due to the two different orientations (Figures 2(a) and (b)) of the benzoyl group and the benzofuran ring.The amide was adopting the S-trans configuration and the packing diagram revealed a rare type of dimeric linkage between the lactone carbonyl and the amide N-H bond.The compound characterized can be essential in medicinal and biological applications.The title structure may be important from a medicinal point of view as well as their widespread biological significance.The structure may be useful for further investigation on the mechanism, potential activity, optimal reaction condition etc.

Figure 1 .
Molecular structure of the compound showing the atomic numbering scheme is shown in Figure 2(a).The crystallography details for the structures determination of the compound are presented in

Figure 1 .
Figure 1.Chemical structure of the title compound.

Figure 2 .
Figure 2. (a): Molecular structure of the title compound showing the atomic numbering system; (b): Molecular structure with different orientation of benzoyl group and benzofuran ring.Displacement ellipsoids are drawn at the 50% probability level.

Figure 3 .
Figure 3. (a): Formation of centrosymmetric dimers; π-π interaction shown as dotted line; (b): Part of the crystal structure of the compound, showing formation of a centrosymmetric R 2 2 (16) dimmer; (c): Packing diagram, showing infinite chains running along the b-axis direction.Hydrogen bonds are shown as dashed lines.For the sake of clarity H atoms not involved in the motif shown have been omitted.

Figure 4 .
Figure 4. Packing diagram and H bonding geometry along the a-axis [symmetry code: 2 -x, -y, -z].H atoms not involved in these interactions have been omitted for clarity.

Table 7 . Hydrogen bonds [Å and ˚], Cg4 is the centroid of the C13-C18 ring; Cg5 is the centroid of the C20-C25 ring.
Note: Symmetry transformations used to generate equivalent atoms: