Ethyl 2-amino-4-(4-bromo­phen­yl)-6-meth­oxy-4H-benzo[h]chromene-3-carboxyl­ate

Ahmed M El-Agrody; Ahmed M Fouda; Mohamed A Al-Omar; Abd El-Galil E Amr; Seik Weng Ng; Edward R T Tiekink

doi:10.1107/S160053681300490X

. 2013 Feb 23;69(Pt 3):o435–o436. doi: 10.1107/S160053681300490X

Ethyl 2-amino-4-(4-bromophenyl)-6-methoxy-4H-benzo[h]chromene-3-carboxylate

Ahmed M El-Agrody ^a,^b, Ahmed M Fouda ^a, Mohamed A Al-Omar ^c,^d, Abd El-Galil E Amr ^d,^e,^‡, Seik Weng Ng ^f,^g, Edward R T Tiekink ^f,^*

PMCID: PMC3588478 PMID: 23476606

Abstract

In the title compound, C₂₃H₂₀BrNO₄, the pyran ring has a flattened boat conformation with the O and methine C atoms lying to one side of the plane [0.160 (5) and 0.256 (6) Å, respectively] defined by the remaining atoms. Nevertheless, the 4H-benzo[h]chromene ring system approximates a plane (r.m.s. deviation = 0.116 Å) with the bromobenzene ring almost perpendicular [dihedral angle = 83.27 (16)°] and the ester group coplanar [C—C—C—O = 3.4 (5)°]; the methoxy substituent is also coplanar [C—O—C—C = 174.5 (3)°]. In addition to an intramolecular N—H⋯O(ester carbonyl) hydrogen bond, the ester carbonyl O atom also forms an intermolecular N—H⋯O hydrogen bond with the second amine H atom, generating a zigzag supramolecular chain along the c axis in the crystal packing. The chains are linked into layers in the bc plane by N—H⋯Br hydrogen bonds, and these layers are consolidated into a three-dimensional architecture by C—H⋯π interactions.

Related literature

For background to the pharmaceutical activity of 4H-chromene and its derivatives, see: Abd-El-Aziz et al. (2004 ▶, 2007 ▶); Kemnitzer et al. (2007 ▶); Alvey et al. (2009 ▶). For the isostructural 4-fluoro analogue, see: El-Agrody et al. (2012 ▶).

Experimental

Crystal data

C₂₃H₂₀BrNO₄
M _r = 454.31
Monoclinic,
a = 13.1543 (14) Å
b = 16.8110 (18) Å
c = 9.3672 (12) Å
β = 96.628 (10)°
V = 2057.6 (4) Å³
Z = 4
Mo Kα radiation
μ = 2.03 mm⁻¹
T = 295 K
0.30 × 0.20 × 0.03 mm

Data collection

Agilent SuperNova Dual diffractometer with an Atlas detector
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011 ▶) T _min = 0.828, T _max = 1.000
12041 measured reflections
4740 independent reflections
2533 reflections with I > 2σ(I)
R _int = 0.054

Refinement

R[F ² > 2σ(F ²)] = 0.060
wR(F ²) = 0.164
S = 1.02
4740 reflections
270 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.91 e Å⁻³
Δρ_min = −0.90 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2011 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶) and DIAMOND (Brandenburg, 2006 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Click here for additional data file.^{(22.6KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S160053681300490X/hg5295sup1.cif

e-69-0o435-sup1.cif^{(22.6KB, cif)}

Click here for additional data file.^{(232.2KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681300490X/hg5295Isup2.hkl

e-69-0o435-Isup2.hkl^{(232.2KB, hkl)}

Click here for additional data file.^{(7.5KB, cml)}

Supplementary material file. DOI: 10.1107/S160053681300490X/hg5295Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

Cg1, Cg2 and Cg3 are the centroids of the C1,C2,C7–C10, C17–C22 and C2–C7 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H2⋯O2	0.88 (1)	2.09 (5)	2.744 (5)	131 (5)
N1—H1⋯O2ⁱ	0.88 (1)	2.22 (2)	3.075 (5)	163 (3)
N1—H2⋯Br1ⁱⁱ	0.88 (4)	2.76 (4)	3.547 (4)	149 (5)
C4—H4⋯Cg1ⁱ	0.93	2.90	3.673 (5)	142
C6—H6⋯Cg2ⁱⁱⁱ	0.93	2.98	3.743 (5)	140
C23—H23C⋯Cg3ⁱⁱⁱ	0.96	2.70	3.593 (5)	154

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

The authors are grateful for the sponsorship of the Research Center, College of Pharmacy and the Deanship of Scientific Research, King Saud University. We also thank the Ministry of Higher Education (Malaysia) for funding structural studies through the High-Impact Research scheme (UM.C/HIR-MOHE/SC/12).

supplementary crystallographic information

Comment

4H-Chromene and its derivatives are biologically interesting compounds known for their anti-microbial, anti-fungal and other pharmaceutical activities (Alvey et al., 2009; Kemnitzer et al., 2007). In continuation of on-going interest in the chemical and pharmacological properties of 4H-chromene and fused 4H-chromene derivatives (Abd-El-Aziz et al., 2004; Abd-El-Aziz et al., 2007), the crystal structure of the title compound, (I), is described herein.

The molecular structure of (I), Fig. 1, is isostructural to the recently reported 4-fluoro analogue (El-Agrody et al., 2012). The pyran ring has a flattened boat conformation with the O1 and C11 atoms lying 0.160 (5) and 0.256 (6) Å, respectively, out of the plane defined by the four remaining atoms (r.m.s. deviation = 0.0174 Å). Overall, the 4H-benzo[h]chromene ring system is approximately planar with the r.m.s. deviation of the 14 non-hydrogen atoms being 0.116 Å. The bromobenzene ring is almost perpendicular to this plane, forming a dihedral angle of 83.27 (16)°. By contrast, the ester group, with an anti conformation [C14—O3—C15—C16 torsion angle = -166.9 (4)°], is co-planar [C11—C12—C14—O3 = 3.4 (5)°] due, in part, to an intramolecular N—H···O2 hydrogen bond, Table 1. The methoxy [C23—O4—C7—C7 = 174.5 (3)°] substituent is also co-planar to the ring to which it is attached.

Zigzag (glide symmetry) supramolecular chains along the c axis feature in the crystal packing owing to N—H···O2 hydrogen bonding, Fig. 2 and Table 1. Chains are linked into layers in the bc plane by N—H···Br hydrogen bonds involving the H atom involved in the intramolecular interaction to the O2 atom, Table 1. A consequence of this interaction is that the Br1 and O2 atoms are brought into close proximity, i.e. Br1···O2ⁱ = 3.179 (3) Å [i: -x, 1/2 + y, 3/2 - z]. The three-dimensional architecture is consolidated by C—H···π interactions, Fig. 3 and Table 1.

Experimental

A solution of 4-methoxy-1-naphthol (0.01 mol) in EtOH (30 ml) was treated with ethyl α-cyano-p-bromocinnamate (0.01 mol) and piperidine (0.5 ml). The reaction mixture was heated until complete precipitation occurred after 2 h. The solid product was collected by filtration and recrystallized from ethanol to give (I); M.pt: 438–439 K.