4-(4-Bromo­phen­yl)-2-methyl­amino-3-nitro-5,6,7,8-tetra­hydro-4H-chromen-5-one

P Narayanan; Jayabal Kamalraja; Paramasivam T Perumal; K Sethusankar

doi:10.1107/S1600536813012774

. 2013 May 22;69(Pt 6):o931–o932. doi: 10.1107/S1600536813012774

4-(4-Bromophenyl)-2-methylamino-3-nitro-5,6,7,8-tetrahydro-4H-chromen-5-one

P Narayanan ^a, Jayabal Kamalraja ^b, Paramasivam T Perumal ^b, K Sethusankar ^a,^*

PMCID: PMC3685080 PMID: 23795099

Abstract

In the title compound, C₁₆H₁₅BrN₂O₄, the six-membered carbocyclic ring of the chromene moiety adopts an envelope conformation with the disordered methylene C atom as the flap. The pyran ring is almost orthogonal to the chlorophenyl ring, making a dihedral angle of 87.11 (12)°. The amine-group N atom deviates significantly from the pyran ring [0.238 (3) Å]. The molecular structure is stabilized by an intramolecular N—H⋯O hydrogen bond, which generates an S(6) ring motif. In the crystal, molecules are linked via C—H⋯O hydrogen bonds, which generate C(8) chains running parallel to the b axis. The chains are linked by C—H⋯π interactions. The methylene-group C atom of the chromene system that is disordered, along with its attached H atoms and the H atoms on the two adjacent C atoms, has an occupancy ratio of 0.791 (7):0.209 (7).

Related literature

For the uses and biological importance of chromene, see: Ercole et al. (2009 ▶); Geen et al. (1996 ▶) Khan et al. (2010 ▶); Raj et al. (2010 ▶). For a related structure, see: Sun et al. (2012 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₆H₁₅BrN₂O₄
M _r = 379.18
Monoclinic,
a = 8.1114 (9) Å
b = 10.8530 (13) Å
c = 18.222 (2) Å
β = 94.399 (6)°
V = 1599.4 (3) Å³
Z = 4
Mo Kα radiation
μ = 2.59 mm⁻¹
T = 296 K
0.30 × 0.25 × 0.25 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.464, T _max = 0.523
12198 measured reflections
3130 independent reflections
2053 reflections with I > 2σ(I)
R _int = 0.047

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.101
S = 1.04
3130 reflections
218 parameters
4 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.41 e Å⁻³
Δρ_min = −0.48 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; 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 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Click here for additional data file.^{(26.6KB, cif)}

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813012774/su2597sup1.cif

e-69-0o931-sup1.cif^{(26.6KB, cif)}

Click here for additional data file.^{(150.5KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813012774/su2597Isup2.hkl

e-69-0o931-Isup2.hkl^{(150.5KB, hkl)}

Click here for additional data file.^{(6KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813012774/su2597Isup3.cml

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

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

Cg1 is the centroid of the pyran ring (C7/C8/C13/O1/C14/C15).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2A⋯O3	0.90 (2)	1.89 (2)	2.595 (3)	134 (2)
C2—H2⋯O4ⁱ	0.93	2.55	3.442 (4)	162
C10—H10B⋯Cg1ⁱⁱ	0.97	2.77	3.527 (3)	136
C16—H16B⋯Cg1ⁱⁱⁱ	0.96	2.73	3.606 (4)	153

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

Acknowledgments

PN and KS thank Dr Babu Varghese, Senior Scientific Officer, SAIF, IIT Madras, Chennai, India, for the X-ray intensity data collection.

supplementary crystallographic information

Comment

Chromene derivatives are very important heterocyclic compounds that have a variety of industrial, biological and chemical synthesis applications (Geen et al., 1996; Ercole et al., 2009). They exhibit a number of pharmacological activities such as anti-HIV, anti-inflammatory, anti-bacterial, anti-allergic, anti-cancer, etc. (Khan et al., 2010, Raj et al., 2010). Against this background an X-ray diffraction study of the title compound and its structural aspects are presented herein.

The title compound, Fig. 1, consists of a chromene moiety attached to a chlorophenyl ring, a nitro group and a methylamine group. The molecular structure is stabilized by an intramolecular N—H···O hydrogen bonds, which generates an S(6) ring motif (Table 1 and Fig. 1). The methylene group carbon atom C11 of the chromene moiety is disordered over two positions (C11/C11') with an occupancy ratio of 0.791 (7): 0.209 (7). The pyran ring (C7/C8/C13-C15/O1) makes a dihedral angle of 87.11 (12) ° with the cholorophenyl ring (C1–C6), indicating that they are almost orthogonal.

The mean planes of the nitro and methylamine groups are almost co-planar with the pyran ring, with dihedral angles of 4.66 (20) and 3.87 (19) °, respectively. The mean plane of six membered carbocyclic ring (C8–C10/C11-C13) makes a dihedral angle of 86.50 (14) ° with the chlorophenyl ring, which shows that they too are almost perpendicular to each other.

The six membered carbocyclic ring (C8-C10/C11-C13) of the chromene moiety adopts an envelope conformation on C11 atom which deviates by 0.302 (4) Å out of the mean plane formed by the remaining ring atoms. The amine group nitrogen atom N2 deviates by -0.2382 (25) Å from the pyran ring. The bromine atom Br1 deviates from the phenyl ring (C1–C6) by 0.0953 (4) Å. The title compound exhibits structural similarities with a related structure (Sun et al., 2012).

In the crystal, molecules are linked via C—H···O hydrogen bonds, which generate C(8) chains running parallel to the b axis (Bernstein et al.,1995); see Table 1 and Fig. 2. The crystal structure is further stabilized by C-H···π interactions (Table 1).

Experimental

A solution of the 4-bromobenzaldehyde (0.18 g, 1.0 mmol), cyclic 1,3-dicarbonyl compound (1.0 mmol), NMSM (0.15 g, 1.0 mmol) and piperidine (0.2 equiv) in EtOH (2 ml) was stirred for 3.5 hrs. After the reaction was complete, as indicated by TLC, the product was filtered and washed with EtOH (2 ml) to remove excess base and other impurities. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in ethanol at room temperature.