rac-4-(4-Chloro­phen­yl)-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/S1600536813014530

. 2013 Jun 8;69(Pt 7):o1053–o1054. doi: 10.1107/S1600536813014530

rac-4-(4-Chlorophenyl)-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: PMC3772485 PMID: 24046628

Abstract

The title compound, C₁₆H₁₅ClN₂O₄, contains a chiral centre and crystallizes as a racemate. The methylene group β-positioned to the carbonyl group is partially (21%) disordered. It flips to the opposite sides of the corresponding six-membered carbocycle by −0.304 (3) and 0.197 (11) Å, producing alternative envelope conformations. The planes of the pyran and chlorophenyl rings form a dihedral angle of 86.25 (9)°. The molecular structure is characterized by an intramolecular N—H⋯O interaction, which generates an S(6) ring motif. The corresponding amino N atom deviates from the plane of the pyran ring by 0.1634 (19) Å. In the crystal, molecules are linked via C—H⋯O hydrogen bonds, forming C(8) chains running parallel to the b-axis direction. The crystal structure also features C—H⋯π interactions.

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 related structures, see: Sun et al., (2012 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₆H₁₅ClN₂O₄
M _r = 334.75
Monoclinic,
a = 8.0285 (4) Å
b = 10.8460 (5) Å
c = 18.2337 (9) Å
β = 94.067 (2)°
V = 1583.74 (13) Å³
Z = 4
Mo Kα radiation
μ = 0.26 mm⁻¹
T = 296 K
0.35 × 0.30 × 0.30 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.912, T _max = 0.924
11848 measured reflections
2786 independent reflections
2208 reflections with I > 2σ(I)
R _int = 0.029

Refinement

R[F ² > 2σ(F ²)] = 0.042
wR(F ²) = 0.119
S = 1.09
2786 reflections
218 parameters
4 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.32 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2008 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 2012 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813014530/ld2104sup1.cif

e-69-o1053-sup1.cif^{(26.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813014530/ld2104Isup2.hkl

e-69-o1053-Isup2.hkl^{(134KB, hkl)}

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

Supplementary material file. DOI: 10.1107/S1600536813014530/ld2104Isup3.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)	1.86 (2)	2.599 (2)	137 (2)
C2—H2⋯O4ⁱ	0.93	2.53	3.420 (3)	160
C10—H10A⋯Cg1ⁱⁱ	0.97	2.75	3.515 (2)	136
C16—H16B⋯Cg1ⁱⁱⁱ	0.96	2.76	3.577 (3)	144

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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 backround, X-ray analysis of the title compound has been carried out to study its structural aspects.

X-ray analysis confirms the molecular structure and atom connectivity. The molecular structure is stabilized by intramolecular N2—H2A···O3 interaction, which generates S(6) ring motif as illustrated in Fig. 1. The methelene group carbon atom C11 of the chromene moiety is disordered over two positions, with an occupancy factor of 0.787 (5):0.213 (5). The pyrane ring (C7/C8/C13/C14/C15/O1) is almost orthogonal to the chlorophenyl ring (C1–C6), with a dihedral angle of 86.25 (9)° between their mean planes.

The pyrane ring is almost coplanar with the least-square planes of the nitro and methylene groups, making dihedral angles of 5.19 (14) and 5.01 (16)°, with them, respectively.

The six-membered carbocyclic rings (C8/C9/C10/C11/C12/C13) and (C8/C9/C10/C11'/C12/C13) of the chromene moiety adopt envelope conformations on the atoms C11 and C11', with puckering paramaters: Q₂ = 0.366 (3) Å, Q₃ = 0.229 (3) Å and φ₂ = 178.1 (2)°, and Q₂ = 0.211 (7) Å, Q₃ = -0.185 (5) Å and φ₂ = 3.1 (2)°, respectively. Also, the atoms C11 and C11' deviate from their respective mean planes of the rest of the ring atoms by -0.304 (3) and 0.197 (11) Å, respectively. The amine group nitrogen atom N2 deviates by 0.1634 (19) Å from the mean plane of the pyran ring. The chlorine atom Cl1 deviates from the phenyl ring (C1–C6) by 0.0571 (9) Å. The title compound exihibits structural similarities with an already reported related structure (Sun et al., 2012).

In the crystal, the molecules are linked via intermolecular C2—H2···O4ⁱ hydrogen-bond interaction, which generates C(8) chains running parallel to b axis (Bernstein et al.,1995). The crystal structure is further stabilized by C10—H10A···Cg1ⁱⁱ and C16—H16B···Cg1ⁱⁱⁱ intermolecular interactions, where Cg1 is the center of gravity of the pyran ring (C7/C8/C13/O1/C14/C15). The symmetry codes: (i) 3/2 - x, 1/2 + y, 1/2 - z (ii) 2 - x, 2 - y, -z (iii) 1 - x, 1 - y, -z. The packing view of the title compound is shown in Fig. 2.

Experimental

A solution of 4-chlorobenzaldehyde (0.14 g, 1.0 mmol), cyclic 1,3-dicarbonyl compound (1.0 mmol), NMSM (0.15 g, 1.0 mmol) and piperidine (0.2 equivalents) in EtOH (2 ml) was stirred for 3.5 h. After the reaction was complete as indicated by TLC, the product was filtered and washed with EtOH (2 ml) to remove the 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.