organic compounds
4-(4-Bromophenyl)-7,7-dimethyl-2-methylamino-3-nitro-7,8-dihydro-4H-chromen-5(6H)-one including an unknown solvate
aSri Ram Engineering College, Chennai 602 024, India, bDepartment of Chemistry, Pondichery University, Pondichery 605 014, India, and cDepartment of Physics, RKM Vivekananda College (Autonomous), Chennai 600 004, India
*Correspondence e-mail: ksethusankar@yahoo.co.in
In the title compound, C18H19BrN2O4, the chromene unit is not quite planar (r.m.s. deviation = 0.199 Å), with the methyl C atoms lying 0.027 (4) and 1.929 (4) Å from the mean plane of the chromene unit. The six-membered carbocyclic ring of the chromene moiety adopts an with the dimethyl-substituted C atom as the flap. The methylamine and nitro groups are slightly twisted from the chromene moiety, with C—N—C—O and O—N—C—C torsion angles of 2.7 (4) and −0.4 (4)°, respectively. The dihedral angle between the mean plane of the chromene unit and the benzene ring is 85.61 (13)°. An intramolecular N—H⋯O hydrogen bond generates an S(6) ring motif, which stabilizes the molecular conformation. In the crystal, molecules are linked via N—H⋯O hydrogen bonds, forming hexagonal rings lying parallel to the ab plane. A region of disordered electron density, most probably disordered ethanol solvent molecules, occupying voids of ca 432 Å3 for an electron count of 158, was treated using the SQUEEZE routine in PLATON [Spek (2009). Acta Cryst. D65, 148–155]. Their formula mass and unit-cell characteristics were not taken into account during refinement.
CCDC reference: 996468
Related literature
For the biological and pharmacological properties of chromene and chromene derivatives, see: Thomas & Zachariah (2013). For graph-set notation, see: Bernstein et al. (1995). For ring puckering parameters, see: Cremer & Pople (1975). For a related structure, see: Narayanan et al. (2013).
Experimental
Crystal data
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Data collection: APEX2 (Bruker, 2008); cell 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: PLATON (Spek, 2009) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009).
Supporting information
CCDC reference: 996468
10.1107/S1600536814007983/su2714sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536814007983/su2714Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536814007983/su2714Isup3.cml
A solution of the 4-bromobenzaldehyde (1.0 mmol), 5,5- dimethylcyclohexane-1,3-dione (1.0 mmol), NMSM (1.0 mmol), and L-proline (0.2 equiv) in EtOH (2 ml) was stirred for the 2.3 h until the reaction was complete as indicated by TLC. The product obtained was filtered and washed with EtOH (2 ml) to remove the excess base and other impurities. Finally, the products were recrystallized from EtOH yielding block-like colourless crystals.
The NH H atom was located in a difference Fourier map and freely refined. The C-bound H atoms were placed in idealized positions and allowed to ride on the parent atoms: C—H = 0.93 - 0.97 Å with Uiso(H)= 1.5 Ueq(C-methyl) and = 1.2Ueq(C) for other H atoms. A region of disordered electron density, most probably disordered ethanol solvent molecules, occupying voids of ca 432 Å3 for an electron count of 158, was treated using the SQUEEZE routine in PLATON [Spek (2009). Acta Cryst. D65, 148–155]. The formula mass and unit-cell characteristics were not taken into account during refinement.
Data collection: APEX2 (Bruker, 2008); cell
SAINT (Bruker, 2008); 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: PLATON (Spek, 2009) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).C18H19BrN2O4 | Dx = 1.520 Mg m−3 |
Mr = 407.26 | Mo Kα radiation, λ = 0.71073 Å |
Trigonal, R3 | Cell parameters from 3206 reflections |
Hall symbol: -R 3 | θ = 2.3–25.2° |
a = 24.2105 (13) Å | µ = 2.34 mm−1 |
c = 15.7745 (9) Å | T = 293 K |
V = 8007.4 (8) Å3 | Block, colourless |
Z = 18 | 0.35 × 0.30 × 0.30 mm |
F(000) = 3744 |
Bruker Kappa APEXII CCD diffractometer | 3206 independent reflections |
Radiation source: fine-focus sealed tube | 2565 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.035 |
ω and ϕ scan | θmax = 25.2°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | h = −28→29 |
Tmin = 0.446, Tmax = 0.496 | k = −29→28 |
25281 measured reflections | l = −12→18 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.038 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.105 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0569P)2 + 9.8133P] where P = (Fo2 + 2Fc2)/3 |
3206 reflections | (Δ/σ)max < 0.001 |
233 parameters | Δρmax = 0.68 e Å−3 |
0 restraints | Δρmin = −0.61 e Å−3 |
C18H19BrN2O4 | Z = 18 |
Mr = 407.26 | Mo Kα radiation |
Trigonal, R3 | µ = 2.34 mm−1 |
a = 24.2105 (13) Å | T = 293 K |
c = 15.7745 (9) Å | 0.35 × 0.30 × 0.30 mm |
V = 8007.4 (8) Å3 |
Bruker Kappa APEXII CCD diffractometer | 3206 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | 2565 reflections with I > 2σ(I) |
Tmin = 0.446, Tmax = 0.496 | Rint = 0.035 |
25281 measured reflections |
R[F2 > 2σ(F2)] = 0.038 | 0 restraints |
wR(F2) = 0.105 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.09 | Δρmax = 0.68 e Å−3 |
3206 reflections | Δρmin = −0.61 e Å−3 |
233 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
Br1 | 0.212132 (19) | 0.139268 (18) | 0.68871 (2) | 0.06222 (17) | |
O1 | 0.43022 (10) | 0.17889 (10) | 0.40027 (13) | 0.0472 (5) | |
O2 | 0.26619 (8) | 0.05160 (8) | 0.21543 (11) | 0.0321 (4) | |
O3 | 0.42426 (10) | 0.09139 (10) | 0.35374 (13) | 0.0447 (5) | |
O4 | 0.27248 (10) | 0.24234 (10) | 0.29435 (14) | 0.0504 (5) | |
N1 | 0.40219 (10) | 0.12873 (11) | 0.35810 (13) | 0.0354 (5) | |
N2 | 0.32782 (12) | 0.01391 (11) | 0.25833 (16) | 0.0374 (6) | |
H2N | 0.3582 (17) | 0.0173 (16) | 0.287 (2) | 0.056 (10)* | |
C1 | 0.24640 (15) | 0.14478 (14) | 0.57850 (17) | 0.0399 (7) | |
C2 | 0.30235 (15) | 0.19826 (14) | 0.55683 (18) | 0.0439 (7) | |
H2 | 0.3238 | 0.2310 | 0.5958 | 0.053* | |
C3 | 0.32632 (14) | 0.20269 (13) | 0.47641 (17) | 0.0390 (7) | |
H3 | 0.3643 | 0.2389 | 0.4613 | 0.047* | |
C4 | 0.29519 (12) | 0.15445 (12) | 0.41766 (16) | 0.0301 (6) | |
C5 | 0.23957 (13) | 0.10049 (13) | 0.44189 (18) | 0.0397 (7) | |
H5 | 0.2186 | 0.0672 | 0.4035 | 0.048* | |
C6 | 0.21442 (15) | 0.09504 (15) | 0.52256 (19) | 0.0455 (7) | |
H6 | 0.1769 | 0.0587 | 0.5384 | 0.055* | |
C7 | 0.32208 (12) | 0.16060 (12) | 0.32833 (15) | 0.0293 (6) | |
H7A | 0.3573 | 0.2044 | 0.3209 | 0.035* | |
C8 | 0.34739 (12) | 0.11581 (12) | 0.31480 (15) | 0.0297 (6) | |
C9 | 0.31590 (12) | 0.06113 (12) | 0.26513 (16) | 0.0297 (6) | |
C10 | 0.24637 (12) | 0.09617 (12) | 0.21277 (15) | 0.0278 (6) | |
C11 | 0.27201 (11) | 0.14784 (12) | 0.26209 (15) | 0.0281 (5) | |
C12 | 0.24891 (12) | 0.19332 (12) | 0.25304 (16) | 0.0313 (6) | |
C13 | 0.19699 (12) | 0.17837 (12) | 0.18972 (17) | 0.0336 (6) | |
H13A | 0.2165 | 0.1994 | 0.1367 | 0.040* | |
H13B | 0.1714 | 0.1963 | 0.2099 | 0.040* | |
C14 | 0.15270 (12) | 0.10710 (13) | 0.17229 (17) | 0.0335 (6) | |
C15 | 0.19391 (12) | 0.07738 (13) | 0.15019 (17) | 0.0321 (6) | |
H15A | 0.1674 | 0.0313 | 0.1494 | 0.039* | |
H15B | 0.2119 | 0.0912 | 0.0940 | 0.039* | |
C16 | 0.10934 (15) | 0.09891 (16) | 0.0969 (2) | 0.0502 (8) | |
H16A | 0.0811 | 0.0543 | 0.0866 | 0.075* | |
H16B | 0.1350 | 0.1182 | 0.0475 | 0.075* | |
H16C | 0.0848 | 0.1191 | 0.1095 | 0.075* | |
C17 | 0.11220 (14) | 0.07477 (14) | 0.2504 (2) | 0.0458 (7) | |
H17A | 0.0850 | 0.0301 | 0.2393 | 0.069* | |
H17B | 0.0866 | 0.0937 | 0.2636 | 0.069* | |
H17C | 0.1395 | 0.0802 | 0.2976 | 0.069* | |
C18 | 0.29496 (15) | −0.04065 (14) | 0.2025 (2) | 0.0477 (8) | |
H18A | 0.3047 | −0.0730 | 0.2189 | 0.072* | |
H18B | 0.3086 | −0.0278 | 0.1452 | 0.072* | |
H18C | 0.2498 | −0.0573 | 0.2066 | 0.072* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br1 | 0.0846 (3) | 0.0630 (3) | 0.0458 (2) | 0.0419 (2) | 0.02115 (17) | 0.00610 (15) |
O1 | 0.0358 (11) | 0.0452 (13) | 0.0568 (13) | 0.0174 (10) | −0.0149 (10) | −0.0151 (10) |
O2 | 0.0316 (10) | 0.0282 (10) | 0.0418 (10) | 0.0190 (8) | −0.0093 (8) | −0.0064 (8) |
O3 | 0.0418 (12) | 0.0528 (13) | 0.0520 (12) | 0.0330 (11) | −0.0116 (9) | −0.0050 (10) |
O4 | 0.0536 (13) | 0.0335 (12) | 0.0689 (14) | 0.0254 (10) | −0.0152 (11) | −0.0155 (10) |
N1 | 0.0303 (12) | 0.0409 (14) | 0.0338 (12) | 0.0169 (12) | −0.0007 (10) | 0.0019 (10) |
N2 | 0.0382 (14) | 0.0366 (14) | 0.0460 (13) | 0.0254 (12) | −0.0108 (11) | −0.0049 (11) |
C1 | 0.0492 (18) | 0.0427 (17) | 0.0363 (14) | 0.0294 (15) | 0.0069 (13) | 0.0028 (12) |
C2 | 0.0535 (19) | 0.0352 (16) | 0.0377 (15) | 0.0183 (15) | −0.0045 (14) | −0.0096 (12) |
C3 | 0.0381 (16) | 0.0269 (15) | 0.0414 (15) | 0.0082 (13) | −0.0028 (12) | −0.0038 (11) |
C4 | 0.0296 (14) | 0.0278 (14) | 0.0359 (13) | 0.0168 (12) | −0.0028 (11) | −0.0024 (11) |
C5 | 0.0357 (16) | 0.0311 (15) | 0.0422 (15) | 0.0091 (13) | −0.0017 (12) | −0.0066 (12) |
C6 | 0.0372 (17) | 0.0399 (17) | 0.0494 (17) | 0.0119 (14) | 0.0076 (13) | 0.0037 (14) |
C7 | 0.0261 (13) | 0.0250 (13) | 0.0344 (13) | 0.0109 (11) | −0.0002 (10) | −0.0011 (11) |
C8 | 0.0241 (13) | 0.0335 (14) | 0.0315 (13) | 0.0143 (12) | −0.0012 (10) | 0.0003 (11) |
C9 | 0.0244 (13) | 0.0325 (14) | 0.0337 (13) | 0.0153 (12) | 0.0009 (10) | 0.0022 (11) |
C10 | 0.0259 (13) | 0.0253 (13) | 0.0345 (13) | 0.0145 (11) | 0.0022 (10) | 0.0019 (10) |
C11 | 0.0238 (13) | 0.0261 (14) | 0.0343 (13) | 0.0125 (11) | 0.0019 (10) | 0.0011 (11) |
C12 | 0.0302 (14) | 0.0252 (14) | 0.0386 (14) | 0.0140 (12) | 0.0026 (11) | −0.0001 (11) |
C13 | 0.0338 (15) | 0.0304 (14) | 0.0423 (15) | 0.0203 (13) | 0.0041 (12) | 0.0037 (12) |
C14 | 0.0286 (14) | 0.0297 (14) | 0.0445 (15) | 0.0164 (12) | −0.0025 (12) | 0.0002 (11) |
C15 | 0.0308 (14) | 0.0314 (14) | 0.0371 (14) | 0.0177 (12) | −0.0062 (11) | −0.0057 (11) |
C16 | 0.0410 (17) | 0.0495 (19) | 0.067 (2) | 0.0275 (16) | −0.0180 (15) | −0.0085 (16) |
C17 | 0.0321 (16) | 0.0385 (17) | 0.0652 (19) | 0.0164 (14) | 0.0095 (14) | 0.0054 (14) |
C18 | 0.0516 (19) | 0.0396 (17) | 0.0617 (19) | 0.0302 (16) | −0.0143 (15) | −0.0141 (15) |
Br1—C1 | 1.902 (3) | C7—H7A | 0.9800 |
O1—N1 | 1.247 (3) | C8—C9 | 1.392 (4) |
O2—C9 | 1.356 (3) | C10—C11 | 1.334 (3) |
O2—C10 | 1.384 (3) | C10—C15 | 1.489 (3) |
O3—N1 | 1.261 (3) | C11—C12 | 1.470 (4) |
O4—C12 | 1.217 (3) | C12—C13 | 1.501 (4) |
N1—C8 | 1.382 (3) | C13—C14 | 1.534 (4) |
N2—C9 | 1.316 (3) | C13—H13A | 0.9700 |
N2—C18 | 1.450 (4) | C13—H13B | 0.9700 |
N2—H2N | 0.83 (3) | C14—C17 | 1.525 (4) |
C1—C2 | 1.369 (4) | C14—C16 | 1.532 (4) |
C1—C6 | 1.377 (4) | C14—C15 | 1.534 (4) |
C2—C3 | 1.377 (4) | C15—H15A | 0.9700 |
C2—H2 | 0.9300 | C15—H15B | 0.9700 |
C3—C4 | 1.382 (4) | C16—H16A | 0.9600 |
C3—H3 | 0.9300 | C16—H16B | 0.9600 |
C4—C5 | 1.381 (4) | C16—H16C | 0.9600 |
C4—C7 | 1.528 (3) | C17—H17A | 0.9600 |
C5—C6 | 1.388 (4) | C17—H17B | 0.9600 |
C5—H5 | 0.9300 | C17—H17C | 0.9600 |
C6—H6 | 0.9300 | C18—H18A | 0.9600 |
C7—C8 | 1.504 (4) | C18—H18B | 0.9600 |
C7—C11 | 1.511 (3) | C18—H18C | 0.9600 |
C9—O2—C10 | 120.62 (19) | C10—C11—C7 | 123.0 (2) |
O1—N1—O3 | 120.5 (2) | C12—C11—C7 | 118.7 (2) |
O1—N1—C8 | 118.5 (2) | O4—C12—C11 | 120.7 (2) |
O3—N1—C8 | 120.9 (2) | O4—C12—C13 | 121.3 (2) |
C9—N2—C18 | 125.6 (2) | C11—C12—C13 | 118.1 (2) |
C9—N2—H2N | 116 (2) | C12—C13—C14 | 114.9 (2) |
C18—N2—H2N | 119 (2) | C12—C13—H13A | 108.6 |
C2—C1—C6 | 121.7 (3) | C14—C13—H13A | 108.6 |
C2—C1—Br1 | 119.0 (2) | C12—C13—H13B | 108.6 |
C6—C1—Br1 | 119.3 (2) | C14—C13—H13B | 108.6 |
C1—C2—C3 | 118.9 (3) | H13A—C13—H13B | 107.5 |
C1—C2—H2 | 120.6 | C17—C14—C16 | 109.7 (2) |
C3—C2—H2 | 120.6 | C17—C14—C15 | 110.2 (2) |
C2—C3—C4 | 121.4 (3) | C16—C14—C15 | 109.1 (2) |
C2—C3—H3 | 119.3 | C17—C14—C13 | 109.9 (2) |
C4—C3—H3 | 119.3 | C16—C14—C13 | 109.5 (2) |
C5—C4—C3 | 118.4 (2) | C15—C14—C13 | 108.4 (2) |
C5—C4—C7 | 120.9 (2) | C10—C15—C14 | 111.2 (2) |
C3—C4—C7 | 120.7 (2) | C10—C15—H15A | 109.4 |
C4—C5—C6 | 121.2 (3) | C14—C15—H15A | 109.4 |
C4—C5—H5 | 119.4 | C10—C15—H15B | 109.4 |
C6—C5—H5 | 119.4 | C14—C15—H15B | 109.4 |
C1—C6—C5 | 118.4 (3) | H15A—C15—H15B | 108.0 |
C1—C6—H6 | 120.8 | C14—C16—H16A | 109.5 |
C5—C6—H6 | 120.8 | C14—C16—H16B | 109.5 |
C8—C7—C11 | 109.2 (2) | H16A—C16—H16B | 109.5 |
C8—C7—C4 | 111.6 (2) | C14—C16—H16C | 109.5 |
C11—C7—C4 | 111.0 (2) | H16A—C16—H16C | 109.5 |
C8—C7—H7A | 108.3 | H16B—C16—H16C | 109.5 |
C11—C7—H7A | 108.3 | C14—C17—H17A | 109.5 |
C4—C7—H7A | 108.3 | C14—C17—H17B | 109.5 |
N1—C8—C9 | 120.0 (2) | H17A—C17—H17B | 109.5 |
N1—C8—C7 | 117.3 (2) | C14—C17—H17C | 109.5 |
C9—C8—C7 | 122.6 (2) | H17A—C17—H17C | 109.5 |
N2—C9—O2 | 111.5 (2) | H17B—C17—H17C | 109.5 |
N2—C9—C8 | 128.2 (2) | N2—C18—H18A | 109.5 |
O2—C9—C8 | 120.3 (2) | N2—C18—H18B | 109.5 |
C11—C10—O2 | 122.2 (2) | H18A—C18—H18B | 109.5 |
C11—C10—C15 | 126.8 (2) | N2—C18—H18C | 109.5 |
O2—C10—C15 | 110.9 (2) | H18A—C18—H18C | 109.5 |
C10—C11—C12 | 118.2 (2) | H18B—C18—H18C | 109.5 |
C6—C1—C2—C3 | 1.3 (5) | C7—C8—C9—N2 | −169.2 (3) |
Br1—C1—C2—C3 | −178.6 (2) | N1—C8—C9—O2 | −172.9 (2) |
C1—C2—C3—C4 | −0.1 (5) | C7—C8—C9—O2 | 11.0 (4) |
C2—C3—C4—C5 | −1.3 (4) | C9—O2—C10—C11 | −4.3 (4) |
C2—C3—C4—C7 | 179.2 (3) | C9—O2—C10—C15 | 176.5 (2) |
C3—C4—C5—C6 | 1.5 (4) | O2—C10—C11—C12 | 178.4 (2) |
C7—C4—C5—C6 | −179.0 (3) | C15—C10—C11—C12 | −2.6 (4) |
C2—C1—C6—C5 | −1.2 (5) | O2—C10—C11—C7 | −3.5 (4) |
Br1—C1—C6—C5 | 178.8 (2) | C15—C10—C11—C7 | 175.5 (2) |
C4—C5—C6—C1 | −0.3 (5) | C8—C7—C11—C10 | 12.9 (3) |
C5—C4—C7—C8 | −69.8 (3) | C4—C7—C11—C10 | −110.6 (3) |
C3—C4—C7—C8 | 109.7 (3) | C8—C7—C11—C12 | −169.0 (2) |
C5—C4—C7—C11 | 52.3 (3) | C4—C7—C11—C12 | 67.5 (3) |
C3—C4—C7—C11 | −128.2 (3) | C10—C11—C12—O4 | −177.2 (3) |
O1—N1—C8—C9 | 178.2 (2) | C7—C11—C12—O4 | 4.6 (4) |
O3—N1—C8—C9 | −0.4 (4) | C10—C11—C12—C13 | 1.0 (3) |
O1—N1—C8—C7 | −5.5 (3) | C7—C11—C12—C13 | −177.2 (2) |
O3—N1—C8—C7 | 176.0 (2) | O4—C12—C13—C14 | −154.1 (3) |
C11—C7—C8—N1 | 167.3 (2) | C11—C12—C13—C14 | 27.6 (3) |
C4—C7—C8—N1 | −69.6 (3) | C12—C13—C14—C17 | 68.6 (3) |
C11—C7—C8—C9 | −16.5 (3) | C12—C13—C14—C16 | −170.8 (2) |
C4—C7—C8—C9 | 106.6 (3) | C12—C13—C14—C15 | −51.9 (3) |
C18—N2—C9—O2 | 2.7 (4) | C11—C10—C15—C14 | −23.9 (4) |
C18—N2—C9—C8 | −177.2 (3) | O2—C10—C15—C14 | 155.2 (2) |
C10—O2—C9—N2 | −179.4 (2) | C17—C14—C15—C10 | −71.9 (3) |
C10—O2—C9—C8 | 0.5 (3) | C16—C14—C15—C10 | 167.6 (2) |
N1—C8—C9—N2 | 6.9 (4) | C13—C14—C15—C10 | 48.5 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2N···O3 | 0.83 (3) | 2.00 (3) | 2.618 (3) | 130 (3) |
N2—H2N···O4i | 0.83 (3) | 2.38 (3) | 2.969 (3) | 129 (3) |
Symmetry code: (i) x−y+1/3, x−1/3, −z+2/3. |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2N···O3 | 0.83 (3) | 2.00 (3) | 2.618 (3) | 130 (3) |
N2—H2N···O4i | 0.83 (3) | 2.38 (3) | 2.969 (3) | 129 (3) |
Symmetry code: (i) x−y+1/3, x−1/3, −z+2/3. |
Acknowledgements
The authors gratefully acknowledge Dr Babu Varghese, SAIF, IIT, Chennai, India, for the data collection.
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Chromene constitutes the basic backbone of various types of polyphenols and is widely found in natural alkaloids, tocopherols, flavonoids and anthocyanins. Natural and synthetic chromene derivatives possess important biological activities such as antitumor, antispasmolytic, antivascular, anticancer, anti-HIV, estrogenic and herbicidal activity. They also plays an important role in the production of highly effective fluorescent dyes for synthetic fibers, daylight fluorescent pigments and electrophotographic and electroluminescent devices (Thomas et al., 2013).
The title compound, Fig. 1, consists of a chromene unit connected to a bromophenyl ring at C7, a nitro group at C8, a methyl amine group at C9, an oxygen atom at C12 and a dimethyl group at C14. The mean plane of the chromene unit (O2/C7–C15) is almost normal to the benzene ring (C1–C6), with a dihedral angle of 85.61 (13)°. The mean plane of the chromene unit makes dihedral angles of 7.25 (21) and 2.89 (21)° with the nitro and methylamine groups, respectively.
The six membered carbocyclic ring (C10–C15) of the chromene moiety has an envelope conformation with puckering parameters (Cremer & Pople, 1975), of Puckering Amplitude (Q) = 0.459 (3) Å, θ = 124.1 (4) °, ϕ = 57.4 (5) °. Atom C14 deviates by -0.324 (3) Å from the mean plane passing through the other five C ring atoms. The sum of the angles around atom N1 (359.9 °) is in accordance with sp2 hybridization. The amine group nitrogen atoms, N1 and N2, deviate by -0.156 (2) and -0.0153 (3) Å from the mean plane of the chromene unit. The bromine atom, Br1, deviates from the benzene ring (C1–C6) by 0.0526 (5) Å. The methyl amine group attached to C9 is coplanar with the chromene unit as indicated by the torsion angle C18-N2-C9-O2 = 2.7 (4)°. The nitro group is also coplanar to the chromene unit, as indicated by the torsion angles O1-N1-C8-C7 = -5.5 (3)° and O3-N1-C8-C9 = -0.4 (4)°, respectively. The molecular structure is characterized by an intramolecular N—H···O hydrogen bond, which generates an S(6) ring motif (Bernstein et al., 1995). The title compound exhibits structural similarities with the related structure, 4-(4-Bromophenyl)-2-methylamino-3-nitro-5,6,7,8-tetrahydro-4H-chromen-5-one (Narayanan et al., 2013).
The crystal packing is stabilized by intermolecular N—H···O hydrogen bonds forming hexagonal rings centered about a threefold rotation axis and lying parallel to the ab plane (Fig. 2 and Table 1). The amide N1 atom is involved in both intra and intermolecular hydrogen bonding, having a bifurcated character (Table 1).