organic compounds
7-(4-Bromophenyl)-9-phenyl-7H-pyrrolo[3,2-e]tetrazolo[1,5-c]pyrimidine
aDepartment of Physics, Bhavan's Sheth R.A. College of Science, Ahmedabad, Gujarat, 380 001, India, bDepartment of Chemistry, M.G. Science Institute, Navrangpura, Navrangpura, Ahmedabad, Gujarat, 380 009, India, cDepartment of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA, and dDepartment of Chemistry, Howard University, 525 College Street NW, Washington DC 20059, USA
*Correspondence e-mail: jjasinski@keene.edu
In the title compound, C18H11BrN6, the phenyl ring is almost coplanar [dihedral angle 7.2 (1)°] with the planar (r.m.s. deviation 0.039 Å) tricyclic ring system while the 4-bromophenyl ring makes a dihedral angle of 33.98 (6)° with the ring system. Weak intermolecular C—H⋯N and C—H⋯Br hydrogen-bonding interactions and π–π stacking [centroid–centroid distances = 3.7971 (17) and 3.5599 (16) Å] stabilize the crystal packing. A comparison of the structure to a MOPAC PM3 geometry optimization calculation in vacuo supports these observations.
Related literature
For anticancer relationships, see: Hiedo & Yasuo (1960, 1961). For the synthesis of derivative compounds, see: Dave & Shukla (1997); Dave & Shah (1998). For graph-set motifs, see: Bernstein et al. (1995). For MOPAC PM3 calculations, see: Schmidt & Polik (2007).
Experimental
Crystal data
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Refinement
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Data collection: CrysAlis PRO (Oxford Diffraction, 2007); cell 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: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536810004368/bt5188sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536810004368/bt5188Isup2.hkl
The synthesis of (I) was carried out by two separate routes. Route 1: To a mixture of NaN3 (0.011 m), NH4Cl (0.011 m) and DMSO (20 ml) was added 4-chloro-5-phenyl-(7-bromophenyl)-7H-pyrrolo[2,3-d]pyrimidine (0.001 m) in portions and stirred for 2 hrs at 363 K to give the title compound. Route 2: 4-hydrazino-5-phenyl-(7-bromophenyl)-7H-pyrrolo[2,3-d]pyrimidine (0.01 m) was diazotized with an aqueous solution of NaNO2 (20% w/v, 4.2 ml) and glacial acetic acid (40 ml) at 273-278 K under stirring conditions for 2 hrs to give the title compound. Colorless, plate-like crystals of (I) were grown by slow evaporation from 1,4-dioxane solution.
All of the H atoms were placed in their calculated positions and then refined using the riding model with C—H = 0.95 Å, and with Uiso(H) = 1.18-1.21Ueq(C).
Data collection: CrysAlis PRO (Oxford Diffraction, 2007); cell
CrysAlis PRO (Oxford Diffraction, 2007); data reduction: CrysAlis PRO (Oxford Diffraction, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C18H11BrN6 | F(000) = 784 |
Mr = 391.24 | Dx = 1.675 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 4168 reflections |
a = 12.0173 (5) Å | θ = 4.8–32.4° |
b = 17.4007 (7) Å | µ = 2.66 mm−1 |
c = 7.4201 (4) Å | T = 200 K |
β = 91.004 (4)° | Plate, colorless |
V = 1551.37 (12) Å3 | 0.47 × 0.39 × 0.22 mm |
Z = 4 |
Oxford Diffraction Gemini diffractometer | 5032 independent reflections |
Radiation source: fine-focus sealed tube | 2606 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.050 |
Detector resolution: 10.5081 pixels mm-1 | θmax = 32.5°, θmin = 4.8° |
ϕ and ω scans | h = −16→18 |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007) | k = −25→26 |
Tmin = 0.494, Tmax = 1.000 | l = −11→11 |
13458 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.036 | H-atom parameters constrained |
wR(F2) = 0.090 | w = 1/[σ2(Fo2) + (0.0295P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.14 | (Δ/σ)max < 0.001 |
5032 reflections | Δρmax = 0.72 e Å−3 |
227 parameters | Δρmin = −0.71 e Å−3 |
0 restraints | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0033 (4) |
C18H11BrN6 | V = 1551.37 (12) Å3 |
Mr = 391.24 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 12.0173 (5) Å | µ = 2.66 mm−1 |
b = 17.4007 (7) Å | T = 200 K |
c = 7.4201 (4) Å | 0.47 × 0.39 × 0.22 mm |
β = 91.004 (4)° |
Oxford Diffraction Gemini diffractometer | 5032 independent reflections |
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007) | 2606 reflections with I > 2σ(I) |
Tmin = 0.494, Tmax = 1.000 | Rint = 0.050 |
13458 measured reflections |
R[F2 > 2σ(F2)] = 0.036 | 0 restraints |
wR(F2) = 0.090 | H-atom parameters constrained |
S = 1.14 | Δρmax = 0.72 e Å−3 |
5032 reflections | Δρmin = −0.71 e Å−3 |
227 parameters |
Experimental. (CrysAlis RED; Oxford Diffraction, 2007) |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 | ||
Br | −0.01667 (2) | 0.226033 (17) | 0.00063 (4) | 0.03758 (11) | |
N1 | 0.35315 (14) | 0.45391 (11) | 0.1749 (3) | 0.0245 (5) | |
N2 | 0.24838 (15) | 0.57000 (12) | 0.2186 (3) | 0.0300 (5) | |
N3 | 0.35441 (16) | 0.67017 (11) | 0.3359 (3) | 0.0292 (5) | |
N4 | 0.3685 (2) | 0.74165 (13) | 0.4080 (3) | 0.0406 (6) | |
N5 | 0.4737 (2) | 0.74487 (13) | 0.4525 (4) | 0.0432 (7) | |
N6 | 0.52928 (17) | 0.67915 (12) | 0.4136 (3) | 0.0359 (6) | |
C1 | 0.34572 (18) | 0.52985 (14) | 0.2224 (3) | 0.0235 (5) | |
C2 | 0.45169 (18) | 0.55548 (13) | 0.2756 (3) | 0.0219 (5) | |
C3 | 0.52682 (19) | 0.49222 (13) | 0.2569 (3) | 0.0230 (5) | |
C4 | 0.46260 (17) | 0.43241 (14) | 0.1955 (4) | 0.0245 (6) | |
H4 | 0.4902 | 0.3825 | 0.1703 | 0.029* | |
C5 | 0.2555 (2) | 0.63991 (16) | 0.2741 (4) | 0.0338 (7) | |
H5 | 0.1908 | 0.6713 | 0.2722 | 0.041* | |
C6 | 0.45368 (19) | 0.63216 (14) | 0.3404 (4) | 0.0263 (6) | |
C7 | 0.64817 (18) | 0.48691 (13) | 0.2913 (3) | 0.0225 (5) | |
C8 | 0.70547 (19) | 0.42147 (14) | 0.2367 (4) | 0.0277 (6) | |
H8 | 0.6659 | 0.3814 | 0.1769 | 0.033* | |
C9 | 0.8188 (2) | 0.41373 (15) | 0.2680 (4) | 0.0344 (7) | |
H9 | 0.8560 | 0.3687 | 0.2289 | 0.041* | |
C10 | 0.8778 (2) | 0.47079 (17) | 0.3551 (4) | 0.0351 (7) | |
H10 | 0.9556 | 0.4654 | 0.3767 | 0.042* | |
C11 | 0.82296 (19) | 0.53569 (16) | 0.4107 (4) | 0.0344 (7) | |
H11 | 0.8634 | 0.5752 | 0.4713 | 0.041* | |
C12 | 0.70894 (18) | 0.54451 (14) | 0.3794 (4) | 0.0283 (6) | |
H12 | 0.6725 | 0.5899 | 0.4181 | 0.034* | |
C13 | 0.26457 (18) | 0.40147 (14) | 0.1343 (3) | 0.0238 (6) | |
C14 | 0.16953 (19) | 0.42519 (15) | 0.0414 (4) | 0.0301 (6) | |
H14 | 0.1623 | 0.4771 | 0.0035 | 0.036* | |
C15 | 0.08552 (19) | 0.37323 (16) | 0.0039 (4) | 0.0308 (6) | |
H15 | 0.0195 | 0.3894 | −0.0574 | 0.037* | |
C16 | 0.09811 (19) | 0.29777 (15) | 0.0561 (4) | 0.0282 (6) | |
C17 | 0.19254 (19) | 0.27285 (15) | 0.1480 (4) | 0.0294 (6) | |
H17 | 0.2005 | 0.2205 | 0.1822 | 0.035* | |
C18 | 0.27530 (18) | 0.32577 (15) | 0.1893 (4) | 0.0293 (6) | |
H18 | 0.3397 | 0.3100 | 0.2556 | 0.035* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Br | 0.03221 (15) | 0.04452 (19) | 0.03605 (18) | −0.01798 (12) | 0.00207 (11) | −0.00499 (15) |
N1 | 0.0192 (9) | 0.0240 (11) | 0.0302 (13) | −0.0015 (8) | −0.0006 (9) | −0.0010 (10) |
N2 | 0.0265 (11) | 0.0277 (12) | 0.0361 (15) | 0.0033 (9) | 0.0021 (10) | −0.0018 (11) |
N3 | 0.0332 (11) | 0.0193 (11) | 0.0354 (14) | 0.0034 (9) | 0.0050 (10) | −0.0002 (10) |
N4 | 0.0478 (14) | 0.0232 (13) | 0.0509 (17) | 0.0014 (10) | 0.0049 (12) | −0.0054 (12) |
N5 | 0.0527 (15) | 0.0195 (12) | 0.057 (2) | −0.0027 (10) | 0.0016 (13) | −0.0071 (12) |
N6 | 0.0398 (12) | 0.0205 (12) | 0.0473 (16) | −0.0030 (9) | −0.0007 (11) | −0.0038 (11) |
C1 | 0.0236 (11) | 0.0220 (12) | 0.0250 (15) | −0.0031 (10) | 0.0021 (10) | −0.0002 (11) |
C2 | 0.0249 (12) | 0.0186 (12) | 0.0222 (15) | −0.0019 (9) | 0.0009 (10) | 0.0026 (11) |
C3 | 0.0279 (13) | 0.0211 (13) | 0.0199 (13) | −0.0029 (9) | −0.0028 (10) | 0.0028 (11) |
C4 | 0.0215 (11) | 0.0226 (13) | 0.0295 (16) | 0.0015 (9) | 0.0001 (10) | −0.0001 (12) |
C5 | 0.0281 (13) | 0.0334 (16) | 0.0399 (18) | 0.0067 (11) | 0.0029 (12) | −0.0003 (14) |
C6 | 0.0299 (13) | 0.0198 (13) | 0.0294 (16) | −0.0005 (10) | 0.0044 (11) | 0.0061 (12) |
C7 | 0.0206 (12) | 0.0232 (13) | 0.0237 (14) | −0.0020 (9) | −0.0001 (10) | 0.0048 (11) |
C8 | 0.0274 (12) | 0.0210 (13) | 0.0343 (17) | −0.0041 (10) | −0.0050 (11) | 0.0037 (12) |
C9 | 0.0342 (14) | 0.0269 (15) | 0.0418 (19) | 0.0075 (11) | −0.0035 (13) | 0.0054 (13) |
C10 | 0.0237 (13) | 0.0426 (16) | 0.0388 (19) | 0.0004 (12) | −0.0085 (12) | 0.0022 (14) |
C11 | 0.0291 (13) | 0.0352 (15) | 0.0387 (19) | −0.0065 (12) | −0.0077 (12) | −0.0027 (14) |
C12 | 0.0261 (12) | 0.0242 (14) | 0.0346 (17) | −0.0022 (10) | −0.0022 (11) | −0.0011 (12) |
C13 | 0.0243 (12) | 0.0256 (13) | 0.0216 (15) | −0.0063 (10) | 0.0034 (10) | −0.0033 (11) |
C14 | 0.0275 (12) | 0.0294 (14) | 0.0334 (17) | −0.0039 (10) | 0.0003 (12) | 0.0052 (13) |
C15 | 0.0251 (13) | 0.0369 (16) | 0.0304 (16) | −0.0043 (11) | −0.0025 (11) | 0.0022 (13) |
C16 | 0.0255 (12) | 0.0331 (15) | 0.0263 (16) | −0.0093 (10) | 0.0075 (11) | −0.0060 (12) |
C17 | 0.0291 (13) | 0.0252 (13) | 0.0341 (16) | −0.0027 (11) | 0.0036 (11) | 0.0019 (13) |
C18 | 0.0213 (12) | 0.0313 (15) | 0.0352 (17) | −0.0008 (10) | −0.0010 (11) | 0.0036 (13) |
Br—C16 | 1.900 (2) | C7—C12 | 1.396 (3) |
N1—C1 | 1.371 (3) | C8—C9 | 1.383 (3) |
N1—C4 | 1.373 (3) | C8—H8 | 0.9500 |
N1—C13 | 1.430 (3) | C9—C10 | 1.375 (4) |
N2—C5 | 1.287 (3) | C9—H9 | 0.9500 |
N2—C1 | 1.362 (3) | C10—C11 | 1.374 (4) |
N3—N4 | 1.363 (3) | C10—H10 | 0.9500 |
N3—C6 | 1.364 (3) | C11—C12 | 1.394 (3) |
N3—C5 | 1.371 (3) | C11—H11 | 0.9500 |
N4—N5 | 1.301 (3) | C12—H12 | 0.9500 |
N5—N6 | 1.358 (3) | C13—C18 | 1.384 (3) |
N6—C6 | 1.331 (3) | C13—C14 | 1.387 (3) |
C1—C2 | 1.400 (3) | C14—C15 | 1.380 (3) |
C2—C6 | 1.418 (3) | C14—H14 | 0.9500 |
C2—C3 | 1.432 (3) | C15—C16 | 1.377 (4) |
C3—C4 | 1.369 (3) | C15—H15 | 0.9500 |
C3—C7 | 1.479 (3) | C16—C17 | 1.383 (3) |
C4—H4 | 0.9500 | C17—C18 | 1.386 (3) |
C5—H5 | 0.9500 | C17—H17 | 0.9500 |
C7—C8 | 1.394 (3) | C18—H18 | 0.9500 |
C1—N1—C4 | 107.48 (18) | C9—C8—H8 | 119.3 |
C1—N1—C13 | 128.14 (18) | C7—C8—H8 | 119.3 |
C4—N1—C13 | 123.9 (2) | C10—C9—C8 | 120.4 (2) |
C5—N2—C1 | 115.2 (2) | C10—C9—H9 | 119.8 |
N4—N3—C6 | 109.3 (2) | C8—C9—H9 | 119.8 |
N4—N3—C5 | 125.7 (2) | C11—C10—C9 | 119.2 (2) |
C6—N3—C5 | 125.1 (2) | C11—C10—H10 | 120.4 |
N5—N4—N3 | 104.6 (2) | C9—C10—H10 | 120.4 |
N4—N5—N6 | 112.9 (2) | C10—C11—C12 | 121.0 (2) |
C6—N6—N5 | 105.6 (2) | C10—C11—H11 | 119.5 |
N2—C1—N1 | 123.28 (19) | C12—C11—H11 | 119.5 |
N2—C1—C2 | 128.2 (2) | C11—C12—C7 | 120.2 (2) |
N1—C1—C2 | 108.47 (19) | C11—C12—H12 | 119.9 |
C1—C2—C6 | 113.9 (2) | C7—C12—H12 | 119.9 |
C1—C2—C3 | 107.4 (2) | C18—C13—C14 | 120.1 (2) |
C6—C2—C3 | 138.5 (2) | C18—C13—N1 | 118.7 (2) |
C4—C3—C2 | 105.3 (2) | C14—C13—N1 | 121.2 (2) |
C4—C3—C7 | 123.9 (2) | C15—C14—C13 | 119.9 (2) |
C2—C3—C7 | 130.7 (2) | C15—C14—H14 | 120.1 |
C3—C4—N1 | 111.3 (2) | C13—C14—H14 | 120.1 |
C3—C4—H4 | 124.3 | C14—C15—C16 | 119.5 (2) |
N1—C4—H4 | 124.3 | C14—C15—H15 | 120.3 |
N2—C5—N3 | 121.5 (2) | C16—C15—H15 | 120.3 |
N2—C5—H5 | 119.2 | C15—C16—C17 | 121.5 (2) |
N3—C5—H5 | 119.2 | C15—C16—Br | 119.33 (19) |
N6—C6—N3 | 107.6 (2) | C17—C16—Br | 119.1 (2) |
N6—C6—C2 | 136.3 (2) | C16—C17—C18 | 118.7 (2) |
N3—C6—C2 | 116.0 (2) | C16—C17—H17 | 120.7 |
C8—C7—C12 | 117.7 (2) | C18—C17—H17 | 120.7 |
C8—C7—C3 | 119.4 (2) | C17—C18—C13 | 120.3 (2) |
C12—C7—C3 | 122.8 (2) | C17—C18—H18 | 119.9 |
C9—C8—C7 | 121.4 (2) | C13—C18—H18 | 119.9 |
C6—N3—N4—N5 | 0.2 (3) | C1—C2—C6—N6 | 175.2 (3) |
C5—N3—N4—N5 | 178.1 (3) | C3—C2—C6—N6 | 0.1 (6) |
N3—N4—N5—N6 | −0.1 (3) | C1—C2—C6—N3 | −2.1 (3) |
N4—N5—N6—C6 | −0.1 (3) | C3—C2—C6—N3 | −177.2 (3) |
C5—N2—C1—N1 | 177.5 (2) | C4—C3—C7—C8 | 9.1 (4) |
C5—N2—C1—C2 | −1.3 (4) | C2—C3—C7—C8 | −170.4 (3) |
C4—N1—C1—N2 | −179.8 (2) | C4—C3—C7—C12 | −169.9 (3) |
C13—N1—C1—N2 | −7.7 (4) | C2—C3—C7—C12 | 10.6 (4) |
C4—N1—C1—C2 | −0.8 (3) | C12—C7—C8—C9 | −0.2 (4) |
C13—N1—C1—C2 | 171.3 (2) | C3—C7—C8—C9 | −179.3 (2) |
N2—C1—C2—C6 | 3.1 (4) | C7—C8—C9—C10 | 0.3 (4) |
N1—C1—C2—C6 | −175.8 (2) | C8—C9—C10—C11 | −0.1 (4) |
N2—C1—C2—C3 | 179.7 (2) | C9—C10—C11—C12 | −0.2 (4) |
N1—C1—C2—C3 | 0.8 (3) | C10—C11—C12—C7 | 0.3 (4) |
C1—C2—C3—C4 | −0.5 (3) | C8—C7—C12—C11 | −0.1 (4) |
C6—C2—C3—C4 | 174.9 (3) | C3—C7—C12—C11 | 178.9 (2) |
C1—C2—C3—C7 | 179.1 (2) | C1—N1—C13—C18 | −143.0 (3) |
C6—C2—C3—C7 | −5.6 (5) | C4—N1—C13—C18 | 27.9 (4) |
C2—C3—C4—N1 | 0.0 (3) | C1—N1—C13—C14 | 37.2 (4) |
C7—C3—C4—N1 | −179.6 (2) | C4—N1—C13—C14 | −151.9 (2) |
C1—N1—C4—C3 | 0.5 (3) | C18—C13—C14—C15 | 0.1 (4) |
C13—N1—C4—C3 | −172.0 (2) | N1—C13—C14—C15 | 179.9 (2) |
C1—N2—C5—N3 | −1.4 (4) | C13—C14—C15—C16 | −1.4 (4) |
N4—N3—C5—N2 | −175.5 (3) | C14—C15—C16—C17 | 1.0 (4) |
C6—N3—C5—N2 | 2.1 (4) | C14—C15—C16—Br | −178.9 (2) |
N5—N6—C6—N3 | 0.2 (3) | C15—C16—C17—C18 | 0.7 (4) |
N5—N6—C6—C2 | −177.2 (3) | Br—C16—C17—C18 | −179.4 (2) |
N4—N3—C6—N6 | −0.3 (3) | C16—C17—C18—C13 | −2.0 (4) |
C5—N3—C6—N6 | −178.2 (2) | C14—C13—C18—C17 | 1.6 (4) |
N4—N3—C6—C2 | 177.8 (2) | N1—C13—C18—C17 | −178.2 (2) |
C5—N3—C6—C2 | −0.1 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
C8—H8···N4i | 0.95 | 2.54 | 3.421 (3) | 154 |
C4—H4···N5i | 0.95 | 2.60 | 3.532 (3) | 166 |
C5—H5···Brii | 0.95 | 2.87 | 3.667 (3) | 142 |
Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) −x, y+1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C18H11BrN6 |
Mr | 391.24 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 200 |
a, b, c (Å) | 12.0173 (5), 17.4007 (7), 7.4201 (4) |
β (°) | 91.004 (4) |
V (Å3) | 1551.37 (12) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.66 |
Crystal size (mm) | 0.47 × 0.39 × 0.22 |
Data collection | |
Diffractometer | Oxford Diffraction Gemini diffractometer |
Absorption correction | Multi-scan (CrysAlis RED; Oxford Diffraction, 2007) |
Tmin, Tmax | 0.494, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13458, 5032, 2606 |
Rint | 0.050 |
(sin θ/λ)max (Å−1) | 0.756 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.036, 0.090, 1.14 |
No. of reflections | 5032 |
No. of parameters | 227 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.72, −0.71 |
Computer programs: CrysAlis PRO (Oxford Diffraction, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C8—H8···N4i | 0.95 | 2.54 | 3.421 (3) | 153.6 |
C4—H4···N5i | 0.95 | 2.60 | 3.532 (3) | 166.4 |
C5—H5···Brii | 0.95 | 2.87 | 3.667 (3) | 141.9 |
Symmetry codes: (i) −x+1, y−1/2, −z+1/2; (ii) −x, y+1/2, −z+1/2. |
Acknowledgements
RJB acknowledges the NSF MRI program (grant No. CHE-0619278) for funds to purchase an X-ray diffractometer.
References
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Fused tetrazoles are known to be related to a variety of biological activities including anticancer relationships (Hiedo & Yasuo, 1960, 1961). Moreover their reductive ring cleavage ability may result in the formation of synthetically important 4-aminopyrimidine derivatives which are building blocks for the construction of ring systems such as pyrimidine and imidazole (Dave & Shukla, 1997). Furthermore, nucleophilic substitution with NaN3 results in either the formation of an azido group or tetrazole ring. An example of these reactions has been the synthesis of (7-Bromophenyl)-9-phenyl 7H-[1,2,3,4]tetrazolo[1,5-c]pyrrolo[3,2-e] pyrimidine by two different routes, either from 4-chloro-5-phenyl-(7-Bromophenyl)-7H-pyrrolo[2,3-d]pyrimidine or from 4-hydrazino-5-phenyl-(7-Bromophenyl)-7H-pyrrolo[2,3-d]pyrimidine (Dave & Shah, 1998) and then reduced to 4-amino-5-phenyl-(7-Bromophenyl)-7H-pyrrolo[2,3-d]pyrimidine. In view of the importance of these findings, we report the crystal structure of the title compound, C18H11BrN6, (I).
The title compond, (I), contains a pyrrole ring with successively fused pyrimidine and tetrazole rings, together with bromophenyl and benzene rings bonded at the N1 and C3 positions in a nearly planar fashion (Fig. 1). The nearly planar conformation of the pyrimidine ring is significant in that it is often found to be puckered which may be affected by the tetrazole and pyrrole ring fusion here. The least squares planes of the pyrimidine and tetrazole rings are oriented at the angles of 2.62 (15)° and 3.15 (15)° with the best plane of the pyrrole ring, respectively. The ortho-substituted 4-bromophenyl ring is twisted considerably, whereas the benzene ring at C3 is almost co-planar with the mean plane of the pyrrole ring, each having dihedral angles of 32.62 (15)° and 9.97 (16)°, respectively.
The crystal sructure is supported by weak C—H···Br and C—H···N intermolecular and weak C—H···N intramolecular interactions which link the molecules into chains along the [011] (Fig. 2, Table 1). An R22(8) graph-set motif (Bernstein et al., 1995) is established between the pyrrole, tetrazole and benzene rings resulting from these intermolecular interactions.
Crystal packing is also supported by two π-π stacking interactions (Fig. 3). One is between the centroids of two pyrrole rings [Cg2—Cg2; 3.7971 (17) Å; slippage = 1.318 Å; 1-x, 1-y, -z; Cg2 = N6/C3/C6/C5/C4]. The second is between the centroids of a pyrimidine (Cg3) and benzene (Cg4) ring [Cg3—Cg4: 3.5599 (16) Å; 1-x, 1-y, 1-z; Cg3 = N4/C1/C6/C3/N5/C2; Cg4 = C7—C12].
After a geometry optimized MOPAC PM3 computational calculation (Schmidt & Polik 2007) on (I), in vacuo, the angle between the mean planes of the pyrimidine, tetrazole and benzene groups become planar with the pyrrole ring in the local minimized structure. The dihedral angle between the ortho-substituted 4-bromophenyl ring and three planar tri-ring group becomes 42.28°. The separation of the H4A···H8A (2.111 Å) and H4A···H14A (2.301 Å) atoms between the pyrrole ring and the 4-bromophenyl and 9-phenyl rings before the calculations changed to 1.954 Å and 2.496 Å, respectively, after the calculation showing how the crystal packing effects significantly determine the twist of the 4-bromophenyl ring, in particular. In addition, the C3–C7 and N1–C13 bond lengths changed from 1.479 (3) Å and 1.430 (3) Å to 1.442 Å and 1.455 Å, respectively. It is clear that hydrogen bonding interactions and π-π stacking interactions significantly influence the twist angles for the molecule in this crystal.