organic compounds
1-(1-Hydroxy-9H-carbazol-2-yl)-3-methylbut-2-en-1-one
aDepartment of Chemistry, Youngstown State University, One University Plaza, Youngstown, OH 44555, USA, and bDepartment of Chemistry, Bharathiar University, Coimbatore 641 046, Tamil Nadu, India
*Correspondence e-mail: mzeller@ysu.edu
The title compound, C17H15NO2, was prepared as one of two products of the AlCl3/POCl3-catalysed reaction of 9-carbazol-1-ol with 3,3-dimethyacrylic acid. It crystallizes with two crystallographically independent molecules, A and B, which are virtually superimposable but not related by any translational or other Both independent molecules are almost planar [r.m.s. deviations from planarity = 0.053 (1) and 0.079 (1) Å in A and B, respectively] and contain an intramolecular O—H⋯O hydrogen bond. Each type of molecules is connected via pairs of N—H⋯O hydrogen bonds, forming centrosymmetric A2 and B2 dimers which are, in turn, arranged in offset π-stacks extending along the a-axis direction. The offset of the dimers and the tilt angle of the molecules allows the formation of alternating C—H⋯π interactions between A and B molecules of parallel stacks.
Related literature
For synthetic strategies for the synthesis of carbazole and its derivatives, see: Chakraborty (1993). For the isolation of pyranocarbazoles from various plant species, see: Knölker & Reddy (2002, and references therein). For the synthesis of related compounds, see: Kavitha & Rajendra Prasad (2003a,b); Patel (1982). For the structure of the second product of the reaction yielding the title compound, see: Sridharan et al. (2008).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXTL, PLATON (Spek, 2009) and publCIF (McMahon & Westrip, 2008).
Supporting information
https://doi.org/10.1107/S1600536810000322/bv2136sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810000322/bv2136Isup2.hkl
The title compound was synthesized as described previously by Sridharan et al. (2008): 9-Carbazole-1-ol (0.001 mol) and 3,3-dimethylacrylic acid (0.001 mol) were dissolved in the mixture of an ice-cold solution of AlCl3/POCl3 (400 mg/ 6 ml) and kept at room temperature for 24 h. The reaction process as monitored by TLC indicated the formation of two compounds. After completion of the reaction (disappearance of starting material), the residue was poured onto ice water. The solid separated out was filtered, dried and then separated by
on silica gel using petroleum ether/ ethyl acetate (98:2) as eluents to yield the title compound 1-(1-hydroxy-9H-carbazol-2-yl)-3-methylbutan-1-one and 2,2-dimethyl-2,3-dihydropyrano[2,3-a]carbazol-4(11H)-one, respectively as yellow prisms (Figure 1). The title compound was recrystallized from ethanol. Yield: 0.114 g (43%), m.p. 482- 484 K (209 - 211°C).Hydrogen atoms were placed in calculated positions with C—H bond distances of 0.95 Å (aromatic H), 0.88 Å (N—H) or 0.84 Å (O—H) and were refined with an isotropic displacement parameter 1.5 (methyl, hydroxyl) or 1.2 times (all others) that of the adjacent carbon or oxygen atom. Methyl and hydroxyl hydrogen atoms were allowed to rotate at fixed angle around the C—C/O bond to best fit the experimental electron density.
A number of carbazole
with intriguing novel structures and useful biological activities were isolated from natural sources over the past decades, which led towards the development of new synthetic strategies for the synthesis of carbazole and its derivatives (Chakraborty, 1993). Among the physiologically active carbazoles found aree pyranocarbazole which have a C-13, C-18 or C-23 framework (Knölker & Reddy, 2002). The basic unit is the C-12 carbazole nucleus with one carbon attached as a methyl, formyl, carboxylic or ester group. This C-13 unit then leads to C-18 or C-23 carbazole depending on whether it combines with a hemi-terpenoid or a mono-terpenoid unit. Another observation is that in all the pyranocarbazole derivatives isolated so far, the oxygen atom of the pyran ring is attached to carbon-2 of the carbazole nucleus to form essentially pyrano[3,2-a]carbazole as in grinimbine. Patel (1982, and references therein) has reported the synthesis of indolo[3,2-h]chromanones from 1-hydroxycarbazoles which were then converted to isomers of grinimbine. Here the yields of compound were reported to be moderate since it was obtained along with the respective 2-acryloyl-1-hydroxycarbazole.In this context we aimed to prepare pyrano[2,3-a]carbazoles using 1-hydroxycarbazoles as starting synthons under various reaction conditions (Kavitha & Rajendra Prasad, 2003a,b, and references therein). Using the catalyst mixture AlCl3/POCl3 along with 9-carbazole-1-ol and 3,3-dimethyacrylic acid as the reactants we obatined a mixture of two products i.e., 1-(1-hydroxy-9H-carbazol-2-yl)-3-methylbutan-1-one and 2,2-dimethyl-2,3-dihydropyrano-[2,3-a]carbazol- 4(11H)-one as described in an earlier publication (Sridharan et al., 2008) and in Figure 1. The structure of the cyclized compound 2,2-dimethyl-2,3-dihydropyrano-[2,3-a]carbazol- 4(11H)-one was described in the earlier structure report (Sridharan et al., 2008). Here we would like to present the structure of the second compound isolated, 1-(1-hydroxy-9H-carbazol-2-yl)-3-methylbutan-1-one.
The title compound crystallizes in a triclinic setting with two crystallographically independent molecules, A and B (Figure 2). The two molecules are virtually superimposable (see overlay of the two structures in Figure 3) but a PLATON symmetry check did not reveal any translational or other
even when using relaxed tolerances (Spek, 2009). Both independent molecules are planar, r.m.s. deviations from planarity are 0.053 and 0.079 Å2, respectively, and they are tilted against each other within the structure with a dihedral angle of the planes of the A and B molecules of 53.11 (2)°.Each molecule exhibits a strong intramolecular O—H···O hydrogen bond between the phenolic hydroxyl group and the keto oxgen atom (Table 1). In addition each type of molecules is connected via pairs of N—H···O hydrogen bonds to another molecule of the same type to form centrosymmetric A2 and B2 dimers (the planes of the dimers are parallel but slightly shifted against each other, Figure 4). The dimers are in turn arranged in offset π-stacks that are extending along the a axis direction. The metrics of the interaction are best given for the interaction of the phenol rings C7A to C12A and C7B to C12B with their respective symmetry equivalent counterparts at 2 - x, -y, 1 - z and 1 - x, -y, 2 - z. For these the centroid to centroid distances are 4.083 (1) and 4.089 (1) Å, the interplanar distances are 3.2985 (6) and 3.2992 (7) Å, and the slippages are 2.407 and 2.415 Å, respectively. The offset of the dimers and the tilt angle of the molecules allows for the formation of alternating C—H···π interactions between A and B molecules of parallel stacks. C—H···π interactions are given in Table 1, with ring centroids 1, 2 and 3 being the phenyl rings C1B to C6B, C7A to C12A and C1A to C6A, respectively.
For synthetic strategies for the synthesis of carbazole and its derivatives, see: Chakraborty (1993). For the isolation of pyranocarbazoles from various plant species, see: Knölker & Reddy (2002, and references therein). For the synthesis of related compounds, see: Kavitha & Rajendra Prasad (2003a,b); Patel (1982). For the structure of the second product of the reaction yielding the title compound, see: Sridharan et al. (2008). PLATON (Spek, 2009) was used for structure validation and to test for pseudosymmetry.
Data collection: APEX2 (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and publCIF (McMahon & Westrip, 2008).Fig. 1. Synthesis of the title compound. | |
Fig. 2. Thermal ellipsoid plot of the two independent molecules with atom numbering scheme. Atomic displacement parameters are at the 50% probablity level. | |
Fig. 3. Least square overlay of molecules A (red) and B (blue) | |
Fig. 4. One of the H-bonded dimers. Dashed blue lines respresent hydrogen bonds. Molecule B (not shown) forms dimers with essentially the same geometry. Symmetry operator ii: -x + 1, -y, -z + 1. | |
Fig. 5. Packing diagram showing the arrangement of molecules and intermolecular interactions. Blue dashed lines: O—H···H and N—H···O hydrogen bonds. Orange dahsed lines: C—H···π interactions. Red dashed lines connect the centroids of π-stacked molecules (see text for details). |
C17H15NO2 | Z = 4 |
Mr = 265.30 | F(000) = 560 |
Triclinic, P1 | Dx = 1.363 Mg m−3 |
Hall symbol: -P 1 | Melting point: 483 K |
a = 6.3416 (9) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 15.202 (2) Å | Cell parameters from 3373 reflections |
c = 15.462 (3) Å | θ = 2.7–29.0° |
α = 115.216 (5)° | µ = 0.09 mm−1 |
β = 95.042 (5)° | T = 100 K |
γ = 101.922 (4)° | Plate, orange |
V = 1293.2 (4) Å3 | 0.31 × 0.19 × 0.16 mm |
Bruker SMART APEX CCD diffractometer | 6364 independent reflections |
Radiation source: fine-focus sealed tube | 4788 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.026 |
ω scans | θmax = 28.3°, θmin = 1.5° |
Absorption correction: multi-scan (APEX2; Bruker, 2007) | h = −8→8 |
Tmin = 0.749, Tmax = 0.986 | k = −20→20 |
13387 measured reflections | l = −20→20 |
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)] = 0.048 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.123 | H-atom parameters constrained |
S = 1.01 | w = 1/[σ2(Fo2) + (0.0531P)2 + 0.5261P] where P = (Fo2 + 2Fc2)/3 |
6364 reflections | (Δ/σ)max < 0.001 |
367 parameters | Δρmax = 0.35 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
C17H15NO2 | γ = 101.922 (4)° |
Mr = 265.30 | V = 1293.2 (4) Å3 |
Triclinic, P1 | Z = 4 |
a = 6.3416 (9) Å | Mo Kα radiation |
b = 15.202 (2) Å | µ = 0.09 mm−1 |
c = 15.462 (3) Å | T = 100 K |
α = 115.216 (5)° | 0.31 × 0.19 × 0.16 mm |
β = 95.042 (5)° |
Bruker SMART APEX CCD diffractometer | 6364 independent reflections |
Absorption correction: multi-scan (APEX2; Bruker, 2007) | 4788 reflections with I > 2σ(I) |
Tmin = 0.749, Tmax = 0.986 | Rint = 0.026 |
13387 measured reflections |
R[F2 > 2σ(F2)] = 0.048 | 0 restraints |
wR(F2) = 0.123 | H-atom parameters constrained |
S = 1.01 | Δρmax = 0.35 e Å−3 |
6364 reflections | Δρmin = −0.25 e Å−3 |
367 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 | ||
C1A | 0.7818 (2) | 0.24361 (12) | 0.56142 (11) | 0.0177 (3) | |
C2A | 0.6819 (3) | 0.31619 (12) | 0.61788 (11) | 0.0198 (3) | |
H2A | 0.5434 | 0.2975 | 0.6334 | 0.024* | |
C3A | 0.7926 (3) | 0.41613 (12) | 0.65017 (12) | 0.0220 (3) | |
H3A | 0.7278 | 0.4672 | 0.6882 | 0.026* | |
C4A | 0.9985 (3) | 0.44455 (12) | 0.62833 (12) | 0.0224 (3) | |
H4A | 1.0709 | 0.5141 | 0.6522 | 0.027* | |
C5A | 1.0970 (3) | 0.37214 (12) | 0.57234 (11) | 0.0206 (3) | |
H5A | 1.2366 | 0.3916 | 0.5580 | 0.025* | |
C6A | 0.9881 (2) | 0.26989 (12) | 0.53716 (11) | 0.0175 (3) | |
C7A | 0.8360 (2) | −0.00303 (12) | 0.40772 (11) | 0.0164 (3) | |
C8A | 0.8533 (2) | 0.09890 (12) | 0.46513 (11) | 0.0165 (3) | |
C9A | 1.0325 (2) | 0.17577 (11) | 0.47439 (11) | 0.0164 (3) | |
C10A | 1.2026 (2) | 0.15003 (12) | 0.42390 (11) | 0.0179 (3) | |
H10A | 1.3252 | 0.2011 | 0.4289 | 0.021* | |
C11A | 1.1880 (2) | 0.04945 (12) | 0.36717 (11) | 0.0177 (3) | |
H11A | 1.3029 | 0.0321 | 0.3334 | 0.021* | |
C12A | 1.0068 (2) | −0.02914 (11) | 0.35748 (11) | 0.0164 (3) | |
C13A | 0.9842 (2) | −0.13732 (12) | 0.29741 (11) | 0.0181 (3) | |
C14A | 1.1542 (3) | −0.17222 (12) | 0.24376 (11) | 0.0190 (3) | |
H14A | 1.2805 | −0.1225 | 0.2493 | 0.023* | |
C15A | 1.1436 (3) | −0.26979 (12) | 0.18718 (11) | 0.0201 (3) | |
C16A | 0.9526 (3) | −0.35834 (12) | 0.16533 (12) | 0.0238 (3) | |
H16A | 0.9365 | −0.3639 | 0.2254 | 0.036* | |
H16B | 0.9790 | −0.4204 | 0.1171 | 0.036* | |
H16C | 0.8178 | −0.3485 | 0.1392 | 0.036* | |
C17A | 1.3362 (3) | −0.29673 (13) | 0.14197 (12) | 0.0237 (3) | |
H17A | 1.4516 | −0.2348 | 0.1590 | 0.036* | |
H17B | 1.2888 | −0.3343 | 0.0709 | 0.036* | |
H17C | 1.3937 | −0.3386 | 0.1665 | 0.036* | |
C1B | 0.6941 (2) | −0.19517 (12) | 0.77600 (11) | 0.0178 (3) | |
C2B | 0.7881 (3) | −0.27530 (12) | 0.73361 (11) | 0.0205 (3) | |
H2B | 0.9299 | −0.2729 | 0.7617 | 0.025* | |
C3B | 0.6655 (3) | −0.35811 (12) | 0.64911 (12) | 0.0224 (3) | |
H3B | 0.7260 | −0.4132 | 0.6179 | 0.027* | |
C4B | 0.4536 (3) | −0.36301 (12) | 0.60808 (12) | 0.0218 (3) | |
H4B | 0.3725 | −0.4217 | 0.5508 | 0.026* | |
C5B | 0.3619 (3) | −0.28337 (12) | 0.65017 (11) | 0.0197 (3) | |
H5B | 0.2188 | −0.2870 | 0.6223 | 0.024* | |
C6B | 0.4834 (2) | −0.19745 (12) | 0.73445 (11) | 0.0171 (3) | |
C7B | 0.6547 (2) | 0.05079 (11) | 0.94208 (11) | 0.0168 (3) | |
C8B | 0.6330 (2) | −0.04659 (11) | 0.86929 (11) | 0.0169 (3) | |
C9B | 0.4459 (2) | −0.10097 (11) | 0.79421 (11) | 0.0163 (3) | |
C10B | 0.2753 (2) | −0.05548 (12) | 0.79034 (11) | 0.0180 (3) | |
H10B | 0.1488 | −0.0906 | 0.7394 | 0.022* | |
C11B | 0.2948 (2) | 0.04032 (12) | 0.86139 (11) | 0.0181 (3) | |
H11B | 0.1798 | 0.0710 | 0.8586 | 0.022* | |
C12B | 0.4818 (2) | 0.09561 (11) | 0.93938 (11) | 0.0168 (3) | |
C13B | 0.5056 (2) | 0.19747 (12) | 1.01756 (11) | 0.0182 (3) | |
C14B | 0.3307 (2) | 0.24795 (12) | 1.02043 (11) | 0.0192 (3) | |
H14B | 0.1949 | 0.2088 | 0.9761 | 0.023* | |
C15B | 0.3472 (3) | 0.34515 (12) | 1.08080 (12) | 0.0205 (3) | |
C16B | 0.5470 (3) | 0.41995 (13) | 1.15485 (13) | 0.0277 (4) | |
H16D | 0.5608 | 0.4072 | 1.2118 | 0.042* | |
H16E | 0.5326 | 0.4885 | 1.1750 | 0.042* | |
H16F | 0.6781 | 0.4130 | 1.1262 | 0.042* | |
C17B | 0.1508 (3) | 0.38542 (13) | 1.07778 (13) | 0.0267 (4) | |
H17D | 0.0296 | 0.3324 | 1.0266 | 0.040* | |
H17E | 0.1892 | 0.4432 | 1.0637 | 0.040* | |
H17F | 0.1055 | 0.4070 | 1.1410 | 0.040* | |
N1A | 0.7042 (2) | 0.13977 (10) | 0.51833 (9) | 0.0180 (3) | |
H1A | 0.5806 | 0.1055 | 0.5239 | 0.022* | |
N1B | 0.7808 (2) | −0.10416 (10) | 0.85829 (9) | 0.0182 (3) | |
H1B | 0.9085 | −0.0858 | 0.8972 | 0.022* | |
O1A | 0.65515 (17) | −0.07178 (8) | 0.40157 (8) | 0.0203 (2) | |
H1C | 0.6662 | −0.1302 | 0.3672 | 0.030* | |
O2A | 0.81641 (18) | −0.20127 (8) | 0.29274 (8) | 0.0235 (3) | |
O1B | 0.83971 (17) | 0.09766 (8) | 1.01146 (8) | 0.0207 (2) | |
H1D | 0.8316 | 0.1547 | 1.0516 | 0.031* | |
O2B | 0.67656 (18) | 0.24120 (8) | 1.08281 (8) | 0.0233 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1A | 0.0170 (7) | 0.0206 (8) | 0.0164 (7) | 0.0041 (6) | 0.0024 (6) | 0.0099 (6) |
C2A | 0.0189 (7) | 0.0237 (8) | 0.0185 (8) | 0.0080 (6) | 0.0058 (6) | 0.0097 (7) |
C3A | 0.0249 (8) | 0.0231 (8) | 0.0192 (8) | 0.0095 (7) | 0.0050 (6) | 0.0093 (7) |
C4A | 0.0245 (8) | 0.0185 (8) | 0.0237 (8) | 0.0043 (6) | 0.0023 (6) | 0.0103 (7) |
C5A | 0.0184 (7) | 0.0236 (8) | 0.0207 (8) | 0.0043 (6) | 0.0033 (6) | 0.0115 (7) |
C6A | 0.0170 (7) | 0.0210 (8) | 0.0166 (7) | 0.0059 (6) | 0.0031 (6) | 0.0103 (6) |
C7A | 0.0139 (7) | 0.0206 (8) | 0.0159 (7) | 0.0037 (6) | 0.0027 (6) | 0.0100 (6) |
C8A | 0.0149 (7) | 0.0214 (8) | 0.0153 (7) | 0.0059 (6) | 0.0034 (6) | 0.0097 (6) |
C9A | 0.0155 (7) | 0.0205 (8) | 0.0149 (7) | 0.0039 (6) | 0.0015 (6) | 0.0102 (6) |
C10A | 0.0153 (7) | 0.0210 (8) | 0.0192 (8) | 0.0032 (6) | 0.0036 (6) | 0.0117 (6) |
C11A | 0.0149 (7) | 0.0228 (8) | 0.0183 (7) | 0.0060 (6) | 0.0056 (6) | 0.0112 (6) |
C12A | 0.0156 (7) | 0.0204 (8) | 0.0152 (7) | 0.0056 (6) | 0.0028 (6) | 0.0097 (6) |
C13A | 0.0168 (7) | 0.0213 (8) | 0.0172 (7) | 0.0045 (6) | 0.0025 (6) | 0.0101 (6) |
C14A | 0.0176 (7) | 0.0213 (8) | 0.0197 (8) | 0.0058 (6) | 0.0052 (6) | 0.0101 (7) |
C15A | 0.0201 (7) | 0.0252 (8) | 0.0181 (8) | 0.0082 (6) | 0.0040 (6) | 0.0117 (7) |
C16A | 0.0226 (8) | 0.0212 (8) | 0.0264 (9) | 0.0071 (6) | 0.0061 (7) | 0.0088 (7) |
C17A | 0.0218 (8) | 0.0263 (9) | 0.0233 (8) | 0.0096 (7) | 0.0065 (6) | 0.0098 (7) |
C1B | 0.0183 (7) | 0.0198 (8) | 0.0167 (7) | 0.0043 (6) | 0.0047 (6) | 0.0097 (6) |
C2B | 0.0215 (8) | 0.0223 (8) | 0.0208 (8) | 0.0077 (6) | 0.0059 (6) | 0.0114 (7) |
C3B | 0.0302 (9) | 0.0203 (8) | 0.0210 (8) | 0.0097 (7) | 0.0098 (7) | 0.0111 (7) |
C4B | 0.0268 (8) | 0.0187 (8) | 0.0167 (8) | 0.0022 (6) | 0.0041 (6) | 0.0071 (6) |
C5B | 0.0191 (7) | 0.0232 (8) | 0.0174 (7) | 0.0033 (6) | 0.0038 (6) | 0.0107 (7) |
C6B | 0.0168 (7) | 0.0194 (8) | 0.0175 (7) | 0.0050 (6) | 0.0057 (6) | 0.0103 (6) |
C7B | 0.0151 (7) | 0.0200 (8) | 0.0151 (7) | 0.0031 (6) | 0.0016 (6) | 0.0090 (6) |
C8B | 0.0154 (7) | 0.0201 (8) | 0.0177 (7) | 0.0054 (6) | 0.0041 (6) | 0.0104 (6) |
C9B | 0.0164 (7) | 0.0184 (7) | 0.0145 (7) | 0.0028 (6) | 0.0043 (6) | 0.0083 (6) |
C10B | 0.0148 (7) | 0.0226 (8) | 0.0173 (7) | 0.0040 (6) | 0.0014 (6) | 0.0106 (6) |
C11B | 0.0157 (7) | 0.0216 (8) | 0.0194 (8) | 0.0068 (6) | 0.0028 (6) | 0.0109 (6) |
C12B | 0.0171 (7) | 0.0187 (8) | 0.0168 (7) | 0.0054 (6) | 0.0047 (6) | 0.0098 (6) |
C13B | 0.0186 (7) | 0.0196 (8) | 0.0179 (7) | 0.0049 (6) | 0.0050 (6) | 0.0097 (6) |
C14B | 0.0169 (7) | 0.0223 (8) | 0.0184 (8) | 0.0055 (6) | 0.0026 (6) | 0.0093 (7) |
C15B | 0.0205 (8) | 0.0233 (8) | 0.0208 (8) | 0.0071 (6) | 0.0080 (6) | 0.0116 (7) |
C16B | 0.0222 (8) | 0.0213 (9) | 0.0325 (10) | 0.0055 (7) | 0.0056 (7) | 0.0060 (8) |
C17B | 0.0264 (9) | 0.0265 (9) | 0.0246 (9) | 0.0128 (7) | 0.0041 (7) | 0.0071 (7) |
N1A | 0.0156 (6) | 0.0186 (6) | 0.0200 (7) | 0.0046 (5) | 0.0070 (5) | 0.0085 (5) |
N1B | 0.0145 (6) | 0.0198 (7) | 0.0187 (6) | 0.0060 (5) | 0.0013 (5) | 0.0071 (5) |
O1A | 0.0173 (5) | 0.0181 (5) | 0.0243 (6) | 0.0028 (4) | 0.0085 (4) | 0.0087 (5) |
O2A | 0.0206 (6) | 0.0208 (6) | 0.0263 (6) | 0.0032 (5) | 0.0082 (5) | 0.0085 (5) |
O1B | 0.0179 (5) | 0.0194 (6) | 0.0194 (6) | 0.0052 (4) | −0.0021 (4) | 0.0048 (5) |
O2B | 0.0209 (6) | 0.0205 (6) | 0.0226 (6) | 0.0048 (5) | −0.0020 (5) | 0.0060 (5) |
C1A—N1A | 1.380 (2) | C1B—C6B | 1.418 (2) |
C1A—C2A | 1.395 (2) | C2B—C3B | 1.383 (2) |
C1A—C6A | 1.418 (2) | C2B—H2B | 0.9500 |
C2A—C3A | 1.379 (2) | C3B—C4B | 1.408 (2) |
C2A—H2A | 0.9500 | C3B—H3B | 0.9500 |
C3A—C4A | 1.406 (2) | C4B—C5B | 1.383 (2) |
C3A—H3A | 0.9500 | C4B—H4B | 0.9500 |
C4A—C5A | 1.385 (2) | C5B—C6B | 1.398 (2) |
C4A—H4A | 0.9500 | C5B—H5B | 0.9500 |
C5A—C6A | 1.400 (2) | C6B—C9B | 1.446 (2) |
C5A—H5A | 0.9500 | C7B—O1B | 1.3478 (17) |
C6A—C9A | 1.449 (2) | C7B—C8B | 1.395 (2) |
C7A—O1A | 1.3479 (17) | C7B—C12B | 1.412 (2) |
C7A—C8A | 1.393 (2) | C8B—N1B | 1.3833 (19) |
C7A—C12A | 1.414 (2) | C8B—C9B | 1.405 (2) |
C8A—N1A | 1.3786 (19) | C9B—C10B | 1.409 (2) |
C8A—C9A | 1.399 (2) | C10B—C11B | 1.372 (2) |
C9A—C10A | 1.410 (2) | C10B—H10B | 0.9500 |
C10A—C11A | 1.378 (2) | C11B—C12B | 1.428 (2) |
C10A—H10A | 0.9500 | C11B—H11B | 0.9500 |
C11A—C12A | 1.421 (2) | C12B—C13B | 1.469 (2) |
C11A—H11A | 0.9500 | C13B—O2B | 1.2545 (19) |
C12A—C13A | 1.472 (2) | C13B—C14B | 1.467 (2) |
C13A—O2A | 1.2577 (18) | C14B—C15B | 1.345 (2) |
C13A—C14A | 1.466 (2) | C14B—H14B | 0.9500 |
C14A—C15A | 1.347 (2) | C15B—C16B | 1.500 (2) |
C14A—H14A | 0.9500 | C15B—C17B | 1.502 (2) |
C15A—C17A | 1.503 (2) | C16B—H16D | 0.9800 |
C15A—C16A | 1.504 (2) | C16B—H16E | 0.9800 |
C16A—H16A | 0.9800 | C16B—H16F | 0.9800 |
C16A—H16B | 0.9800 | C17B—H17D | 0.9800 |
C16A—H16C | 0.9800 | C17B—H17E | 0.9800 |
C17A—H17A | 0.9800 | C17B—H17F | 0.9800 |
C17A—H17B | 0.9800 | N1A—H1A | 0.8800 |
C17A—H17C | 0.9800 | N1B—H1B | 0.8800 |
C1B—N1B | 1.378 (2) | O1A—H1C | 0.8400 |
C1B—C2B | 1.399 (2) | O1B—H1D | 0.8400 |
N1A—C1A—C2A | 128.77 (14) | C3B—C2B—H2B | 121.5 |
N1A—C1A—C6A | 108.97 (13) | C1B—C2B—H2B | 121.5 |
C2A—C1A—C6A | 122.23 (14) | C2B—C3B—C4B | 121.82 (15) |
C3A—C2A—C1A | 117.24 (15) | C2B—C3B—H3B | 119.1 |
C3A—C2A—H2A | 121.4 | C4B—C3B—H3B | 119.1 |
C1A—C2A—H2A | 121.4 | C5B—C4B—C3B | 120.82 (15) |
C2A—C3A—C4A | 121.82 (15) | C5B—C4B—H4B | 119.6 |
C2A—C3A—H3A | 119.1 | C3B—C4B—H4B | 119.6 |
C4A—C3A—H3A | 119.1 | C4B—C5B—C6B | 118.86 (15) |
C5A—C4A—C3A | 120.66 (15) | C4B—C5B—H5B | 120.6 |
C5A—C4A—H4A | 119.7 | C6B—C5B—H5B | 120.6 |
C3A—C4A—H4A | 119.7 | C5B—C6B—C1B | 119.39 (14) |
C4A—C5A—C6A | 119.11 (15) | C5B—C6B—C9B | 133.95 (14) |
C4A—C5A—H5A | 120.4 | C1B—C6B—C9B | 106.65 (13) |
C6A—C5A—H5A | 120.4 | O1B—C7B—C8B | 118.52 (13) |
C5A—C6A—C1A | 118.91 (14) | O1B—C7B—C12B | 123.14 (14) |
C5A—C6A—C9A | 134.61 (14) | C8B—C7B—C12B | 118.34 (13) |
C1A—C6A—C9A | 106.44 (13) | N1B—C8B—C7B | 127.82 (14) |
O1A—C7A—C8A | 118.30 (13) | N1B—C8B—C9B | 109.87 (13) |
O1A—C7A—C12A | 123.26 (14) | C7B—C8B—C9B | 122.31 (14) |
C8A—C7A—C12A | 118.43 (13) | C8B—C9B—C10B | 119.36 (14) |
N1A—C8A—C7A | 127.35 (14) | C8B—C9B—C6B | 106.02 (13) |
N1A—C8A—C9A | 110.20 (13) | C10B—C9B—C6B | 134.60 (14) |
C7A—C8A—C9A | 122.44 (14) | C11B—C10B—C9B | 118.89 (14) |
C8A—C9A—C10A | 119.29 (14) | C11B—C10B—H10B | 120.6 |
C8A—C9A—C6A | 106.02 (13) | C9B—C10B—H10B | 120.6 |
C10A—C9A—C6A | 134.66 (14) | C10B—C11B—C12B | 122.35 (14) |
C11A—C10A—C9A | 118.85 (14) | C10B—C11B—H11B | 118.8 |
C11A—C10A—H10A | 120.6 | C12B—C11B—H11B | 118.8 |
C9A—C10A—H10A | 120.6 | C7B—C12B—C11B | 118.72 (14) |
C10A—C11A—C12A | 122.25 (14) | C7B—C12B—C13B | 117.64 (13) |
C10A—C11A—H11A | 118.9 | C11B—C12B—C13B | 123.64 (14) |
C12A—C11A—H11A | 118.9 | O2B—C13B—C14B | 119.83 (14) |
C7A—C12A—C11A | 118.74 (14) | O2B—C13B—C12B | 119.54 (14) |
C7A—C12A—C13A | 117.25 (13) | C14B—C13B—C12B | 120.63 (14) |
C11A—C12A—C13A | 124.01 (14) | C15B—C14B—C13B | 125.25 (15) |
O2A—C13A—C14A | 119.28 (14) | C15B—C14B—H14B | 117.4 |
O2A—C13A—C12A | 119.28 (14) | C13B—C14B—H14B | 117.4 |
C14A—C13A—C12A | 121.43 (13) | C14B—C15B—C16B | 125.88 (15) |
C15A—C14A—C13A | 124.55 (14) | C14B—C15B—C17B | 119.22 (15) |
C15A—C14A—H14A | 117.7 | C16B—C15B—C17B | 114.89 (14) |
C13A—C14A—H14A | 117.7 | C15B—C16B—H16D | 109.5 |
C14A—C15A—C17A | 119.65 (15) | C15B—C16B—H16E | 109.5 |
C14A—C15A—C16A | 125.41 (15) | H16D—C16B—H16E | 109.5 |
C17A—C15A—C16A | 114.93 (14) | C15B—C16B—H16F | 109.5 |
C15A—C16A—H16A | 109.5 | H16D—C16B—H16F | 109.5 |
C15A—C16A—H16B | 109.5 | H16E—C16B—H16F | 109.5 |
H16A—C16A—H16B | 109.5 | C15B—C17B—H17D | 109.5 |
C15A—C16A—H16C | 109.5 | C15B—C17B—H17E | 109.5 |
H16A—C16A—H16C | 109.5 | H17D—C17B—H17E | 109.5 |
H16B—C16A—H16C | 109.5 | C15B—C17B—H17F | 109.5 |
C15A—C17A—H17A | 109.5 | H17D—C17B—H17F | 109.5 |
C15A—C17A—H17B | 109.5 | H17E—C17B—H17F | 109.5 |
H17A—C17A—H17B | 109.5 | C8A—N1A—C1A | 108.35 (12) |
C15A—C17A—H17C | 109.5 | C8A—N1A—H1A | 125.8 |
H17A—C17A—H17C | 109.5 | C1A—N1A—H1A | 125.8 |
H17B—C17A—H17C | 109.5 | C1B—N1B—C8B | 108.43 (12) |
N1B—C1B—C2B | 128.95 (14) | C1B—N1B—H1B | 125.8 |
N1B—C1B—C6B | 109.01 (13) | C8B—N1B—H1B | 125.8 |
C2B—C1B—C6B | 122.02 (14) | C7A—O1A—H1C | 109.5 |
C3B—C2B—C1B | 117.05 (15) | C7B—O1B—H1D | 109.5 |
N1A—C1A—C2A—C3A | −178.05 (15) | C3B—C4B—C5B—C6B | 0.0 (2) |
C6A—C1A—C2A—C3A | −0.2 (2) | C4B—C5B—C6B—C1B | −1.7 (2) |
C1A—C2A—C3A—C4A | −0.6 (2) | C4B—C5B—C6B—C9B | 176.91 (15) |
C2A—C3A—C4A—C5A | 0.5 (2) | N1B—C1B—C6B—C5B | −179.42 (13) |
C3A—C4A—C5A—C6A | 0.3 (2) | C2B—C1B—C6B—C5B | 2.0 (2) |
C4A—C5A—C6A—C1A | −1.1 (2) | N1B—C1B—C6B—C9B | 1.62 (16) |
C4A—C5A—C6A—C9A | 176.35 (16) | C2B—C1B—C6B—C9B | −176.96 (14) |
N1A—C1A—C6A—C5A | 179.28 (13) | O1B—C7B—C8B—N1B | 0.3 (2) |
C2A—C1A—C6A—C5A | 1.1 (2) | C12B—C7B—C8B—N1B | −179.84 (14) |
N1A—C1A—C6A—C9A | 1.17 (16) | O1B—C7B—C8B—C9B | 180.00 (13) |
C2A—C1A—C6A—C9A | −177.06 (14) | C12B—C7B—C8B—C9B | −0.1 (2) |
O1A—C7A—C8A—N1A | 0.1 (2) | N1B—C8B—C9B—C10B | −178.81 (13) |
C12A—C7A—C8A—N1A | 178.99 (14) | C7B—C8B—C9B—C10B | 1.4 (2) |
O1A—C7A—C8A—C9A | −178.67 (13) | N1B—C8B—C9B—C6B | 0.17 (17) |
C12A—C7A—C8A—C9A | 0.2 (2) | C7B—C8B—C9B—C6B | −179.61 (13) |
N1A—C8A—C9A—C10A | −178.80 (13) | C5B—C6B—C9B—C8B | −179.81 (16) |
C7A—C8A—C9A—C10A | 0.2 (2) | C1B—C6B—C9B—C8B | −1.08 (16) |
N1A—C8A—C9A—C6A | −0.38 (16) | C5B—C6B—C9B—C10B | −1.1 (3) |
C7A—C8A—C9A—C6A | 178.57 (13) | C1B—C6B—C9B—C10B | 177.67 (16) |
C5A—C6A—C9A—C8A | −178.16 (16) | C8B—C9B—C10B—C11B | −1.3 (2) |
C1A—C6A—C9A—C8A | −0.48 (16) | C6B—C9B—C10B—C11B | −179.88 (15) |
C5A—C6A—C9A—C10A | −0.1 (3) | C9B—C10B—C11B—C12B | −0.2 (2) |
C1A—C6A—C9A—C10A | 177.58 (16) | O1B—C7B—C12B—C11B | 178.60 (14) |
C8A—C9A—C10A—C11A | −0.4 (2) | C8B—C7B—C12B—C11B | −1.3 (2) |
C6A—C9A—C10A—C11A | −178.27 (15) | O1B—C7B—C12B—C13B | −1.2 (2) |
C9A—C10A—C11A—C12A | 0.3 (2) | C8B—C7B—C12B—C13B | 178.92 (13) |
O1A—C7A—C12A—C11A | 178.50 (13) | C10B—C11B—C12B—C7B | 1.5 (2) |
C8A—C7A—C12A—C11A | −0.3 (2) | C10B—C11B—C12B—C13B | −178.77 (14) |
O1A—C7A—C12A—C13A | −1.2 (2) | C7B—C12B—C13B—O2B | 0.6 (2) |
C8A—C7A—C12A—C13A | 180.00 (13) | C11B—C12B—C13B—O2B | −179.21 (14) |
C10A—C11A—C12A—C7A | 0.1 (2) | C7B—C12B—C13B—C14B | −178.87 (14) |
C10A—C11A—C12A—C13A | 179.72 (14) | C11B—C12B—C13B—C14B | 1.4 (2) |
C7A—C12A—C13A—O2A | 0.3 (2) | O2B—C13B—C14B—C15B | 9.6 (2) |
C11A—C12A—C13A—O2A | −179.31 (14) | C12B—C13B—C14B—C15B | −170.95 (15) |
C7A—C12A—C13A—C14A | −178.98 (13) | C13B—C14B—C15B—C16B | 1.0 (3) |
C11A—C12A—C13A—C14A | 1.4 (2) | C13B—C14B—C15B—C17B | −177.81 (15) |
O2A—C13A—C14A—C15A | 1.0 (2) | C7A—C8A—N1A—C1A | −177.76 (14) |
C12A—C13A—C14A—C15A | −179.66 (15) | C9A—C8A—N1A—C1A | 1.12 (17) |
C13A—C14A—C15A—C17A | −175.27 (14) | C2A—C1A—N1A—C8A | 176.66 (15) |
C13A—C14A—C15A—C16A | 3.4 (3) | C6A—C1A—N1A—C8A | −1.42 (16) |
N1B—C1B—C2B—C3B | −178.80 (15) | C2B—C1B—N1B—C8B | 176.92 (15) |
C6B—C1B—C2B—C3B | −0.5 (2) | C6B—C1B—N1B—C8B | −1.54 (17) |
C1B—C2B—C3B—C4B | −1.2 (2) | C7B—C8B—N1B—C1B | −179.39 (14) |
C2B—C3B—C4B—C5B | 1.5 (2) | C9B—C8B—N1B—C1B | 0.85 (17) |
Cg1, Cg2 and Cg3 are the centroids of the phenyl rings C1B–C6B, C7A–C12A and C1A–C6A, respectively. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1B—H1D···O2B | 0.84 | 1.73 | 2.4762 (16) | 146 |
O1A—H1C···O2A | 0.84 | 1.72 | 2.4626 (16) | 146 |
N1B—H1B···O1Bi | 0.88 | 2.12 | 2.9561 (17) | 157 |
N1A—H1A···O1Aii | 0.88 | 2.08 | 2.8996 (16) | 155 |
C10A—H10A···Cg1iii | 0.95 | 2.66 | 3.365 (2) | 132 |
C10B—H10B···Cg2ii | 0.95 | 2.68 | 3.427 (2) | 136 |
C16A—H16A···Cg3iii | 0.95 | 2.77 | 3.659 (2) | 152 |
C16B—H16D···Cg1iv | 0.95 | 2.96 | 3.846 (2) | 151 |
Symmetry codes: (i) −x+2, −y, −z+2; (ii) −x+1, −y, −z+1; (iii) −x+2, −y, −z+1; (iv) −x+1, −y, −z+2. |
Experimental details
Crystal data | |
Chemical formula | C17H15NO2 |
Mr | 265.30 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 100 |
a, b, c (Å) | 6.3416 (9), 15.202 (2), 15.462 (3) |
α, β, γ (°) | 115.216 (5), 95.042 (5), 101.922 (4) |
V (Å3) | 1293.2 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.31 × 0.19 × 0.16 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD diffractometer |
Absorption correction | Multi-scan (APEX2; Bruker, 2007) |
Tmin, Tmax | 0.749, 0.986 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13387, 6364, 4788 |
Rint | 0.026 |
(sin θ/λ)max (Å−1) | 0.667 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.048, 0.123, 1.01 |
No. of reflections | 6364 |
No. of parameters | 367 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.35, −0.25 |
Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2008), SHELXTL (Sheldrick, 2008) and publCIF (McMahon & Westrip, 2008).
Cg1, Cg2 and Cg3 are the centroids of the phenyl rings C1B–C6B, C7A–C12A and C1A–C6A, respectively. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1B—H1D···O2B | 0.84 | 1.73 | 2.4762 (16) | 146.2 |
O1A—H1C···O2A | 0.84 | 1.72 | 2.4626 (16) | 146.1 |
N1B—H1B···O1Bi | 0.88 | 2.12 | 2.9561 (17) | 157.2 |
N1A—H1A···O1Aii | 0.88 | 2.08 | 2.8996 (16) | 155.1 |
C10A—H10A···Cg1iii | 0.95 | 2.66 | 3.365 (2) | 132 |
C10B—H10B···Cg2ii | 0.95 | 2.68 | 3.427 (2) | 136 |
C16A—H16A···Cg3iii | 0.95 | 2.77 | 3.659 (2) | 152 |
C16B—H16D···Cg1iv | 0.95 | 2.96 | 3.846 (2) | 151 |
Symmetry codes: (i) −x+2, −y, −z+2; (ii) −x+1, −y, −z+1; (iii) −x+2, −y, −z+1; (iv) −x+1, −y, −z+2. |
Acknowledgements
We acknowledge the UGC, New Delhi, India, for the award of Major Research Project grant No. F. 31–122/2005. MS thanks the UGC, New Delhi, for the award of a research fellowship. The diffractometer was funded by NSF grant No. 0087210, by Ohio Board of Regents grant CAP-491 and by YSU.
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
A number of carbazole alkaloids with intriguing novel structures and useful biological activities were isolated from natural sources over the past decades, which led towards the development of new synthetic strategies for the synthesis of carbazole and its derivatives (Chakraborty, 1993). Among the physiologically active carbazoles found aree pyranocarbazole alkaloids, which have a C-13, C-18 or C-23 framework (Knölker & Reddy, 2002). The basic unit is the C-12 carbazole nucleus with one carbon attached as a methyl, formyl, carboxylic or ester group. This C-13 unit then leads to C-18 or C-23 carbazole alkaloids depending on whether it combines with a hemi-terpenoid or a mono-terpenoid unit. Another observation is that in all the pyranocarbazole derivatives isolated so far, the oxygen atom of the pyran ring is attached to carbon-2 of the carbazole nucleus to form essentially pyrano[3,2-a]carbazole as in grinimbine. Patel (1982, and references therein) has reported the synthesis of indolo[3,2-h]chromanones from 1-hydroxycarbazoles which were then converted to isomers of grinimbine. Here the yields of compound were reported to be moderate since it was obtained along with the respective 2-acryloyl-1-hydroxycarbazole.
In this context we aimed to prepare pyrano[2,3-a]carbazoles using 1-hydroxycarbazoles as starting synthons under various reaction conditions (Kavitha & Rajendra Prasad, 2003a,b, and references therein). Using the catalyst mixture AlCl3/POCl3 along with 9-carbazole-1-ol and 3,3-dimethyacrylic acid as the reactants we obatined a mixture of two products i.e., 1-(1-hydroxy-9H-carbazol-2-yl)-3-methylbutan-1-one and 2,2-dimethyl-2,3-dihydropyrano-[2,3-a]carbazol- 4(11H)-one as described in an earlier publication (Sridharan et al., 2008) and in Figure 1. The structure of the cyclized compound 2,2-dimethyl-2,3-dihydropyrano-[2,3-a]carbazol- 4(11H)-one was described in the earlier structure report (Sridharan et al., 2008). Here we would like to present the structure of the second compound isolated, 1-(1-hydroxy-9H-carbazol-2-yl)-3-methylbutan-1-one.
The title compound crystallizes in a triclinic setting with two crystallographically independent molecules, A and B (Figure 2). The two molecules are virtually superimposable (see overlay of the two structures in Figure 3) but a PLATON symmetry check did not reveal any translational or other pseudosymmetry even when using relaxed tolerances (Spek, 2009). Both independent molecules are planar, r.m.s. deviations from planarity are 0.053 and 0.079 Å2, respectively, and they are tilted against each other within the structure with a dihedral angle of the planes of the A and B molecules of 53.11 (2)°.
Each molecule exhibits a strong intramolecular O—H···O hydrogen bond between the phenolic hydroxyl group and the keto oxgen atom (Table 1). In addition each type of molecules is connected via pairs of N—H···O hydrogen bonds to another molecule of the same type to form centrosymmetric A2 and B2 dimers (the planes of the dimers are parallel but slightly shifted against each other, Figure 4). The dimers are in turn arranged in offset π-stacks that are extending along the a axis direction. The metrics of the interaction are best given for the interaction of the phenol rings C7A to C12A and C7B to C12B with their respective symmetry equivalent counterparts at 2 - x, -y, 1 - z and 1 - x, -y, 2 - z. For these the centroid to centroid distances are 4.083 (1) and 4.089 (1) Å, the interplanar distances are 3.2985 (6) and 3.2992 (7) Å, and the slippages are 2.407 and 2.415 Å, respectively. The offset of the dimers and the tilt angle of the molecules allows for the formation of alternating C—H···π interactions between A and B molecules of parallel stacks. C—H···π interactions are given in Table 1, with ring centroids 1, 2 and 3 being the phenyl rings C1B to C6B, C7A to C12A and C1A to C6A, respectively.