Abstract
C28H18ClN3, monoclinic, P21/c, (no. 14) a = 5.9519(2) Å, b = 8.0511(3) Å, c = 43.4071(14) Å, β = 90.001(2)°, V =2080.04(12) Å3, Z = 4, Rgt(F) = 0.066, wRref(F2) = 0.190, T = 173 K.
Tables 1 and 2 contain details on crystal structure and measurement conditions and a list of the atoms including atomic coordinates and displacement parameters.
Crystal: | Colorless rod |
Size: | 0.47 × 0.19 × 0.04 mm |
Wavelength: | Mo Kα radiation (0.71073 Å) |
μ: | 0.206 mm−1 |
Diffractometer, scan mode: | Bruker D8 Venture, ω (0.5° width) |
θmax, completeness: | 25.49°, 96% |
N(hkl)measured, N(hkl)unique, Rint: | 10748,3720, 0.0980 |
Criterion for Iobs, N(hkl)gt: | Iobs > 2 σ(Iobs), 3009 |
N(param)refined: | 290 |
Programs: | XPREP [2], WinGX [4], SHELXS [3] |
Atom | x | y | z | Uiso*/Ueq |
---|---|---|---|---|
C1 | 0.7902(7) | 0.5667(5) | 0.10136(10) | 0.0326(9) |
C2 | 0.8760(9) | 0.5319(5) | 0.07259(10) | 0.0398(10) |
H2 | 1.0169 | 0.4777 | 0.0704 | 0.048* |
C3 | 0.7519(9) | 0.5778(6) | 0.04686(11) | 0.0432(11) |
H3 | 0.8082 | 0.5568 | 0.0268 | 0.052* |
C4 | 0.5448(8) | 0.6546(6) | 0.05075(11) | 0.0409(11) |
C5 | 0.4628(8) | 0.6884(5) | 0.07956(11) | 0.0406(11) |
H5 | 0.3206 | 0.7406 | 0.0818 | 0.049* |
C6 | 0.5849(8) | 0.6470(5) | 0.10514(11) | 0.0375(10) |
H6 | 0.5304 | 0.6727 | 0.1252 | 0.045* |
C7 | 1.1560(8) | 0.5054(6) | 0.16335(10) | 0.0395(10) |
H7 | 1.2833 | 0.5328 | 0.1756 | 0.047* |
C8 | 1.0106(8) | 0.3707(5) | 0.16969(10) | 0.0326(9) |
C9 | 0.9907(8) | 0.2425(5) | 0.19190(10) | 0.0334(9) |
H9 | 1.0971 | 0.2399 | 0.2082 | 0.040* |
C10 | 0.6785(7) | 0.1312(5) | 0.16763(9) | 0.0293(9) |
C11 | 0.6773(7) | 0.2527(5) | 0.14389(9) | 0.0302(9) |
C12 | 0.8507(7) | 0.3747(5) | 0.14645(9) | 0.0317(9) |
C13 | 0.5199(7) | 0.2438(5) | 0.11996(9) | 0.0307(9) |
H13 | 0.5198 | 0.3269 | 0.1044 | 0.037* |
C14 | 0.3657(7) | 0.1171(5) | 0.11852(9) | 0.0297(9) |
C15 | 0.3600(7) | −0.0006(5) | 0.14265(9) | 0.0301(9) |
H15 | 0.2485 | −0.0850 | 0.1424 | 0.036* |
C16 | 0.5144(7) | 0.0044(5) | 0.16673(9) | 0.0296(9) |
C17 | 0.2097(7) | 0.1035(5) | 0.09169(9) | 0.0286(9) |
C18 | 0.2744(8) | 0.1631(5) | 0.06268(10) | 0.0338(10) |
H18 | 0.4170 | 0.2145 | 0.0603 | 0.041* |
C19 | 0.1340(9) | 0.1483(5) | 0.03749(10) | 0.0401(11) |
H19 | 0.1810 | 0.1880 | 0.0179 | 0.048* |
C20 | −0.0772(8) | 0.0748(6) | 0.04083(11) | 0.0420(11) |
H20 | −0.1753 | 0.0650 | 0.0237 | 0.050* |
C21 | −0.1407(8) | 0.0171(5) | 0.06916(10) | 0.0384(10) |
H21 | −0.2847 | −0.0321 | 0.0716 | 0.046* |
C22 | 0.0019(8) | 0.0292(5) | 0.09456(10) | 0.0360(10) |
H22 | −0.0443 | −0.0139 | 0.1139 | 0.043* |
C23 | 0.4975(7) | −0.1273(5) | 0.19095(9) | 0.0300(9) |
Source of material
The title compound was previously prepared by the reaction of 6,8-dibromo-4-chloroquinoline-3-carbaldehyde with 4-chlorophenylhydrazine hydrochloride (1.5 equiv.) in ethanol in the presence of triethylamine (1.5 equiv.) to afford the corresponding (6,8-dibromo-4-chloroquinolin-3-yl)methylene]-2-(4-chlorophenyl)hydrazide. This hydrazide derivative was, in turn, cyclized with ethanolic KOH (5% in ethanol) to afford the corresponding 6,8-dibromo-1-(2-chlorophenyl)-1H-pyrazolo[4,3-c]quinoline. The 1,6,8-triaryl-1H-pyrazolo[4,3-c]quinoline used in this investigation was prepared via Suzuki-Miyaura cross-coupling of the corresponding 1-aryl-6,8-dibromo-1H-pyrazolo[4,3-c]quinoline with arylboronic acids [1]. Crystals of the title compound were obtained by recrystallization in dimethylformamide.
Experimental details
Data reduction was carried out using SAINT+ software, and SADABS was used to make empirical absorption corrections [2]. The crystal structure was solved through direct methods using SHELXS-97 [3]. Hydrogen atoms were positioned geometrically and allowed to ride on their respective parent atoms with d(C–H) = 0.95 Å and Uiso(H) = 1.2Ueq(C). Diagrams and publication material were generated using WinGX [4] and PLATON [5].
Discussion
In recent years there has been growing interest in the design and synthesis of pyrazolo[4,3-c]quinoline-based compounds [6] due to their wide-range of biological properties. Pyrazolo[4,3-c]quinoline derivatives serve as photosensitizing anti-cancer agents [7], benzodiazepine antagonists [8], selective cyclooxygenase-2 (COX-2) inhibitors [9] and others exhibit anti-inflammatory properties [6]. Interest in pyrazolo[4,3-c]quinoline-based compounds is not only limited to the synthesis or development of more diverse and complex bioactive derivatives for structure-activity relationship evaluations, but has since been extended to focus on their photophysical properties as potential photosensitizing anti-cancer agents and fluorescence probes. The crystallographic study of the 1-(4-chlorophenyl)-6,8-diphenyl-1H-pyrazolo[4,3-c]quinolone was carried out to determine its molecular structure and the geometry of the pyrazolo[4,3-c]quinoline tricyclic system. The 1-aryl ring is highly deformed out of plane of the pyrazoloquinazoline framework (average torsion angle ca. 75.2°) compared to other aryl substituents to avoid steric interaction between its ortho-hydrogen atoms and H-9 (C13). The slight twist of the 6-aryl ring from co-planarity (average torsion angle ca. −59.2°), on the other hand, minimizes steric interaction between its ortho-hydrogen atoms on C24 and C28 with the lone pair electrons on N3 and C15, respectively.
Acknowledgement
The authors are grateful to the University of South Africa and the National Research Foundation for financial assistance.
References
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©2017 Marole M. Maluleka et al., published by De Gruyter.
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