organic compounds
5,5-Diphenyl-2-thioxoimidazolidin-4-one dimethyl sulfoxide monosolvate
aDepartment of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan, and bDepartment of Chemistry, University of Otago, PO Box 56, Dunedin, New Zealand
*Correspondence e-mail: hamidazizwazir@gmail.com
In the title solvate, C15H12N2OS·C2H6OS, the thioxoimidazolidin-4-one molecule and solvent molecule are linked by an N—H⋯O hydrogen bond. The planar imidazolidine ring (r.m.s. deviation = 0.022 Å) is inclined to the phenyl substituents in the 5-position by 69.57 (7) and 72.62 (6)°. In the crystal, N—H⋯O, C—H⋯O and C—H⋯S hydrogen bonds, together with C—H⋯π interactions, generate [100] chains, which stack along the a-axis direction.
Keywords: crystal structure; 2-thioxoimidazolidin-4-one; DMSO solvate; hydrogen bonds; C—H⋯π(ring) contacts.
CCDC reference: 1855614
Structure description
Thiohydantoins (2-thioxoimidazolidin-4-one derivatives) display a broad and potent biological profile and are found in anticonvulsant, antimetastatic, anti-angiogenic (Mudit et al., 2009; Kumar et al., 2009), antimicrobial (Kieć-Kononowicz & Szymańska, 2003; Khodair et al., 2001) and anticancer drugs (Azizmohammadi et al., 2013). As part of our studies in this area, we now present the synthesis and structural analysis of 5,5-diphenyl-2-thioxoimidazolidin-4-one dimethyl sulfoxide monosolvate. A search of the Cambridge Structural Database (Groom et al., 2016) for related structures found 27 hits, including 2-thiohydantoin itself (Walker et al., 1969), the unsolvated stucture of the molecule reported here (Roszak & Weaver, 1998) and the closely related 5-phenyl-2-thioxoimidazolidin-4-one (Ogawa et al., 2007).
The N⋯O1S hydrogen bond (Fig. 1 and Table 1). As expected, the imidazolidine ring is almost planar, with an r.m.s. deviation of 0.022 Å from the best-fit plane, with atoms S2 and O4 deviating by 0.138 (3) and −0.021 (3) Å, respectively, from that plane. The C51–C56 and C61–C66 phenyl rings are inclined to the imidazolidine ring plane by 69.57 (7) and 72.62 (6)°, respectively.
of the title compound consists of a thiohydantoin molecule with two phenyl substituents at the 5-position and a dimethyl sulfoxide solvent molecule. The molecules are linked by an N3—H3In the crystal, N1—H1N⋯O1Si and the already-mentioned N3—H3N⋯O1S hydrogen bonds (Table 1) link two DMSO solvent molecules to each thiohydantoin ring, with the former contact augmented by a C2S—H2S1⋯S2 hydrogen bonds and a weaker C2S—H2S3⋯Cg3 contact to the C61–C66 phenyl ring. In addition, O4 acts as a triple acceptor with C66—H66⋯O4i hydrogen bonds linking adjacent main molecules, while C1S—H1S2⋯O4iii and C2S—H2S2⋯O4iii hydrogen bonds bind a third DMSO molecule to a thiohydantoin unit, enclosing an R22(6) ring (Fig. 2 and Table 1). The net effect of these contacts is to create independent chains of thiohydantoin and solvent molecules along c and these independent chains are stacked along the a-axis direction (Fig. 3).
Synthesis and crystallization
The synthesis of 5,5-diphenyl-2-thioxoimidazolidin-4-one was performed by a method reported in the literature (Ghanbari et al., 2014) (Fig. 4). The resulting colourless solid was purified by recrystallization from DMSO solution to give colourless blocks (yield 90%). FT–IR (ATR cm−1): 3251 (N—H amide, CO—NH—CS), 3156 (N—H, amide, CPh2—NH—CS), 3022 (aromatic C—H stretch), 1746 (s, C=O amide), 1584, 1526, 1495 (Ar—C=C), 1226.10 (C=S).
Refinement
Crystal data, data collection and structure .
details are summarized in Table 2
|
Structural data
CCDC reference: 1855614
https://doi.org/10.1107/S2414314618010106/hb4245sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314618010106/hb4245Isup2.hkl
Data collection: CrysAlis PRO (Rigaku OD, 2015); cell
CrysAlis PRO (Rigaku OD, 2015); data reduction: CrysAlis PRO (Rigaku OD, 2015); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b) and TITAN (Hunter & Simpson, 1999); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2018 (Sheldrick, 2015b), enCIFer (Allen et al., 2004), PLATON (Spek, 2009), publCIF (Westrip 2010) and WinGX (Farrugia, 2012).C15H12N2OS·C2H6OS | F(000) = 728 |
Mr = 346.45 | Dx = 1.324 Mg m−3 |
Monoclinic, P21/n | Cu Kα radiation, λ = 1.54184 Å |
a = 7.3167 (2) Å | Cell parameters from 4420 reflections |
b = 15.5894 (4) Å | θ = 4.0–74.1° |
c = 15.5627 (3) Å | µ = 2.86 mm−1 |
β = 101.820 (2)° | T = 100 K |
V = 1737.49 (7) Å3 | Block, colourless |
Z = 4 | 0.23 × 0.16 × 0.09 mm |
Rigaku SuperNova Dual Source diffractometer with an Atlas detector | 3444 independent reflections |
Radiation source: SuperNova (Cu) X-ray Source | 2966 reflections with I > 2σ(I) |
Detector resolution: 5.1725 pixels mm-1 | Rint = 0.030 |
ω scans | θmax = 74.3°, θmin = 4.1° |
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2015) | h = −5→8 |
Tmin = 0.932, Tmax = 1.000 | k = −19→17 |
6995 measured reflections | l = −19→19 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.036 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.093 | w = 1/[σ2(Fo2) + (0.039P)2 + 0.8354P] where P = (Fo2 + 2Fc2)/3 |
S = 1.07 | (Δ/σ)max = 0.001 |
3444 reflections | Δρmax = 0.34 e Å−3 |
216 parameters | Δρmin = −0.29 e Å−3 |
0 restraints |
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. |
x | y | z | Uiso*/Ueq | ||
N1 | 0.5315 (2) | 0.63041 (10) | 0.26867 (10) | 0.0130 (3) | |
H1N | 0.629 (3) | 0.6288 (14) | 0.2450 (14) | 0.016* | |
C2 | 0.3597 (2) | 0.61437 (12) | 0.22220 (11) | 0.0137 (3) | |
S2 | 0.30117 (6) | 0.57231 (3) | 0.12248 (3) | 0.01927 (13) | |
N3 | 0.2341 (2) | 0.64016 (10) | 0.27276 (10) | 0.0150 (3) | |
H3N | 0.128 (3) | 0.6354 (15) | 0.2566 (15) | 0.018* | |
C4 | 0.3192 (2) | 0.67809 (11) | 0.34936 (11) | 0.0131 (4) | |
O4 | 0.24401 (17) | 0.70732 (9) | 0.40519 (8) | 0.0172 (3) | |
C5 | 0.5311 (2) | 0.67650 (12) | 0.35075 (11) | 0.0129 (4) | |
C51 | 0.6305 (2) | 0.62745 (12) | 0.43169 (11) | 0.0144 (4) | |
C52 | 0.6650 (3) | 0.66932 (13) | 0.51249 (12) | 0.0192 (4) | |
H52 | 0.631743 | 0.727945 | 0.515909 | 0.023* | |
C53 | 0.7479 (3) | 0.62539 (15) | 0.58791 (13) | 0.0248 (4) | |
H53 | 0.769965 | 0.653945 | 0.642995 | 0.030* | |
C54 | 0.7987 (3) | 0.54028 (15) | 0.58349 (14) | 0.0274 (5) | |
H54 | 0.856898 | 0.510665 | 0.635227 | 0.033* | |
C55 | 0.7642 (3) | 0.49844 (14) | 0.50326 (14) | 0.0270 (5) | |
H55 | 0.798726 | 0.439965 | 0.500054 | 0.032* | |
C56 | 0.6792 (3) | 0.54174 (13) | 0.42730 (13) | 0.0205 (4) | |
H56 | 0.654498 | 0.512635 | 0.372505 | 0.025* | |
C61 | 0.6099 (2) | 0.76653 (12) | 0.34460 (11) | 0.0133 (4) | |
C62 | 0.4968 (3) | 0.83874 (12) | 0.32742 (12) | 0.0164 (4) | |
H62 | 0.365790 | 0.833533 | 0.322920 | 0.020* | |
C63 | 0.5742 (3) | 0.91861 (13) | 0.31679 (12) | 0.0202 (4) | |
H63 | 0.496298 | 0.967842 | 0.306047 | 0.024* | |
C64 | 0.7652 (3) | 0.92639 (13) | 0.32186 (13) | 0.0211 (4) | |
H64 | 0.818091 | 0.980714 | 0.313805 | 0.025* | |
C65 | 0.8781 (3) | 0.85458 (13) | 0.33871 (12) | 0.0194 (4) | |
H65 | 1.008674 | 0.859784 | 0.341895 | 0.023* | |
C66 | 0.8021 (3) | 0.77493 (12) | 0.35102 (11) | 0.0158 (4) | |
H66 | 0.880976 | 0.726208 | 0.363810 | 0.019* | |
S1S | −0.14712 (6) | 0.68634 (3) | 0.11382 (3) | 0.01591 (12) | |
O1S | −0.14346 (17) | 0.63681 (8) | 0.19917 (8) | 0.0152 (3) | |
C1S | −0.2253 (3) | 0.61145 (14) | 0.02807 (12) | 0.0223 (4) | |
H1S1 | −0.132121 | 0.565890 | 0.030446 | 0.033* | |
H1S2 | −0.242805 | 0.640771 | −0.028726 | 0.033* | |
H1S3 | −0.344131 | 0.586385 | 0.035218 | 0.033* | |
C2S | −0.3494 (3) | 0.75316 (14) | 0.09889 (13) | 0.0223 (4) | |
H2S1 | −0.460088 | 0.717679 | 0.098649 | 0.033* | |
H2S2 | −0.363686 | 0.783686 | 0.042859 | 0.033* | |
H2S3 | −0.335511 | 0.794801 | 0.146974 | 0.033* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0117 (7) | 0.0138 (7) | 0.0142 (7) | −0.0002 (6) | 0.0041 (6) | −0.0017 (6) |
C2 | 0.0133 (8) | 0.0123 (8) | 0.0166 (8) | −0.0001 (7) | 0.0055 (7) | 0.0008 (7) |
S2 | 0.0159 (2) | 0.0247 (3) | 0.0172 (2) | −0.00250 (18) | 0.00345 (17) | −0.00768 (18) |
N3 | 0.0090 (7) | 0.0193 (8) | 0.0166 (7) | −0.0012 (6) | 0.0027 (6) | −0.0030 (6) |
C4 | 0.0135 (9) | 0.0104 (8) | 0.0151 (8) | 0.0006 (7) | 0.0024 (7) | 0.0034 (7) |
O4 | 0.0155 (6) | 0.0212 (7) | 0.0162 (6) | 0.0026 (5) | 0.0063 (5) | −0.0006 (5) |
C5 | 0.0119 (8) | 0.0132 (9) | 0.0144 (8) | 0.0007 (7) | 0.0043 (6) | −0.0003 (7) |
C51 | 0.0101 (8) | 0.0181 (9) | 0.0152 (8) | −0.0009 (7) | 0.0031 (6) | 0.0040 (7) |
C52 | 0.0174 (9) | 0.0224 (10) | 0.0178 (9) | −0.0025 (8) | 0.0034 (7) | 0.0007 (8) |
C53 | 0.0227 (10) | 0.0337 (12) | 0.0169 (9) | −0.0062 (9) | 0.0019 (8) | 0.0051 (8) |
C54 | 0.0199 (10) | 0.0348 (12) | 0.0257 (10) | −0.0010 (9) | 0.0003 (8) | 0.0164 (9) |
C55 | 0.0257 (11) | 0.0206 (11) | 0.0345 (12) | 0.0025 (9) | 0.0054 (9) | 0.0099 (9) |
C56 | 0.0190 (9) | 0.0189 (10) | 0.0238 (10) | 0.0016 (8) | 0.0050 (8) | 0.0026 (8) |
C61 | 0.0147 (8) | 0.0141 (9) | 0.0109 (8) | −0.0011 (7) | 0.0021 (6) | −0.0012 (7) |
C62 | 0.0144 (9) | 0.0174 (9) | 0.0171 (8) | 0.0023 (7) | 0.0026 (7) | 0.0006 (7) |
C63 | 0.0233 (10) | 0.0154 (9) | 0.0215 (9) | 0.0029 (8) | 0.0039 (8) | 0.0005 (8) |
C64 | 0.0267 (10) | 0.0145 (9) | 0.0214 (9) | −0.0061 (8) | 0.0034 (8) | −0.0005 (7) |
C65 | 0.0157 (9) | 0.0199 (10) | 0.0222 (9) | −0.0034 (8) | 0.0033 (7) | −0.0004 (8) |
C66 | 0.0151 (9) | 0.0152 (9) | 0.0161 (8) | 0.0016 (7) | 0.0014 (7) | −0.0004 (7) |
S1S | 0.0153 (2) | 0.0171 (2) | 0.0165 (2) | −0.00021 (17) | 0.00602 (16) | 0.00133 (17) |
O1S | 0.0147 (6) | 0.0181 (7) | 0.0134 (6) | 0.0014 (5) | 0.0039 (5) | 0.0010 (5) |
C1S | 0.0261 (10) | 0.0249 (10) | 0.0153 (9) | 0.0010 (9) | 0.0027 (7) | −0.0024 (8) |
C2S | 0.0256 (10) | 0.0213 (10) | 0.0216 (9) | 0.0071 (8) | 0.0088 (8) | 0.0063 (8) |
N1—C2 | 1.339 (2) | C56—H56 | 0.9500 |
N1—C5 | 1.466 (2) | C61—C62 | 1.390 (3) |
N1—H1N | 0.86 (2) | C61—C66 | 1.396 (3) |
C2—N3 | 1.387 (2) | C62—C63 | 1.392 (3) |
C2—S2 | 1.6581 (18) | C62—H62 | 0.9500 |
N3—C4 | 1.362 (2) | C63—C64 | 1.389 (3) |
N3—H3N | 0.77 (2) | C63—H63 | 0.9500 |
C4—O4 | 1.209 (2) | C64—C65 | 1.384 (3) |
C4—C5 | 1.546 (2) | C64—H64 | 0.9500 |
C5—C51 | 1.525 (2) | C65—C66 | 1.390 (3) |
C5—C61 | 1.528 (2) | C65—H65 | 0.9500 |
C51—C56 | 1.388 (3) | C66—H66 | 0.9500 |
C51—C52 | 1.393 (3) | S1S—O1S | 1.5318 (13) |
C52—C53 | 1.387 (3) | S1S—C1S | 1.777 (2) |
C52—H52 | 0.9500 | S1S—C2S | 1.786 (2) |
C53—C54 | 1.383 (3) | C1S—H1S1 | 0.9800 |
C53—H53 | 0.9500 | C1S—H1S2 | 0.9800 |
C54—C55 | 1.385 (3) | C1S—H1S3 | 0.9800 |
C54—H54 | 0.9500 | C2S—H2S1 | 0.9800 |
C55—C56 | 1.392 (3) | C2S—H2S2 | 0.9800 |
C55—H55 | 0.9500 | C2S—H2S3 | 0.9800 |
C2—N1—C5 | 113.14 (15) | C55—C56—H56 | 120.0 |
C2—N1—H1N | 121.8 (14) | C62—C61—C66 | 119.29 (17) |
C5—N1—H1N | 122.2 (15) | C62—C61—C5 | 122.59 (16) |
N1—C2—N3 | 107.31 (15) | C66—C61—C5 | 117.99 (16) |
N1—C2—S2 | 127.83 (14) | C61—C62—C63 | 120.45 (17) |
N3—C2—S2 | 124.86 (14) | C61—C62—H62 | 119.8 |
C4—N3—C2 | 112.64 (16) | C63—C62—H62 | 119.8 |
C4—N3—H3N | 125.3 (17) | C64—C63—C62 | 120.04 (18) |
C2—N3—H3N | 122.0 (17) | C64—C63—H63 | 120.0 |
O4—C4—N3 | 126.78 (17) | C62—C63—H63 | 120.0 |
O4—C4—C5 | 126.79 (16) | C65—C64—C63 | 119.65 (18) |
N3—C4—C5 | 106.44 (14) | C65—C64—H64 | 120.2 |
N1—C5—C51 | 112.84 (14) | C63—C64—H64 | 120.2 |
N1—C5—C61 | 109.12 (14) | C64—C65—C66 | 120.58 (17) |
C51—C5—C61 | 112.97 (15) | C64—C65—H65 | 119.7 |
N1—C5—C4 | 100.17 (14) | C66—C65—H65 | 119.7 |
C51—C5—C4 | 109.08 (14) | C65—C66—C61 | 119.98 (18) |
C61—C5—C4 | 111.99 (15) | C65—C66—H66 | 120.0 |
C56—C51—C52 | 119.65 (17) | C61—C66—H66 | 120.0 |
C56—C51—C5 | 121.72 (16) | O1S—S1S—C1S | 105.41 (9) |
C52—C51—C5 | 118.56 (17) | O1S—S1S—C2S | 105.88 (8) |
C53—C52—C51 | 119.96 (19) | C1S—S1S—C2S | 98.90 (10) |
C53—C52—H52 | 120.0 | S1S—C1S—H1S1 | 109.5 |
C51—C52—H52 | 120.0 | S1S—C1S—H1S2 | 109.5 |
C54—C53—C52 | 120.5 (2) | H1S1—C1S—H1S2 | 109.5 |
C54—C53—H53 | 119.8 | S1S—C1S—H1S3 | 109.5 |
C52—C53—H53 | 119.8 | H1S1—C1S—H1S3 | 109.5 |
C53—C54—C55 | 119.69 (19) | H1S2—C1S—H1S3 | 109.5 |
C53—C54—H54 | 120.2 | S1S—C2S—H2S1 | 109.5 |
C55—C54—H54 | 120.2 | S1S—C2S—H2S2 | 109.5 |
C54—C55—C56 | 120.3 (2) | H2S1—C2S—H2S2 | 109.5 |
C54—C55—H55 | 119.9 | S1S—C2S—H2S3 | 109.5 |
C56—C55—H55 | 119.9 | H2S1—C2S—H2S3 | 109.5 |
C51—C56—C55 | 119.95 (19) | H2S2—C2S—H2S3 | 109.5 |
C51—C56—H56 | 120.0 | ||
C5—N1—C2—N3 | −5.9 (2) | C5—C51—C52—C53 | 177.23 (16) |
C5—N1—C2—S2 | 173.76 (14) | C51—C52—C53—C54 | 0.7 (3) |
N1—C2—N3—C4 | 4.0 (2) | C52—C53—C54—C55 | −0.8 (3) |
S2—C2—N3—C4 | −175.60 (14) | C53—C54—C55—C56 | 0.1 (3) |
C2—N3—C4—O4 | 179.16 (18) | C52—C51—C56—C55 | −0.8 (3) |
C2—N3—C4—C5 | −0.7 (2) | C5—C51—C56—C55 | −177.83 (17) |
C2—N1—C5—C51 | 120.98 (16) | C54—C55—C56—C51 | 0.7 (3) |
C2—N1—C5—C61 | −112.57 (17) | N1—C5—C61—C62 | 101.61 (19) |
C2—N1—C5—C4 | 5.14 (18) | C51—C5—C61—C62 | −132.01 (17) |
O4—C4—C5—N1 | 177.63 (18) | C4—C5—C61—C62 | −8.4 (2) |
N3—C4—C5—N1 | −2.46 (17) | N1—C5—C61—C66 | −74.20 (19) |
O4—C4—C5—C51 | 59.0 (2) | C51—C5—C61—C66 | 52.2 (2) |
N3—C4—C5—C51 | −121.10 (16) | C4—C5—C61—C66 | 175.82 (15) |
O4—C4—C5—C61 | −66.8 (2) | C66—C61—C62—C63 | 0.0 (3) |
N3—C4—C5—C61 | 113.10 (16) | C5—C61—C62—C63 | −175.80 (16) |
N1—C5—C51—C56 | −12.6 (2) | C61—C62—C63—C64 | 1.1 (3) |
C61—C5—C51—C56 | −136.94 (17) | C62—C63—C64—C65 | −0.9 (3) |
C4—C5—C51—C56 | 97.82 (19) | C63—C64—C65—C66 | −0.3 (3) |
N1—C5—C51—C52 | 170.41 (15) | C64—C65—C66—C61 | 1.4 (3) |
C61—C5—C51—C52 | 46.0 (2) | C62—C61—C66—C65 | −1.2 (3) |
C4—C5—C51—C52 | −79.2 (2) | C5—C61—C66—C65 | 174.80 (16) |
C56—C51—C52—C53 | 0.1 (3) |
Cg3 is the centroid of the C61–C66 phenyl ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3N···O1S | 0.77 (2) | 2.00 (2) | 2.766 (2) | 171 (2) |
N1—H1N···O1Si | 0.86 (2) | 1.95 (2) | 2.8089 (19) | 174 (2) |
C66—H66···O4i | 0.95 | 2.62 | 3.341 (2) | 133 |
C1S—H1S3···S2ii | 0.98 | 3.17 | 4.077 (2) | 154 |
C1S—H1S2···O4iii | 0.98 | 2.58 | 3.393 (2) | 141 |
C2S—H2S2···O4iii | 0.98 | 2.43 | 3.283 (2) | 145 |
C2S—H2S1···S2ii | 0.98 | 2.93 | 3.874 (2) | 162 |
C2S—HS23···Cg3ii | 0.98 | 2.98 | 3.887 (2) | 154 |
Symmetry codes: (i) x+1, y, z; (ii) x−1, y, z; (iii) x−1/2, −y+3/2, z−1/2. |
Acknowledgements
HA is very grateful to the Higher Education Commission (HEC), Pakistan, for providing a scholarship award for MS/MPhil leading to PhD studies under the Indigenous PhD fellowship for 5000 Scholars Phase-II, Batch-1. We also thank the University of Otago, for purchase of the diffractometer and the Chemistry Department, University of Otago for support of the work of JS.
References
Allen, F. H., Johnson, O., Shields, G. P., Smith, B. R. & Towler, M. (2004). J. Appl. Cryst. 37, 335–338. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Azizmohammadi, M., Khoobi, M., Ramazani, A., Emami, S., Zarrin, A., Firuzi, O., Miri, R. & Shafiee, A. (2013). Eur. J. Med. Chem. 59, 15–22. CrossRef Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Ghanbari, M. M., Jamali, M. & Batta, G. (2014). J. Sulfur Chem. 35, 394–398. CrossRef Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CSD CrossRef IUCr Journals Google Scholar
Hunter, K. A. & Simpson, J. (1999). TITAN2000. University of Otago, New Zealand. Google Scholar
Khodair, A. I., El-barbary, A. A., Abbas, Y. A. & Imam, D. R. (2001). Phosphorus Sulfur Silicon, 170, 261–278. CrossRef Google Scholar
Kieć-Kononowicz, K. & Szymańska, E. (2003). Farmaco, 57, 909–916. Google Scholar
Kumar, C. A., Swamy, S. N., Sugahara, K. & Rangappa, K. S. (2009). Bioorg, Med. Chem. 17, 4928–4934. Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Mudit, M., Khanfar, M., Muralidharan, A., Thomas, S., Shah, G. V., van Soest, R. W. & El Sayed, K. A. (2009). Bioorg. Med. Chem. 17, 1731–1738. CrossRef Google Scholar
Ogawa, T., Kitoh, S., Ichitani, M., Kuwae, A., Hanai, K. & Kunimoto, K.-K. (2007). Anal. Sci. X, 23, x199–x200. CrossRef Google Scholar
Rigaku OD (2015). CrysAlis PRO. Rigaku Oxford Diffraction Ltd, Yarnton, Oxfordshire, England. Google Scholar
Roszak, A. W. & Weaver, D. F. (1998). Acta Cryst. C54, 1168–1170. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Walker, L. A., Folting, K. & Merritt, L. L. (1969). Acta Cryst. B25, 88–93. CSD CrossRef CAS IUCr Journals Web of Science Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
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