research communications
E)-N-(4-propyloxybenzylidene)benzo[d]thiazol-2-amine
and Hirshfeld surface analysis of (aSalahaddin University, College of Science, Department of Chemistry, Erbil, Iraq, bKoya University, Faculty of Science and Health, Department of Chemistry, Koya, Iraq, cSalahaddin University, College of Education, Department of Chemistry, Erbil, Iraq, and dOndokuz Mayıs University, Faculty of Arts and Sciences, Department of Physics, 55139, Samsun, Turkey
*Correspondence e-mail: ropak.shekhmohamad@su.edu.krd, wali.hmd@koyauniversity.org
The title compound, C17H16N2OS, was synthesized by a condensation reaction between 2-amino benzothiazole and 4-N-propoxybenzaldehyde. The benzo[d]thiazole ring system is nearly planar (r.m.s. deviation 0.0088 Å) and makes a dihedral angle of 3.804 (12)° with the phenyl ring. The configuration about the C=N double bond is E. In the pairs of C—H⋯N hydrogen bonds and C—H⋯π interactions link the molecules into inversion dimers with an R22(16) ring motif. These dimers are additionally linked by weak π–π stacking interactions between the phenyl rings, leading to a layered arrangement parallel to (010). Hirshfeld surface analysis of the indicates that the most important contributions for the packing arrangement are from H⋯H (47.9%) and C⋯H/H⋯C (25.6%) interactions.
Keywords: crystal structure; heterocyclic compound; 2-aminobenzothiazole; Schiff base; Hirshfeld surface.
CCDC reference: 1979807
1. Chemical context
Benzothiazole is one of the most important ). Benzothiazole and its derivatives show numerous biological activities such as antimicrobial, anticancer, anthelmintic or anti-diabetic. They have also found application in industry as antioxidants and vulcanization accelerators (Achaiah et al., 2016).
comprising of a sulfur and a nitrogen atom that constitute the core structure of thiazole. Benzothiazole is a weak base, and is widely found in bioorganic and medicinal chemistry with application in drug discovery as a pharmacologically and biologically active compound (Quin & Tyrell, 2010) are nitrogen analogues of or in which the corresponding has been replaced by an imine or azomethine group. They can be synthesized from the reaction of primary with an aldehyde or a ketone under particular conditions. are some of the most widely used organic compounds, utilized, for example, as catalysts, pigments and dyes, intermediates in organic synthesis, or as polymer stabilizers. Moreover, exhibit a broad range of biological activities such as antiviral, antibacterial, anti-inflammatory, antimalarial, antifungal, anti-proliferative and antipyretic properties (Bhoi et al., 2015).
(Schiff, 1864In the context given above, we report here the synthesis, molecular and 17H16N2OS, comprising a benzothiazole moiety.
of the Schiff base C2. Structural commentary
The ), which exhibits an E configuration for the imine functionality. The benzo[d]thiazole ring system is nearly planar [r.m.s. deviation 0.0088 Å, with the largest deviation being 0.0127 (18) Å for atom C4]. The benzo[d]thiazole ring system and the phenyl ring (C9–C14) are slightly twisted with respect to each other, making a dihedral angle of 3.804 (12)°. In the thiazole ring, the C6—N1 [1.379 (3) Å] and C7—N1 [1.288 (3) Å] distances indicate substantial electronic delocalization. The C8=N2 double bond has a length of 1.272 (3) Å, and thus is slightly longer than comparable bonds found in other Schiff base structures (Sen et al., 2018; Kansiz et al., 2018), which are in the range of 1.262 (3)–1.270 (3) Å. The methyl group of the propyl chain is moved out by 59.2 (3)° from the mean plane of the rest of the molecule.
of the title compound is comprised of one molecule (Fig. 13. Supramolecular features
In the π hydrogen bonds (Table 1) between one of the methylene C atoms of the propyl group (C16—H16A) and the centroid of the C1–C6 phenyl ring (Cg2) of an adjacent molecule (Fig. 2). Pairs of additional C—H⋯N hydrogen bonds form inversion dimers with an R22(16) ring motif (Fig. 2). The dimers are additionally linked by weak π–π interactions, with a centroid-to-centroid distance of 4.695 (2) Å between Cg3 and Cg3i [Symmetry code: (i): −x + 1, −y + 2, −z) where Cg3 is the centroid of the C9–C14 phenyl ring. The resulting supramolecular network is layered and expands parallel to (010).
molecules are linked by C—H⋯4. Hirshfeld surface analysis
Hirshfeld surface analysis together with two-dimensional fingerprint plots are a powerful tool for the visualization and interpretation of intermolecular contacts in molecular crystals (Spackman & Jayatilaka, 2009). The corresponding surfaces and fingerprint plots were obtained using CrystalExplorer (Turner et al., 2017). The dnorm and molecular electrostatic potential maps for the title compound are shown in Fig. 3a and 3b, respectively, with the prominent hydrogen-bonding interactions shown as red spots. The red spots identified in Fig. 3a correspond to the H⋯N contacts resulting from hydrogen bond C—H⋯N (Table 1). The most important contribution to the Hirshfeld surface comes from H⋯H contacts with 47.9%. C⋯H and N⋯H interactions follow with 25.6% and 10.1% contributions, respectively (Fig. 4). Other minor contributors are S⋯H/H⋯S (7.1%), C⋯C (2.5%), O⋯H/H⋯O (2.1%), C⋯N/N⋯C (1.8%), C⋯S/S⋯C (1.1%) and C⋯O/O⋯C (0.8%).
5. Database survey
A search of the Cambridge Structural Database (CSD, version 5.41, update of November 2019; Groom et al., 2016) for an (E)-N-benzylidenebenzo[d]thiazol-2-amine skeleton gave 20 hits. Of these 20, the most similar to the title compound are 2-[(6-methoxy-1,3-benzothiazol-2-yl)carbonoimidoyl]phenol (SUFFEG; Hijji et al., 2015), (E)-2-[(6-ethoxybenzothiazol-2-yl)iminomethyl]-6-methoxyphenol (VOQKAO; Kong, 2009) and 2-[(1,3-benzothiazol-2-ylimino)methyl]phenol (VOQXOP01; Asiri et al., 2010). All these compounds have an E configuration about the C=N imine bond, and have similar bond lengths and angles as mentioned above for the title compound.
6. Synthesis and crystallization
2-Amino benzothiazole (0.3 g, 2 mmol) was dissolved in 10 ml of 1-propanol in a 50 ml borosilicate glass beaker. 4-N-Propoxybenzaldehyde (0.328 g, 2 mmol) was then added dropwise into the mixture under stirring, in the presence of a catalytic amount of glacial acetic acid. The reaction mixture was then placed inside an unmodified household microwave oven and was irradiated for 32 min (eight pulses each of 4 min) at 540 W power, with short interruptions of one minute. The progress of the reaction was monitored by using ethyl acetate and n-hexane (3:7 v:v) as (Rf = 0.69). The formed precipitate was filtered off, washed with 1-propanol, and dried. The resulting solid was further purified by recrystallization from n-hexane to give the pure imine as a crystalline solid (yield: 72.4%, m.p. 357–358 K).
7. Refinement
Crystal data, data collection and structure . C-bound H atoms were placed in idealized positions and refined using a riding model with C—H = 0.93–0.97 Å with Uiso(H) = 1.5Ueq(C-methyl) and 1.2Ueq(C) for other C–bound H atoms.
details are summarized in Table 2Supporting information
CCDC reference: 1979807
https://doi.org/10.1107/S2056989020012128/wm5582sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989020012128/wm5582Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2056989020012128/wm5582Isup3.cml
Data collection: X-AREA (Stoe & Cie, 2002); cell
X-AREA (Stoe & Cie, 2002); data reduction: X-RED (Stoe & Cie, 2002); program(s) used to solve structure: SHELXT2017/1 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2017/1 (Sheldrick, 2015b); molecular graphics: PLATON (Spek, 2020); software used to prepare material for publication: WinGX (Farrugia, 2012).C17H16N2OS | F(000) = 624 |
Mr = 296.38 | Dx = 1.301 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 17.251 (1) Å | Cell parameters from 9824 reflections |
b = 5.6849 (3) Å | θ = 2.4–28.1° |
c = 17.3101 (11) Å | µ = 0.21 mm−1 |
β = 116.958 (4)° | T = 296 K |
V = 1513.14 (16) Å3 | Plate, yellow |
Z = 4 | 0.67 × 0.34 × 0.04 mm |
Stoe IPDS 2 diffractometer | 2962 independent reflections |
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus | 1950 reflections with I > 2σ(I) |
Detector resolution: 6.67 pixels mm-1 | Rint = 0.048 |
rotation method scans | θmax = 26.0°, θmin = 2.4° |
Absorption correction: integration (X-RED32; Stoe & Cie, 2002) | h = −21→21 |
Tmin = 0.896, Tmax = 0.983 | k = −7→7 |
10315 measured reflections | l = −21→19 |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.045 | H-atom parameters constrained |
wR(F2) = 0.099 | w = 1/[σ2(Fo2) + (0.0451P)2] where P = (Fo2 + 2Fc2)/3 |
S = 0.98 | (Δ/σ)max < 0.001 |
2962 reflections | Δρmax = 0.14 e Å−3 |
191 parameters | Δρmin = −0.13 e Å−3 |
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 | ||
S1 | 0.18402 (4) | 0.57314 (11) | 0.34622 (4) | 0.0693 (2) | |
O1 | 0.68408 (9) | 0.4674 (3) | 0.79162 (9) | 0.0670 (4) | |
N2 | 0.34892 (11) | 0.7538 (3) | 0.44924 (11) | 0.0594 (4) | |
N1 | 0.25411 (11) | 0.9575 (3) | 0.32624 (11) | 0.0605 (4) | |
C7 | 0.27040 (13) | 0.7771 (4) | 0.37623 (13) | 0.0548 (5) | |
C9 | 0.44990 (12) | 0.5343 (4) | 0.57024 (12) | 0.0536 (5) | |
C12 | 0.60529 (13) | 0.4773 (4) | 0.72070 (12) | 0.0543 (5) | |
C8 | 0.36920 (13) | 0.5628 (4) | 0.49215 (13) | 0.0594 (5) | |
H8 | 0.330649 | 0.436935 | 0.472533 | 0.071* | |
C6 | 0.17124 (13) | 0.9462 (4) | 0.25862 (13) | 0.0574 (5) | |
C1 | 0.12228 (13) | 0.7506 (4) | 0.25832 (13) | 0.0591 (5) | |
C10 | 0.51498 (13) | 0.7056 (4) | 0.59654 (12) | 0.0570 (5) | |
H10 | 0.506190 | 0.841213 | 0.563558 | 0.068* | |
C11 | 0.59124 (13) | 0.6761 (4) | 0.67003 (13) | 0.0581 (5) | |
H11 | 0.634211 | 0.790845 | 0.686230 | 0.070* | |
C14 | 0.46538 (14) | 0.3363 (4) | 0.62163 (14) | 0.0635 (6) | |
H14 | 0.422987 | 0.219895 | 0.604920 | 0.076* | |
C15 | 0.70221 (14) | 0.2747 (4) | 0.85021 (13) | 0.0671 (6) | |
H15A | 0.700893 | 0.127967 | 0.821055 | 0.081* | |
H15B | 0.658921 | 0.266962 | 0.871337 | 0.081* | |
C13 | 0.54145 (14) | 0.3061 (4) | 0.69666 (13) | 0.0619 (5) | |
H13 | 0.549857 | 0.172823 | 0.730695 | 0.074* | |
C5 | 0.13532 (15) | 1.1122 (4) | 0.19285 (14) | 0.0718 (6) | |
H5 | 0.167215 | 1.243665 | 0.192412 | 0.086* | |
C16 | 0.79051 (15) | 0.3130 (5) | 0.92404 (15) | 0.0773 (7) | |
H16A | 0.832723 | 0.320157 | 0.901537 | 0.093* | |
H16B | 0.805157 | 0.179131 | 0.962854 | 0.093* | |
C2 | 0.03805 (15) | 0.7197 (5) | 0.19350 (15) | 0.0742 (6) | |
H2 | 0.005409 | 0.589611 | 0.193574 | 0.089* | |
C3 | 0.00415 (16) | 0.8855 (5) | 0.12943 (16) | 0.0789 (7) | |
H3 | −0.052292 | 0.867632 | 0.085531 | 0.095* | |
C4 | 0.05246 (17) | 1.0798 (5) | 0.12880 (15) | 0.0777 (7) | |
H4 | 0.028216 | 1.189367 | 0.084265 | 0.093* | |
C17 | 0.7977 (2) | 0.5324 (5) | 0.97463 (17) | 0.0988 (9) | |
H17A | 0.790480 | 0.667237 | 0.938607 | 0.148* | |
H17B | 0.853871 | 0.538215 | 1.024129 | 0.148* | |
H17C | 0.753332 | 0.532467 | 0.993616 | 0.148* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.0643 (3) | 0.0685 (4) | 0.0671 (3) | −0.0171 (3) | 0.0228 (3) | 0.0012 (3) |
O1 | 0.0604 (9) | 0.0715 (10) | 0.0616 (8) | −0.0100 (7) | 0.0210 (7) | 0.0101 (8) |
N2 | 0.0560 (10) | 0.0623 (12) | 0.0584 (10) | −0.0022 (9) | 0.0246 (9) | −0.0007 (9) |
N1 | 0.0549 (10) | 0.0621 (11) | 0.0612 (10) | −0.0054 (9) | 0.0236 (9) | 0.0008 (9) |
C7 | 0.0539 (12) | 0.0579 (13) | 0.0551 (11) | −0.0053 (10) | 0.0271 (10) | −0.0050 (11) |
C9 | 0.0524 (11) | 0.0560 (13) | 0.0557 (11) | −0.0021 (10) | 0.0274 (10) | −0.0045 (10) |
C12 | 0.0536 (11) | 0.0575 (13) | 0.0550 (11) | −0.0029 (10) | 0.0275 (10) | −0.0014 (10) |
C8 | 0.0570 (12) | 0.0614 (14) | 0.0635 (12) | −0.0044 (11) | 0.0305 (11) | −0.0050 (12) |
C6 | 0.0565 (12) | 0.0599 (13) | 0.0550 (11) | 0.0021 (11) | 0.0246 (10) | −0.0044 (11) |
C1 | 0.0572 (12) | 0.0614 (13) | 0.0594 (12) | −0.0056 (10) | 0.0270 (10) | −0.0093 (10) |
C10 | 0.0651 (13) | 0.0516 (12) | 0.0592 (12) | −0.0013 (10) | 0.0325 (11) | 0.0027 (10) |
C11 | 0.0584 (12) | 0.0552 (12) | 0.0616 (12) | −0.0137 (10) | 0.0282 (11) | −0.0034 (11) |
C14 | 0.0579 (13) | 0.0548 (13) | 0.0759 (14) | −0.0098 (10) | 0.0286 (12) | 0.0004 (12) |
C15 | 0.0700 (15) | 0.0647 (14) | 0.0652 (13) | 0.0009 (12) | 0.0294 (12) | 0.0079 (12) |
C13 | 0.0603 (13) | 0.0539 (12) | 0.0696 (13) | −0.0032 (11) | 0.0278 (11) | 0.0088 (11) |
C5 | 0.0758 (16) | 0.0652 (15) | 0.0683 (14) | −0.0010 (12) | 0.0273 (13) | 0.0016 (12) |
C16 | 0.0734 (16) | 0.0823 (17) | 0.0662 (14) | 0.0032 (13) | 0.0230 (12) | 0.0061 (13) |
C2 | 0.0589 (14) | 0.0809 (17) | 0.0744 (15) | −0.0115 (13) | 0.0229 (12) | −0.0076 (14) |
C3 | 0.0581 (13) | 0.096 (2) | 0.0686 (15) | 0.0044 (14) | 0.0160 (12) | −0.0107 (15) |
C4 | 0.0792 (16) | 0.0786 (17) | 0.0643 (13) | 0.0142 (15) | 0.0229 (13) | 0.0020 (13) |
C17 | 0.117 (2) | 0.093 (2) | 0.0732 (15) | −0.0224 (17) | 0.0309 (16) | −0.0068 (15) |
S1—C1 | 1.731 (2) | C14—C13 | 1.376 (3) |
S1—C7 | 1.770 (2) | C14—H14 | 0.9300 |
O1—C12 | 1.358 (2) | C15—C16 | 1.495 (3) |
O1—C15 | 1.428 (2) | C15—H15A | 0.9700 |
N2—C8 | 1.272 (3) | C15—H15B | 0.9700 |
N2—C7 | 1.378 (2) | C13—H13 | 0.9300 |
N1—C7 | 1.288 (3) | C5—C4 | 1.367 (3) |
N1—C6 | 1.379 (3) | C5—H5 | 0.9300 |
C9—C14 | 1.384 (3) | C16—C17 | 1.496 (3) |
C9—C10 | 1.397 (3) | C16—H16A | 0.9700 |
C9—C8 | 1.444 (3) | C16—H16B | 0.9700 |
C12—C11 | 1.383 (3) | C2—C3 | 1.368 (3) |
C12—C13 | 1.385 (3) | C2—H2 | 0.9300 |
C8—H8 | 0.9300 | C3—C4 | 1.387 (4) |
C6—C5 | 1.390 (3) | C3—H3 | 0.9300 |
C6—C1 | 1.395 (3) | C4—H4 | 0.9300 |
C1—C2 | 1.387 (3) | C17—H17A | 0.9600 |
C10—C11 | 1.364 (3) | C17—H17B | 0.9600 |
C10—H10 | 0.9300 | C17—H17C | 0.9600 |
C11—H11 | 0.9300 | ||
C1—S1—C7 | 88.68 (10) | O1—C15—H15A | 110.1 |
C12—O1—C15 | 118.74 (16) | C16—C15—H15A | 110.1 |
C8—N2—C7 | 120.89 (19) | O1—C15—H15B | 110.1 |
C7—N1—C6 | 111.07 (18) | C16—C15—H15B | 110.1 |
N1—C7—N2 | 121.13 (18) | H15A—C15—H15B | 108.5 |
N1—C7—S1 | 115.23 (15) | C14—C13—C12 | 119.0 (2) |
N2—C7—S1 | 123.60 (16) | C14—C13—H13 | 120.5 |
C14—C9—C10 | 117.71 (18) | C12—C13—H13 | 120.5 |
C14—C9—C8 | 121.1 (2) | C4—C5—C6 | 119.1 (2) |
C10—C9—C8 | 121.2 (2) | C4—C5—H5 | 120.4 |
O1—C12—C11 | 115.01 (17) | C6—C5—H5 | 120.4 |
O1—C12—C13 | 125.19 (19) | C15—C16—C17 | 113.8 (2) |
C11—C12—C13 | 119.79 (19) | C15—C16—H16A | 108.8 |
N2—C8—C9 | 122.4 (2) | C17—C16—H16A | 108.8 |
N2—C8—H8 | 118.8 | C15—C16—H16B | 108.8 |
C9—C8—H8 | 118.8 | C17—C16—H16B | 108.8 |
N1—C6—C5 | 124.7 (2) | H16A—C16—H16B | 107.7 |
N1—C6—C1 | 115.69 (19) | C3—C2—C1 | 118.3 (2) |
C5—C6—C1 | 119.6 (2) | C3—C2—H2 | 120.8 |
C2—C1—C6 | 121.0 (2) | C1—C2—H2 | 120.8 |
C2—C1—S1 | 129.72 (19) | C2—C3—C4 | 121.2 (2) |
C6—C1—S1 | 109.32 (15) | C2—C3—H3 | 119.4 |
C11—C10—C9 | 120.7 (2) | C4—C3—H3 | 119.4 |
C11—C10—H10 | 119.6 | C5—C4—C3 | 120.8 (2) |
C9—C10—H10 | 119.6 | C5—C4—H4 | 119.6 |
C10—C11—C12 | 120.63 (19) | C3—C4—H4 | 119.6 |
C10—C11—H11 | 119.7 | C16—C17—H17A | 109.5 |
C12—C11—H11 | 119.7 | C16—C17—H17B | 109.5 |
C13—C14—C9 | 122.1 (2) | H17A—C17—H17B | 109.5 |
C13—C14—H14 | 118.9 | C16—C17—H17C | 109.5 |
C9—C14—H14 | 118.9 | H17A—C17—H17C | 109.5 |
O1—C15—C16 | 107.79 (18) | H17B—C17—H17C | 109.5 |
C6—N1—C7—N2 | −178.59 (17) | C14—C9—C10—C11 | 0.6 (3) |
C6—N1—C7—S1 | −0.9 (2) | C8—C9—C10—C11 | −179.48 (19) |
C8—N2—C7—N1 | −170.83 (19) | C9—C10—C11—C12 | −0.8 (3) |
C8—N2—C7—S1 | 11.7 (3) | O1—C12—C11—C10 | 179.34 (18) |
C1—S1—C7—N1 | 0.44 (17) | C13—C12—C11—C10 | 0.1 (3) |
C1—S1—C7—N2 | 178.05 (17) | C10—C9—C14—C13 | 0.5 (3) |
C15—O1—C12—C11 | 176.51 (18) | C8—C9—C14—C13 | −179.47 (19) |
C15—O1—C12—C13 | −4.3 (3) | C12—O1—C15—C16 | −177.16 (18) |
C7—N2—C8—C9 | −178.31 (17) | C9—C14—C13—C12 | −1.2 (3) |
C14—C9—C8—N2 | 171.56 (19) | O1—C12—C13—C14 | −178.23 (19) |
C10—C9—C8—N2 | −8.4 (3) | C11—C12—C13—C14 | 1.0 (3) |
C7—N1—C6—C5 | −178.5 (2) | N1—C6—C5—C4 | 179.4 (2) |
C7—N1—C6—C1 | 1.1 (2) | C1—C6—C5—C4 | −0.2 (3) |
N1—C6—C1—C2 | −179.90 (19) | O1—C15—C16—C17 | 61.6 (3) |
C5—C6—C1—C2 | −0.3 (3) | C6—C1—C2—C3 | 0.3 (3) |
N1—C6—C1—S1 | −0.7 (2) | S1—C1—C2—C3 | −178.68 (18) |
C5—C6—C1—S1 | 178.91 (16) | C1—C2—C3—C4 | 0.1 (4) |
C7—S1—C1—C2 | 179.3 (2) | C6—C5—C4—C3 | 0.6 (4) |
C7—S1—C1—C6 | 0.16 (15) | C2—C3—C4—C5 | −0.6 (4) |
Cg2 is the centroid of the C1–C6 phenyl ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
C11—H11···N1i | 0.93 | 2.49 | 3.362 (3) | 157 |
C16—H16A···Cg2ii | 0.97 | 2.91 (2) | 3.765 (3) | 147 |
Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) −x+1, −y+2, −z. |
Funding information
This study was supported by Ondokuz Mayıs University under project No. PYO·FEN.1906.19.001.
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