organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoIUCrDATA
ISSN: 2414-3146

4,4-Di­methyl-2-phenyl-4,5-di­hydro­pyrrolo­[2,3,4-kl]acridin-1(2H)-one

crossmark logo

aDepartment of Chemistry, University of Rajshahi, Rajshahi-6205, Bangladesh, bDepartment of Chemistry, Faculty of Science, Mawlana Bhashani Science and Technology University, Tangail-1902, Bangladesh, cDepartment of Chemical and Pharmaceutical Sciences, University of Trieste, Italy, and dChemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637002, People's Republic of China
*Correspondence e-mail: hnroy19@ru.ac.bd

Edited by W. T. A. Harrison, University of Aberdeen, United Kingdom (Received 15 April 2025; accepted 22 April 2025; online 24 April 2025)

In the title compound, C22H18N2O, the pendant phenyl ring is twisted by 43.85 (1)° with respect to the acridine moiety, which has almost coplanar atoms apart from the sp3 carbon atoms. The extended structure features aromatic ππ stacking with a centroid-to-centroid distance of 3.489 (2) Å and weak C—H⋯O hydrogen bonds.

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

Structure description

Pyrrolo­acridines are a type of fused heterocyclic compounds that combine the structures of pyrrole and acridine. As a result of their appealing biological and therapeutic properties attributed to their ability to inter­calate DNA (Belmont et al., 2007[Belmont, P., Bosson, J., Godet, T. & Tiano, M. (2007). Anticancer Agents Med. Chem. 7, 139-169.]), organic chemists are currently paying close attention to the synthesis of these compounds through multi-step procedures (Dandia et al. 2015[Dandia, A., Sharma, A., Parewa, V., Kumawat, B., Rathore, K. S. & Sharma, A. (2015). RSC Adv. 5, 91888-91902.]; Hao et al. 2013[Hao, W.-J., Wang, J.-Q., Xu, X.-P., Zhang, S.-L., Wang, S.-Y. & Ji, S.-J. (2013). J. Org. Chem. 78, 12362-12373.]; Jiang et al. 2012[Jiang, B., Wang, X., Li, M.-Y., Wu, Q., Ye, Q., Xu, H.-W. & Tu, S.-J. (2012). Org. Biomol. Chem. 10, 8533-8538.]; Ray et al. 2014[Ray, S., Bhaumik, A., Pramanik, M. & Mukhopadhyay, C. (2014). RSC Adv. 4, 15441-15450.]; Wang et al. 2012[Wang, H., Li, L., Lin, W., Xu, P., Huang, Z. & Shi, D. (2012). Org. Lett. 14, 4598-4601.]). As part of our work in this area, we now describe the synthesis and structure of the title compound, C22H18N2O.

The mol­ecular structure of the title mol­ecule is shown in Fig. 1[link]. The chemical structure consists of a central acridine core fused to a pyrrolidone ring, a combination of rings that contributes to its planarity with the exception of the sp3 carbon atoms (C19, C20 displaced by 0.445 (2), and −0.157 (2) Å, respectively), and of the C1–C6 phenyl ring bound to the pyrrol N atom. The carbonyl C=O bond length is 1.2187 (15) Å, and all other bond distances are as expected. The phenyl ring forms a dihedral angle of 43.85 (1)° with the mean plane through the acridin moiety. This conformation is similar to that found in the structures having a 3-nitro­phenyl or 4-methyl­phenyl ring replacing the phenyl ring, where the corresponding dihedral angles are 48.84 (5) and 44.72 (4)°, respectively (Hao et al. 2013[Hao, W.-J., Wang, J.-Q., Xu, X.-P., Zhang, S.-L., Wang, S.-Y. & Ji, S.-J. (2013). J. Org. Chem. 78, 12362-12373.]). The 9-fluoro derivative (Dandia et al. 2015[Dandia, A., Sharma, A., Parewa, V., Kumawat, B., Rathore, K. S. & Sharma, A. (2015). RSC Adv. 5, 91888-91902.]) has the phenyl ring tilted by 49.32 (1)° with respect to the acridin fragment. Thus all the cited analogous derivatives exhibit similar conformations.

[Figure 1]
Figure 1
The mol­ecular structure of the title mol­ecule (displacement ellipsoids at the 50% probability level).

The crystal packing evidences ππ-stacked dimers with a centroid-to-centroid distance of 3.489 (2) Å (Fig. 2[link]). In addition, a weak C3—H3⋯O1(2 − x, 2 − y, 1 − z) hydrogen bond is observed with H⋯O = 2.53 Å, C⋯O = 3.438 (2) Å and C—H⋯O = 165°.

[Figure 2]
Figure 2
Detail of the crystal packing showing the π-stacking inter­actions as dashed lines (H atoms not indicated for the sake of clarity).

Synthesis and crystallization

Dimedone (1.00 mmol), aniline (1.00 mmol) and nicotinic acid (5–10 mol %) were mixed in 5.0 ml of toluene and the reaction mixture was heated over an oil-bath at reflux conditions with an efficient CaCl2 guard-tube for 6–8 h. Isatin (1.00 mmol) was added sequentially to the reaction mixture and it was heated to reflux till the completion of the reaction that was monitored by TLC with UV detector at 365 nm. Then, the solvent was evaporated and the residue purified by column chromatography (acetone/petroleum ether, 1:6). Single crystals suitable for X-ray analysis were obtained from slow evaporation of an ethano­lic solution of the product containing few drops of acetone: colour: light brown, yield: 80%, melting point: 191–193°C

1H NMR (400 MHz, CDCl3): δH (p.p.m.)= 8.73 (dd, J = 8, 8 Hz, 1H, Ar—H), 8.16 (d, J = 8 Hz, 1H, Ar—H), 7.83 (m, 1H, Ar—H), 7.75 (m, 1H, Ar—H), 7.68–7.54 (m, 4H, Ar—H), 7.53–7.41 (1H, Ar—H), 5.63 (s, 1H, ali-H), 3.22 (s, 2H, ali-H), 1.33 (s, 6H, ali-H).

13C NMR (100 MHz, CDCl3): δC (p.p.m.), 166.75, 154.60, 149.73, 134.78, 133.37, 129.55, 129.46, 129.39, 127.80, 127.48, 126.46, 126.40, 124.99, 124.25, 122.63, 118.36, 44.21, 37.11, 30.89.

HRMS(ESI): m/z [M + H]+ calculated for C22H19N2O: 327.399, found 327.1491.

Refinement

Crystal data, data collection and structure refinement are summarized in Table 1[link].

Table 1
Experimental details

Crystal data
Chemical formula C22H18N2O
Mr 326.38
Crystal system, space group Triclinic, P[\overline{1}]
Temperature (K) 297
a, b, c (Å) 9.430 (3), 9.997 (4), 10.203 (4)
α, β, γ (°) 99.833 (14), 107.559 (14), 106.866 (14)
V3) 841.8 (6)
Z 2
Radiation type Mo Kα
μ (mm−1) 0.08
Crystal size (mm) 0.30 × 0.30 × 0.28
 
Data collection
Diffractometer Bruker APEXII CCD
No. of measured, independent and observed [I > 2σ(I)] reflections 22780, 3806, 3047
Rint 0.041
(sin θ/λ)max−1) 0.650
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.053, 0.138, 1.12
No. of reflections 3806
No. of parameters 228
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.37, −0.49
Computer programs: APEX2 and SAINT (Bruker, 2012[Bruker (2012). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXT2014/5 (Sheldrick, 2015a[Sheldrick, G. M. (2015a). Acta Cryst. A71, 3-8.]), SHELXL2019/2 (Sheldrick, 2015b[Sheldrick, G. M. (2015b). Acta Cryst. C71, 3-8.]) and DIAMOND (Brandenburg & Putz, 1999[Brandenburg, K. & Putz, H. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.]).

Structural data


Computing details top

11,11-Dimethyl-14-phenyl-8,14-diazatetracyclo[7.6.1.02,7.013,16]hexadeca-1(16),2(7),3,5,8,12-hexaen-15-one top
Crystal data top
C22H18N2OZ = 2
Mr = 326.38F(000) = 344
Triclinic, P1Dx = 1.288 Mg m3
a = 9.430 (3) ÅMo Kα radiation, λ = 0.71073 Å
b = 9.997 (4) ÅCell parameters from 9587 reflections
c = 10.203 (4) Åθ = 2.2–26.7°
α = 99.833 (14)°µ = 0.08 mm1
β = 107.559 (14)°T = 297 K
γ = 106.866 (14)°Block, brown
V = 841.8 (6) Å30.30 × 0.30 × 0.28 mm
Data collection top
Bruker APEXII CCD
diffractometer
Rint = 0.041
Radiation source: sealed tubeθmax = 27.5°, θmin = 2.2°
φ and ω scansh = 1212
22780 measured reflectionsk = 1212
3806 independent reflectionsl = 1313
3047 reflections with I > 2σ(I)
Refinement top
Refinement on F2Primary atom site location: dual
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.053H-atom parameters constrained
wR(F2) = 0.138 w = 1/[σ2(Fo2) + (0.0778P)2 + 0.0906P]
where P = (Fo2 + 2Fc2)/3
S = 1.12(Δ/σ)max < 0.001
3806 reflectionsΔρmax = 0.37 e Å3
228 parametersΔρmin = 0.48 e Å3
0 restraints
Special details top

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. H atoms were located at geometrical positions and refined as riding atoms.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.77493 (12)0.67107 (10)0.34393 (10)0.0482 (3)
N10.85067 (12)0.60933 (10)0.55938 (10)0.0351 (3)
N20.39760 (12)0.19595 (11)0.39073 (12)0.0404 (3)
C10.99874 (14)0.72885 (12)0.63425 (12)0.0346 (3)
C21.00582 (16)0.86935 (13)0.62965 (14)0.0409 (3)
H20.9145710.8848590.5795720.049*
C31.14935 (18)0.98514 (14)0.70003 (15)0.0502 (4)
H31.1552811.0785530.6951820.060*
C41.28445 (18)0.96283 (16)0.77777 (17)0.0560 (4)
H41.3802401.0414670.8266270.067*
C51.27703 (17)0.82358 (17)0.78282 (17)0.0538 (4)
H51.3679440.8090070.8352610.065*
C61.13471 (16)0.70562 (14)0.71007 (15)0.0442 (3)
H61.1303040.6118660.7120110.053*
C70.74945 (15)0.59113 (12)0.41867 (13)0.0347 (3)
C80.61124 (14)0.45417 (12)0.38158 (12)0.0328 (3)
C90.46972 (14)0.37668 (13)0.25861 (12)0.0344 (3)
C100.42702 (17)0.41674 (15)0.12990 (14)0.0429 (3)
H100.4938070.5013970.1219150.052*
C110.28797 (18)0.33172 (17)0.01693 (14)0.0515 (4)
H110.2610210.3585210.0675120.062*
C120.18646 (18)0.20460 (17)0.02846 (15)0.0526 (4)
H120.0921010.1476520.0485690.063*
C130.22420 (16)0.16301 (15)0.15150 (15)0.0475 (3)
H130.1547900.0784170.1571190.057*
C140.36693 (15)0.24652 (13)0.27015 (13)0.0368 (3)
C150.53139 (14)0.27159 (13)0.50142 (13)0.0357 (3)
C160.63918 (14)0.39923 (12)0.49598 (12)0.0325 (3)
C170.78949 (14)0.48942 (12)0.60979 (12)0.0326 (3)
C180.84327 (16)0.44642 (13)0.72607 (13)0.0387 (3)
H180.9332640.5097300.8042890.046*
C190.75654 (16)0.29286 (13)0.73030 (13)0.0389 (3)
C200.57421 (16)0.23479 (15)0.64175 (14)0.0420 (3)
H20A0.5322910.1296980.6227420.050*
H20B0.5226410.2748770.6988540.050*
C210.83069 (18)0.19303 (15)0.66618 (16)0.0499 (4)
H21A0.7869130.0970450.6750340.075*
H21B0.9442990.2315610.7167660.075*
H21C0.8070880.1882380.5667750.075*
C220.7832 (2)0.29030 (18)0.88549 (15)0.0551 (4)
H22A0.7379580.3530050.9262320.083*
H22B0.8956820.3236820.9402870.083*
H22C0.7328000.1925980.8871740.083*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0543 (6)0.0394 (5)0.0430 (5)0.0031 (4)0.0157 (4)0.0210 (4)
N10.0367 (6)0.0278 (5)0.0364 (5)0.0061 (4)0.0118 (4)0.0115 (4)
N20.0362 (6)0.0375 (6)0.0434 (6)0.0065 (5)0.0132 (5)0.0163 (5)
C10.0364 (7)0.0288 (6)0.0358 (6)0.0063 (5)0.0163 (5)0.0064 (5)
C20.0475 (7)0.0315 (6)0.0423 (7)0.0109 (5)0.0183 (6)0.0105 (5)
C30.0618 (9)0.0289 (6)0.0526 (8)0.0053 (6)0.0244 (7)0.0073 (6)
C40.0456 (8)0.0440 (8)0.0585 (9)0.0038 (6)0.0194 (7)0.0011 (7)
C50.0364 (7)0.0560 (9)0.0589 (9)0.0108 (6)0.0147 (6)0.0080 (7)
C60.0412 (7)0.0369 (7)0.0532 (8)0.0133 (6)0.0184 (6)0.0099 (6)
C70.0382 (6)0.0302 (6)0.0351 (6)0.0100 (5)0.0138 (5)0.0111 (5)
C80.0351 (6)0.0305 (6)0.0350 (6)0.0108 (5)0.0155 (5)0.0120 (5)
C90.0352 (6)0.0335 (6)0.0347 (6)0.0116 (5)0.0141 (5)0.0100 (5)
C100.0452 (7)0.0439 (7)0.0367 (6)0.0101 (6)0.0148 (6)0.0153 (5)
C110.0532 (9)0.0582 (9)0.0341 (7)0.0136 (7)0.0096 (6)0.0150 (6)
C120.0437 (8)0.0550 (8)0.0388 (7)0.0057 (6)0.0038 (6)0.0062 (6)
C130.0395 (7)0.0429 (7)0.0461 (7)0.0023 (6)0.0104 (6)0.0106 (6)
C140.0338 (6)0.0351 (6)0.0380 (6)0.0085 (5)0.0129 (5)0.0104 (5)
C150.0331 (6)0.0339 (6)0.0405 (6)0.0093 (5)0.0145 (5)0.0152 (5)
C160.0336 (6)0.0295 (6)0.0348 (6)0.0098 (5)0.0136 (5)0.0113 (5)
C170.0359 (6)0.0267 (5)0.0350 (6)0.0094 (5)0.0143 (5)0.0098 (5)
C180.0401 (7)0.0334 (6)0.0348 (6)0.0078 (5)0.0088 (5)0.0096 (5)
C190.0434 (7)0.0366 (6)0.0366 (6)0.0115 (5)0.0132 (5)0.0184 (5)
C200.0414 (7)0.0405 (7)0.0438 (7)0.0084 (6)0.0165 (6)0.0216 (6)
C210.0546 (8)0.0415 (7)0.0583 (8)0.0198 (6)0.0212 (7)0.0214 (6)
C220.0647 (10)0.0584 (9)0.0421 (7)0.0191 (8)0.0166 (7)0.0259 (7)
Geometric parameters (Å, º) top
O1—C71.2187 (15)C11—C121.399 (2)
N1—C71.4102 (17)C11—H110.9300
N1—C171.4222 (15)C12—C131.368 (2)
N1—C11.4275 (16)C12—H120.9300
N2—C151.3169 (17)C13—C141.4120 (18)
N2—C141.3912 (17)C13—H130.9300
C1—C61.3900 (19)C15—C161.4037 (17)
C1—C21.3962 (18)C15—C201.5052 (18)
C2—C31.381 (2)C16—C171.4416 (17)
C2—H20.9300C17—C181.3369 (17)
C3—C41.385 (2)C18—C191.5307 (18)
C3—H30.9300C18—H180.9300
C4—C51.384 (2)C19—C221.5325 (19)
C4—H40.9300C19—C211.540 (2)
C5—C61.387 (2)C19—C201.5538 (19)
C5—H50.9300C20—H20A0.9700
C6—H60.9300C20—H20B0.9700
C7—C81.4855 (17)C21—H21A0.9600
C8—C161.3605 (17)C21—H21B0.9600
C8—C91.4189 (17)C21—H21C0.9600
C9—C101.4147 (18)C22—H22A0.9600
C9—C141.4269 (18)C22—H22B0.9600
C10—C111.370 (2)C22—H22C0.9600
C10—H100.9300
C7—N1—C17110.79 (10)C12—C13—H13119.5
C7—N1—C1123.16 (10)C14—C13—H13119.5
C17—N1—C1125.95 (10)N2—C14—C13117.52 (11)
C15—N2—C14118.19 (11)N2—C14—C9124.43 (11)
C6—C1—C2120.32 (12)C13—C14—C9118.04 (12)
C6—C1—N1120.42 (11)N2—C15—C16120.22 (11)
C2—C1—N1119.26 (11)N2—C15—C20123.64 (11)
C3—C2—C1119.52 (13)C16—C15—C20116.03 (11)
C3—C2—H2120.2C8—C16—C15123.23 (12)
C1—C2—H2120.2C8—C16—C17111.80 (11)
C2—C3—C4120.34 (13)C15—C16—C17124.96 (11)
C2—C3—H3119.8C18—C17—N1135.06 (11)
C4—C3—H3119.8C18—C17—C16120.24 (11)
C5—C4—C3120.05 (13)N1—C17—C16104.60 (10)
C5—C4—H4120.0C17—C18—C19119.91 (11)
C3—C4—H4120.0C17—C18—H18120.0
C4—C5—C6120.36 (14)C19—C18—H18120.0
C4—C5—H5119.8C18—C19—C22110.21 (11)
C6—C5—H5119.8C18—C19—C21106.57 (11)
C5—C6—C1119.39 (13)C22—C19—C21109.13 (11)
C5—C6—H6120.3C18—C19—C20112.81 (10)
C1—C6—H6120.3C22—C19—C20109.02 (11)
O1—C7—N1126.03 (11)C21—C19—C20109.02 (11)
O1—C7—C8128.23 (12)C15—C20—C19114.02 (10)
N1—C7—C8105.72 (10)C15—C20—H20A108.7
C16—C8—C9119.06 (11)C19—C20—H20A108.7
C16—C8—C7106.99 (11)C15—C20—H20B108.7
C9—C8—C7133.94 (11)C19—C20—H20B108.7
C10—C9—C8125.67 (12)H20A—C20—H20B107.6
C10—C9—C14119.51 (12)C19—C21—H21A109.5
C8—C9—C14114.81 (11)C19—C21—H21B109.5
C11—C10—C9120.48 (13)H21A—C21—H21B109.5
C11—C10—H10119.8C19—C21—H21C109.5
C9—C10—H10119.8H21A—C21—H21C109.5
C10—C11—C12120.07 (13)H21B—C21—H21C109.5
C10—C11—H11120.0C19—C22—H22A109.5
C12—C11—H11120.0C19—C22—H22B109.5
C13—C12—C11120.87 (13)H22A—C22—H22B109.5
C13—C12—H12119.6C19—C22—H22C109.5
C11—C12—H12119.6H22A—C22—H22C109.5
C12—C13—C14121.01 (13)H22B—C22—H22C109.5
C7—N1—C1—C6135.02 (13)C10—C9—C14—N2179.36 (11)
C17—N1—C1—C640.75 (17)C8—C9—C14—N20.47 (18)
C7—N1—C1—C244.53 (16)C10—C9—C14—C130.68 (18)
C17—N1—C1—C2139.71 (12)C8—C9—C14—C13179.57 (11)
C6—C1—C2—C30.56 (19)C14—N2—C15—C160.26 (18)
N1—C1—C2—C3178.99 (11)C14—N2—C15—C20175.80 (11)
C1—C2—C3—C41.7 (2)C9—C8—C16—C152.69 (18)
C2—C3—C4—C51.4 (2)C7—C8—C16—C15178.19 (11)
C3—C4—C5—C60.1 (2)C9—C8—C16—C17178.58 (10)
C4—C5—C6—C11.2 (2)C7—C8—C16—C170.54 (13)
C2—C1—C6—C50.9 (2)N2—C15—C16—C82.16 (19)
N1—C1—C6—C5179.56 (11)C20—C15—C16—C8174.19 (11)
C17—N1—C7—O1175.27 (12)N2—C15—C16—C17179.28 (11)
C1—N1—C7—O11.07 (19)C20—C15—C16—C174.37 (18)
C17—N1—C7—C83.10 (13)C7—N1—C17—C18172.77 (13)
C1—N1—C7—C8179.43 (10)C1—N1—C17—C183.4 (2)
O1—C7—C8—C16176.78 (12)C7—N1—C17—C163.37 (13)
N1—C7—C8—C161.54 (13)C1—N1—C17—C16179.58 (10)
O1—C7—C8—C92.2 (2)C8—C16—C17—C18174.48 (11)
N1—C7—C8—C9179.53 (12)C15—C16—C17—C186.82 (19)
C16—C8—C9—C10177.48 (11)C8—C16—C17—N12.37 (13)
C7—C8—C9—C101.4 (2)C15—C16—C17—N1176.33 (11)
C16—C8—C9—C141.34 (17)N1—C17—C18—C19167.75 (12)
C7—C8—C9—C14179.83 (12)C16—C17—C18—C197.93 (18)
C8—C9—C10—C11178.88 (12)C17—C18—C19—C22153.29 (12)
C14—C9—C10—C110.1 (2)C17—C18—C19—C2188.42 (15)
C9—C10—C11—C120.3 (2)C17—C18—C19—C2031.17 (17)
C10—C11—C12—C130.2 (2)N2—C15—C20—C19155.80 (12)
C11—C12—C13—C140.4 (2)C16—C15—C20—C1927.98 (16)
C15—N2—C14—C13179.03 (12)C18—C19—C20—C1540.35 (16)
C15—N2—C14—C91.02 (19)C22—C19—C20—C15163.13 (11)
C12—C13—C14—N2179.24 (12)C21—C19—C20—C1577.82 (14)
C12—C13—C14—C90.8 (2)
 

Acknowledgements

The authors acknowledge the Department of Chemistry, University of Rajshahi, Bangladesh, for the facilities provided during this work, and Dr Pran Gopal Karmaker, Associate Professor, China West Normal University, China, for providing facilities for single-crystal X-ray analysis.

Funding information

Funding for this research was provided by: Rajshahi University, project title: One-Pot Green Synthesis of some Bio-active Heterocycles Mediated by Organocatalyst in Aqueous Medium.

References

First citationBelmont, P., Bosson, J., Godet, T. & Tiano, M. (2007). Anticancer Agents Med. Chem. 7, 139–169.  CrossRef PubMed CAS Google Scholar
First citationBrandenburg, K. & Putz, H. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
First citationBruker (2012). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationDandia, A., Sharma, A., Parewa, V., Kumawat, B., Rathore, K. S. & Sharma, A. (2015). RSC Adv. 5, 91888–91902.  CSD CrossRef CAS Google Scholar
First citationHao, W.-J., Wang, J.-Q., Xu, X.-P., Zhang, S.-L., Wang, S.-Y. & Ji, S.-J. (2013). J. Org. Chem. 78, 12362–12373.  CSD CrossRef CAS PubMed Google Scholar
First citationJiang, B., Wang, X., Li, M.-Y., Wu, Q., Ye, Q., Xu, H.-W. & Tu, S.-J. (2012). Org. Biomol. Chem. 10, 8533–8538.  CSD CrossRef CAS PubMed Google Scholar
First citationRay, S., Bhaumik, A., Pramanik, M. & Mukhopadhyay, C. (2014). RSC Adv. 4, 15441–15450.  CSD CrossRef CAS Google Scholar
First citationSheldrick, G. M. (2015a). Acta Cryst. A71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015b). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationWang, H., Li, L., Lin, W., Xu, P., Huang, Z. & Shi, D. (2012). Org. Lett. 14, 4598–4601.  CSD CrossRef CAS PubMed Google Scholar

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.

Journal logoIUCrDATA
ISSN: 2414-3146