The asymmetric unit of the title compound consists of a benzyl moiety bonded to the nitrogen atom of a 1H-benzo[f]isoindole-4-carboxylic acid group. In the crystal, O—H⋯O and C—H⋯O hydrogen bonds link the molecules into infinite double-chains along the a-axis direction. π–π stacking interactions and C—H⋯π(ring) interactions help to consolidate the packing.
Keywords: isoindole, benzo[f]isoindole, IMDAV reaction, Diels–Alder reaction, crystal structure
Abstract
The title compound, C20H19NO3, consists of a benzyl moiety bonded to the nitrogen atom of a 1H-benzo[f]isoindole-4-carboxylic acid group. The fused pyrrole and cyclohexene rings of the isoindole group are in envelope and flattened-boat conformations, respectively. The planar benzene rings are oriented at a dihedral angle of 69.64 (3)°. In the crystal, O—H⋯O and C—H⋯O hydrogen bonds link the molecules, enclosing R22(14) and R22(9) ring motifs, into infinite double-chains along the a-axis direction. π–π stacking interactions and C—H⋯π(ring) interactions help to consolidate the packing. Hirshfeld surface analysis revealed that the most important contributions for the crystal packing are from H⋯H (52.2%), H⋯C/C⋯H (24.0%) and H⋯O/O⋯H (21.2%) interactions. The volume of the crystal voids and the percentage of free space were calculated to be 92.25 Å3 and 11.52%, showing that there is no large cavity in the crystal packing. Computational methods revealed O—H⋯O and C—H⋯O hydrogen-bonding energies of −103.8, −82.2 and −35.5 kJ mol−1. Evaluations of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated by the electrostatic energy contributions.
1. Chemical context
One of the earliest reports on the synthesis of benzo[f]isoindoles via a [4 + 2] cycloaddition was published by Michael T. Cox (1975 ▸). Since then, the intramolecular Diels–Alder (IMDA) reaction has become a powerful and widely employed strategy for the construction of complex carbo- and heterocyclic scaffolds (Krishna et al., 2022 ▸). IMDA-based approaches enable concise synthetic routes, often providing target compounds in high yields and with significant functional and biological relevance.
The majority of reported IMDA transformations rely on structurally elaborate substrates (Cox, 1975 ▸; Ozawa et al., 2011 ▸; Kim et al., 2014 ▸), in which the dienophilic moiety is typically introduced via acyl halide derivatives (Dawson & Mellor, 1995 ▸; Rodríguez et al., 2004 ▸; Bober et al., 2017 ▸). Cyclic anhydrides also exhibit high reactivity in such processes, while the resulting carboxylic acid functionality offers opportunities for further downstream functionalization (Kolesnik et al., 2025 ▸; Sadikhova et al., 2024 ▸) as well as applications in coordination and supramolecular chemistry (Huseynov et al., 2021 ▸; Naghiyev et al., 2023 ▸; Mamedov et al., 2006 ▸).
In our previous study, we reported an efficient approach to N-alkyl-substituted benzo[f]isoindoles based on the reaction of allylamines with maleic anhydride (Alekseeva et al., 2026 ▸). Herein, we present an additional example of this transformation.
The reaction of cinnamylamine (2) with an equimolar amount of maleic acid anhydride in boiling acetonitrile affords the target benzo[f]isoindole-4-carboxylic acid in satisfactory yield (Fig. 1 ▸). The product crystallizes directly from the reaction mixture and requires no further purification.
Figure 1.
The reaction scheme for the synthesis of the title compound.
It should be noted that establishing the structure and describing the structural features of such a type of compounds is an important task, as a number of derivatives of benzo[f]isoindole are known to be used as bichromophores (Denissen et al., 2017 ▸), plant protections (Song et al., 2023 ▸) and demonstrate the potential of transformation into BODIPY scaffolds (Dvoracek et al., 2025 ▸). Herein, we studied the title compound’s molecular and crystal structures together with its Hirshfeld surface (HS) and carried out crystal void analyses, interaction energy calculations and energy framework determinations.
2. Structural commentary
The title compound consists of a benzyl moiety bonded to the nitrogen atom of a 1H-benzo[f]isoindole-4-carboxylic acid group (Fig. 2 ▸). In the isoindole group, the fused pyrrole and cyclohexene, A (N2/C1/C3/C23A/C9A) and B (C3A/C4/C4A/C8A/C9/C9A), rings are in envelope (Fig. 3 ▸a) and flattened-boat (Fig. 3 ▸b) conformations with puckering parameters (Cremer & Pople, 1975 ▸) φ = 252.21 (19)° (for the pyrrole ring) and QT = 0.5318 (13) Å, θ = 127.60 (13)° and φ = 138.60 (17)° (for the cyclohexene ring). Atom C9A is at the flap position and it is 0.5488 (12) Å away from the best least-squares plane of the other four atoms in the pyrrole ring. Atom C10 is −0.0268 (13) Å away from the best plane of the benzene, D (C11–C16), ring. The planar benzene, C (C4a/C5–C8/C8a) and D (C11–C16), rings are oriented at a dihedral angle of 69.64 (3)°. In the carboxylic acid moiety, the O2—C17—O3 [123.68 (11)°] bond angle is slightly widened with respect to that present in the free acid [122.2°] (Sim et al., 1955 ▸), and it is reported to be 124.27 (17)° in diaquabis(2-bromobenzoato-κO)bis(nicotinamide-κN1)zinc(II) (Hökelek et al., 2009 ▸). In a broader analysis, the observed O2—C17—O3 [123.68 (11)°] bond angle is quite normal and very similar to the median value of 124.36° calculated from ca. 2700 deposited structures in the CSD (Groom et al., 2016 ▸).
Figure 2.
The asymmetric unit of the title compound with the atom-numbering scheme and 50% probability ellipsoids.
Figure 3.
The conformations of the pyrrole (a) and cyclohexene (b) rings of the isoindole ring system.
3. Supramolecular features
In the crystal, O—H⋯O and C—H⋯O hydrogen bonds (Table 1 ▸) link the molecules, enclosing 
(14) and (9) ring motifs (Etter et al., 1990 ▸) (Fig. 4 ▸a), into infinite double-chains along the a-axis direction (Fig. 4 ▸b). π–π stacking interactions between the D rings with centroid-to-centroid distance, α and slippage values of 3.8650 (13) Å, 0.00 (7)° and 1.710 Å, respectively (Table 1 ▸) may help consolidate the packing. More notably, the C—H⋯π(ring) interactions (Table 1 ▸) with a C—H⋯centroid distance of 2.53 Å between atom C3A and the C ring are very efficiently arranged and bidirectional between the two molecules, giving rise to the formation of additional pairs to those generated by the O—H⋯O contacts. The C—H⋯π(ring) interactions link the infinite double chains in the c-axis direction resulting from hydrogen bonding, leading to broad sheets in the ac plane.
Table 1. Hydrogen-bond geometry (Å, °).
Cg3 is the centroid of the C4A/C5–C8/C8A ring.
| D—H⋯A | D—H | H⋯A | D⋯A | D—H⋯A |
|---|---|---|---|---|
| O3—H3⋯O1i | 0.888 (19) | 1.752 (19) | 2.6227 (14) | 166.1 (17) |
| C9—H9B⋯O2ii | 0.99 | 2.59 | 3.3397 (19) | 133 |
| C10—H10A⋯O2i | 0.99 | 2.47 | 3.2689 (19) | 138 |
| C3A—H3A⋯Cg3iii | 1.00 | 2.53 | 3.5088 (16) | 166 |
Symmetry codes: (i) 
; (ii) 
; (iii) 
.
Figure 4.
Partial packing diagrams of the title compound showing the O—H⋯O and C—H⋯O hydrogen bonds as dashed lines with (a) the (9) and (14) ring motifs and (b) the infinite double-chains viewed along the a-axis direction.
The intermolecular interactions in the crystal are visualized through a Hirshfeld surface (HS) analysis using CrystalExplorer 17.5 (Spackman et al., 2021 ▸). Fig. 5 ▸ shows the Hirshfeld surface as impacted by several adjacent molecules in the crystal. The white surface indicates contacts with distances equal to the sum of van der Waals radii, and the red and blue colours indicate distances shorter (in close contact) or longer (more distant atom) than the van der Waals radii, respectively. The red spots indicate their roles as the respective donors and/or acceptors in the hydrogen bonding patterns, as discussed above; they also appear as the blue and red regions corresponding to positive and negative potentials on the HS mapped over the electrostatic potential as shown in Fig. 6 ▸. The blue and red regions indicate positive (hydrogen-bond donor) and negative (hydrogen-bond acceptor) electrostatic potentials. The π–π stacking and C—H⋯π(ring) interactions (Table 1 ▸) are indicated in Fig. 7 ▸a,b by the presence of adjacent red and blue triangles and red π-holes, respectively. In Fig. 7 ▸b, the extensive blue dot for the C—H from the interaction with the similarly notable red π-hole of the adjacent molecule can be very clearly seen. This suggests that this contact is of significant importance for the packing.
Figure 5.
View of the three-dimensional Hirshfeld surface for the title compound plotted over dnorm in the range −0.7390 to 1.6319 a.u.
Figure 6.
View of the three-dimensional Hirshfeld surface of the title compound plotted over the electrostatic potential in the range of −0.0500 to 0.0500 a.u. using the STO-3 G basis set at the Hartree–Fock level of theory. Hydrogen-bond donors and acceptors are shown as blue and red regions around the atoms, corresponding to positive and negative potentials, respectively.
Figure 7.
Two orientations of the shape-index surface showing (a) the π–π and (b) the C—H⋯π(ring) interactions.
The overall two-dimensional fingerprint plot is shown in Fig. 8 ▸a and those delineated into H⋯H, H⋯C/C⋯H, H⋯O/O⋯H, C⋯C, H⋯N/N⋯H and C⋯O/O⋯C interactions are illustrated in Fig. 8 ▸(b)–(g), respectively. According to the two-dimensional fingerprint plots, H⋯H, H⋯C/C⋯H and H⋯O/O⋯H contacts make the most significant contributions to the HS, at 52.2%, 24.0% and 21.2%, respectively (Fig. 8 ▸).
Figure 8.
The full two-dimensional fingerprint plots for the title molecule, showing (a) all interactions, and those delineated into (b) H⋯H, (c) H⋯C/C⋯H, (d) H⋯O/O⋯H, (e) C⋯C, (f) H⋯N/N⋯H and (g) C⋯O/O⋯C interactions. The di and de values are the closest internal and external distances (in Å) from given points on the Hirshfeld surface.
The strength of the crystal depends on the tight packing of the molecules and having concomittantly insignificant voids only. For checking the strength of the crystal, a void analysis was performed. The volume of the crystal voids (Fig. 9 ▸a,b) and the percentage of free space in the unit cell were calculated as 92.25 Å3 and 11.52%, respectively. Thus, the crystal packing appears rather compact.
Figure 9.
Crystal voids viewed down the crystallographic a-axis (a) and b-axis (b) directions.
The intermolecular interaction energies were calculated using the CE–B3LYP/6–31G(d,p) energy model available in CrystalExplorer 17.5 (Spackman et al., 2021 ▸), where a cluster of molecules is generated by applying crystallographic symmetry operations with respect to a selected central molecule within the radius of 3.8 Å by default. The total intermolecular energy (Etot) is the sum of electrostatic (Eele), polarization (Epol), dispersion (Edis) and exchange-repulsion (Erep) energies (Turner et al., 2015 ▸) with scale factors of 1.057, 0.740, 0.871 and 0.618, respectively (Mackenzie et al., 2017 ▸). Hydrogen-bonding interaction energies (in kJ mol−1) were calculated to be −141.4 (Eele), −42.8 (Epol), −32.0 (Edis), 119.5 (Erep) and −103.8 (Etot) for the O3—H3⋯O1 hydrogen-bonding interaction, −30.4 (Eele), −7.5 (Epol), −96.2 (Edis), 49.8 (Erep) and −82.2 (Etot) for the C10—H10A⋯O2 hydrogen-bonding interaction and −12.5 (Eele), −7.0 (Epol), −38.7 (Edis), 20.5 (Erep) and −35.5 (Etot) for the C9—H9B⋯O2 hydrogen-bonding interaction.
Energy frameworks combine the calculation of intermolecular interaction energies with a graphical representation of their magnitudes, in which they were constructed for Eele (red cylinders), Edis (green cylinders) and Etot (blue cylinders) (Fig. 10 ▸a,b,c). The evaluations of the electrostatic, dispersion and total energy frameworks indicate that the electrostatic energy contributions dominate in the crystal structure of the title compound.
Figure 10.
The energy frameworks for a cluster of molecules of the title compound viewed down the a-axis showing (a) the electrostatic energy, (b) the dispersion energy and (c) the total energy diagrams. The cylindrical radius is proportional to the relative strength of the corresponding energies and they were adjusted to the same scale factor of 80 with cut-off value of 5 kJ mol−1 within 3 × 3 × 3 unit cells.
4. Synthesis and crystallization
(2E)-N-Benzyl-3-phenylprop-2-en-1-amine (2) (0.67 g, 3.00 mmol) was dissolved in acetonitrile (15 ml), and maleic anhydride (0.29 g, 3.00 mmol) was added. The reaction mixture was refluxed for 8 h. Upon cooling to room temperature, the resulting solid was collected by filtration, washed with diethyl ether (2 × 10 ml), and air-dried to afford the target compound (1) as white crystalline powder (0.47 g, 1.47 mmol, 49%, m.p. 503-505 K). A single crystal suitable for X-ray diffraction analysis was found in the obtained crystalline material. 1H NMR (700 MHz, DMSO-d6, 298 K) (J, Hz): δ 12.49 (br. s, 1H, COOH), 7.47–7.46 (m, 1H, Harom), 7.35–7.33 (m, 2H, Harom), 7.28–7.26 (m, 3H, Harom), 7.20–7.16 (m, 3H, Harom), 4.50 (d, J = 15.3, 1H, H10A—NCH2Ph), 4.36 (d, J = 15.3, 1H, H10B—NCH2Ph), 4.00 (dd, J = 6.1, 1H, H4methine), 3.42–3.39 (m, 1H, H1Amethylene), 3.09–3.07 (m, 1H, H1Bmethylene), 3.05–3.00 (m, 1H, H9Cmethine), 2.93 (dd, J = 4.3, 15.7, 1H, H9Amethylene), 2.70 (dd, J = 12.4, 15.0, 1H, H9Bmethylene), 2.40 (dd, J = 5.5, 12.6, 1H, H3Amethine) ppm. 13C{1H} NMR (176 MHz, DMSO-d6, 298 K): δ 173.15, 173.12, 137.3, 136.7, 133.0, 130.1, 128.5 (2C), 127.4 (2C), 127.1, 127.0, 126.1, 50.2, 45.7, 45.3, 42.4, 32.7, 32.2 ppm. IR (KBr), ν (cm−1) 2943, 2542, 1732, 1633, 1485, 1440, 1319, 1274, 1234, 1202, 1171. Analysis calculated for C20H19NO3: C, 74.75; H, 5.96; N, 4.36. Found: C, 74.68; H, 6.12; N, 4.21.
5. Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. The OH hydrogen atom was located in a difference-Fourier map and refined isotropically. The C-bound hydrogen-atom positions were calculated geometrically at distances of 1.00 Å (for methine CH), 0.95 Å (for aromatic CH) and 0.99 Å (for methylene CH) and refined using a riding model with Uiso(H) = 1.2Ueq(C).
Table 2. Experimental details.
| Crystal data | |
| Chemical formula | C20H19NO3 |
| M r | 321.36 |
| Crystal system, space group | Triclinic, P
|
| Temperature (K) | 100 |
| a, b, c (Å) | 6.7225 (15), 11.102 (3), 11.108 (3) |
| α, β, γ (°) | 84.894 (4), 76.890 (4), 83.580 (3) |
| V (Å3) | 800.6 (4) |
| Z | 2 |
| Radiation type | Mo Kα |
| μ (mm−1) | 0.09 |
| Crystal size (mm) | 0.30 × 0.25 × 0.20 |
| Data collection | |
| Diffractometer | Bruker APEXII area detector |
| Absorption correction | Multi-scan (SADABS; Krause et al., 2015 ▸) |
| Tmin, Tmax | 0.963, 0.980 |
| No. of measured, independent and observed [I > 2σ(I)] reflections | 13680, 5546, 4248 |
| R int | 0.022 |
| (sin θ/λ)max (Å−1) | 0.761 |
| Refinement | |
| R[F2 > 2σ(F2)], wR(F2), S | 0.054, 0.136, 1.03 |
| No. of reflections | 5546 |
| No. of parameters | 220 |
| H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
| Δρmax, Δρmin (e Å−3) | 0.56, −0.25 |
Supplementary Material
Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S2056989026005189/yz2079sup1.cif
Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989026005189/yz2079Isup2.hkl
Supporting information file. DOI: 10.1107/S2056989026005189/yz2079Isup3.cml
CCDC reference: 2486562
Additional supporting information: crystallographic information; 3D view; checkCIF report
Acknowledgments
The authors’ contributions are as follows. Conceptualization, TH and ANB; synthesis, KAA and MYK; NMR analysis, AAP; X-ray analysis, VNK and TH; Hirshfeld surface analysis, TH; writing (review and editing of the manuscript) TH and KIH; supervision, TH and ANB.
supplementary crystallographic information
(3aRS,4RS,9aRS)-2-Benzyl-3-oxo-2,3,3a,4,9,9a-hexahydro-1H-benzo[f]isoindole-4-carboxylic acid . Crystal data
| C20H19NO3 | Z = 2 |
| Mr = 321.36 | F(000) = 340 |
| Triclinic, P1 | Dx = 1.333 Mg m−3 |
| a = 6.7225 (15) Å | Mo Kα radiation, λ = 0.71073 Å |
| b = 11.102 (3) Å | Cell parameters from 6018 reflections |
| c = 11.108 (3) Å | θ = 2.6–32.6° |
| α = 84.894 (4)° | µ = 0.09 mm−1 |
| β = 76.890 (4)° | T = 100 K |
| γ = 83.580 (3)° | Prism, colourless |
| V = 800.6 (4) Å3 | 0.30 × 0.25 × 0.20 mm |
(3aRS,4RS,9aRS)-2-Benzyl-3-oxo-2,3,3a,4,9,9a-hexahydro-1H-benzo[f]isoindole-4-carboxylic acid . Data collection
| Bruker APEXII area detector diffractometer | 4248 reflections with I > 2σ(I) |
| Radiation source: fine-focus sealed tube | Rint = 0.022 |
| φ and ω scans | θmax = 32.8°, θmin = 1.9° |
| Absorption correction: multi-scan (SADABS; Krause et al., 2015) | h = −10→9 |
| Tmin = 0.963, Tmax = 0.980 | k = −16→16 |
| 13680 measured reflections | l = −16→16 |
| 5546 independent reflections |
(3aRS,4RS,9aRS)-2-Benzyl-3-oxo-2,3,3a,4,9,9a-hexahydro-1H-benzo[f]isoindole-4-carboxylic acid . Refinement
| Refinement on F2 | Primary atom site location: difference Fourier map |
| Least-squares matrix: full | Secondary atom site location: difference Fourier map |
| R[F2 > 2σ(F2)] = 0.054 | Hydrogen site location: mixed |
| wR(F2) = 0.136 | H atoms treated by a mixture of independent and constrained refinement |
| S = 1.03 | w = 1/[σ2(Fo2) + (0.0621P)2 + 0.37P] where P = (Fo2 + 2Fc2)/3 |
| 5546 reflections | (Δ/σ)max < 0.001 |
| 220 parameters | Δρmax = 0.56 e Å−3 |
| 0 restraints | Δρmin = −0.25 e Å−3 |
(3aRS,4RS,9aRS)-2-Benzyl-3-oxo-2,3,3a,4,9,9a-hexahydro-1H-benzo[f]isoindole-4-carboxylic acid . Special details
| 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. |
(3aRS,4RS,9aRS)-2-Benzyl-3-oxo-2,3,3a,4,9,9a-hexahydro-1H-benzo[f]isoindole-4-carboxylic acid . Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)
| x | y | z | Uiso*/Ueq | ||
| O1 | 0.47170 (13) | 0.17245 (8) | 0.11760 (8) | 0.01417 (18) | |
| O2 | 0.29170 (15) | −0.16976 (10) | 0.18918 (9) | 0.0225 (2) | |
| O3 | 0.59880 (14) | −0.11167 (9) | 0.09065 (8) | 0.01539 (19) | |
| H3 | 0.565 (3) | −0.1419 (16) | 0.0275 (17) | 0.023* | |
| C1 | 0.95288 (19) | 0.10015 (12) | 0.20139 (12) | 0.0154 (2) | |
| H1A | 0.968369 | 0.153351 | 0.264981 | 0.019* | |
| H1B | 1.089892 | 0.075125 | 0.150450 | 0.019* | |
| N2 | 0.81469 (16) | 0.16053 (10) | 0.12427 (10) | 0.0138 (2) | |
| C3 | 0.62090 (18) | 0.13013 (11) | 0.16167 (11) | 0.0113 (2) | |
| C3A | 0.61601 (17) | 0.04056 (11) | 0.27320 (11) | 0.0104 (2) | |
| H3A | 0.582024 | 0.090138 | 0.347302 | 0.012* | |
| C4 | 0.46745 (17) | −0.05682 (11) | 0.30006 (10) | 0.0105 (2) | |
| H4 | 0.329661 | −0.016392 | 0.337862 | 0.013* | |
| C4A | 0.52742 (18) | −0.15235 (11) | 0.39842 (11) | 0.0115 (2) | |
| C5 | 0.39286 (19) | −0.24037 (12) | 0.45008 (12) | 0.0154 (2) | |
| H5 | 0.269579 | −0.240813 | 0.422016 | 0.018* | |
| C6 | 0.4354 (2) | −0.32699 (13) | 0.54135 (13) | 0.0197 (3) | |
| H6 | 0.341939 | −0.385686 | 0.575476 | 0.024* | |
| C7 | 0.6163 (2) | −0.32686 (13) | 0.58225 (13) | 0.0204 (3) | |
| H7 | 0.646653 | −0.385144 | 0.645110 | 0.024* | |
| C8 | 0.7520 (2) | −0.24141 (12) | 0.53094 (12) | 0.0169 (2) | |
| H8 | 0.875866 | −0.242600 | 0.558770 | 0.020* | |
| C8A | 0.71126 (18) | −0.15299 (11) | 0.43877 (11) | 0.0124 (2) | |
| C9 | 0.86880 (18) | −0.06341 (12) | 0.38610 (11) | 0.0140 (2) | |
| H9A | 0.853288 | 0.002468 | 0.442969 | 0.017* | |
| H9B | 1.008710 | −0.105233 | 0.378223 | 0.017* | |
| C9A | 0.83988 (18) | −0.01002 (11) | 0.26026 (11) | 0.0121 (2) | |
| H9C | 0.871886 | −0.075616 | 0.200736 | 0.015* | |
| C10 | 0.8754 (2) | 0.26392 (12) | 0.03716 (12) | 0.0156 (2) | |
| H10A | 0.784425 | 0.277362 | −0.022431 | 0.019* | |
| H10B | 1.017686 | 0.245513 | −0.010136 | 0.019* | |
| C11 | 0.86246 (19) | 0.37789 (11) | 0.10473 (11) | 0.0144 (2) | |
| C12 | 0.6812 (2) | 0.45538 (13) | 0.12481 (13) | 0.0196 (3) | |
| H12 | 0.567626 | 0.436842 | 0.094474 | 0.023* | |
| C13 | 0.6653 (2) | 0.55930 (13) | 0.18871 (14) | 0.0255 (3) | |
| H13 | 0.541318 | 0.611417 | 0.201913 | 0.031* | |
| C14 | 0.8304 (3) | 0.58691 (13) | 0.23320 (14) | 0.0268 (3) | |
| H14 | 0.819651 | 0.657971 | 0.276873 | 0.032* | |
| C15 | 1.0114 (2) | 0.51058 (13) | 0.21384 (14) | 0.0242 (3) | |
| H15 | 1.124517 | 0.529574 | 0.244299 | 0.029* | |
| C16 | 1.0277 (2) | 0.40614 (12) | 0.14984 (13) | 0.0182 (3) | |
| H16 | 1.151744 | 0.354112 | 0.136972 | 0.022* | |
| C17 | 0.44251 (18) | −0.11850 (11) | 0.18782 (11) | 0.0124 (2) |
(3aRS,4RS,9aRS)-2-Benzyl-3-oxo-2,3,3a,4,9,9a-hexahydro-1H-benzo[f]isoindole-4-carboxylic acid . Atomic displacement parameters (Å2)
| U11 | U22 | U33 | U12 | U13 | U23 | |
| O1 | 0.0157 (4) | 0.0146 (4) | 0.0127 (4) | 0.0013 (3) | −0.0054 (3) | −0.0011 (3) |
| O2 | 0.0173 (4) | 0.0333 (6) | 0.0190 (5) | −0.0097 (4) | −0.0027 (4) | −0.0077 (4) |
| O3 | 0.0151 (4) | 0.0210 (5) | 0.0107 (4) | −0.0035 (3) | −0.0021 (3) | −0.0039 (3) |
| C1 | 0.0129 (5) | 0.0164 (6) | 0.0179 (6) | −0.0040 (4) | −0.0055 (4) | 0.0026 (5) |
| N2 | 0.0141 (5) | 0.0136 (5) | 0.0140 (5) | −0.0026 (4) | −0.0040 (4) | 0.0019 (4) |
| C3 | 0.0145 (5) | 0.0103 (5) | 0.0093 (5) | −0.0009 (4) | −0.0028 (4) | −0.0022 (4) |
| C3A | 0.0109 (5) | 0.0111 (5) | 0.0096 (5) | −0.0018 (4) | −0.0029 (4) | −0.0005 (4) |
| C4 | 0.0102 (5) | 0.0116 (5) | 0.0096 (5) | −0.0007 (4) | −0.0021 (4) | −0.0002 (4) |
| C4A | 0.0127 (5) | 0.0117 (5) | 0.0098 (5) | 0.0001 (4) | −0.0020 (4) | −0.0007 (4) |
| C5 | 0.0146 (5) | 0.0152 (6) | 0.0160 (6) | −0.0016 (4) | −0.0030 (4) | 0.0005 (4) |
| C6 | 0.0201 (6) | 0.0159 (6) | 0.0206 (6) | −0.0019 (5) | −0.0013 (5) | 0.0048 (5) |
| C7 | 0.0223 (6) | 0.0185 (6) | 0.0182 (6) | 0.0013 (5) | −0.0044 (5) | 0.0066 (5) |
| C8 | 0.0169 (6) | 0.0194 (6) | 0.0144 (6) | 0.0018 (5) | −0.0057 (4) | 0.0009 (5) |
| C8A | 0.0124 (5) | 0.0140 (5) | 0.0102 (5) | 0.0009 (4) | −0.0021 (4) | −0.0011 (4) |
| C9 | 0.0120 (5) | 0.0173 (6) | 0.0135 (5) | −0.0015 (4) | −0.0052 (4) | 0.0005 (4) |
| C9A | 0.0103 (5) | 0.0142 (5) | 0.0119 (5) | −0.0009 (4) | −0.0030 (4) | −0.0002 (4) |
| C10 | 0.0198 (6) | 0.0136 (6) | 0.0130 (5) | −0.0051 (5) | −0.0019 (4) | 0.0016 (4) |
| C11 | 0.0174 (6) | 0.0128 (5) | 0.0120 (5) | −0.0028 (4) | −0.0014 (4) | 0.0020 (4) |
| C12 | 0.0184 (6) | 0.0178 (6) | 0.0206 (6) | −0.0006 (5) | −0.0029 (5) | 0.0039 (5) |
| C13 | 0.0280 (7) | 0.0167 (6) | 0.0262 (7) | 0.0035 (5) | 0.0021 (6) | 0.0017 (5) |
| C14 | 0.0428 (9) | 0.0139 (6) | 0.0215 (7) | −0.0022 (6) | −0.0016 (6) | −0.0027 (5) |
| C15 | 0.0342 (8) | 0.0191 (7) | 0.0226 (7) | −0.0066 (6) | −0.0113 (6) | −0.0005 (5) |
| C16 | 0.0200 (6) | 0.0144 (6) | 0.0206 (6) | −0.0021 (5) | −0.0056 (5) | 0.0004 (5) |
| C17 | 0.0132 (5) | 0.0127 (5) | 0.0114 (5) | 0.0006 (4) | −0.0037 (4) | −0.0006 (4) |
(3aRS,4RS,9aRS)-2-Benzyl-3-oxo-2,3,3a,4,9,9a-hexahydro-1H-benzo[f]isoindole-4-carboxylic acid . Geometric parameters (Å, º)
| O1—C3 | 1.2421 (14) | C7—C8 | 1.385 (2) |
| O2—C17 | 1.2134 (15) | C7—H7 | 0.9500 |
| O3—C17 | 1.3280 (15) | C8—C8A | 1.4054 (17) |
| O3—H3 | 0.888 (19) | C8—H8 | 0.9500 |
| C1—N2 | 1.4717 (16) | C8A—C9 | 1.5179 (18) |
| C1—C9A | 1.5300 (18) | C9—C9A | 1.5143 (17) |
| C1—H1A | 0.9900 | C9—H9A | 0.9900 |
| C1—H1B | 0.9900 | C9—H9B | 0.9900 |
| N2—C3 | 1.3459 (16) | C9A—H9C | 1.0000 |
| N2—C10 | 1.4657 (16) | C10—C11 | 1.5122 (18) |
| C3—C3A | 1.5147 (17) | C10—H10A | 0.9900 |
| C3A—C4 | 1.5179 (17) | C10—H10B | 0.9900 |
| C3A—C9A | 1.5258 (16) | C11—C16 | 1.3934 (19) |
| C3A—H3A | 1.0000 | C11—C12 | 1.3971 (18) |
| C4—C17 | 1.5244 (17) | C12—C13 | 1.389 (2) |
| C4—C4A | 1.5423 (17) | C12—H12 | 0.9500 |
| C4—H4 | 1.0000 | C13—C14 | 1.386 (2) |
| C4A—C5 | 1.4018 (17) | C13—H13 | 0.9500 |
| C4A—C8A | 1.4061 (17) | C14—C15 | 1.389 (2) |
| C5—C6 | 1.3896 (18) | C14—H14 | 0.9500 |
| C5—H5 | 0.9500 | C15—C16 | 1.395 (2) |
| C6—C7 | 1.392 (2) | C15—H15 | 0.9500 |
| C6—H6 | 0.9500 | C16—H16 | 0.9500 |
| C17—O3—H3 | 108.1 (11) | C8—C8A—C9 | 118.55 (11) |
| N2—C1—C9A | 101.85 (9) | C4A—C8A—C9 | 122.92 (11) |
| N2—C1—H1A | 111.4 | C9A—C9—C8A | 109.98 (10) |
| C9A—C1—H1A | 111.4 | C9A—C9—H9A | 109.7 |
| N2—C1—H1B | 111.4 | C8A—C9—H9A | 109.7 |
| C9A—C1—H1B | 111.4 | C9A—C9—H9B | 109.7 |
| H1A—C1—H1B | 109.3 | C8A—C9—H9B | 109.7 |
| C3—N2—C10 | 124.17 (11) | H9A—C9—H9B | 108.2 |
| C3—N2—C1 | 113.24 (10) | C9—C9A—C3A | 108.19 (9) |
| C10—N2—C1 | 120.97 (10) | C9—C9A—C1 | 118.81 (10) |
| O1—C3—N2 | 126.58 (11) | C3A—C9A—C1 | 101.80 (10) |
| O1—C3—C3A | 126.31 (11) | C9—C9A—H9C | 109.2 |
| N2—C3—C3A | 107.00 (10) | C3A—C9A—H9C | 109.2 |
| C3—C3A—C4 | 120.42 (10) | C1—C9A—H9C | 109.2 |
| C3—C3A—C9A | 103.52 (9) | N2—C10—C11 | 110.98 (10) |
| C4—C3A—C9A | 113.53 (10) | N2—C10—H10A | 109.4 |
| C3—C3A—H3A | 106.1 | C11—C10—H10A | 109.4 |
| C4—C3A—H3A | 106.1 | N2—C10—H10B | 109.4 |
| C9A—C3A—H3A | 106.1 | C11—C10—H10B | 109.4 |
| C3A—C4—C17 | 115.75 (10) | H10A—C10—H10B | 108.0 |
| C3A—C4—C4A | 109.62 (9) | C16—C11—C12 | 119.07 (12) |
| C17—C4—C4A | 110.39 (10) | C16—C11—C10 | 121.05 (11) |
| C3A—C4—H4 | 106.9 | C12—C11—C10 | 119.86 (12) |
| C17—C4—H4 | 106.9 | C13—C12—C11 | 120.64 (13) |
| C4A—C4—H4 | 106.9 | C13—C12—H12 | 119.7 |
| C5—C4A—C8A | 119.09 (11) | C11—C12—H12 | 119.7 |
| C5—C4A—C4 | 118.79 (10) | C14—C13—C12 | 119.98 (13) |
| C8A—C4A—C4 | 122.12 (10) | C14—C13—H13 | 120.0 |
| C6—C5—C4A | 121.61 (12) | C12—C13—H13 | 120.0 |
| C6—C5—H5 | 119.2 | C13—C14—C15 | 119.92 (14) |
| C4A—C5—H5 | 119.2 | C13—C14—H14 | 120.0 |
| C5—C6—C7 | 119.30 (12) | C15—C14—H14 | 120.0 |
| C5—C6—H6 | 120.3 | C14—C15—C16 | 120.22 (14) |
| C7—C6—H6 | 120.3 | C14—C15—H15 | 119.9 |
| C8—C7—C6 | 119.74 (12) | C16—C15—H15 | 119.9 |
| C8—C7—H7 | 120.1 | C11—C16—C15 | 120.17 (13) |
| C6—C7—H7 | 120.1 | C11—C16—H16 | 119.9 |
| C7—C8—C8A | 121.72 (12) | C15—C16—H16 | 119.9 |
| C7—C8—H8 | 119.1 | O2—C17—O3 | 123.68 (11) |
| C8A—C8—H8 | 119.1 | O2—C17—C4 | 121.90 (11) |
| C8—C8A—C4A | 118.53 (11) | O3—C17—C4 | 114.43 (10) |
| C9A—C1—N2—C3 | 21.91 (13) | C4—C4A—C8A—C9 | −2.30 (18) |
| C9A—C1—N2—C10 | −172.05 (10) | C8—C8A—C9—C9A | 158.54 (11) |
| C10—N2—C3—O1 | 10.3 (2) | C4A—C8A—C9—C9A | −20.69 (16) |
| C1—N2—C3—O1 | 175.87 (12) | C8A—C9—C9A—C3A | 52.82 (13) |
| C10—N2—C3—C3A | −166.01 (11) | C8A—C9—C9A—C1 | 168.06 (10) |
| C1—N2—C3—C3A | −0.49 (14) | C3—C3A—C9A—C9 | 159.39 (10) |
| O1—C3—C3A—C4 | 34.16 (17) | C4—C3A—C9A—C9 | −68.34 (13) |
| N2—C3—C3A—C4 | −149.48 (11) | C3—C3A—C9A—C1 | 33.45 (11) |
| O1—C3—C3A—C9A | 162.28 (12) | C4—C3A—C9A—C1 | 165.73 (10) |
| N2—C3—C3A—C9A | −21.35 (12) | N2—C1—C9A—C9 | −151.69 (11) |
| C3—C3A—C4—C17 | 41.27 (15) | N2—C1—C9A—C3A | −33.08 (11) |
| C9A—C3A—C4—C17 | −82.19 (12) | C3—N2—C10—C11 | 89.25 (14) |
| C3—C3A—C4—C4A | 166.90 (10) | C1—N2—C10—C11 | −75.21 (14) |
| C9A—C3A—C4—C4A | 43.44 (13) | N2—C10—C11—C16 | 87.71 (14) |
| C3A—C4—C4A—C5 | 170.64 (10) | N2—C10—C11—C12 | −91.00 (14) |
| C17—C4—C4A—C5 | −60.71 (14) | C16—C11—C12—C13 | 0.07 (19) |
| C3A—C4—C4A—C8A | −8.61 (15) | C10—C11—C12—C13 | 178.80 (12) |
| C17—C4—C4A—C8A | 120.04 (12) | C11—C12—C13—C14 | 0.0 (2) |
| C8A—C4A—C5—C6 | 0.94 (18) | C12—C13—C14—C15 | 0.0 (2) |
| C4—C4A—C5—C6 | −178.33 (11) | C13—C14—C15—C16 | 0.0 (2) |
| C4A—C5—C6—C7 | −0.3 (2) | C12—C11—C16—C15 | −0.13 (19) |
| C5—C6—C7—C8 | −0.6 (2) | C10—C11—C16—C15 | −178.86 (12) |
| C6—C7—C8—C8A | 0.7 (2) | C14—C15—C16—C11 | 0.1 (2) |
| C7—C8—C8A—C4A | −0.04 (19) | C3A—C4—C17—O2 | −158.11 (12) |
| C7—C8—C8A—C9 | −179.30 (12) | C4A—C4—C17—O2 | 76.65 (14) |
| C5—C4A—C8A—C8 | −0.77 (17) | C3A—C4—C17—O3 | 22.31 (15) |
| C4—C4A—C8A—C8 | 178.47 (11) | C4A—C4—C17—O3 | −102.94 (12) |
| C5—C4A—C8A—C9 | 178.45 (11) |
(3aRS,4RS,9aRS)-2-Benzyl-3-oxo-2,3,3a,4,9,9a-hexahydro-1H-benzo[f]isoindole-4-carboxylic acid . Hydrogen-bond geometry (Å, º)
Cg3 is the centroid of the C4A/C5–C8/C8A ring.
| D—H···A | D—H | H···A | D···A | D—H···A |
| O3—H3···O1i | 0.888 (19) | 1.752 (19) | 2.6227 (14) | 166.1 (17) |
| C9—H9B···O2ii | 0.99 | 2.59 | 3.3397 (19) | 133 |
| C10—H10A···O2i | 0.99 | 2.47 | 3.2689 (19) | 138 |
| C3A—H3A···Cg3iii | 1.00 | 2.53 | 3.5088 (16) | 166 |
Symmetry codes: (i) −x+1, −y, −z; (ii) x+1, y, z; (iii) −x+1, −y, −z+1.
Funding Statement
This work has been supported by the RUDN University Scientific Projects Grant System (grant No. 021422–2-000) and by the Azerbaijan Medical University. TH is also grateful to Hacettepe University Scientific Research Project Unit (grant No. 013 D04 602 004).
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S2056989026005189/yz2079sup1.cif
Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989026005189/yz2079Isup2.hkl
Supporting information file. DOI: 10.1107/S2056989026005189/yz2079Isup3.cml
CCDC reference: 2486562
Additional supporting information: crystallographic information; 3D view; checkCIF report