research communications
H-1,5-benzodiazepin-2-one
and Hirshfeld surface analysis of a new benzodiazepine derivative: 4-dichloromethyl-2,3-dihydro-1aLaboratory of Heterocyclic Organic Chemistry URAC 21, Pole of Competence Pharmacochemistry, Av Ibn Battouta, BP 1014, Faculty of Sciences, Mohammed V University, Rabat, Morocco, bOndokuz Mayıs University, Faculty of Arts and Sciences, Department of Physics, 55139, Kurupelit, Samsun, Turkey, cPhysicochemical Service, Drugs Quality Control Laboratory, Division of Drugs and Pharmacy, Ministry of Health, 10100 Rabat, Morocco, and dDepartment of Chemistry, Tulane University, New Orleans, LA 70118, USA
*Correspondence e-mail: chkirate.karim1@gmail.com
In the title compound, C10H8Cl2N2O, the seven-membered diazepine ring adopts a boat-shaped conformation. The mean planes of the two rings of the benzodiazepine unit are inclined to each other by 22.05 (6)°. In the crystal, molecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers with an R22(8) ring motif. The dimers are linked by C—H⋯π interactions, forming layers lying parallel to (10). The roles of the intermolecular interactions in the crystal packing were clarified using Hirshfeld surface analysis; the most important contributions are from Cl⋯H/H⋯Cl (30.5%) and H⋯H (22.5%) interactions.
Keywords: crystal structure; benzodiazepin-2-one; phase-transfer catalysis; hydrogen bonding; C—H⋯π(ring) interaction; Hirshfeld surface analysis.
CCDC reference: 1881324
1. Chemical context
Interest in benzodiazepines and their derivatives has concentrated on their pharmacological (Beaulieu, 2006; Tosti et al., 2007) and chemical (Ahabchane & Essassi, 2000) properties. In addition, they are used as raw materials for the synthesis of substances with antibacterial (Essassi et al., 1991) and antitumor (Lee et al., 1978) activities. They are also used as secondary analgesics or as co-analgesics (Aveline et al., 2001; Muster & Ben Slama, 2004). 1,5-Benzodiazepine derivatives have been shown to exhibit anti-inflammatory (Roma et al., 1991), hypnotics (Kudo, 1982), anti-HIV-1 (Di Braccio et al., 2001), anticonvulsant (De Sarro et al., 1996), antimicrobial (Kumar & Joshi, 2007) and antitumor (Kamal et al., 2008) activities. In a continuation of our work on the synthesis of 1,5-benzodiazepine derivatives (Chkirate et al., 2018), we report herein on the synthesis and of the title compound, 4-dichloromethyl-2,3-dihydro-1H-1,5-benzodiazepin-2-one, together with the Hirshfeld surface analysis.
2. Structural commentary
The molecular structure of the title compound is illustrated in Fig. 1. The seven-membered diazepine ring (C1/C6/N1/C7–C9/N2) adopts a boat-shaped conformation: puckering parameters are Q(2) = 0.7692 (14) Å, φ(2) = 21.25 (10)°, Q(3) = 0.2131 (14) Å, φ(3) = 131.2 (4)°, with a total puckering amplitude Q of 0.7982 (14) Å. The mean planes of the two rings are inclined to each other by 22.05 (6)°. The C9=N2 bond has a Z configuration and a bond length of 1.2737 (18) Å. The C1—N2 [1.4124 (17) Å] and C6—N1 [1.4068 (18) Å] bond lengths are typical for a 2,3-dihydro-1H-1,5-benzodiazepin-2-one ring system and similar to those observed for the structure of a very similar compound, 4-methyl-2,3-dihydro-1H-15-benzodiazepin-2-one monohydrate (Saber et al., 2010); see also the Database survey section below.
3. Supramolecular features
In the crystal, molecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers with an (8) ring motif (Table 1 and Fig. 2). The dimers are linked by C—H⋯π interactions, forming layers that lie parallel to the (10) plane (Fig. 3 and Table 1). There are no other significant intermolecular interactions present. The H⋯H or H⋯Cl intermolecular distances all exceed the sum of their van der Waals radii.
4. Database survey
A search of the Cambridge Structural Database (CSD, version 5.39, update August 2018; Groom et al., 2016) for the 2,3-dihydro-1H-1,5-benzodiazepin-2-one skeleton yielded 12 hits (see supporting information). In all 12 compounds, the diazopine ring has a boat-shaped conformation, as does the title compound. The benzene ring and the mean plane of the diazepine ring are inclined to each other by dihedral angles ranging from ca 19.95 to 29.16°, compared to 22.05 (6)° in the title compound. The C=O bond lengths vary from ca 1.217–1.241 Å and the C=N bond lengths vary from ca 1.272–1.295 Å. In the title compound, the corresponding bond lengths are 1.2288 (18) and 1.2737 (18) Å, respectively. The Caromatic—N bond lengths in the diazepine ring range from ca 1.391 to 1.415 Å, compared to values of 1.4124 (17) and 1.4068 (18) Å for bonds C1—N2 and C6—N1, respectively, in the title compound. Hence, the various geometrical parameters mentioned above for the title compound are typical for 2,3-dihydro-1H-1,5-benzodiazepin-2-ones. In the crystals of all but one compound, molecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers with an (8) ring motif. The same arrangement is observed in the crystal of the title compound.
5. Hirshfeld surface analysis
The molecular Hirshfeld surfaces were generated using a standard (high) surface resolution with the three-dimensional dnorm surfaces mapped over a fixed colour scale of −0.456 (red) to 1.092 (blue) Å using the CrystalExplorer program (Turner et al., 2017). The red spots on the surface indicate the intermolecular contacts involved in the hydrogen bonds. In Figs. 4 and 5, the red spots are attributed to the H⋯O close contacts.
Fig. 6 shows the two-dimensional fingerprint plot for the sum of the contacts contributing to the Hirshfeld surface represented in normal mode. The graph shown in Fig. 7 represents the O⋯H/H⋯O contacts (30.4%) between the oxygen atoms inside the surface and the hydrogen atoms outside the surface at de + di = 2.5 Å and two symmetrical points at the top, bottom left and right. These data are characteristic of C—H⋯O hydrogen bonding.
The H⋯H graph in Fig. 7 shows the two-dimensional fingerprint of the (di, de) points associated with hydrogen atoms. It is characterized by an end point that points to the origin and corresponds to di = de = 1.08 Å, which indicates the presence of the H⋯H contacts in this study, which make a contribution of 54.3% to the crystal packing. The C⋯H/H⋯C graph in Fig. 7 shows the contacts between carbon atoms inside the Hirshfeld surface and hydrogen atoms outside and vice versa and has two symmetrical wings on the left and right sides (6.8%). Much weaker C⋯C (5.5%), O⋯N/N⋯O (2.4%), O⋯O (0.3%) and S⋯H/H⋯S (0.2%) contacts also occur.
A view of the three-dimensional Hirshfeld surface of the title compound plotted over electrostatic where the N—H⋯O and C—H⋯π hydrogen-bond donors and acceptors are shown as blue and red areas around the atoms related with positive (hydrogen-bond donors) and negative (hydrogen-bond acceptors) electrostatic potentials, respectively.
in the range −0.082 to 0.042 a.u. using the STO-3G basis set at the Hartree–Fock level of theory is shown in Fig. 86. Synthesis and crystallization
The title compound was synthesized by the reaction of dichloromethane with (Z)-4-(2-oxopropylidene)-4,5-dihydro-1H-benzo [b][1,5]-diazepine-2(3H)-one under (PTC) conditions using tetra-n-bromide butylammonium (TBAB) as catalyst and potassium carbonate as base.
To a solution of 4-(2-oxopropylidene)-4,5-dihydro-1H-benzo-[b][1,5]diazepine-2(3H)-one (2.87 mmol) in dichloromethane (30 ml) as reagent and solvent, potassium carbonate (5.71 mmol) and a catalytic amount of tetra-n-butylammonium bromide (0.37 mmol) were added. The mixture was stirred for 48 h. The solid material was removed by filtration and the solvent evaporated under vacuum. The residue was purified through silica gel using hexane/ethyl acetate (ratio 8:2). Slow evaporation at room temperature lead to the formation of colourless single crystals (yield 69%).
7. Refinement
Crystal data, data collection and structure . All H atoms were located in a difference-Fourier map and freely refined.
details are summarized in Table 2Supporting information
CCDC reference: 1881324
https://doi.org/10.1107/S205698901801681X/xu5953sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698901801681X/xu5953Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S205698901801681X/xu5953Isup4.cml
CSD search results. DOI: https://doi.org/10.1107/S205698901801681X/xu5953sup3.pdf
Data collection: APEX3 (Bruker, 2016); cell
SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg & Putz, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C10H8Cl2N2O | F(000) = 496 |
Mr = 243.08 | Dx = 1.571 Mg m−3 |
Monoclinic, P21/n | Cu Kα radiation, λ = 1.54178 Å |
a = 12.1783 (6) Å | Cell parameters from 7262 reflections |
b = 5.7217 (3) Å | θ = 3.0–74.6° |
c = 14.8258 (7) Å | µ = 5.46 mm−1 |
β = 95.740 (1)° | T = 150 K |
V = 1027.89 (9) Å3 | Block, colourless |
Z = 4 | 0.33 × 0.24 × 0.14 mm |
Bruker D8 VENTURE PHOTON 100 CMOS diffractometer | 2051 independent reflections |
Radiation source: INCOATEC IµS micro-focus source | 2020 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.028 |
Detector resolution: 10.4167 pixels mm-1 | θmax = 74.6°, θmin = 4.5° |
ω scans | h = −15→15 |
Absorption correction: multi-scan (SADABS; Krause et al., 2015) | k = −6→7 |
Tmin = 0.36, Tmax = 0.51 | l = −18→17 |
7403 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.028 | All H-atom parameters refined |
wR(F2) = 0.074 | w = 1/[σ2(Fo2) + (0.0392P)2 + 0.599P] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max = 0.001 |
2051 reflections | Δρmax = 0.32 e Å−3 |
169 parameters | Δρmin = −0.31 e Å−3 |
0 restraints | Extinction correction: SHELXL2018 (Sheldrick, 2015b), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0137 (7) |
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. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2sigma(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
Cl1 | 0.09759 (3) | −0.04560 (6) | 0.60350 (3) | 0.02813 (14) | |
Cl2 | 0.08781 (3) | 0.37781 (6) | 0.71005 (2) | 0.02306 (14) | |
O1 | 0.40917 (8) | −0.0195 (2) | 0.59019 (7) | 0.0239 (2) | |
N1 | 0.38241 (9) | 0.2146 (2) | 0.46776 (8) | 0.0168 (3) | |
H1 | 0.4316 (17) | 0.132 (4) | 0.4445 (14) | 0.031 (5)* | |
N2 | 0.16589 (9) | 0.4612 (2) | 0.47917 (8) | 0.0146 (2) | |
C1 | 0.25109 (10) | 0.5411 (2) | 0.42893 (9) | 0.0140 (3) | |
C2 | 0.22893 (11) | 0.7435 (3) | 0.37666 (9) | 0.0181 (3) | |
H2 | 0.1585 (16) | 0.826 (4) | 0.3825 (13) | 0.030 (5)* | |
C3 | 0.30118 (12) | 0.8234 (3) | 0.31737 (10) | 0.0210 (3) | |
H3 | 0.2849 (15) | 0.963 (3) | 0.2844 (13) | 0.021 (4)* | |
C4 | 0.39584 (12) | 0.6952 (3) | 0.30557 (10) | 0.0220 (3) | |
H4 | 0.4448 (16) | 0.745 (3) | 0.2612 (13) | 0.025 (4)* | |
C5 | 0.41957 (11) | 0.4960 (3) | 0.35629 (9) | 0.0187 (3) | |
H5 | 0.4819 (17) | 0.403 (3) | 0.3483 (13) | 0.026 (5)* | |
C6 | 0.35036 (11) | 0.4207 (2) | 0.42047 (9) | 0.0144 (3) | |
C7 | 0.36854 (10) | 0.1586 (3) | 0.55461 (9) | 0.0168 (3) | |
C8 | 0.30141 (11) | 0.3298 (3) | 0.60421 (9) | 0.0182 (3) | |
H8A | 0.3361 (17) | 0.485 (4) | 0.6036 (14) | 0.032 (5)* | |
H8B | 0.2984 (15) | 0.268 (3) | 0.6639 (14) | 0.024 (4)* | |
C9 | 0.18779 (10) | 0.3589 (2) | 0.55513 (9) | 0.0139 (3) | |
C10 | 0.09010 (11) | 0.2661 (2) | 0.59849 (9) | 0.0166 (3) | |
H10 | 0.0224 (15) | 0.308 (3) | 0.5653 (12) | 0.016 (4)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0370 (2) | 0.0167 (2) | 0.0315 (2) | −0.00336 (14) | 0.00773 (16) | −0.00190 (14) |
Cl2 | 0.0278 (2) | 0.0245 (2) | 0.0190 (2) | −0.00043 (13) | 0.01315 (14) | −0.00376 (13) |
O1 | 0.0217 (5) | 0.0304 (6) | 0.0204 (5) | 0.0108 (4) | 0.0055 (4) | 0.0079 (4) |
N1 | 0.0161 (5) | 0.0205 (6) | 0.0145 (6) | 0.0065 (5) | 0.0052 (4) | 0.0004 (5) |
N2 | 0.0135 (5) | 0.0151 (6) | 0.0156 (5) | 0.0019 (4) | 0.0042 (4) | −0.0011 (4) |
C1 | 0.0135 (6) | 0.0159 (7) | 0.0129 (6) | −0.0013 (5) | 0.0027 (5) | −0.0012 (5) |
C2 | 0.0187 (6) | 0.0172 (7) | 0.0183 (7) | 0.0011 (5) | 0.0019 (5) | −0.0001 (5) |
C3 | 0.0257 (7) | 0.0172 (7) | 0.0201 (7) | −0.0044 (6) | 0.0015 (5) | 0.0029 (6) |
C4 | 0.0198 (7) | 0.0273 (8) | 0.0196 (7) | −0.0087 (6) | 0.0051 (5) | 0.0013 (6) |
C5 | 0.0136 (6) | 0.0252 (7) | 0.0180 (7) | −0.0019 (5) | 0.0043 (5) | −0.0010 (6) |
C6 | 0.0134 (6) | 0.0171 (6) | 0.0129 (6) | −0.0005 (5) | 0.0013 (5) | −0.0019 (5) |
C7 | 0.0119 (6) | 0.0233 (7) | 0.0151 (6) | 0.0025 (5) | 0.0012 (5) | 0.0005 (5) |
C8 | 0.0142 (6) | 0.0281 (8) | 0.0125 (6) | 0.0044 (5) | 0.0019 (5) | −0.0015 (6) |
C9 | 0.0132 (6) | 0.0153 (6) | 0.0136 (6) | 0.0024 (5) | 0.0034 (5) | −0.0025 (5) |
C10 | 0.0166 (6) | 0.0177 (7) | 0.0162 (6) | 0.0014 (5) | 0.0055 (5) | 0.0010 (5) |
Cl1—C10 | 1.7868 (15) | C3—C4 | 1.392 (2) |
Cl2—C10 | 1.7761 (14) | C3—H3 | 0.95 (2) |
O1—C7 | 1.2288 (18) | C4—C5 | 1.380 (2) |
N1—C7 | 1.3539 (18) | C4—H4 | 0.97 (2) |
N1—C6 | 1.4068 (18) | C5—C6 | 1.4006 (19) |
N1—H1 | 0.86 (2) | C5—H5 | 0.94 (2) |
N2—C9 | 1.2737 (18) | C7—C8 | 1.5130 (19) |
N2—C1 | 1.4124 (17) | C8—C9 | 1.5068 (18) |
C1—C2 | 1.405 (2) | C8—H8A | 0.99 (2) |
C1—C6 | 1.4080 (18) | C8—H8B | 0.96 (2) |
C2—C3 | 1.382 (2) | C9—C10 | 1.5045 (18) |
C2—H2 | 0.99 (2) | C10—H10 | 0.949 (18) |
C7—N1—C6 | 128.15 (12) | C5—C6—C1 | 119.36 (13) |
C7—N1—H1 | 114.2 (14) | N1—C6—C1 | 124.31 (12) |
C6—N1—H1 | 115.4 (14) | O1—C7—N1 | 121.44 (13) |
C9—N2—C1 | 121.01 (11) | O1—C7—C8 | 122.85 (13) |
C2—C1—C6 | 118.27 (12) | N1—C7—C8 | 115.71 (12) |
C2—C1—N2 | 116.55 (11) | C9—C8—C7 | 110.57 (11) |
C6—C1—N2 | 124.84 (12) | C9—C8—H8A | 105.7 (12) |
C3—C2—C1 | 121.60 (13) | C7—C8—H8A | 109.1 (12) |
C3—C2—H2 | 120.6 (12) | C9—C8—H8B | 111.6 (11) |
C1—C2—H2 | 117.7 (12) | C7—C8—H8B | 106.6 (12) |
C2—C3—C4 | 119.59 (14) | H8A—C8—H8B | 113.3 (17) |
C2—C3—H3 | 119.6 (11) | N2—C9—C10 | 115.81 (11) |
C4—C3—H3 | 120.8 (11) | N2—C9—C8 | 125.35 (12) |
C5—C4—C3 | 119.84 (13) | C10—C9—C8 | 118.82 (12) |
C5—C4—H4 | 120.1 (12) | C9—C10—Cl2 | 110.96 (10) |
C3—C4—H4 | 120.1 (12) | C9—C10—Cl1 | 109.31 (9) |
C4—C5—C6 | 121.12 (13) | Cl2—C10—Cl1 | 109.03 (7) |
C4—C5—H5 | 121.6 (12) | C9—C10—H10 | 111.8 (11) |
C6—C5—H5 | 117.3 (12) | Cl2—C10—H10 | 107.3 (10) |
C5—C6—N1 | 116.14 (12) | Cl1—C10—H10 | 108.4 (11) |
C9—N2—C1—C2 | −147.75 (13) | N2—C1—C6—N1 | −6.1 (2) |
C9—N2—C1—C6 | 39.04 (19) | C6—N1—C7—O1 | −173.53 (13) |
C6—C1—C2—C3 | 0.7 (2) | C6—N1—C7—C8 | 5.9 (2) |
N2—C1—C2—C3 | −172.94 (13) | O1—C7—C8—C9 | −122.19 (15) |
C1—C2—C3—C4 | 3.1 (2) | N1—C7—C8—C9 | 58.41 (16) |
C2—C3—C4—C5 | −3.2 (2) | C1—N2—C9—C10 | −175.53 (11) |
C3—C4—C5—C6 | −0.6 (2) | C1—N2—C9—C8 | 5.9 (2) |
C4—C5—C6—N1 | 179.62 (13) | C7—C8—C9—N2 | −70.12 (18) |
C4—C5—C6—C1 | 4.4 (2) | C7—C8—C9—C10 | 111.35 (14) |
C7—N1—C6—C5 | 146.34 (14) | N2—C9—C10—Cl2 | −124.87 (11) |
C7—N1—C6—C1 | −38.7 (2) | C8—C9—C10—Cl2 | 53.79 (15) |
C2—C1—C6—C5 | −4.42 (19) | N2—C9—C10—Cl1 | 114.86 (12) |
N2—C1—C6—C5 | 168.68 (12) | C8—C9—C10—Cl1 | −66.48 (14) |
C2—C1—C6—N1 | −179.21 (12) |
Cg1 is the centroid of the C1–C6 benzene ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O1i | 0.86 (2) | 2.15 (2) | 2.977 (2) | 160 (2) |
C3—H3···Cg1ii | 0.95 (2) | 2.66 (2) | 3.450 (2) | 142 (1) |
Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x+1/2, y+1/2, −z+1/2. |
Funding information
The support of NSF–MRI grant No. 1228232 for the purchase of the diffractometer and Tulane University for support of the Tulane Crystallography Laboratory are gratefully acknowledged.
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