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Acta Cryst. (2009). E65, o2362    [ doi:10.1107/S1600536809034825 ]

4-Methyl-2-oxo-2,3,4,5-tetrahydro-1H-1,5-benzodiazepine-5-carbaldehyde

K. Ravichandran, P. Sakthivel, S. Ponnuswamy, P. Ramesh and M. N. Ponnuswamy

Abstract top

In the title compound, C11H12N2O2, a benzodiazepine derivative, the seven-membered ring adopts a distorted boat conformation. The crystal packing is controlled by intermolecular N-H...O and C-H...O interactions.

Comment top

Benzodiazepines are used for the purpose of hypnotic effects, owing to their less toxic and less severe withdrawal effects when compared with barbiturates (Gringauz, 1999). Benzodiazepines from aspergillus include asperlicin, which is used for treatment of gastrointestinal and central nervous system (CNS) disorders (Rahbaek et al.,1999). The other therapeutic applications (Lee et al., 1999) of benzodiazepines include vasopressin antagonists (Albright et al., 1998). In view of these importance and to ascertain the molecular conformation, crystallographic study of the title compound has been carried out.

The ORTEP diagram of the title compound is shown in Fig.1. The benzodiazepine ring adopts a distorted boat conformation. The puckering parameters (Cremer & Pople, 1975) and the asymmetry parameters (Nardelli, 1983) for this ring are q2 = 0.933 (1) Å, q3 = 0.170 (1) Å, φ2 = 144.8 (1)°, φ3 = 18.0 (4)° and Δ2(C4)=13.2 (1)°. The sum of the bond angles at N1(359.8°) and N5(359.8°) of the benzodiazepine ring is in accordance with sp2 hybridization.

The crystal packing is controlled by N—H···O and C—H···O types of intermolecular interactions in addition to van der Waals forces. Atom N1 at (x, y, z) donates a proton to O2 (1 - x, 1/2 + y, 1/2 - z), which forms a C7 (Bernstein et al., 1995) one dimensional chain running along b–axis. The intermolecular hydrogen bond C13—H13···O1 also connects the molecule into another C7 chain running along b–axis. Thus the combination of N—H···O and C—H···O intermolecular hydrogen bonds form a graph set motif of R22(7) dimer to stabilize the molecules and extend along b–axis (Fig. 2).

Related literature top

For the hypnotic effects of benzodiazepines, see: Gringauz (1999). For their use in the treatment of gastrointestinal and central

nervous system disorders, see: Rahbaek et al. (1999). For other therapeutic applications, see: Albright et al. (1998); Lee et al. (1999). For hydrogen-bond motifs, see: Bernstein et al. (1995). For puckering and asymmetry parameters, see: Cremer & Pople (1975); ); Nardelli (1983). For details of the preparation, see: Venkatraj et al. (2008).

Experimental top

An ice-cold solution of acetic-formic anhydride was prepared from acetic anhydride (10 ml) and 85% formic acid (5 ml) was added slowly to a cold solution of tetrahydrobenzodiazepin-2-one (0.88 g) in anhydrous benzene (30 ml). The reaction mixture was stirred at room temperature for 4 hrs. The organic layer was separated, dried over anhydrous Na2SO4 and concentrated. The resulting mass was purified by crystallization from benzene-petroleum ether (333–353° K) mixture (1:1) (Venkatraj et al., 2008)

Refinement top

The H atom bonded to N was freely refined whereas the other H atoms were positioned geometrically (C—H=0.93–0.98 Å) and allowed to ride on their parent atoms, with 1.5Ueq(C) for methyl H and 1.2 Ueq(C) for other H atoms.

Computing details top

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. Perspective view of the molecule showing the thermal ellipsoids are drawn at 50% probability level.
[Figure 2] Fig. 2. The crystal packing of the molecules viewed down a–axis. H atoms not involved in hydrogen bonding have been omitted for clarity.
4-Methyl-2-oxo-2,3,4,5-tetrahydro-1H-1,5-benzodiazepine-5-carbaldehyde top
Crystal data top
C11H12N2O2F(000) = 432
Mr = 204.23Dx = 1.359 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 2563 reflections
a = 5.3284 (1) Åθ = 2.1–32.9°
b = 12.9387 (4) ŵ = 0.10 mm−1
c = 14.6227 (5) ÅT = 293 K
β = 97.968 (2)°Block, colourless
V = 998.39 (5) Å30.30 × 0.20 × 0.15 mm
Z = 4
Data collection top
Bruker Kappa APEXII area-detector
diffractometer		3727 independent reflections
Radiation source: fine-focus sealed tube2453 reflections with I > 2σ(I)
graphiteRint = 0.028
ω and φ scansθmax = 32.9°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2001)		h = −8→8
Tmin = 0.977, Tmax = 0.986k = −19→19
14697 measured reflectionsl = −22→12
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.055Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.163H atoms treated by a mixture of independent and constrained refinement
S = 1.05 w = 1/[σ2(Fo2) + (0.076P)2 + 0.1596P]
where P = (Fo2 + 2Fc2)/3
3727 reflections(Δ/σ)max = 0.004
141 parametersΔρmax = 0.40 e Å−3
0 restraintsΔρmin = −0.17 e Å−3
Crystal data top
C11H12N2O2V = 998.39 (5) Å3
Mr = 204.23Z = 4
Monoclinic, P21/cMo Kα radiation
a = 5.3284 (1) ŵ = 0.10 mm−1
b = 12.9387 (4) ÅT = 293 K
c = 14.6227 (5) Å0.30 × 0.20 × 0.15 mm
β = 97.968 (2)°
Data collection top
Bruker Kappa APEXII area-detector
diffractometer		3727 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2001)		2453 reflections with I > 2σ(I)
Tmin = 0.977, Tmax = 0.986Rint = 0.028
14697 measured reflectionsθmax = 32.9°
Refinement top
R[F2 > 2σ(F2)] = 0.055H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.163Δρmax = 0.40 e Å−3
S = 1.05Δρmin = −0.17 e Å−3
3727 reflectionsAbsolute structure: ?
141 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.5676 (2)0.55730 (10)0.36634 (8)0.0596 (3)
O20.4734 (2)0.15716 (8)0.36319 (8)0.0498 (3)
N10.3101 (2)0.49320 (9)0.24515 (8)0.0411 (3)
H10.395 (4)0.5303 (15)0.2083 (14)0.060 (5)*
C20.3797 (3)0.50642 (10)0.33737 (10)0.0391 (3)
C30.2127 (3)0.45788 (10)0.39982 (9)0.0370 (3)
H3A0.03720.47250.37620.044*
H3B0.24900.48890.46060.044*
C40.2483 (2)0.34179 (10)0.40847 (8)0.0320 (3)
H40.42140.32860.43850.038*
N50.22002 (19)0.29427 (8)0.31600 (7)0.0319 (2)
C60.0534 (2)0.33715 (10)0.24086 (8)0.0313 (3)
C7−0.1530 (3)0.27966 (12)0.19987 (10)0.0421 (3)
H7−0.19120.21680.22560.051*
C8−0.3011 (3)0.31534 (14)0.12141 (11)0.0522 (4)
H8−0.43770.27640.09380.063*
C9−0.2459 (3)0.40821 (15)0.08435 (11)0.0552 (4)
H9−0.34350.43150.03060.066*
C10−0.0470 (3)0.46775 (12)0.12580 (10)0.0479 (4)
H10−0.01380.53150.10060.057*
C110.1037 (2)0.43294 (10)0.20486 (9)0.0343 (3)
C120.0669 (3)0.29350 (14)0.46723 (11)0.0503 (4)
H12A−0.10430.30470.43870.075*
H12B0.09090.32450.52740.075*
H12C0.09900.22060.47280.075*
C130.3356 (3)0.20421 (10)0.30322 (10)0.0388 (3)
H130.30900.17540.24440.047*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0699 (7)0.0577 (7)0.0464 (7)−0.0305 (6)−0.0085 (5)0.0062 (5)
O20.0557 (6)0.0390 (5)0.0529 (7)0.0129 (4)0.0013 (5)0.0044 (5)
N10.0551 (7)0.0357 (6)0.0325 (6)−0.0110 (5)0.0055 (5)0.0007 (5)
C20.0496 (7)0.0299 (6)0.0359 (7)−0.0042 (5)−0.0012 (5)0.0001 (5)
C30.0445 (7)0.0363 (6)0.0298 (6)0.0006 (5)0.0036 (5)−0.0063 (5)
C40.0333 (5)0.0362 (6)0.0259 (5)−0.0012 (4)0.0019 (4)−0.0012 (5)
N50.0358 (5)0.0295 (5)0.0297 (5)0.0016 (4)0.0026 (4)−0.0011 (4)
C60.0319 (5)0.0347 (6)0.0269 (6)0.0025 (4)0.0027 (4)−0.0038 (5)
C70.0389 (7)0.0466 (8)0.0404 (7)−0.0060 (5)0.0034 (5)−0.0092 (6)
C80.0389 (7)0.0694 (10)0.0453 (8)0.0016 (7)−0.0052 (6)−0.0185 (8)
C90.0544 (9)0.0720 (11)0.0348 (7)0.0229 (8)−0.0100 (6)−0.0063 (7)
C100.0634 (9)0.0443 (8)0.0337 (7)0.0138 (7)−0.0012 (6)0.0021 (6)
C110.0407 (6)0.0338 (6)0.0278 (6)0.0033 (5)0.0027 (5)−0.0041 (5)
C120.0563 (9)0.0571 (9)0.0397 (8)−0.0147 (7)0.0142 (6)0.0001 (7)
C130.0428 (7)0.0298 (6)0.0436 (7)0.0026 (5)0.0055 (5)−0.0019 (5)
Geometric parameters (Å, °) top
O1—C21.2240 (16)C6—C111.3872 (18)
O2—C131.2248 (17)C6—C71.3925 (17)
N1—C21.3589 (18)C7—C81.379 (2)
N1—C111.4088 (17)C7—H70.9300
N1—H10.89 (2)C8—C91.367 (3)
C2—C31.498 (2)C8—H80.9300
C3—C41.5170 (18)C9—C101.381 (2)
C3—H3A0.9700C9—H90.9300
C3—H3B0.9700C10—C111.3881 (18)
C4—N51.4740 (16)C10—H100.9300
C4—C121.5145 (19)C12—H12A0.9600
C4—H40.9800C12—H12B0.9600
N5—C131.3430 (16)C12—H12C0.9600
N5—C61.4259 (15)C13—H130.9300
C2—N1—C11125.06 (12)C8—C7—C6120.40 (14)
C2—N1—H1116.2 (13)C8—C7—H7119.8
C11—N1—H1118.5 (13)C6—C7—H7119.8
O1—C2—N1120.58 (14)C9—C8—C7119.65 (14)
O1—C2—C3122.74 (13)C9—C8—H8120.2
N1—C2—C3116.67 (12)C7—C8—H8120.2
C2—C3—C4112.83 (11)C8—C9—C10120.70 (14)
C2—C3—H3A109.0C8—C9—H9119.6
C4—C3—H3A109.0C10—C9—H9119.6
C2—C3—H3B109.0C9—C10—C11120.32 (15)
C4—C3—H3B109.0C9—C10—H10119.8
H3A—C3—H3B107.8C11—C10—H10119.8
N5—C4—C12110.87 (11)C6—C11—C10119.08 (13)
N5—C4—C3109.94 (10)C6—C11—N1121.10 (11)
C12—C4—C3111.93 (12)C10—C11—N1119.78 (13)
N5—C4—H4108.0C4—C12—H12A109.5
C12—C4—H4108.0C4—C12—H12B109.5
C3—C4—H4108.0H12A—C12—H12B109.5
C13—N5—C6118.62 (11)C4—C12—H12C109.5
C13—N5—C4119.93 (11)H12A—C12—H12C109.5
C6—N5—C4121.21 (10)H12B—C12—H12C109.5
C11—C6—C7119.78 (12)O2—C13—N5124.93 (13)
C11—C6—N5120.50 (10)O2—C13—H13117.5
C7—C6—N5119.61 (12)N5—C13—H13117.5
C11—N1—C2—O1177.36 (14)N5—C6—C7—C8−173.39 (13)
C11—N1—C2—C3−3.9 (2)C6—C7—C8—C9−0.7 (2)
O1—C2—C3—C4−105.49 (15)C7—C8—C9—C10−1.4 (2)
N1—C2—C3—C475.77 (15)C8—C9—C10—C111.4 (2)
C2—C3—C4—N5−52.89 (14)C7—C6—C11—C10−2.81 (19)
C2—C3—C4—C12−176.57 (11)N5—C6—C11—C10173.34 (12)
C12—C4—N5—C13−81.79 (15)C7—C6—C11—N1179.59 (12)
C3—C4—N5—C13153.92 (12)N5—C6—C11—N1−4.25 (18)
C12—C4—N5—C692.50 (14)C9—C10—C11—C60.7 (2)
C3—C4—N5—C6−31.80 (15)C9—C10—C11—N1178.38 (13)
C13—N5—C6—C11−118.66 (14)C2—N1—C11—C6−42.1 (2)
C4—N5—C6—C1166.98 (16)C2—N1—C11—C10140.35 (15)
C13—N5—C6—C757.50 (17)C6—N5—C13—O2−176.50 (13)
C4—N5—C6—C7−116.86 (13)C4—N5—C13—O2−2.1 (2)
C11—C6—C7—C82.8 (2)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O2i0.89 (2)2.12 (2)2.9745 (16)161.3 (18)
C13—H13···O1ii0.932.383.2220 (18)150
Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) −x+1, y−1/2, −z+1/2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O2i0.89 (2)2.12 (2)2.9745 (16)161.3 (18)
C13—H13···O1ii0.932.383.2220 (18)150
Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) −x+1, y−1/2, −z+1/2.
Acknowledgements top

KR thanks Dr Babu Varghese, SAIF, IIT-Madras, India, for his help with the data collection and the management of Kandaswami Kandar's College, Velur, Namakkal, India, for their encouragement to pursue the programme.

references
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