2,4-Bis(4-fluoro­phen­yl)-2,3-dihydro-1H-1,5-benzodiazepine

Zeliha Baktır; Mehmet Akkurt; S Samshuddin; B Narayana; H S Yathirajan

doi:10.1107/S1600536811015455

. 2011 Apr 29;67(Pt 5):o1262–o1263. doi: 10.1107/S1600536811015455

2,4-Bis(4-fluorophenyl)-2,3-dihydro-1H-1,5-benzodiazepine

Zeliha Baktır ^a, Mehmet Akkurt ^a,^*, S Samshuddin ^b, B Narayana ^b, H S Yathirajan ^c

PMCID: PMC3089231 PMID: 21754550

Abstract

In the title compound, C₂₁H₁₆F₂N₂, the seven-membered 1,4-diazepine ring of the benzodiazepine ring system adopts a distorted-boat conformation. The benzene ring of this system makes dihedral angles of 18.6 (2) and 78.8 (2)° with those of two fluorophenyl substituents. In the crystal, inversion dimers linked by two weak C—H⋯F hydrogen bonds generate R ₂ ²(20) ring motifs. There are also weak N—H⋯π and C—H⋯π interactions.

Related literature

For related structures, see: An et al. (2007 ▶); Bibila Mayaya Bisseyou et al. (2010 ▶); Harrison et al. (2005 ▶); Peeters et al. (1997 ▶). For puckering parameters, see: Cremer & Pople (1975 ▶). For graph-set nomenclature of hydrogen bonds, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₂₁H₁₆F₂N₂
M _r = 334.36
Monoclinic,
a = 12.9151 (4) Å
b = 6.0438 (3) Å
c = 21.2851 (7) Å
β = 92.147 (3)°
V = 1660.27 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 294 K
0.20 × 0.20 × 0.20 mm

Data collection

Rigaku R-AXIS RAPID-S diffractometer
Absorption correction: refined from ΔF (XABS2; Parkin et al., 1995 ▶) T _min = 0.981, T _max = 0.981
3413 measured reflections
3413 independent reflections
1226 reflections with I > 2σ(I)

Refinement

R[F ² > 2σ(F ²)] = 0.061
wR(F ²) = 0.151
S = 1.04
3413 reflections
233 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.16 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811015455/hb5848sup1.cif

e-67-o1262-sup1.cif^{(19.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811015455/hb5848Isup2.hkl

e-67-o1262-Isup2.hkl^{(167.4KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811015455/hb5848Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

Cg1 and Cg2 are the centroids of the benzene rings of the two fluorophenyl substituents (C10–C15 and C16–C21, respectively).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯F1ⁱ	0.93	2.54	3.469 (6)	175
N1—H1N⋯Cg2ⁱ	0.86 (3)	2.82 (5)	3.601 (4)	151 (4)
C2—H2⋯Cg1ⁱⁱ	0.93	2.89	3.640 (5)	138
C11—H11⋯Cg2	0.93	2.79	3.494 (5)	134

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

ZB and MA thank the Unit of the Scientific Research Projects of Erciyes University, Turkey for the research grant FBD-10–2949, and for support of the data collection at Atatürk University, Turkey. SS and BN thank Mangalore University and the UGC SAP for financial assistance for the purchase of chemicals. HSY thanks the UOM for sabbatical leave.

supplementary crystallographic information

Comment

The crystal structures of some 1,5-benzodiazepines, viz., 2-[2-(4-methoxyphenyl)-2,3-dihydro-1H-1,5-benzodiazepin-4-yl]phenol (Bibila Mayaya Bisseyou et al., 2010), 1-(2-bromo-5-methoxyphenyl)-8-chloro-6-(2-fluorophenyl)-4H-1,2,4-triazolo[4,3-a][1,4] benzodiazepine (Harrison et al., 2005), 5-(4-fluorophenyl)-1,8-dimethyl-2-(p-toluoylaminomethyl)-2,3-dihydro-1H-1,4-benzodiazepine monohydrate (Peeters et al., 1997) and 2,4-bis(4-chlorophenyl)-2-methyl-2,3-dihydro-1H-1,5-benzodiazepine (An et al., 2007) have been reported. In continuation of this work, the title compound, (I), is synthesized and its crystal structure is reported here.

The seven-membered 1,4-diazepine ring (C1/C6–C9/N1/N2) of the benzodiazepine ring system (C1–C9/N1/N2) adopts a distorted-boat conformation [the puckering parameters (Cremer & Pople, 1975) for this eleven-membered ring system are: Q₂ = 0.917 (4) Å, Q₃ = 0.155 (4) Å, φ₂ = 16.6 (3)° and φ₃ = 92.6 (17)°] as shown in Fig. 1. The benzene ring (C1–C6) of this system forms dihedral angles of 18.6 (2)° and 78.8 (2)° with the benzene rings (C10–C15 and C16–C21) of two fluorophenyl fragments, respectively which make a dihedral angle of 62.1 (2)° with each other.

In the crystal, the two weak C—H···F hydrogen bonds link pairs of inversion-related molecules to form cyclic centrosymmetric dimers containing the R²₂(20) ring motif (Bernstein et al., 1995; Table 1, Fig. 2). In addtion, three C—H···π interactions are observed (Table 1).

Experimental

To a solution of 4,4'-difluoro chalcone (2.44 g, 0.01 mol) in ethanol (30 ml) a few drops of piperidine and 1, 2-diaminobenzene (1.08 g, 01 mol) were added. The mixture was heated under reflux for 10 h. The reaction mixture was cooled and poured into 50 ml ice-cold water. The precipitate was collected by filtration and purified by recrystallization from ethanol. Pale yellow blocks of (I) were grown from DMF by slow evaporation method in 66% yield (m. p.: 409 K).