1,1-Bis(4-fluoro­phen­yl)-3,4-dihydro-1H-1,3-oxazino[3,4-a]indole

Weijun Fu; Dongsheng Deng; Dongfeng Hong; Zhiqiang Wang; Baoming Ji

doi:10.1107/S160053680803376X

. 2008 Oct 31;64(Pt 11):o2227. doi: 10.1107/S160053680803376X

1,1-Bis(4-fluorophenyl)-3,4-dihydro-1H-1,3-oxazino[3,4-a]indole

Weijun Fu ^a, Dongsheng Deng ^a, Dongfeng Hong ^a, Zhiqiang Wang ^a, Baoming Ji ^a,^*

PMCID: PMC2959698 PMID: 21581082

Abstract

The title compound, C₂₃H₁₇F₂NO, which crystallizes with two independent molecules in the asymmetric unit, was prepared by the cyclization of 4-[2-bis(4-fluorophenyl)methyleneamino]but-3-yn-1-ol at room temperature. The molecules display a tripod conformation. The two fluorophenyl rings make dihedral angles of 79.26 (2) and 85.87 (1)° [86.53 (1) and 83.67 (2)° in the second molecule] with the indole ring, and the dihedral angles between the fluorophenyl rings are 67.74 (2) and 66.33 (2)°, respectively. Furthermore, the indole rings are located on the edge of the respective oxazine half-chair ring systems. Nonconventional C—H⋯π contacts between indole and fluorophenyl rings are observed.

Related literature

For bond-length and angle data, see: Lee et al. (2000 ▶). For the synthesis of palladium-catalysed key intermediates to condensed heteroaromatic rings, see: Sakamoto et al. (1988 ▶). For the biological function of tryptamines and their derivatives, see: Monckton & McCormick (2002 ▶).

Experimental

Crystal data

C₂₃H₁₇F₂NO
M _r = 361.38
Triclinic,
a = 10.9845 (11) Å
b = 11.2002 (11) Å
c = 15.1964 (16) Å
α = 87.6150 (10)°
β = 80.7510 (10)°
γ = 76.9900 (10)°
V = 1797.9 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 291 (2) K
0.38 × 0.30 × 0.20 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.965, T _max = 0.981
13827 measured reflections
6630 independent reflections
4487 reflections with I > 2σ(I)
R _int = 0.019

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.106
S = 1.02
6630 reflections
487 parameters
H-atom parameters constrained
Δρ_max = 0.13 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053680803376X/si2115sup1.cif

e-64-o2227-sup1.cif^{(32.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680803376X/si2115Isup2.hkl

e-64-o2227-Isup2.hkl^{(324.4KB, hkl)}

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

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

Cg3, Cg5, Cg9 and Cg11 are the centroids of the C3–C8, C26–C31, N2/C24–C26/C31 and C18–C23 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C14—H14⋯Cg3ⁱ	0.93	2.88	3.769 (2)	159
C29—H29⋯Cg5ⁱⁱ	0.93	2.93	3.747 (2)	148
C43—H43⋯Cg11ⁱⁱⁱ	0.93	2.79	3.695 (2)	165
C40—H40⋯Cg9	0.93	2.74	3.3790 (7)	127

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

Acknowledgments

This work was supported by the Doctor Foundation of Luoyang Normal University.

supplementary crystallographic information

Comment

Indoles are one of the most widely distributed heterocyclic compounds in nature (Sakamoto et al., 1988). The indole ring appeares in tryptophan, an essential amino acid, and metabolites of tryptophan are important in the biological chemistry of both plants and animals (Monckton & McCormick, 2002). The potent physiological properties of these indole derivatives led to vast research of their use as medicines in the field of pharmaceutical chemistry. So in the recent decades, many chemists have been attracted by the synthesis of indoles. In this context, we report the synthesis of the title compound.

The asymmetric unit of the title compound contains two independent molecules (Fig. 1.), in both of which the bond lengths and angles are within ranges as reported by Lee et al. (2000). The structural analysis reveals that a surprizing feature is the lack of C—H···F interactions, but three weak non-conventional intermolecular C—H···π contacts with two fluorophenyl rings (F1, F4) and one indole ring are donors, whereas the indole rings (C3 - C8 and C26 - C31) and a fluorophenyl ring (C18 - C23) are π acceptors. Cg3, Cg5 and Cg11 are the centroids of the acceptor rings, for the intramolecular C—H···π contact, Cg9 is the centroid of the five-membered ring (N2, C24, C25, C26, C31). Details are given in Table 1. Furthermore, pseudosymmetry between the independent molecules can be described as an approximate twofold screw axis when viewed down the a axis.

Experimental

To a solution of 4-(2-bis(4-fluoridophenyl)methyleneamino)phenyl)but-3-yn-1-ol (0.5 mmol) in dry CH₂Cl₂ was added AuCl₃ (5 mg). The mixture was stirred for 1 h at room temperature. After evaporation of the solvent, the residue was purified by column chromatography on silica gel(petroleum ether) to afford the title compound as a colorless solid (163 mg, yield 90%). The title compound was recrystallized from petroleum ether at room temperature to give the desired crystals suitable for single-crystal X-ray diffraction.