Diethyl 7,8-dibromo-4,11-dioxo-11b,11c-dihydro-5H,10H-2-oxa-3a,4a,10a,11a-tetra­azabenz[f]indeno[2,1,7,7a-ija]azulene-11b,11c-dicarboxyl­ate

Yan Chen; Nengfang She

doi:10.1107/S160053680903284X

. 2009 Aug 26;65(Pt 9):o2252. doi: 10.1107/S160053680903284X

Diethyl 7,8-dibromo-4,11-dioxo-11b,11c-dihydro-5H,10H-2-oxa-3a,4a,10a,11a-tetraazabenz[f]indeno[2,1,7,7a-ija]azulene-11b,11c-dicarboxylate

Yan Chen ^a, Nengfang She ^a,^*

PMCID: PMC2969905 PMID: 21577649

Abstract

The title compound, C₂₀H₂₀Br₂N₄O₇, is an intermediate for molecular clips. The seven- and six-membered rings have chair conformations, while the five-membered rings adopt envelope conformations. In the crystal structure, weak C—H⋯O and C—H⋯Br interactions link the molecules into a three-dimensional network. The ethoxy and ethyl groups are disordered over two orientations, with occupancy ratios of 0.735 (16):0.265 (16) and 0.51 (2):0.49 (2), respectively.

Related literature

For general background, see: Burnett et al. (2003 ▶). For a related structure, see: Wu et al. (2002 ▶). For ring-puckering parameters, see: Cremer & Pople (1975 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₂₀H₂₀Br₂N₄O₇
M _r = 588.22
Monoclinic,
a = 12.4679 (10) Å
b = 15.1505 (13) Å
c = 11.5383 (10) Å
β = 90.189 (1)°
V = 2179.5 (3) Å³
Z = 4
Mo Kα radiation
μ = 3.77 mm⁻¹
T = 292 K
0.30 × 0.20 × 0.20 mm

Data collection

Bruker SMART 4K CCD area-detector diffractometer
Absorption correction: none
18344 measured reflections
4736 independent reflections
2983 reflections with I > 2σ(I)
R _int = 0.097

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.134
S = 0.91
4736 reflections
349 parameters
30 restraints
H-atom parameters constrained
Δρ_max = 1.00 e Å⁻³
Δρ_min = −0.59 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680903284X/hk2753sup1.cif

e-65-o2252-sup1.cif^{(27KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680903284X/hk2753Isup2.hkl

e-65-o2252-Isup2.hkl^{(232KB, hkl)}

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C19—H19B⋯O2ⁱ	0.97	2.51	3.353 (4)	146
C17—H17A⋯Br1ⁱⁱ	0.97	2.94	3.625 (10)	129
C8—H8B⋯O2ⁱⁱⁱ	0.97	2.39	3.324 (4)	161

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

Acknowledgments

The authors are grateful to the Central China Normal University, and Professor Wu Anxin for financial support.

supplementary crystallographic information

Comment

Diethoxycarbonyl glycoluril bearing a range of electron withdrawing functional groups on its convex face is an important building block for both molecular and supramolecular chemistry (Burnett et al., 2003). The title compound derived from diethoxycarbonyl glycoluril is an important intermediate for methylene-bridged glycoluril dimers, and we report herein its crystal structure.

In the molecule of the title compound, (Fig. 1), the bond lengths (Allen et al., 1987) and angles are within normal ranges. Ring A (C1-C6) is, of course, planar. The seven-membered ring B (N1/N2/C1/C6-C8/c11) is not planar, having total puckering amplitude, Q_T, of 2.878 (2) Å (Cremer & Pople, 1975), and resembles chair conformation. Rings C (N1/N3/C9/C11/C15) and D (N2/N4/C10/C11/C15) adopt envelope conformations with atoms N1 and N4 displaced by -0.208 (3) and -0.174 (3) Å from the planes of the other ring atoms, respectively, while ring E (O7/N3/N4/C15/C19/C20) is not planar, having total puckering amplitude, Q_T, of 0.429 (2) Å and adopts chair conformation [φ = -90.18 (3) and θ = 91.16 (3) °] (Cremer & Pople, 1975).

In the crystal structure, weak C-H···O and C-H···Br interactions link the molecules into a three-dimensional network (Fig. 2), in which they may be effective in the stabilization of the structure.

Experimental

The title compound was synthesized according to a literature method (Wu et al., 2002). Crystals suitable for X-ray analysis were obtained by slow evaporation of a dichloride methane solution at 283 K.