(1RS,4RS,5RS)-Methyl 2-(3,5-dinitro­benzo­yl)-2-oxa-3-aza­bicyclo­[3.3.0]oct-7-ene-4-carboxyl­ate

Carlos A D Sousa; José E Rodríguez-Borges; M Luísa C Vale; Xerardo Garcia-Mera

doi:10.1107/S160053680901246X

. 2009 Apr 8;65(Pt 5):o992–o993. doi: 10.1107/S160053680901246X

(1RS,4RS,5RS)-Methyl 2-(3,5-dinitrobenzoyl)-2-oxa-3-azabicyclo[3.3.0]oct-7-ene-4-carboxylate

Carlos A D Sousa ^a,^*, José E Rodríguez-Borges ^a, M Luísa C Vale ^a, Xerardo Garcia-Mera ^b

PMCID: PMC2977685 PMID: 21584028

Abstract

The title compound, C₁₅H₁₃N₃O₈, comprises two crystallographically independent molecules in the asymmetric unit. In the crystal, intermolecular C—H⋯O hydrogen bonds link the molecules and short C=O⋯π contacts are seen.

Related literature

For the preparation of the precursor of the title compound, see: Sousa et al. (2008 ▶). For examples of the use of the 3,5dinitrobenzoylation technique for the assignment of structures by X-ray, see: Caamaño et al. (2000 ▶); Fernández et al. (2001 ▶).

Experimental

Crystal data

C₁₅H₁₃N₃O₈
M _r = 363.28
Triclinic,
a = 8.7157 (3) Å
b = 10.8269 (3) Å
c = 17.0677 (5) Å
α = 79.881 (1)°
β = 77.773 (1)°
γ = 78.281 (1)°
V = 1526.35 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.13 mm⁻¹
T = 100 K
0.26 × 0.23 × 0.1 mm

Data collection

Bruker ApexII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶) T _min = 0.913, T _max = 0.99
28142 measured reflections
6012 independent reflections
4564 reflections with I > 2σ(I)
R _int = 0.039

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.124
S = 1.05
6012 reflections
471 parameters
H-atom parameters constrained
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1997 ▶); 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 publication routines (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680901246X/kp2206sup1.cif

e-65-0o992-sup1.cif^{(29.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680901246X/kp2206Isup2.hkl

e-65-0o992-Isup2.hkl^{(288.3KB, 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
C17—H17⋯O11ⁱ	0.98	2.40	3.064 (3)	124
C47—H47⋯O41ⁱⁱ	0.98	2.45	3.083 (3)	122

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

Table 2. Geometric parameters of Y—X⋯Cg contacts (Å, °).

Y—X⋯Cg	X⋯Cg	Y—X⋯Cg	Y⋯Cg
C13—O14⋯Cg2	3.2009 (18)	106.47 (13)	3.736 (3)
C43—O44⋯Cg1	3.1434 (18)	104.52 (13)	3.649 (3)

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Cg1 and Cg2 are the centroids of the rings defined by C1, C2, C3, C7, C8, C12 and C31, C32, C33, C37, C38, C42, respectively.

Acknowledgments

This work was supported by Centro de Investigação em Química of the University of Porto. The X-ray data were collected at the Unidade de Raios X, RIAIDT, University of Santiago de Compostela. The authors thank Fundação para a Ciência e Tecnologia (FCT) (POCTI/QUI/44471/2002) and Xunta de Galicia (07CSA008203-PR) for financial support. CADS thanks the FCT for a grant (No. SFRH/BD/31526/2006).

supplementary crystallographic information

Comment

In organic synthesis, the usual techniques as NMR, mass or infra-red spectrometry and elemental analysis are often not enough for the unequivocally determination of a structure of a compound. When it is possible to crystallize desired compound, the X-ray crystallography is the ultimate analysis. 3,5-dinitrobenzoylation of 2-oxa-3-azabicyclo[3.3.0]oct-7-ene-4- carboxylate leaded to title compound (I) that was unambigously analysed by X-ray analysis.

The two independent molecules of the title compound (I) are coupled by π···π interactions of the 3,5-dinitrobenzoyl rings (Fig. 1) [Cg1-Cg2^iv = 4.2295 Å, symmetry code: (iv) 1 + x, y, z]. It is also possible to verify the existence of the three stereogenic centres of the same chirality in both molecules of the asymmetric unit. As the space group is centrosymmetric, a racemate is present in a crystal. No other stereoisomers of methyl 2-oxa-3-azabicyclo[3.3.0]oct-7-ene-4-carboxylate are obtained from the reported synthetic methodology (Sousa et al. 2008).

In the crystal structure, each pair of the molecules are linked by π··· π contacts between the 3,5-dinitrobenzoyl rings along [100] direction (Fig. 2) (Cg1-Cg2ⁱⁱⁱ = 4.4862 Å, Cg2-Cg1ⁱⁱⁱ = 4.4862 Å; symmetry code: (iii) x, y, z). Intermolecular interactions between carbonyl and nitro groups (distance C···O ≈ 3.0 Å), between nitro groups (distance N···O ≈ 3.0 Å) and C—H···O intermolecular hydrogen bonds (Table 1) generate an assembly by packing these chains along [010] direction (Fig. 3). Table 2 lists the interactions between aromatic rings (resulting in a π···π stacking assembly).

The carbonyl and nitro groups are very electronegative; as a result, the electronic density of the 3,5-dinitrobenzoyl rings is delocalized from the centre of π-system towards the electronegative O atoms. This delocalization origins from electrostatic intermolecular interactions between the oxygen atoms and the centre of the π-system (Table 3).

This analysis suggest that the most important intermolecular interactions in compound (I) are due to the 3,5-dinitrobenzoyl ring (including the nitro and carbonyl groups), which seems to be the main reason why compound (I) is a solid.

Experimental

The title compound was synthesized from 2-oxa-3-azabicyclo[3.3.0]oct-7-ene-4-carboxylate as reported in literature (Sousa et al. 2008). Crystals were obtained from a slow evaporation of a dichlorometane/methanol/hexane solution of (I).