3-{1-[(2,4-Dinitrophenyl)hydrazino]­ethyl­idene}-5-(1-methylpropyl)pyrrolidine-2,4-dione

David Siegel; Stefan Merkel; Matthias Koch; Franziska Emmerling; Irene Nehls

doi:10.1107/S1600536809012458

. 2009 Apr 8;65(Pt 5):o988–o989. doi: 10.1107/S1600536809012458

3-{1-[(2,4-Dinitrophenyl)hydrazino]ethylidene}-5-(1-methylpropyl)pyrrolidine-2,4-dione

David Siegel ^a,^*, Stefan Merkel ^a, Matthias Koch ^a, Franziska Emmerling ^a, Irene Nehls ^a

PMCID: PMC2977683 PMID: 21584026

Abstract

In the title compound, C₁₆H₁₉N₅O₆, two intramolecular N—H⋯O hydrogen bonds help to establish the conformation. In the crystal, intermolecular N—H⋯O links result in chains propagating in [010].

Related literature

For the use of the title compound in instrumental analytical chemistry, see: Siegel et al. (2009 ▶). For the crystal structure of the tenuazonic copper(II) salt, see: Dippenaar et al. (1977 ▶). For the structures of other 2,4-dinitrophenylhydrazones, see: Tameem et al. (2006 ▶); Monfared et al. (2007 ▶); Valente et al. (2008 ▶); Yin et al. (2008 ▶). Solubilized tetramic acids and their hydrazones display a variety of tautomeric forms, see: Gelin et al. (1982 ▶); Nolte et al. (1980 ▶); Royles (1995 ▶); Yamaguchi et al. (1976a ▶, 1976b ▶). For the synthesis, see: Lebrun et al. (1988 ▶).

Experimental

Crystal data

C₁₆H₁₉N₅O₆
M _r = 377.36
Monoclinic,
a = 10.6710 (10) Å
b = 4.9387 (5) Å
c = 16.839 (2) Å
β = 107.363 (4)°
V = 846.98 (15) Å³
Z = 2
Cu Kα radiation
μ = 0.98 mm⁻¹
T = 193 K
0.64 × 0.06 × 0.06 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (CORINC; Dräger & Gattow, 1971 ▶) T _min = 0.78, T _max = 0.94
3890 measured reflections
3282 independent reflections
3103 reflections with I > 2σ(I)
R _int = 0.025
3 standard reflections frequency: 60 min intensity decay: 2%

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.111
S = 0.99
3282 reflections
247 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.24 e Å⁻³
Δρ_min = −0.21 e Å⁻³
Absolute structure: (Flack,1983 ▶)
Flack parameter: 0.1 (2)

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ▶); cell refinement: CAD-4 Software; data reduction: CORINC (Dräger & Gattow, 1971 ▶); program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809012458/kj2118sup1.cif

e-65-0o988-sup1.cif^{(21.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809012458/kj2118Isup2.hkl

e-65-0o988-Isup2.hkl^{(161KB, 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
N3—H3N⋯O2	0.93	1.99	2.630 (2)	125
N4—H4N⋯O5	0.89	2.00	2.710 (2)	135
N3—H3N⋯O5ⁱ	0.93	2.36	2.949 (2)	121
N4—H4N⋯O5ⁱ	0.89	2.43	2.898 (2)	113
N5—H5N⋯O2ⁱⁱ	0.86	2.48	3.293 (2)	159

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

supplementary crystallographic information

Comment

The title compound is the condensation product of the Alternaria spp. mycotoxin tenuazonic acid and 2,4-dinitrophenylhydrazine. It is formed during the derivatization step of a novel HPLC-ESI multistage MS method for tenuazonic acid quantification in cereals (Siegel et al., 2009). While tenuazonic acid itself occurs as a non-crystallizable gum, the crystal structure of its copper salt has previously been reported (Dippenaar et al., 1977). For exemplary crystal structures of other 2,4-dinitrophenylhydrazones see Tameem et al., 2006, Monfared et al., 2007, Valente et al., 2008, Yin et al., 2008. The structure of the title compound is of particular interest, since solubilized tetramic acids and their hydrazones display a variety of tautomeric forms (Yamaguchi et al., 1976a,b, Nolte et al., 1980, Gelin et al., 1982, Royles, 1995, Siegel et al., 2009) (see Fig. 1). While the two rotameric groups I—II and III-IV (Fig. 1) may be differentiated using 1H-NMR, the tautomeric equilibria which are fast on the NMR timescale can not be characterized like that. Furthermore, although common NMR experiments allow for the differentiation of the two rotameric tautomers, the structural assignment of the predominant species is not possible. The presented crystal structure indicates that a six-membered ring involving an intramolecular hydrogen bond between the O5 and N4 is in fact favoured for this compound. On the basis of the presented crystal structure, it can also be assumed, that the thermodynamically favoured tautomer does not involve a double bond of N3 or N4 and thus is tautomer I (Fig. 1). Six N—H···O hydrogen bonds connect each molecule to four adjacent molecules, which are all screw images and span a length of four unit cells. As depicted in Fig. 3 these interactions result in indefinite chains along the b axis.

Experimental

The tenuazonic acid natrium salt was supplied by the workgroup of Professor R. Faust (University of Kassel, Germany) by total synthesis from L-isoleucine according to a literature procedure (Lebrun et al., 1988). The title compound was synthesized by adding the tenuazonic acid natrium salt (1 eq.) to a 15 mM solution of 2,4-dinitrophenylhydrazine in 2 N HCl (2 eq.). After 30 minutes of shaking the precipitate was collected, washed with water, dissolved in ethyl acetate and dried with natrium sulfate. After evaporation of the solvent, a yellow powder was obtained, which was recrystallized from ethanol five times to obtain the title compound in analytical purity. For X-ray analysis yellow crystals of tenuazonic acid 2,4-dinitrophenylhydrazone were grown by solvent evaporation from ethanol at ambient temperature over a period of three weeks.