organic compounds
(E)-1-(2,4-Dinitrophenyl)-2-pentylidenehydrazine
aDepartamento de Química Orgânica, Universidade Federal de Pelotas (UFPel), Campus Universitário, s/n°, Caixa Postal 354, 96010-900 Pelotas, RS, Brazil, bCHEMSOL, 1 Harcourt Road, Aberdeen AB15 5NY, Scotland, cDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia, and dCentro de Desenvolvimento Tecnológico em Saúde (CDTS), Fundação Oswaldo Cruz (FIOCRUZ), Casa Amarela, Campus de Manguinhos, Av. Brasil 4365, 21040-900 Rio de Janeiro, RJ, Brazil
*Correspondence e-mail: edward.tiekink@gmail.com
The title compound, C11H14N4O4, is essentially planar with an r.m.s. deviation for the 19 non-H atoms of 0.152 Å. The conformation about the C=N bond is E, and the molecule has a U-shape as the butyl group folds over towards the aromatic system. An intramolecular C—H⋯N interaction occurs. The crystal packing is dominated by N—H⋯O hydrogen bonding and C—H⋯O contacts, leading to twisted zigzag supramolecular chains along the c direction. The crystal packing brings two nitro O atoms into an unusually close proximity of 2.686 (4) Å. While the nature of this interaction is not obvious, there are several precendents for such short nitro–nitro O⋯O contacts of less than 2.70 Å in the crystallographic literature.
Related literature
For background to the biological uses of ). For background to the synthesis, see: Furniss et al. (1999); Neuenfeldt et al. (2009). For a description of the Cambridge Structural Database, see: Allen (2002).
see: Rollas & Küçükgüzel (2007Experimental
Crystal data
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Refinement
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Data collection: COLLECT (Hooft, 1998); cell DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).
Supporting information
https://doi.org/10.1107/S1600536810002102/fj2271sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810002102/fj2271Isup2.hkl
A mixture of 2,4-dinitrophenylhydrazine 1 (3 mmol) and pentanal 2 (3 mmol) in toluene (35 ml) was heated at 403 K with a Dean-Stark trap for 3 h. The reaction was cooled and the crude product was recrystallized from ethanol, yield 69%. m.p. 371–372 K. 1H NMR (400 MHz, CDCl3): d 11.00 (br, 1H, NH), 9.11 (d, 1H, J = 2.4 Hz), 8.29 (dd, 1H, J = 9.6 and 2.4 Hz), 7.93 (d, 1H, J = 9.6 Hz), 7.54 (t, 1H, J = 5.2 Hz), 2.43 (m, 2H), 1.60 (m, 2H), 1.43 (sext, 2H, J = 7.6 Hz), 0.97 (t, 3H, J = 7.6 Hz) p.p.m.
The C-bound H atoms were geometrically placed (C–H = 0.95–0.99 Å) and refined as riding with Uiso(H) = 1.2–1.5Ueq(C). The methyl H atoms were rotated to fit the electron density. The N–H atom was located in a difference map and refined with Uiso(H) = 1.2Ueq(N). The reported structure, while unambiguous, is not optimal owing to the poor quality of the crystals available for analysis.
2,4-Dinitrophenylhydrazine is a frequently used reagent for the characterization of
and (Furniss et al., 1999). The 2,4-dinitrophenylhydrazone products are generally formed readily in good yield and purity. The ready formation of 2,4-dinitrophenyl of can be a disadvantage as found during the attempted formation of a thiazolidinone from 2,4-dinitrophenylhydrazine, pentanal and mercaptoacetic acid, using a similar one-pot synthesis to that used successfully with and mercaptoacetic acid (Neuenfeldt et al., 2009). Instead of the targeted thiazolidinone derivative, the 2,4-dinitrophenylhydrazone of pentanal was isolated in very high yield: as shown below, this compound was efficiently produced from a reaction mixture reaction just involving 2,4-dinitrophenylhydrazine and pentanal. containing the –NHN=CH moiety constitute an important class of antimicrobial, anticonvulsant, analgesic, antiinflammatory, antiplatelet, antitubercular and antitumoral agents. (Rollas & Küçükgüzel, 2007).To a first approximation, the molecule of (I), Fig. 1, is flat with the maximum deviations of torsion angles from the ideal 0 or 180 ° being 9.0 (7) ° for N2–C7–C8–C9, and -170.7 (4) ° for C1–N1–N2–C7; the r.m.s. deviation of the non-hydrogen atoms = 0.152 Å. The n-butyl side-chain folds over to be oriented towards the benzene ring. The conformation about the C7═N3 bond [1.270 (5) Å] is E. In the crystal packing, supramolecular chains are formed along the c direction. These are sustained by four-membered {···H···O}2 synthons as the amine-H1n atom is bifurcated forming intra- and intermolecular N–H···Onitro hydrogen bonds, Fig. 2 and Table 1. Additional stabilization to the chain is afforded by ten-membered {···ONC2H}2 synthons, Fig. 2 and Table 1. Whereas the smaller of the synthons is disposed about a centre of inversion, the larger has crystallographic 2-fold symmetry and has a distinct folded conformation. The latter induces considerable kinks in the chain as emphasized in Fig. 3 which illustrates the formation of 2-D arrays via N–O···π interactions [N–O3···Cg(C1–C6)i = 3.163 (3) Å with an angle at O3 = 89.9 (2) ° where Cg is the ring centroid of the C1–C6 ring and i = x, -1 + y, z]. Globally, the layers formed in the bc plane stack along the a direction with interdigitation of the saturated residues. It is noted that the packing of molecules brings into close proximity two nitro-O atoms, i.e. O4···O4ii = 2.686 (4) Å for ii: -x, 1 - y, 1 - z. While the nature of this interaction is not obvious, there are approximately 50 precendents for such Onitro···Onitro contacts < 2.70 Å in the crystallographic literature (Allen, 2002).
For background to the biological uses of
see: Rollas & Küçükgüzel (2007). For background to the synthesis, see: Furniss et al. (1999); Neuenfeldt et al. (2009). For a description of the Cambridge Structural Database, see: Allen (2002).Data collection: COLLECT (Hooft, 1998); cell
DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); data reduction: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).C11H14N4O4 | F(000) = 1120 |
Mr = 266.26 | Dx = 1.404 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 14843 reflections |
a = 31.162 (3) Å | θ = 2.9–27.5° |
b = 4.4930 (4) Å | µ = 0.11 mm−1 |
c = 18.7329 (14) Å | T = 120 K |
β = 106.159 (4)° | Needle, yellow |
V = 2519.2 (4) Å3 | 0.32 × 0.03 × 0.02 mm |
Z = 8 |
-Nonius KappaCCD area-detector diffractometer | 2174 independent reflections |
Radiation source: Enraf Nonius FR591 rotating anode | 1451 reflections with I > 2σ(I) |
10 cm confocal mirrors monochromator | Rint = 0.115 |
Detector resolution: 9.091 pixels mm-1 | θmax = 25.0°, θmin = 3.0° |
φ and ω scans | h = −36→36 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2007) | k = −5→5 |
Tmin = 0.628, Tmax = 1.000 | l = −22→22 |
8172 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.078 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.183 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.10 | w = 1/[σ2(Fo2) + (0.0406P)2 + 14.6755P] where P = (Fo2 + 2Fc2)/3 |
2174 reflections | (Δ/σ)max < 0.001 |
179 parameters | Δρmax = 0.28 e Å−3 |
0 restraints | Δρmin = −0.27 e Å−3 |
C11H14N4O4 | V = 2519.2 (4) Å3 |
Mr = 266.26 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 31.162 (3) Å | µ = 0.11 mm−1 |
b = 4.4930 (4) Å | T = 120 K |
c = 18.7329 (14) Å | 0.32 × 0.03 × 0.02 mm |
β = 106.159 (4)° |
-Nonius KappaCCD area-detector diffractometer | 2174 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2007) | 1451 reflections with I > 2σ(I) |
Tmin = 0.628, Tmax = 1.000 | Rint = 0.115 |
8172 measured reflections |
R[F2 > 2σ(F2)] = 0.078 | 0 restraints |
wR(F2) = 0.183 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.10 | w = 1/[σ2(Fo2) + (0.0406P)2 + 14.6755P] where P = (Fo2 + 2Fc2)/3 |
2174 reflections | Δρmax = 0.28 e Å−3 |
179 parameters | Δρmin = −0.27 e Å−3 |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.04985 (11) | −0.5722 (7) | 0.23571 (16) | 0.0294 (8) | |
O2 | 0.11770 (10) | −0.4264 (8) | 0.24360 (16) | 0.0360 (9) | |
O3 | −0.03340 (10) | −0.1033 (7) | 0.37999 (16) | 0.0263 (8) | |
O4 | −0.00644 (9) | 0.2652 (7) | 0.45386 (15) | 0.0240 (7) | |
N1 | 0.07910 (11) | 0.3841 (8) | 0.49031 (18) | 0.0194 (8) | |
H1N | 0.0551 (14) | 0.401 (10) | 0.505 (2) | 0.023* | |
N2 | 0.11897 (11) | 0.5276 (8) | 0.52633 (18) | 0.0224 (9) | |
N3 | 0.08254 (13) | −0.4163 (9) | 0.26201 (19) | 0.0267 (9) | |
N4 | −0.00244 (11) | 0.0661 (8) | 0.41033 (19) | 0.0213 (8) | |
C1 | 0.07833 (13) | 0.2003 (10) | 0.4333 (2) | 0.0197 (10) | |
C2 | 0.04022 (13) | 0.0353 (10) | 0.3940 (2) | 0.0185 (9) | |
C3 | 0.04158 (14) | −0.1701 (9) | 0.3391 (2) | 0.0191 (9) | |
H3 | 0.0161 | −0.2868 | 0.3159 | 0.023* | |
C4 | 0.08074 (14) | −0.2003 (10) | 0.3192 (2) | 0.0222 (10) | |
C5 | 0.11852 (14) | −0.0324 (10) | 0.3534 (2) | 0.0242 (10) | |
H5 | 0.1450 | −0.0528 | 0.3381 | 0.029* | |
C6 | 0.11736 (14) | 0.1613 (10) | 0.4090 (2) | 0.0230 (10) | |
H6 | 0.1434 | 0.2733 | 0.4321 | 0.028* | |
C7 | 0.11826 (14) | 0.6629 (11) | 0.5855 (2) | 0.0248 (10) | |
H7 | 0.0922 (15) | 0.660 (11) | 0.604 (2) | 0.030* | |
C8 | 0.15800 (14) | 0.8254 (11) | 0.6307 (2) | 0.0281 (11) | |
H8A | 0.1693 | 0.7207 | 0.6788 | 0.034* | |
H8B | 0.1485 | 1.0266 | 0.6415 | 0.034* | |
C9 | 0.19629 (14) | 0.8581 (12) | 0.5957 (2) | 0.0292 (11) | |
H9A | 0.2041 | 0.6593 | 0.5802 | 0.035* | |
H9B | 0.1863 | 0.9830 | 0.5505 | 0.035* | |
C10 | 0.23763 (15) | 0.9966 (13) | 0.6476 (3) | 0.0382 (13) | |
H10A | 0.2293 | 1.1896 | 0.6655 | 0.046* | |
H10B | 0.2485 | 0.8654 | 0.6914 | 0.046* | |
C11 | 0.27528 (16) | 1.0479 (14) | 0.6126 (3) | 0.0481 (15) | |
H11A | 0.2826 | 0.8602 | 0.5921 | 0.072* | |
H11B | 0.3016 | 1.1216 | 0.6503 | 0.072* | |
H11C | 0.2660 | 1.1951 | 0.5727 | 0.072* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0374 (18) | 0.0244 (18) | 0.0233 (16) | 0.0013 (17) | 0.0035 (14) | −0.0058 (15) |
O2 | 0.0333 (18) | 0.050 (2) | 0.0308 (17) | 0.0130 (18) | 0.0186 (15) | −0.0036 (17) |
O3 | 0.0273 (16) | 0.0281 (19) | 0.0246 (15) | −0.0065 (15) | 0.0090 (13) | −0.0059 (15) |
O4 | 0.0244 (16) | 0.0223 (18) | 0.0265 (15) | 0.0017 (13) | 0.0093 (13) | −0.0074 (15) |
N1 | 0.0163 (18) | 0.019 (2) | 0.0236 (18) | 0.0000 (16) | 0.0061 (15) | −0.0035 (17) |
N2 | 0.0181 (17) | 0.026 (2) | 0.0231 (19) | −0.0029 (16) | 0.0052 (15) | 0.0018 (17) |
N3 | 0.037 (2) | 0.023 (2) | 0.0218 (19) | 0.010 (2) | 0.0108 (18) | 0.0006 (17) |
N4 | 0.0228 (19) | 0.020 (2) | 0.0219 (18) | 0.0005 (17) | 0.0078 (16) | 0.0023 (18) |
C1 | 0.022 (2) | 0.017 (2) | 0.019 (2) | 0.0026 (19) | 0.0042 (18) | 0.0026 (19) |
C2 | 0.019 (2) | 0.017 (2) | 0.019 (2) | −0.0002 (18) | 0.0047 (18) | 0.0006 (19) |
C3 | 0.024 (2) | 0.010 (2) | 0.021 (2) | 0.0042 (18) | 0.0025 (18) | 0.0015 (18) |
C4 | 0.029 (2) | 0.018 (2) | 0.021 (2) | 0.005 (2) | 0.0091 (19) | 0.0028 (19) |
C5 | 0.022 (2) | 0.025 (3) | 0.028 (2) | 0.005 (2) | 0.0105 (19) | 0.009 (2) |
C6 | 0.019 (2) | 0.022 (3) | 0.028 (2) | −0.0008 (19) | 0.0082 (19) | 0.006 (2) |
C7 | 0.023 (2) | 0.027 (3) | 0.024 (2) | −0.004 (2) | 0.0054 (19) | −0.003 (2) |
C8 | 0.030 (2) | 0.028 (3) | 0.027 (2) | −0.008 (2) | 0.009 (2) | −0.005 (2) |
C9 | 0.027 (2) | 0.033 (3) | 0.027 (2) | −0.006 (2) | 0.006 (2) | 0.001 (2) |
C10 | 0.032 (3) | 0.043 (4) | 0.033 (3) | −0.010 (2) | −0.002 (2) | 0.004 (3) |
C11 | 0.032 (3) | 0.056 (4) | 0.054 (3) | −0.008 (3) | 0.009 (3) | 0.010 (3) |
O1—N3 | 1.221 (5) | C5—H5 | 0.9500 |
O2—N3 | 1.238 (4) | C6—H6 | 0.9500 |
O3—N4 | 1.236 (4) | C7—C8 | 1.483 (6) |
O4—N4 | 1.240 (4) | C7—H7 | 0.96 (4) |
N1—C1 | 1.345 (5) | C8—C9 | 1.521 (6) |
N1—N2 | 1.396 (5) | C8—H8A | 0.9900 |
N1—H1N | 0.87 (4) | C8—H8B | 0.9900 |
N2—C7 | 1.270 (5) | C9—C10 | 1.515 (6) |
N3—C4 | 1.458 (5) | C9—H9A | 0.9900 |
N4—C2 | 1.451 (5) | C9—H9B | 0.9900 |
C1—C2 | 1.420 (6) | C10—C11 | 1.513 (6) |
C1—C6 | 1.423 (5) | C10—H10A | 0.9900 |
C2—C3 | 1.391 (6) | C10—H10B | 0.9900 |
C3—C4 | 1.378 (5) | C11—H11A | 0.9800 |
C3—H3 | 0.9500 | C11—H11B | 0.9800 |
C4—C5 | 1.395 (6) | C11—H11C | 0.9800 |
C5—C6 | 1.365 (6) | ||
C1—N1—N2 | 118.9 (3) | N2—C7—C8 | 121.3 (4) |
C1—N1—H1N | 119 (3) | N2—C7—H7 | 122 (3) |
N2—N1—H1N | 122 (3) | C8—C7—H7 | 117 (3) |
C7—N2—N1 | 114.4 (3) | C7—C8—C9 | 115.5 (4) |
O1—N3—O2 | 124.8 (4) | C7—C8—H8A | 108.4 |
O1—N3—C4 | 118.7 (3) | C9—C8—H8A | 108.4 |
O2—N3—C4 | 116.6 (4) | C7—C8—H8B | 108.4 |
O3—N4—O4 | 122.6 (3) | C9—C8—H8B | 108.4 |
O3—N4—C2 | 119.2 (3) | H8A—C8—H8B | 107.5 |
O4—N4—C2 | 118.2 (3) | C10—C9—C8 | 113.0 (4) |
N1—C1—C2 | 124.0 (4) | C10—C9—H9A | 109.0 |
N1—C1—C6 | 120.1 (4) | C8—C9—H9A | 109.0 |
C2—C1—C6 | 115.8 (4) | C10—C9—H9B | 109.0 |
C3—C2—C1 | 122.5 (4) | C8—C9—H9B | 109.0 |
C3—C2—N4 | 115.9 (4) | H9A—C9—H9B | 107.8 |
C1—C2—N4 | 121.6 (4) | C11—C10—C9 | 114.0 (4) |
C4—C3—C2 | 118.5 (4) | C11—C10—H10A | 108.7 |
C4—C3—H3 | 120.8 | C9—C10—H10A | 108.7 |
C2—C3—H3 | 120.8 | C11—C10—H10B | 108.7 |
C3—C4—C5 | 121.3 (4) | C9—C10—H10B | 108.7 |
C3—C4—N3 | 118.8 (4) | H10A—C10—H10B | 107.6 |
C5—C4—N3 | 119.8 (4) | C10—C11—H11A | 109.5 |
C6—C5—C4 | 119.8 (4) | C10—C11—H11B | 109.5 |
C6—C5—H5 | 120.1 | H11A—C11—H11B | 109.5 |
C4—C5—H5 | 120.1 | C10—C11—H11C | 109.5 |
C5—C6—C1 | 121.9 (4) | H11A—C11—H11C | 109.5 |
C5—C6—H6 | 119.0 | H11B—C11—H11C | 109.5 |
C1—C6—H6 | 119.0 |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1n···O4 | 0.87 (4) | 1.99 (4) | 2.616 (5) | 128 (3) |
N1—H1n···O4i | 0.87 (4) | 2.41 (4) | 3.166 (5) | 146 (4) |
C3—H3···O1ii | 0.95 | 2.39 | 3.335 (5) | 176 |
C6—H6···N2 | 0.95 | 2.40 | 2.735 (5) | 100 |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x, y, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C11H14N4O4 |
Mr | 266.26 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 120 |
a, b, c (Å) | 31.162 (3), 4.4930 (4), 18.7329 (14) |
β (°) | 106.159 (4) |
V (Å3) | 2519.2 (4) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.32 × 0.03 × 0.02 |
Data collection | |
Diffractometer | -Nonius KappaCCD area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2007) |
Tmin, Tmax | 0.628, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8172, 2174, 1451 |
Rint | 0.115 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.078, 0.183, 1.10 |
No. of reflections | 2174 |
No. of parameters | 179 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
w = 1/[σ2(Fo2) + (0.0406P)2 + 14.6755P] where P = (Fo2 + 2Fc2)/3 | |
Δρmax, Δρmin (e Å−3) | 0.28, −0.27 |
Computer programs: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1n···O4 | 0.87 (4) | 1.99 (4) | 2.616 (5) | 128 (3) |
N1—H1n···O4i | 0.87 (4) | 2.41 (4) | 3.166 (5) | 146 (4) |
C3—H3···O1ii | 0.95 | 2.39 | 3.335 (5) | 176 |
C6—H6···N2 | 0.95 | 2.40 | 2.735 (5) | 100 |
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x, y, −z+1/2. |
Footnotes
‡Additional correspondence author, e-mail: j.wardell@abdn.ac.uk.
Acknowledgements
The use of the EPSRC X-ray crystallographic service at the University of Southampton, England and the valuable assistance of the staff there is gratefully acknowledged. JLW acknowledges support from CAPES (Brazil).
References
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2,4-Dinitrophenylhydrazine is a frequently used reagent for the characterization of aldehydes and ketones (Furniss et al., 1999). The 2,4-dinitrophenylhydrazone products are generally formed readily in good yield and purity. The ready formation of 2,4-dinitrophenyl hydrazones of carbonyl compounds can be a disadvantage as found during the attempted formation of a thiazolidinone from 2,4-dinitrophenylhydrazine, pentanal and mercaptoacetic acid, using a similar one-pot synthesis to that used successfully with amines, carbonyl compounds and mercaptoacetic acid (Neuenfeldt et al., 2009). Instead of the targeted thiazolidinone derivative, the 2,4-dinitrophenylhydrazone of pentanal was isolated in very high yield: as shown below, this compound was efficiently produced from a reaction mixture reaction just involving 2,4-dinitrophenylhydrazine and pentanal. Hydrazones containing the –NHN=CH moiety constitute an important class of antimicrobial, anticonvulsant, analgesic, antiinflammatory, antiplatelet, antitubercular and antitumoral agents. (Rollas & Küçükgüzel, 2007).
To a first approximation, the molecule of (I), Fig. 1, is flat with the maximum deviations of torsion angles from the ideal 0 or 180 ° being 9.0 (7) ° for N2–C7–C8–C9, and -170.7 (4) ° for C1–N1–N2–C7; the r.m.s. deviation of the non-hydrogen atoms = 0.152 Å. The n-butyl side-chain folds over to be oriented towards the benzene ring. The conformation about the C7═N3 bond [1.270 (5) Å] is E. In the crystal packing, supramolecular chains are formed along the c direction. These are sustained by four-membered {···H···O}2 synthons as the amine-H1n atom is bifurcated forming intra- and intermolecular N–H···Onitro hydrogen bonds, Fig. 2 and Table 1. Additional stabilization to the chain is afforded by ten-membered {···ONC2H}2 synthons, Fig. 2 and Table 1. Whereas the smaller of the synthons is disposed about a centre of inversion, the larger has crystallographic 2-fold symmetry and has a distinct folded conformation. The latter induces considerable kinks in the chain as emphasized in Fig. 3 which illustrates the formation of 2-D arrays via N–O···π interactions [N–O3···Cg(C1–C6)i = 3.163 (3) Å with an angle at O3 = 89.9 (2) ° where Cg is the ring centroid of the C1–C6 ring and symmetry operation i = x, -1 + y, z]. Globally, the layers formed in the bc plane stack along the a direction with interdigitation of the saturated residues. It is noted that the packing of molecules brings into close proximity two nitro-O atoms, i.e. O4···O4ii = 2.686 (4) Å for ii: -x, 1 - y, 1 - z. While the nature of this interaction is not obvious, there are approximately 50 precendents for such Onitro···Onitro contacts < 2.70 Å in the crystallographic literature (Allen, 2002).