organic compounds
1-Nitro-2,3-di-2-pyridyl-2,3-dihydroindolizine
aInstitute of Inorganic and Analytical Chemistry, Friedrich-Schiller-Universität Jena, August-Bebel-Strasse 2, D-07743 Jena, Germany
*Correspondence e-mail: m.we@uni-jena.de
The title compound, C18H14N4O2, was found as a by-product in the nitroaldol reaction between 2-(nitromethyl)pyridine and N-(pyridin-2-ylmethylidene)methaneamine. Its two stereogenic centers give rise to four of which only the anti isomers are found in this crystal structure.
Related literature
For the synthesis of 2-(nitromethyl)pyridine, see: Feuer & Lawrence (1972). For nitroaldol reactions, see: Cwik et al. (2005). For β-nitroamines, see Lucet et al. (1998). For comparison of bond lengths, see: Allen et al. (1987).
Experimental
Crystal data
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Data collection: COLLECT (Nonius, 1998); cell DENZO (Otwinowski & Minor, 1997); data reduction: DENZO and the SQUEEZE option (Sluis & Spek, 1990) in PLATON (Spek, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL/PC (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.
Supporting information
10.1107/S1600536809011842/bt2909sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809011842/bt2909Isup2.hkl
A nitroaldol reaction (Henry reaction) was carried out with 2-(nitromethyl)pyridine 1 (0.20 g; 1.4 mmol) and N-(pyridin-2-ylmethylidene)methaneamine 2 (0.15 g; 1.2 mmol) in 3.5 ml anhydrous THF with hydrotalcite Syntal 696 (0.13 g) as catalyst (Cwik et al., 2005). The mixture was stirred for eight hours at 60 °C and then cooled to r.t.. Then the solvent was removed in vacuo yielding a sticky brown residue. Thereafter 3 ml of diethylether were added and the yellow etheral solution was separated from the insoluble brownish residue, which was then dissolved in THF. From the latter solution yellow crystals of the title compound were obtained at r.t. (0.017 g). The compound is stable at room temperature and under atmospheric conditions. NMR measurements were carried out on a Bruker AC 200 and Bruker AC 400 spectrometer and referenced to the solvent resonances. Signals were assigned by DEPT 135, HSQC, HMBC experiments.
1H-NMR (CD2Cl2): δ = 8.59 (d, 1H, J = 4.0 Hz, H13), 8.55 (d, 1H, J = 4.0 Hz, H18), 8.30 (d, 1H, J = 8.8 Hz, H5), 7.80–7.77 (m, 1H, H11), 7.76–7.73 (m, 1H, H6), 7.69–7.65 (m, 1H, H16), 7.58 (d, 1H, J = 6.4 Hz, H8), 7.43 (d, 1H, J = 7.6 Hz, H12), 7.35–7.33 (m, 1H, H15), 7.33–7.31(m, 1H, H17), 7.23–7.20 (m, 1H, H19), 6.74–6.71 (m, 1H, H7), 6.08 (d, 1H, J = 4.0 Hz, H3), 4.89 (d, 1H, J = 4.0 Hz, H2);
13C-NMR (CD2Cl2): δ = 159.7 (q,C14), 157.5 (q,C4,C9), 150.7 (t,C13), 150.4 (q,C1), 150.1(t,C18), 142.2 (t,C6), 138.0 (t,C11), 137.3 (t,C8), 136.7 (t,C16), 124.5 (t,C15), 124.1 (t,C12), 122.8 (t,C10), 121.8 (t,C17), 119.6 (t,C5), 114.8 (t,C7), 75.3 (t,C3), 54.1 (t,C2).
All hydrogen atoms were calculated at idealized positions and were refined with 1.2 times the isotropic displacement parameter of the corresponding carbon atoms. At the final stage of
clear evidence of the presence of solvent voids of 201.00 Å 3 was obtained. Several trials to find a reasonable model for this were unfruitful. Thus, a correction for diffuse effects due to the inclusion of disordered solvent molecules in the was made using the the SQUEEZE option (van der Sluis & Spek, 1990) in the program PLATON (Spek, 2009). Further details are given in the cif.Data collection: COLLECT (Nonius, 1998); cell
DENZO (Otwinowski & Minor, 1997); data reduction: DENZO (Otwinowski & Minor, 1997) and the SQUEEZE option (Sluis & Spek, 1990) in PLATON (Spek, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL/PC (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).Fig. 1. Molecular structure an numbering scheme of 3. The ellipsoids represent a probability of 40%, H atoms are shown with arbitrary radii. | |
Fig. 2. The formation of the title compound. |
C18H14N4O2 | F(000) = 1364 |
Mr = 318.33 | Dx = 1.219 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 10925 reflections |
a = 28.0688 (19) Å | θ = 2.6–27.5° |
b = 7.9672 (6) Å | µ = 0.08 mm−1 |
c = 21.1859 (15) Å | T = 183 K |
β = 131.408 (4)° | Prism, light yellow |
V = 3553.4 (4) Å3 | 0.06 × 0.06 × 0.05 mm |
Z = 8 |
Nonius KappaCCD diffractometer | 2564 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.057 |
Graphite monochromator | θmax = 27.5°, θmin = 2.6° |
ϕ and ω scans | h = −36→36 |
10925 measured reflections | k = −10→8 |
4021 independent reflections | l = −22→27 |
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)] = 0.065 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.216 | H-atom parameters constrained |
S = 0.74 | w = 1/[σ2(Fo2) + (0.1821P)2 + 4.6408P] where P = (Fo2 + 2Fc2)/3 |
4021 reflections | (Δ/σ)max < 0.001 |
217 parameters | Δρmax = 0.28 e Å−3 |
0 restraints | Δρmin = −0.26 e Å−3 |
C18H14N4O2 | V = 3553.4 (4) Å3 |
Mr = 318.33 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 28.0688 (19) Å | µ = 0.08 mm−1 |
b = 7.9672 (6) Å | T = 183 K |
c = 21.1859 (15) Å | 0.06 × 0.06 × 0.05 mm |
β = 131.408 (4)° |
Nonius KappaCCD diffractometer | 2564 reflections with I > 2σ(I) |
10925 measured reflections | Rint = 0.057 |
4021 independent reflections |
R[F2 > 2σ(F2)] = 0.065 | 0 restraints |
wR(F2) = 0.216 | H-atom parameters constrained |
S = 0.74 | Δρmax = 0.28 e Å−3 |
4021 reflections | Δρmin = −0.26 e Å−3 |
217 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > σ(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 | 0.17598 (9) | 1.2960 (2) | 0.14775 (13) | 0.0452 (5) | |
O2 | 0.16787 (9) | 1.2549 (2) | 0.03788 (12) | 0.0485 (5) | |
N1 | 0.17260 (9) | 1.1975 (2) | 0.09773 (14) | 0.0371 (5) | |
N2 | 0.17010 (8) | 0.7804 (2) | 0.15264 (11) | 0.0298 (4) | |
N3 | 0.04544 (10) | 0.8231 (3) | −0.00295 (16) | 0.0518 (6) | |
N4 | 0.27897 (9) | 0.8055 (3) | 0.13515 (12) | 0.0357 (5) | |
C1 | 0.17419 (10) | 1.0305 (3) | 0.10757 (14) | 0.0325 (5) | |
C2 | 0.17024 (10) | 0.9055 (3) | 0.05051 (14) | 0.0323 (5) | |
H2A | 0.1348 | 0.9368 | −0.0097 | 0.039* | |
C3 | 0.15344 (10) | 0.7422 (3) | 0.07139 (14) | 0.0320 (5) | |
H3A | 0.1790 | 0.6456 | 0.0776 | 0.038* | |
C4 | 0.17739 (10) | 0.9488 (3) | 0.16928 (13) | 0.0309 (5) | |
C5 | 0.18579 (10) | 1.0032 (3) | 0.23890 (14) | 0.0338 (5) | |
H5A | 0.1914 | 1.1190 | 0.2528 | 0.041* | |
C6 | 0.18587 (11) | 0.8876 (3) | 0.28665 (15) | 0.0395 (6) | |
H6A | 0.1912 | 0.9242 | 0.3337 | 0.047* | |
C7 | 0.17820 (12) | 0.7160 (3) | 0.26747 (16) | 0.0408 (6) | |
H7A | 0.1781 | 0.6365 | 0.3008 | 0.049* | |
C8 | 0.17096 (11) | 0.6654 (3) | 0.20010 (15) | 0.0349 (5) | |
H8A | 0.1665 | 0.5496 | 0.1866 | 0.042* | |
C9 | 0.08294 (11) | 0.7031 (3) | 0.00711 (14) | 0.0344 (5) | |
C10 | 0.06039 (11) | 0.5554 (3) | −0.03744 (15) | 0.0385 (6) | |
H10A | 0.0886 | 0.4714 | −0.0278 | 0.046* | |
C11 | −0.00528 (12) | 0.5328 (3) | −0.09736 (17) | 0.0473 (7) | |
H11A | −0.0227 | 0.4328 | −0.1299 | 0.057* | |
C12 | −0.04402 (12) | 0.6548 (4) | −0.10870 (16) | 0.0451 (6) | |
H12A | −0.0889 | 0.6421 | −0.1494 | 0.054* | |
C13 | −0.01697 (13) | 0.7973 (4) | −0.0600 (2) | 0.0525 (7) | |
H13A | −0.0443 | 0.8817 | −0.0675 | 0.063* | |
C14 | 0.23253 (10) | 0.8989 (3) | 0.06895 (13) | 0.0317 (5) | |
C15 | 0.24114 (12) | 0.9906 (3) | 0.02183 (15) | 0.0394 (6) | |
H15A | 0.2071 | 1.0545 | −0.0250 | 0.047* | |
C16 | 0.29952 (13) | 0.9886 (3) | 0.04343 (17) | 0.0444 (6) | |
H16A | 0.3066 | 1.0520 | 0.0123 | 0.053* | |
C17 | 0.34797 (12) | 0.8915 (3) | 0.11200 (17) | 0.0437 (6) | |
H17A | 0.3887 | 0.8865 | 0.1286 | 0.052* | |
C18 | 0.33500 (12) | 0.8037 (3) | 0.15471 (16) | 0.0401 (6) | |
H18A | 0.3680 | 0.7373 | 0.2013 | 0.048* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0509 (11) | 0.0294 (9) | 0.0678 (12) | 0.0003 (7) | 0.0446 (10) | −0.0052 (8) |
O2 | 0.0574 (12) | 0.0393 (10) | 0.0642 (12) | 0.0097 (8) | 0.0467 (11) | 0.0178 (9) |
N1 | 0.0373 (11) | 0.0281 (10) | 0.0527 (12) | 0.0046 (8) | 0.0327 (10) | 0.0056 (9) |
N2 | 0.0270 (9) | 0.0276 (10) | 0.0322 (9) | −0.0005 (7) | 0.0185 (8) | 0.0000 (7) |
N3 | 0.0335 (11) | 0.0431 (13) | 0.0634 (14) | 0.0014 (9) | 0.0254 (11) | −0.0136 (11) |
N4 | 0.0336 (10) | 0.0381 (11) | 0.0356 (10) | −0.0006 (8) | 0.0229 (9) | 0.0012 (8) |
C1 | 0.0313 (11) | 0.0288 (12) | 0.0382 (12) | 0.0004 (9) | 0.0233 (10) | 0.0015 (9) |
C2 | 0.0326 (11) | 0.0305 (12) | 0.0303 (10) | 0.0002 (9) | 0.0193 (10) | 0.0020 (9) |
C3 | 0.0313 (11) | 0.0285 (11) | 0.0366 (11) | 0.0008 (9) | 0.0226 (10) | −0.0028 (9) |
C4 | 0.0253 (10) | 0.0260 (11) | 0.0363 (11) | 0.0020 (8) | 0.0182 (9) | 0.0006 (9) |
C5 | 0.0335 (11) | 0.0298 (12) | 0.0377 (12) | 0.0009 (9) | 0.0234 (10) | −0.0031 (9) |
C6 | 0.0384 (13) | 0.0440 (15) | 0.0386 (12) | 0.0032 (10) | 0.0266 (11) | 0.0006 (10) |
C7 | 0.0402 (13) | 0.0415 (14) | 0.0443 (13) | 0.0045 (10) | 0.0295 (12) | 0.0092 (11) |
C8 | 0.0333 (12) | 0.0282 (12) | 0.0420 (12) | 0.0001 (9) | 0.0244 (11) | 0.0026 (10) |
C9 | 0.0324 (12) | 0.0328 (12) | 0.0371 (12) | 0.0001 (9) | 0.0226 (10) | −0.0013 (9) |
C10 | 0.0377 (12) | 0.0325 (13) | 0.0449 (13) | −0.0023 (10) | 0.0272 (11) | −0.0042 (10) |
C11 | 0.0372 (13) | 0.0426 (15) | 0.0526 (15) | −0.0113 (11) | 0.0256 (12) | −0.0134 (12) |
C12 | 0.0303 (12) | 0.0531 (16) | 0.0452 (14) | −0.0063 (11) | 0.0221 (11) | −0.0039 (12) |
C13 | 0.0345 (13) | 0.0471 (16) | 0.0651 (17) | 0.0043 (11) | 0.0284 (13) | −0.0086 (13) |
C14 | 0.0352 (12) | 0.0307 (12) | 0.0305 (10) | −0.0021 (9) | 0.0223 (10) | −0.0032 (9) |
C15 | 0.0469 (14) | 0.0398 (14) | 0.0369 (12) | 0.0043 (11) | 0.0299 (12) | 0.0055 (10) |
C16 | 0.0566 (16) | 0.0427 (15) | 0.0532 (15) | −0.0055 (12) | 0.0445 (14) | −0.0008 (12) |
C17 | 0.0408 (13) | 0.0468 (15) | 0.0539 (15) | −0.0062 (11) | 0.0357 (13) | −0.0068 (12) |
C18 | 0.0357 (12) | 0.0430 (14) | 0.0410 (13) | 0.0024 (10) | 0.0252 (11) | 0.0015 (10) |
O1—N1 | 1.271 (3) | C6—H6A | 0.9500 |
O2—N1 | 1.269 (3) | C7—C8 | 1.363 (4) |
N1—C1 | 1.342 (3) | C7—H7A | 0.9500 |
N2—C8 | 1.349 (3) | C8—H8A | 0.9500 |
N2—C4 | 1.367 (3) | C9—C10 | 1.373 (3) |
N2—C3 | 1.487 (3) | C10—C11 | 1.395 (3) |
N3—C13 | 1.331 (3) | C10—H10A | 0.9500 |
N3—C9 | 1.331 (3) | C11—C12 | 1.356 (4) |
N4—C18 | 1.335 (3) | C11—H11A | 0.9500 |
N4—C14 | 1.342 (3) | C12—C13 | 1.377 (4) |
C1—C4 | 1.410 (3) | C12—H12A | 0.9500 |
C1—C2 | 1.513 (3) | C13—H13A | 0.9500 |
C2—C14 | 1.519 (3) | C14—C15 | 1.381 (3) |
C2—C3 | 1.545 (3) | C15—C16 | 1.380 (4) |
C2—H2A | 1.0000 | C15—H15A | 0.9500 |
C3—C9 | 1.517 (3) | C16—C17 | 1.394 (4) |
C3—H3A | 1.0000 | C16—H16A | 0.9500 |
C4—C5 | 1.400 (3) | C17—C18 | 1.370 (4) |
C5—C6 | 1.367 (3) | C17—H17A | 0.9500 |
C5—H5A | 0.9500 | C18—H18A | 0.9500 |
C6—C7 | 1.402 (4) | ||
O1—N1—O2 | 120.7 (2) | C6—C7—H7A | 120.7 |
O1—N1—C1 | 120.4 (2) | C7—C8—N2 | 119.8 (2) |
O2—N1—C1 | 118.9 (2) | C7—C8—H8A | 120.1 |
C8—N2—C4 | 123.25 (19) | N2—C8—H8A | 120.1 |
C8—N2—C3 | 124.12 (19) | N3—C9—C10 | 123.3 (2) |
C4—N2—C3 | 112.24 (18) | N3—C9—C3 | 114.8 (2) |
C13—N3—C9 | 117.5 (2) | C10—C9—C3 | 121.8 (2) |
C18—N4—C14 | 117.4 (2) | C9—C10—C11 | 117.9 (2) |
N1—C1—C4 | 125.2 (2) | C9—C10—H10A | 121.1 |
N1—C1—C2 | 123.4 (2) | C11—C10—H10A | 121.1 |
C4—C1—C2 | 111.29 (19) | C12—C11—C10 | 119.4 (2) |
C1—C2—C14 | 110.71 (18) | C12—C11—H11A | 120.3 |
C1—C2—C3 | 101.58 (17) | C10—C11—H11A | 120.3 |
C14—C2—C3 | 114.49 (18) | C11—C12—C13 | 118.6 (2) |
C1—C2—H2A | 109.9 | C11—C12—H12A | 120.7 |
C14—C2—H2A | 109.9 | C13—C12—H12A | 120.7 |
C3—C2—H2A | 109.9 | N3—C13—C12 | 123.4 (2) |
N2—C3—C9 | 107.82 (17) | N3—C13—H13A | 118.3 |
N2—C3—C2 | 103.72 (17) | C12—C13—H13A | 118.3 |
C9—C3—C2 | 112.33 (18) | N4—C14—C15 | 122.4 (2) |
N2—C3—H3A | 110.9 | N4—C14—C2 | 116.42 (19) |
C9—C3—H3A | 110.9 | C15—C14—C2 | 121.2 (2) |
C2—C3—H3A | 110.9 | C16—C15—C14 | 119.4 (2) |
N2—C4—C5 | 117.9 (2) | C16—C15—H15A | 120.3 |
N2—C4—C1 | 107.89 (19) | C14—C15—H15A | 120.3 |
C5—C4—C1 | 134.2 (2) | C15—C16—C17 | 118.6 (2) |
C6—C5—C4 | 119.2 (2) | C15—C16—H16A | 120.7 |
C6—C5—H5A | 120.4 | C17—C16—H16A | 120.7 |
C4—C5—H5A | 120.4 | C18—C17—C16 | 118.0 (2) |
C5—C6—C7 | 121.2 (2) | C18—C17—H17A | 121.0 |
C5—C6—H6A | 119.4 | C16—C17—H17A | 121.0 |
C7—C6—H6A | 119.4 | N4—C18—C17 | 124.2 (2) |
C8—C7—C6 | 118.7 (2) | N4—C18—H18A | 117.9 |
C8—C7—H7A | 120.7 | C17—C18—H18A | 117.9 |
O1—N1—C1—C4 | 2.2 (3) | C6—C7—C8—N2 | −1.2 (3) |
O2—N1—C1—C4 | −178.0 (2) | C4—N2—C8—C7 | 1.3 (3) |
O1—N1—C1—C2 | 179.84 (19) | C3—N2—C8—C7 | −170.9 (2) |
O2—N1—C1—C2 | −0.4 (3) | C13—N3—C9—C10 | −0.8 (4) |
N1—C1—C2—C14 | 74.7 (3) | C13—N3—C9—C3 | 178.4 (2) |
C4—C1—C2—C14 | −107.4 (2) | N2—C3—C9—N3 | 56.2 (3) |
N1—C1—C2—C3 | −163.3 (2) | C2—C3—C9—N3 | −57.5 (3) |
C4—C1—C2—C3 | 14.6 (2) | N2—C3—C9—C10 | −124.6 (2) |
C8—N2—C3—C9 | 69.8 (3) | C2—C3—C9—C10 | 121.8 (2) |
C4—N2—C3—C9 | −103.2 (2) | N3—C9—C10—C11 | 1.4 (4) |
C8—N2—C3—C2 | −170.94 (19) | C3—C9—C10—C11 | −177.8 (2) |
C4—N2—C3—C2 | 16.1 (2) | C9—C10—C11—C12 | −0.7 (4) |
C1—C2—C3—N2 | −17.3 (2) | C10—C11—C12—C13 | −0.4 (4) |
C14—C2—C3—N2 | 102.0 (2) | C9—N3—C13—C12 | −0.5 (5) |
C1—C2—C3—C9 | 98.8 (2) | C11—C12—C13—N3 | 1.0 (5) |
C14—C2—C3—C9 | −141.83 (19) | C18—N4—C14—C15 | 0.1 (3) |
C8—N2—C4—C5 | −0.3 (3) | C18—N4—C14—C2 | −177.2 (2) |
C3—N2—C4—C5 | 172.68 (18) | C1—C2—C14—N4 | 80.8 (2) |
C8—N2—C4—C1 | 179.81 (18) | C3—C2—C14—N4 | −33.3 (3) |
C3—N2—C4—C1 | −7.2 (2) | C1—C2—C14—C15 | −96.5 (2) |
N1—C1—C4—N2 | 172.5 (2) | C3—C2—C14—C15 | 149.4 (2) |
C2—C1—C4—N2 | −5.3 (2) | N4—C14—C15—C16 | −0.7 (4) |
N1—C1—C4—C5 | −7.3 (4) | C2—C14—C15—C16 | 176.4 (2) |
C2—C1—C4—C5 | 174.8 (2) | C14—C15—C16—C17 | 0.8 (4) |
N2—C4—C5—C6 | −0.5 (3) | C15—C16—C17—C18 | −0.4 (4) |
C1—C4—C5—C6 | 179.3 (2) | C14—N4—C18—C17 | 0.4 (4) |
C4—C5—C6—C7 | 0.5 (3) | C16—C17—C18—N4 | −0.3 (4) |
C5—C6—C7—C8 | 0.4 (4) |
Experimental details
Crystal data | |
Chemical formula | C18H14N4O2 |
Mr | 318.33 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 183 |
a, b, c (Å) | 28.0688 (19), 7.9672 (6), 21.1859 (15) |
β (°) | 131.408 (4) |
V (Å3) | 3553.4 (4) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.06 × 0.06 × 0.05 |
Data collection | |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10925, 4021, 2564 |
Rint | 0.057 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.065, 0.216, 0.74 |
No. of reflections | 4021 |
No. of parameters | 217 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.28, −0.26 |
Computer programs: COLLECT (Nonius, 1998), DENZO (Otwinowski & Minor, 1997) and the SQUEEZE option (Sluis & Spek, 1990) in PLATON (Spek, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL/PC (Sheldrick, 2008).
Acknowledgements
We thank the Deutsche Forschungsgemeinschaft (DFG, Bonn–Bad Godesberg, Germany) for generous financial support. We also acknowledge funding from the Fonds der Chemischen Industrie (Frankfurt/Main, Germany). Additionally we thank Südchemie AG (München, Germany) for providing the hydrotalcite Syntal 696.
References
Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19. CrossRef Web of Science Google Scholar
Cwik, A., Fuchs, A., Hell, Z. & Clacens, J. M. (2005). Tetrahedron, 61, 4015–4021. Web of Science CrossRef CAS Google Scholar
Feuer, H. & Lawrence, J. P. (1972). J. Org. Chem. 37, 3662–3670. CrossRef CAS Web of Science Google Scholar
Lucet, D., Gall, T. L. & Mioskowski, C. (1998). Angew. Chem. 110, 2724-2772. CrossRef Google Scholar
Nonius (1998). COLLECT, Nonius BV, Delft, The Netherlands. Google Scholar
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sluis, P. van der & Spek, A. L. (1990). Acta Cryst. A46, 194–201. CrossRef Web of Science IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
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β-nitroamines are promising precursors for vicinal diamines, which themselves are a versatile class of compounds (Lucet et al., 1998). The nitroaldol reaction between 2-(nitromethyl)pyridine 1 (Feuer & Lawrence, 1972) and N-(pyridin-2-ylmethylidene)methaneamine 2 yielded the title compound 3 as a byproduct together with methylamine. Although four stereo isomers are possible, only the anti-isomers are found in the crystal structure. The 2-pyridyl rings of neighbouring molecules are arrangend coplanarily with an approximate intermolecular distance of 3.70 Å. Not surprisingly the five-membered dihydroindolizine ring is strained and conjugation of the six-membered ring with the nitro group is observed regarding the bond lengths. They are found to lie between those for single and double bonds (Allen et al., 1987).