organic compounds
[1-Methoxy-3-(pyridin-2-yl)indolizin-2-yl](pyridin-2-yl)methanone
aInstitut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humboldt-Strasse 8, 07743 Jena, Germany
*Correspondence e-mail: m.we@uni-jena.de
Methylation of [1-hydroxy-3-(pyridin-2-yl)indolizin-2-yl](pyridin-2-yl)methanone was performed via metalation with potassium tert-butanolate in toluene and a subsequent metathesis reaction with methyl iodide yielded the yellow title compound, C20H15N3O2. The substituents at the indolizine unit are twisted [the indolizine ring system makes dihedral angles of 34.67 (7) and 77.49 (5)°, respectively, with the pyridyl and pyridinoyl rings] with single bonds between the central unit and the attached pyridine ring [1.459 (3) Å] and the pyridinoyl group [1.483 (3) Å]. There are no classical hydrogen bonds in the crystal structure.
Related literature
Indolizines are used as dyes (Weidner et al., 1989), pharmaceuticals (Singh & Mmatli, 2011), and spectroscopic sensitizers (Gilchrist, 2001; Katrizky et al., 1999; Sarkunam & Nallu, 2005; Vemula et al., 2011; Weeler, 1985a,b). Indolizines are rather scarce in nature whereas the reduced form of these heteroaromatic bicyclic compounds, the indolizidines, are quite common, see: Michael (2007) and references therein. Well defined substitution patterns are required (Sarkunam & Nallu, 2005; Swinbourne et al., 1978; Uchida & Matsumoto, 1976) and therefore, different transition-metal mediated and metal-free strategies for the synthesis of substituted indolizines have been developed (Jacobs et al., 2011; Swinbourne et al., 1978; Kel'in et al., 2001; Kim et al., 2010; Liu et al., 2007; Morra et al., 2006; Seregin & Gevorgyan, 2006; Yan & Liu, 2007). Pyridinium N-methylides react with acetylenes or with ethylenes in the presence of an oxidant to make indolizines (Miki et al., 1984; Padwa et al., 1993; Wei et al., 1993). For of 1,1-diacetyl-2-(2-pyridyl)ethylene in acetic acid anhydride or in dimethylsulfoxide-yielding indolizines, see: Pohjala (1974, 1977).
Experimental
Crystal data
|
Data collection: COLLECT (Nonius, 1998); cell DENZO (Otwinowski, Minor, 1997); data reduction: DENZO; 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/S160053681203396X/gg2090sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S160053681203396X/gg2090Isup2.hkl
Supporting information file. DOI: 10.1107/S160053681203396X/gg2090Isup3.cml
[1-Hydroxy-3-(pyridin-2-yl)indolizin-2-yl](pyridin-2-yl)methanone (4.1 g, 13 mmol) was suspended in 120 ml of toluene. Potassium tert-butanolate (1.61 g, 14.33 mmol) was added and stirred for 18 h. To the resulting green reaction mixture, methyl iodide (890 µL, 14.33 mmol) was added drop-wise. Then the solution was stirred for 24 h. The reaction mixture was filtered. The removal of all volatiles from the filtrate gave a dark yellow solid. Yield: 4.05 g of 1 (12.27 mmol, 94%). – 1H NMR (200 MHz, 303 K, [D8]DMSO): δ = 8.81 (d, 1H); 8.47 (d, 1H); 8.32 (dt, 1H); 7.91 (m, 2H); 7.55(dd, 2H); 7.45 (m, 1H); 7.18 (d, 1H); 7.11 (dt, 1H); 6.80 (dt, 1H); 6.67 (dt, 1H); 3.75 (s, 3H). – MS (EI): m/z (%) = 329 (92) [M]+; 314 (100); 298 (6); 286 (6); 143 (16); 106 (33); 78 (72). – Elemental analysis for C20H15N3O2 (329.36): calcd. C72.94, H 4.59, N 12.76 found C 72.25, H 4.67 N 12.57.
The hydrogen atoms of the methyl-group C20 were set to idealized positions and were refined with 1.5 times the isotropic displacement parameter of the carbon atom. The methyl groups were allowed to rotate but not to tip. All other hydrogen atoms were located by difference Fourier synthesis and freely refined.
Data collection: COLLECT (Nonius, 1998); cell
DENZO (Otwinowski, Minor, 1997); data reduction: DENZO (Otwinowski, Minor, 1997); 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).C20H15N3O2 | F(000) = 1376 |
Mr = 329.35 | Dx = 1.364 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 10598 reflections |
a = 25.822 (2) Å | θ = 1.7–27.5° |
b = 11.4406 (9) Å | µ = 0.09 mm−1 |
c = 11.3602 (7) Å | T = 183 K |
β = 107.070 (4)° | Prism, brown |
V = 3208.2 (4) Å3 | 0.05 × 0.05 × 0.05 mm |
Z = 8 |
Nonius KappaCCD diffractometer | 2207 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.070 |
Graphite monochromator | θmax = 27.5°, θmin = 1.7° |
phi– + ω–scan | h = −29→33 |
10598 measured reflections | k = −14→14 |
3667 independent reflections | l = −14→13 |
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)] = 0.054 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.132 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0651P)2] where P = (Fo2 + 2Fc2)/3 |
3667 reflections | (Δ/σ)max < 0.001 |
275 parameters | Δρmax = 0.22 e Å−3 |
0 restraints | Δρmin = −0.28 e Å−3 |
C20H15N3O2 | V = 3208.2 (4) Å3 |
Mr = 329.35 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 25.822 (2) Å | µ = 0.09 mm−1 |
b = 11.4406 (9) Å | T = 183 K |
c = 11.3602 (7) Å | 0.05 × 0.05 × 0.05 mm |
β = 107.070 (4)° |
Nonius KappaCCD diffractometer | 2207 reflections with I > 2σ(I) |
10598 measured reflections | Rint = 0.070 |
3667 independent reflections |
R[F2 > 2σ(F2)] = 0.054 | 0 restraints |
wR(F2) = 0.132 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.22 e Å−3 |
3667 reflections | Δρmin = −0.28 e Å−3 |
275 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 | 0.04698 (6) | 0.09288 (12) | 0.06993 (13) | 0.0364 (4) | |
O2 | 0.12184 (6) | 0.12783 (12) | 0.35467 (12) | 0.0383 (4) | |
N1 | 0.15233 (6) | 0.26387 (13) | 0.01130 (13) | 0.0259 (4) | |
N2 | 0.22178 (7) | 0.32179 (13) | 0.33083 (14) | 0.0285 (4) | |
N3 | 0.08352 (7) | 0.41960 (14) | 0.28790 (15) | 0.0348 (4) | |
C1 | 0.18167 (9) | 0.29453 (18) | −0.06859 (18) | 0.0315 (5) | |
H1 | 0.2132 (10) | 0.3465 (18) | −0.0350 (19) | 0.042 (6)* | |
C2 | 0.16708 (9) | 0.25249 (19) | −0.18445 (19) | 0.0365 (5) | |
H2 | 0.1893 (9) | 0.2805 (18) | −0.238 (2) | 0.042 (6)* | |
C3 | 0.12207 (10) | 0.17639 (19) | −0.22799 (19) | 0.0381 (5) | |
H3 | 0.1124 (9) | 0.1416 (18) | −0.313 (2) | 0.039 (6)* | |
C4 | 0.09303 (9) | 0.14572 (17) | −0.15113 (17) | 0.0328 (5) | |
H4 | 0.0638 (9) | 0.0923 (18) | −0.1749 (18) | 0.032 (6)* | |
C5 | 0.10777 (8) | 0.18737 (16) | −0.02876 (17) | 0.0272 (4) | |
C6 | 0.08989 (8) | 0.16467 (15) | 0.07313 (17) | 0.0276 (4) | |
C7 | 0.12235 (8) | 0.22698 (15) | 0.17367 (16) | 0.0254 (4) | |
C8 | 0.16079 (8) | 0.28941 (15) | 0.13492 (16) | 0.0248 (4) | |
C9 | 0.20472 (8) | 0.35985 (16) | 0.21281 (16) | 0.0265 (4) | |
C10 | 0.22672 (9) | 0.45894 (18) | 0.17435 (19) | 0.0323 (5) | |
H10 | 0.2123 (9) | 0.4926 (19) | 0.095 (2) | 0.041 (6)* | |
C11 | 0.26848 (9) | 0.51716 (19) | 0.2576 (2) | 0.0388 (5) | |
H11 | 0.2828 (9) | 0.5875 (19) | 0.2335 (19) | 0.045 (6)* | |
C12 | 0.28677 (9) | 0.47791 (19) | 0.3779 (2) | 0.0383 (5) | |
H12 | 0.3157 (10) | 0.513 (2) | 0.442 (2) | 0.060 (7)* | |
C13 | 0.26168 (8) | 0.38150 (18) | 0.40973 (18) | 0.0328 (5) | |
H13 | 0.2725 (8) | 0.3486 (16) | 0.4960 (19) | 0.033 (5)* | |
C14 | 0.11818 (8) | 0.22114 (17) | 0.30094 (17) | 0.0270 (4) | |
C15 | 0.10492 (8) | 0.32971 (16) | 0.36106 (16) | 0.0271 (4) | |
C16 | 0.11300 (9) | 0.3300 (2) | 0.48702 (19) | 0.0372 (5) | |
H16 | 0.1298 (9) | 0.2654 (18) | 0.5342 (18) | 0.031 (5)* | |
C17 | 0.09646 (10) | 0.4251 (2) | 0.5409 (2) | 0.0424 (6) | |
H17 | 0.1002 (10) | 0.425 (2) | 0.629 (2) | 0.053 (7)* | |
C18 | 0.07292 (9) | 0.5171 (2) | 0.4673 (2) | 0.0404 (6) | |
H18 | 0.0603 (9) | 0.5834 (19) | 0.500 (2) | 0.045 (6)* | |
C19 | 0.06806 (10) | 0.5113 (2) | 0.3431 (2) | 0.0423 (6) | |
H19 | 0.0544 (10) | 0.576 (2) | 0.290 (2) | 0.056 (7)* | |
C20 | −0.00098 (11) | 0.1550 (2) | 0.0648 (3) | 0.0683 (8) | |
H20C | −0.0300 | 0.0995 | 0.0643 | 0.102* | |
H20B | −0.0117 | 0.2023 | −0.0104 | 0.102* | |
H20A | 0.0055 | 0.2061 | 0.1369 | 0.102* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0330 (9) | 0.0298 (8) | 0.0470 (9) | −0.0081 (6) | 0.0125 (7) | −0.0046 (6) |
O2 | 0.0521 (10) | 0.0285 (8) | 0.0367 (8) | −0.0005 (7) | 0.0169 (7) | 0.0041 (6) |
N1 | 0.0272 (9) | 0.0271 (9) | 0.0239 (8) | 0.0024 (7) | 0.0082 (7) | 0.0018 (7) |
N2 | 0.0298 (10) | 0.0293 (8) | 0.0260 (8) | −0.0013 (7) | 0.0074 (7) | −0.0022 (7) |
N3 | 0.0443 (11) | 0.0292 (9) | 0.0332 (9) | 0.0047 (8) | 0.0151 (8) | 0.0022 (8) |
C1 | 0.0309 (12) | 0.0356 (12) | 0.0302 (11) | 0.0044 (10) | 0.0123 (9) | 0.0043 (9) |
C2 | 0.0423 (13) | 0.0419 (13) | 0.0286 (11) | 0.0085 (10) | 0.0154 (10) | 0.0058 (10) |
C3 | 0.0507 (15) | 0.0377 (12) | 0.0248 (11) | 0.0066 (11) | 0.0091 (10) | −0.0013 (9) |
C4 | 0.0414 (14) | 0.0261 (11) | 0.0272 (11) | 0.0018 (10) | 0.0042 (9) | −0.0014 (9) |
C5 | 0.0292 (11) | 0.0221 (9) | 0.0290 (10) | 0.0023 (8) | 0.0067 (8) | −0.0016 (8) |
C6 | 0.0280 (11) | 0.0221 (10) | 0.0326 (10) | 0.0002 (8) | 0.0087 (8) | −0.0015 (8) |
C7 | 0.0273 (11) | 0.0215 (9) | 0.0272 (10) | 0.0026 (8) | 0.0079 (8) | 0.0003 (8) |
C8 | 0.0279 (11) | 0.0203 (9) | 0.0255 (9) | 0.0010 (8) | 0.0068 (8) | −0.0004 (8) |
C9 | 0.0289 (11) | 0.0256 (10) | 0.0266 (10) | 0.0021 (8) | 0.0105 (8) | −0.0015 (8) |
C10 | 0.0352 (12) | 0.0305 (11) | 0.0325 (11) | −0.0017 (9) | 0.0119 (9) | 0.0029 (9) |
C11 | 0.0369 (13) | 0.0300 (11) | 0.0514 (14) | −0.0090 (10) | 0.0159 (10) | −0.0018 (10) |
C12 | 0.0356 (13) | 0.0374 (12) | 0.0399 (12) | −0.0067 (10) | 0.0080 (10) | −0.0084 (10) |
C13 | 0.0347 (13) | 0.0337 (11) | 0.0289 (11) | −0.0004 (9) | 0.0076 (9) | −0.0032 (9) |
C14 | 0.0263 (11) | 0.0260 (10) | 0.0282 (10) | −0.0023 (8) | 0.0070 (8) | 0.0019 (8) |
C15 | 0.0280 (11) | 0.0258 (10) | 0.0297 (10) | −0.0048 (8) | 0.0119 (8) | −0.0003 (8) |
C16 | 0.0452 (14) | 0.0382 (12) | 0.0295 (11) | −0.0028 (11) | 0.0129 (10) | 0.0017 (10) |
C17 | 0.0554 (16) | 0.0420 (13) | 0.0342 (12) | −0.0089 (11) | 0.0199 (11) | −0.0096 (11) |
C18 | 0.0443 (14) | 0.0343 (12) | 0.0492 (14) | −0.0100 (11) | 0.0241 (11) | −0.0168 (11) |
C19 | 0.0497 (15) | 0.0322 (12) | 0.0485 (14) | 0.0073 (11) | 0.0202 (11) | 0.0026 (11) |
C20 | 0.0404 (16) | 0.0635 (18) | 0.109 (2) | −0.0123 (14) | 0.0349 (15) | −0.0344 (16) |
O1—C6 | 1.371 (2) | C8—C9 | 1.459 (3) |
O1—C20 | 1.414 (3) | C9—C10 | 1.395 (3) |
O2—C14 | 1.220 (2) | C10—C11 | 1.379 (3) |
N1—C1 | 1.387 (2) | C10—H10 | 0.95 (2) |
N1—C8 | 1.387 (2) | C11—C12 | 1.383 (3) |
N1—C5 | 1.411 (2) | C11—H11 | 0.96 (2) |
N2—C13 | 1.338 (2) | C12—C13 | 1.380 (3) |
N2—C9 | 1.354 (2) | C12—H12 | 0.97 (2) |
N3—C15 | 1.336 (2) | C13—H13 | 1.01 (2) |
N3—C19 | 1.341 (3) | C14—C15 | 1.505 (3) |
C1—C2 | 1.347 (3) | C15—C16 | 1.384 (3) |
C1—H1 | 0.99 (2) | C16—C17 | 1.376 (3) |
C2—C3 | 1.420 (3) | C16—H16 | 0.94 (2) |
C2—H2 | 1.00 (2) | C17—C18 | 1.371 (3) |
C3—C4 | 1.353 (3) | C17—H17 | 0.98 (2) |
C3—H3 | 1.01 (2) | C18—C19 | 1.382 (3) |
C4—C5 | 1.412 (3) | C18—H18 | 0.94 (2) |
C4—H4 | 0.95 (2) | C19—H19 | 0.96 (3) |
C5—C6 | 1.391 (3) | C20—H20C | 0.9800 |
C6—C7 | 1.398 (3) | C20—H20B | 0.9800 |
C7—C8 | 1.395 (3) | C20—H20A | 0.9800 |
C7—C14 | 1.483 (3) | ||
C6—O1—C20 | 113.04 (16) | C9—C10—H10 | 122.9 (13) |
C1—N1—C8 | 130.92 (17) | C10—C11—C12 | 119.5 (2) |
C1—N1—C5 | 119.75 (16) | C10—C11—H11 | 119.9 (13) |
C8—N1—C5 | 109.17 (15) | C12—C11—H11 | 120.4 (13) |
C13—N2—C9 | 117.51 (17) | C13—C12—C11 | 117.9 (2) |
C15—N3—C19 | 115.91 (17) | C13—C12—H12 | 116.9 (14) |
C2—C1—N1 | 119.9 (2) | C11—C12—H12 | 125.2 (14) |
C2—C1—H1 | 123.6 (12) | N2—C13—C12 | 124.12 (19) |
N1—C1—H1 | 116.4 (12) | N2—C13—H13 | 113.5 (11) |
C1—C2—C3 | 121.7 (2) | C12—C13—H13 | 122.3 (11) |
C1—C2—H2 | 115.6 (12) | O2—C14—C7 | 120.69 (17) |
C3—C2—H2 | 122.7 (12) | O2—C14—C15 | 119.34 (17) |
C4—C3—C2 | 119.1 (2) | C7—C14—C15 | 119.79 (16) |
C4—C3—H3 | 119.4 (12) | N3—C15—C16 | 123.41 (18) |
C2—C3—H3 | 121.5 (12) | N3—C15—C14 | 117.44 (16) |
C3—C4—C5 | 120.5 (2) | C16—C15—C14 | 119.08 (18) |
C3—C4—H4 | 122.0 (12) | C17—C16—C15 | 119.3 (2) |
C5—C4—H4 | 117.4 (12) | C17—C16—H16 | 121.3 (12) |
C6—C5—N1 | 106.62 (15) | C15—C16—H16 | 119.4 (12) |
C6—C5—C4 | 134.18 (19) | C18—C17—C16 | 118.4 (2) |
N1—C5—C4 | 119.05 (18) | C18—C17—H17 | 120.9 (14) |
O1—C6—C5 | 123.57 (16) | C16—C17—H17 | 120.6 (14) |
O1—C6—C7 | 127.84 (17) | C17—C18—C19 | 118.5 (2) |
C5—C6—C7 | 108.59 (17) | C17—C18—H18 | 121.3 (13) |
C8—C7—C6 | 108.36 (16) | C19—C18—H18 | 120.2 (13) |
C8—C7—C14 | 126.37 (16) | N3—C19—C18 | 124.4 (2) |
C6—C7—C14 | 125.17 (17) | N3—C19—H19 | 115.0 (14) |
N1—C8—C7 | 107.24 (15) | C18—C19—H19 | 120.6 (14) |
N1—C8—C9 | 126.40 (17) | O1—C20—H20C | 109.5 |
C7—C8—C9 | 126.14 (16) | O1—C20—H20B | 109.5 |
N2—C9—C10 | 121.83 (17) | H20C—C20—H20B | 109.5 |
N2—C9—C8 | 113.07 (16) | O1—C20—H20A | 109.5 |
C10—C9—C8 | 125.07 (17) | H20C—C20—H20A | 109.5 |
C11—C10—C9 | 119.08 (19) | H20B—C20—H20A | 109.5 |
C11—C10—H10 | 117.7 (13) |
Experimental details
Crystal data | |
Chemical formula | C20H15N3O2 |
Mr | 329.35 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 183 |
a, b, c (Å) | 25.822 (2), 11.4406 (9), 11.3602 (7) |
β (°) | 107.070 (4) |
V (Å3) | 3208.2 (4) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.05 × 0.05 × 0.05 |
Data collection | |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10598, 3667, 2207 |
Rint | 0.070 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.054, 0.132, 1.03 |
No. of reflections | 3667 |
No. of parameters | 275 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.22, −0.28 |
Computer programs: COLLECT (Nonius, 1998), DENZO (Otwinowski, Minor, 1997), 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).
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Indolizines which offer manifold applications as e.g. dyes (Weidner et al., 1989), pharmaceuticals (Singh & Mmatli, 2011), and spectral sensitizers (Gilchrist, 2001; Katritzky et al., 1999; Vemula et al., 2011; Sarkunam & Nallu, 2005; Weeler, 1985a,b) are rather scarce in nature whereas the reduced form of these heteroaromatic bicyclic compounds, the indolizidines, are quite common (Michael, 2007, and references therein). In these cases, i.e. the application of indolizines themselves or as intermediates in the synthesis of indolizidines, a well defined substitution pattern is required (Sarkunam & Nallu, 2005; Swinbourne et al., 1978; Uchida & Matsumoto, 1976) and different transition-metal mediated and metal-free strategies for the synthesis of substituted indolizines have been investigated (Jacobs et al., 2011; Kel'in et al., 2001; Kim et al., 2010; Liu et al., 2007; Morra et al., 2006; Seregin & Gevorgyan, 2006, Yan & Liu, 2007). The reaction of pyridinium N-methylides with acetylenes or with ethylenes in the presence of an oxidant causes limitations on the choice of substituents (Miki et al., 1984; Padwa et al., 1993) and applied oxidizers (Wei et al., 1993). Another pathway, namely the cyclization reaction of 1,1-diacetyl-2-(2-pyridyl)ethylene in acetic acid anhydride at 60 °C or in refluxing dimethylsulfoxide, has also yielded substituted indolizines (Pohjala, 1974 and 1977).