organic compounds
Ethyl 4-acetyl-5-oxo-3-phenylhexanoate
aCollege of Chemistry and Materials Science, Anhui Key Laboratory of Molecular-Based Materials, Anhui Normal University, Wuhu, Anhui 241000, People's Republic of China
*Correspondence e-mail: yiminhu@yahoo.cn
The reaction of ethyl 3-bromo-3-phenylpropanoate with pentane-2,4-dione, in the presence of palladium(II) acetate and triphenylphosphine, in dimethylformamide, unexpectedly gave the title product, C16H20O4. The molecule contains one chiral C atom but the crystal is racemic. In the crystal, neighboring molecules form a chain along [100] through three weak C—H⋯O interactions. Furthermore, a double-stranded structure is formed through weak C—H⋯O interactions between two parallel chains.
Related literature
For Pd-catalysed coupling reactions, see: Hu et al. (2008); Hu, Ouyang et al. (2009); Hu, Yu et al. (2009). For the biological activity of pentane-2,4-dione derivatives, see: Vijaikumar & Pitchumani (2010). For related structures, see: Hu, Lin et al. (2010); Hu, Ren et al. (2010).
Experimental
Crystal data
|
Refinement
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Data collection: SMART (Bruker, 2000); cell SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S160053681100955X/bh2342sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S160053681100955X/bh2342Isup2.hkl
An oven-dried Schlenk flask was evacuated, filled with nitrogen, and then charged with pentane-2,4-dione (1.00 g, 10 mmol), ethyl-3-bromo-3-phenylpropanoate (2.82 g, 11 mmol), tributylamine (3 ml), PPh3 (52.5 mg, 0.2 mmol), Pd(OAc)2 (24 mg, 0.1 mmol), and DMF (10 ml) to give a yellow solution. The reaction mixture was heated at 373 K with stirring. The reaction mixture was cooled to room temperature after 22 h and the resulting yellow-orange mixture was diluted with Et2O (10 ml). The mixture was washed with H2O (15 ml) and the aqueous layer was extracted with Et2O (20 ml). The combined organic layers were dried (MgSO4), filtered, and concentrated in vacuo. The crude material was purified by flash
on silica gel (petroleum ether:EtOAc, 9:1) and recrystallized from EtOAc, yield 2.27 g (82%). Colorless crystals suitable for X-ray diffraction were obtained by recrystallization from a solution of the title compound from ethyl acetate, over a period of one week.H atoms were positioned geometrically and refined using a riding model (including
about the methyl C—C bond), with C—H = 0.93–0.97 Å and with Uiso(H) = 1.2 (1.5 for methyl groups) times Ueq(carrier C).Data collection: SMART (Bruker, 2000); cell
SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C16H20O4 | Z = 2 |
Mr = 276.32 | F(000) = 296 |
Triclinic, P1 | Dx = 1.192 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 5.8213 (11) Å | Cell parameters from 3519 reflections |
b = 7.7638 (18) Å | θ = 2.2–23.2° |
c = 17.8532 (15) Å | µ = 0.09 mm−1 |
α = 80.973 (2)° | T = 291 K |
β = 88.977 (3)° | Block, colourless |
γ = 75.033 (2)° | 0.28 × 0.24 × 0.22 mm |
V = 769.6 (2) Å3 |
Bruker SMART APEX CCD diffractometer | 3033 independent reflections |
Radiation source: sealed tube | 1726 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.050 |
ϕ and ω scans | θmax = 26.0°, θmin = 1.2° |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | h = −7→7 |
Tmin = 0.977, Tmax = 0.982 | k = −9→9 |
8564 measured reflections | l = −21→21 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.050 | H-atom parameters constrained |
wR(F2) = 0.099 | w = 1/[σ2(Fo2) + (0.03P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.07 | (Δ/σ)max < 0.001 |
3033 reflections | Δρmax = 0.16 e Å−3 |
185 parameters | Δρmin = −0.15 e Å−3 |
0 restraints | Extinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 constraints | Extinction coefficient: 0.017 (3) |
Primary atom site location: structure-invariant direct methods |
C16H20O4 | γ = 75.033 (2)° |
Mr = 276.32 | V = 769.6 (2) Å3 |
Triclinic, P1 | Z = 2 |
a = 5.8213 (11) Å | Mo Kα radiation |
b = 7.7638 (18) Å | µ = 0.09 mm−1 |
c = 17.8532 (15) Å | T = 291 K |
α = 80.973 (2)° | 0.28 × 0.24 × 0.22 mm |
β = 88.977 (3)° |
Bruker SMART APEX CCD diffractometer | 3033 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2000) | 1726 reflections with I > 2σ(I) |
Tmin = 0.977, Tmax = 0.982 | Rint = 0.050 |
8564 measured reflections |
R[F2 > 2σ(F2)] = 0.050 | 0 restraints |
wR(F2) = 0.099 | H-atom parameters constrained |
S = 1.07 | Δρmax = 0.16 e Å−3 |
3033 reflections | Δρmin = −0.15 e Å−3 |
185 parameters |
x | y | z | Uiso*/Ueq | ||
C1 | 0.9743 (3) | 0.8135 (3) | 0.22191 (11) | 0.0424 (5) | |
C2 | 0.8295 (4) | 0.7260 (3) | 0.19182 (11) | 0.0473 (5) | |
H2 | 0.7199 | 0.6823 | 0.2226 | 0.057* | |
C3 | 0.8438 (4) | 0.7019 (3) | 0.11675 (11) | 0.0463 (5) | |
H3 | 0.7450 | 0.6411 | 0.0978 | 0.056* | |
C4 | 1.0006 (4) | 0.7658 (3) | 0.07023 (12) | 0.0464 (5) | |
H4 | 1.0075 | 0.7507 | 0.0195 | 0.056* | |
C5 | 1.1474 (3) | 0.8521 (3) | 0.09850 (11) | 0.0463 (5) | |
H5 | 1.2557 | 0.8957 | 0.0671 | 0.056* | |
C6 | 1.1361 (3) | 0.8750 (3) | 0.17330 (11) | 0.0436 (5) | |
H6 | 1.2389 | 0.9329 | 0.1920 | 0.052* | |
C7 | 0.9534 (4) | 0.8488 (3) | 0.30314 (11) | 0.0411 (5) | |
H7 | 0.8304 | 0.7949 | 0.3272 | 0.049* | |
C8 | 0.8736 (3) | 1.0549 (3) | 0.30396 (11) | 0.0400 (5) | |
H8A | 0.8589 | 1.0774 | 0.3560 | 0.048* | |
H8B | 0.9929 | 1.1111 | 0.2802 | 0.048* | |
C9 | 0.6410 (3) | 1.1362 (3) | 0.26269 (11) | 0.0411 (5) | |
C10 | 0.4381 (4) | 1.3543 (3) | 0.16176 (11) | 0.0488 (5) | |
H10A | 0.4133 | 1.4844 | 0.1540 | 0.059* | |
H10B | 0.3032 | 1.3256 | 0.1887 | 0.059* | |
C11 | 0.4545 (4) | 1.2916 (3) | 0.08822 (11) | 0.0470 (5) | |
H11A | 0.5764 | 1.3323 | 0.0593 | 0.070* | |
H11B | 0.3048 | 1.3394 | 0.0612 | 0.070* | |
H11C | 0.4931 | 1.1621 | 0.0960 | 0.070* | |
C12 | 1.1855 (3) | 0.7662 (3) | 0.34946 (11) | 0.0409 (5) | |
H12 | 1.3046 | 0.8279 | 0.3281 | 0.049* | |
C13 | 1.2830 (3) | 0.5652 (3) | 0.34769 (11) | 0.0441 (5) | |
C14 | 1.1213 (4) | 0.4433 (3) | 0.36507 (12) | 0.0490 (5) | |
H14A | 1.2115 | 0.3200 | 0.3675 | 0.074* | |
H14B | 1.0003 | 0.4717 | 0.3259 | 0.074* | |
H14C | 1.0483 | 0.4599 | 0.4130 | 0.074* | |
C15 | 1.1577 (4) | 0.7879 (3) | 0.43302 (12) | 0.0498 (5) | |
C16 | 1.3691 (4) | 0.8014 (3) | 0.47412 (12) | 0.0471 (5) | |
H16A | 1.3837 | 0.9232 | 0.4638 | 0.071* | |
H16B | 1.5089 | 0.7214 | 0.4577 | 0.071* | |
H16C | 1.3520 | 0.7683 | 0.5276 | 0.071* | |
O1 | 0.4638 (2) | 1.0866 (2) | 0.27737 (8) | 0.0483 (4) | |
O2 | 0.6542 (2) | 1.2691 (2) | 0.20664 (8) | 0.0509 (4) | |
O3 | 1.4918 (2) | 0.50694 (19) | 0.33553 (7) | 0.0458 (4) | |
O4 | 0.9718 (2) | 0.7909 (2) | 0.46421 (8) | 0.0488 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0433 (11) | 0.0391 (11) | 0.0406 (10) | −0.0055 (9) | −0.0051 (8) | −0.0021 (8) |
C2 | 0.0545 (12) | 0.0471 (13) | 0.0438 (11) | −0.0141 (10) | −0.0010 (9) | −0.0156 (9) |
C3 | 0.0473 (12) | 0.0497 (12) | 0.0450 (11) | −0.0135 (10) | −0.0033 (9) | −0.0146 (9) |
C4 | 0.0454 (11) | 0.0485 (12) | 0.0480 (12) | −0.0147 (10) | −0.0068 (9) | −0.0103 (9) |
C5 | 0.0433 (12) | 0.0503 (13) | 0.0472 (12) | −0.0173 (10) | 0.0016 (9) | −0.0047 (9) |
C6 | 0.0412 (11) | 0.0426 (12) | 0.0476 (12) | −0.0110 (9) | −0.0007 (9) | −0.0080 (9) |
C7 | 0.0464 (11) | 0.0380 (11) | 0.0403 (11) | −0.0132 (9) | 0.0007 (8) | −0.0061 (8) |
C8 | 0.0374 (10) | 0.0419 (11) | 0.0428 (11) | −0.0108 (9) | 0.0021 (8) | −0.0122 (9) |
C9 | 0.0432 (12) | 0.0350 (11) | 0.0471 (11) | −0.0120 (9) | 0.0015 (9) | −0.0095 (8) |
C10 | 0.0559 (13) | 0.0427 (12) | 0.0440 (11) | −0.0128 (10) | −0.0086 (9) | 0.0062 (9) |
C11 | 0.0435 (11) | 0.0469 (12) | 0.0532 (12) | −0.0131 (9) | −0.0146 (9) | −0.0118 (10) |
C12 | 0.0341 (10) | 0.0470 (12) | 0.0445 (11) | −0.0182 (9) | 0.0047 (8) | −0.0034 (9) |
C13 | 0.0344 (11) | 0.0526 (12) | 0.0452 (11) | −0.0115 (9) | 0.0020 (8) | −0.0066 (9) |
C14 | 0.0525 (13) | 0.0453 (13) | 0.0474 (12) | −0.0148 (10) | 0.0069 (9) | 0.0013 (10) |
C15 | 0.0417 (12) | 0.0572 (14) | 0.0509 (12) | −0.0127 (10) | −0.0015 (10) | −0.0095 (10) |
C16 | 0.0522 (12) | 0.0447 (11) | 0.0487 (11) | −0.0125 (10) | −0.0114 (9) | −0.0183 (9) |
O1 | 0.0402 (8) | 0.0558 (9) | 0.0467 (8) | −0.0135 (7) | −0.0032 (6) | 0.0010 (7) |
O2 | 0.0538 (9) | 0.0545 (9) | 0.0414 (8) | −0.0152 (7) | −0.0036 (6) | 0.0040 (7) |
O3 | 0.0435 (8) | 0.0476 (9) | 0.0474 (8) | −0.0082 (6) | 0.0065 (6) | −0.0177 (6) |
O4 | 0.0493 (9) | 0.0499 (9) | 0.0495 (8) | −0.0138 (7) | 0.0131 (7) | −0.0142 (7) |
C1—C2 | 1.374 (3) | C10—O2 | 1.450 (2) |
C1—C6 | 1.393 (3) | C10—C11 | 1.464 (3) |
C1—C7 | 1.515 (3) | C10—H10A | 0.9700 |
C2—C3 | 1.380 (3) | C10—H10B | 0.9700 |
C2—H2 | 0.9300 | C11—H11A | 0.9600 |
C3—C4 | 1.359 (3) | C11—H11B | 0.9600 |
C3—H3 | 0.9300 | C11—H11C | 0.9600 |
C4—C5 | 1.360 (3) | C12—C13 | 1.522 (3) |
C4—H4 | 0.9300 | C12—C15 | 1.528 (3) |
C5—C6 | 1.373 (3) | C12—H12 | 0.9800 |
C5—H5 | 0.9300 | C13—O3 | 1.211 (2) |
C6—H6 | 0.9300 | C13—C14 | 1.495 (3) |
C7—C12 | 1.532 (3) | C14—H14A | 0.9600 |
C7—C8 | 1.549 (3) | C14—H14B | 0.9600 |
C7—H7 | 0.9800 | C14—H14C | 0.9600 |
C8—C9 | 1.491 (3) | C15—O4 | 1.205 (2) |
C8—H8A | 0.9700 | C15—C16 | 1.479 (3) |
C8—H8B | 0.9700 | C16—H16A | 0.9600 |
C9—O1 | 1.202 (2) | C16—H16B | 0.9600 |
C9—O2 | 1.337 (2) | C16—H16C | 0.9600 |
C2—C1—C6 | 116.86 (19) | C11—C10—H10A | 109.6 |
C2—C1—C7 | 121.89 (19) | O2—C10—H10B | 109.6 |
C6—C1—C7 | 121.21 (19) | C11—C10—H10B | 109.6 |
C1—C2—C3 | 121.2 (2) | H10A—C10—H10B | 108.1 |
C1—C2—H2 | 119.4 | C10—C11—H11A | 109.5 |
C3—C2—H2 | 119.4 | C10—C11—H11B | 109.5 |
C4—C3—C2 | 120.8 (2) | H11A—C11—H11B | 109.5 |
C4—C3—H3 | 119.6 | C10—C11—H11C | 109.5 |
C2—C3—H3 | 119.6 | H11A—C11—H11C | 109.5 |
C3—C4—C5 | 119.4 (2) | H11B—C11—H11C | 109.5 |
C3—C4—H4 | 120.3 | C13—C12—C15 | 106.57 (16) |
C5—C4—H4 | 120.3 | C13—C12—C7 | 113.03 (16) |
C4—C5—C6 | 120.2 (2) | C15—C12—C7 | 112.55 (16) |
C4—C5—H5 | 119.9 | C13—C12—H12 | 108.2 |
C6—C5—H5 | 119.9 | C15—C12—H12 | 108.2 |
C5—C6—C1 | 121.58 (19) | C7—C12—H12 | 108.2 |
C5—C6—H6 | 119.2 | O3—C13—C14 | 121.6 (2) |
C1—C6—H6 | 119.2 | O3—C13—C12 | 119.19 (18) |
C1—C7—C12 | 112.74 (16) | C14—C13—C12 | 119.09 (17) |
C1—C7—C8 | 109.58 (15) | C13—C14—H14A | 109.5 |
C12—C7—C8 | 109.89 (15) | C13—C14—H14B | 109.5 |
C1—C7—H7 | 108.2 | H14A—C14—H14B | 109.5 |
C12—C7—H7 | 108.2 | C13—C14—H14C | 109.5 |
C8—C7—H7 | 108.2 | H14A—C14—H14C | 109.5 |
C9—C8—C7 | 110.65 (15) | H14B—C14—H14C | 109.5 |
C9—C8—H8A | 109.5 | O4—C15—C16 | 121.6 (2) |
C7—C8—H8A | 109.5 | O4—C15—C12 | 121.10 (18) |
C9—C8—H8B | 109.5 | C16—C15—C12 | 117.33 (19) |
C7—C8—H8B | 109.5 | C15—C16—H16A | 109.5 |
H8A—C8—H8B | 108.1 | C15—C16—H16B | 109.5 |
O1—C9—O2 | 124.06 (18) | H16A—C16—H16B | 109.5 |
O1—C9—C8 | 124.11 (18) | C15—C16—H16C | 109.5 |
O2—C9—C8 | 111.82 (16) | H16A—C16—H16C | 109.5 |
O2—C10—C11 | 110.33 (17) | H16B—C16—H16C | 109.5 |
O2—C10—H10A | 109.6 | C9—O2—C10 | 116.13 (15) |
C6—C1—C2—C3 | −0.4 (3) | C1—C7—C12—C13 | −54.2 (2) |
C7—C1—C2—C3 | 177.12 (18) | C8—C7—C12—C13 | −176.77 (16) |
C1—C2—C3—C4 | −0.7 (3) | C1—C7—C12—C15 | −175.02 (18) |
C2—C3—C4—C5 | 1.0 (3) | C8—C7—C12—C15 | 62.4 (2) |
C3—C4—C5—C6 | −0.3 (3) | C15—C12—C13—O3 | −102.9 (2) |
C4—C5—C6—C1 | −0.8 (3) | C7—C12—C13—O3 | 132.96 (18) |
C2—C1—C6—C5 | 1.1 (3) | C15—C12—C13—C14 | 73.9 (2) |
C7—C1—C6—C5 | −176.43 (18) | C7—C12—C13—C14 | −50.2 (2) |
C2—C1—C7—C12 | 122.1 (2) | C13—C12—C15—O4 | −93.4 (2) |
C6—C1—C7—C12 | −60.5 (2) | C7—C12—C15—O4 | 31.0 (3) |
C2—C1—C7—C8 | −115.2 (2) | C13—C12—C15—C16 | 85.4 (2) |
C6—C1—C7—C8 | 62.2 (2) | C7—C12—C15—C16 | −150.14 (18) |
C1—C7—C8—C9 | 58.7 (2) | O1—C9—O2—C10 | −0.5 (3) |
C12—C7—C8—C9 | −176.91 (16) | C8—C9—O2—C10 | 178.60 (17) |
C7—C8—C9—O1 | 55.4 (3) | C11—C10—O2—C9 | −103.9 (2) |
C7—C8—C9—O2 | −123.67 (17) |
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6···O1i | 0.93 | 2.63 | 3.534 (2) | 165 |
C8—H8B···O1i | 0.97 | 2.70 | 3.525 (2) | 144 |
C12—H12···O1i | 0.98 | 2.46 | 3.387 (2) | 157 |
C14—H14C···O4ii | 0.96 | 2.72 | 3.405 (2) | 129 |
Symmetry codes: (i) x+1, y, z; (ii) −x+2, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C16H20O4 |
Mr | 276.32 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 291 |
a, b, c (Å) | 5.8213 (11), 7.7638 (18), 17.8532 (15) |
α, β, γ (°) | 80.973 (2), 88.977 (3), 75.033 (2) |
V (Å3) | 769.6 (2) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.28 × 0.24 × 0.22 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2000) |
Tmin, Tmax | 0.977, 0.982 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8564, 3033, 1726 |
Rint | 0.050 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.050, 0.099, 1.07 |
No. of reflections | 3033 |
No. of parameters | 185 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.16, −0.15 |
Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2000), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C6—H6···O1i | 0.93 | 2.63 | 3.534 (2) | 165 |
C8—H8B···O1i | 0.97 | 2.70 | 3.525 (2) | 144 |
C12—H12···O1i | 0.98 | 2.46 | 3.387 (2) | 157 |
C14—H14C···O4ii | 0.96 | 2.72 | 3.405 (2) | 129 |
Symmetry codes: (i) x+1, y, z; (ii) −x+2, −y+1, −z+1. |
Acknowledgements
We thank the National Science Foundation of China (project Nos. 21072003 and 20872002) for financial support for this work.
References
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Palladium-catalyzed coupling reactions have become an important tool in modern organic synthesis chemistry (Hu et al. 2008). They have made a wide variety of active pharmaceutical ingredients, natural substances and other complex organic molecules economically accessible (Hu & Yu et al., 2009; Hu, Ouyang et al., 2009). The pentane-2,4-dione derivatives, which have physiological activity, are effective intermediates in the synthesis of many complex natural products (Vijaikumar & Pitchumani, 2010). We have reported some novel palladium-catalyzed intermolecular and intramolecular reactions of aryl halides with the olefins and diynes (Hu, Lin et al., 2010; Hu, Ren et al., 2010). The reaction of ethyl 3-bromo-3-phenylpropanoate with pentane-2,4-dione, in the presence of palladium(II) acetate and triphenylphosphine, in DMF at 373 K for 22 h, gave the unexpected title product.
The molecular structure of the title compound, C16H20O4, reveals that all the bond lengths and angles have normal values. As shown in Fig. 1, one chiral carbon, C7, was observed in the molecule. Due to the existence of inversion centers in the crystal packing, the C7 atoms exhibit R-conformation in the half of the molecules, and display S-conformation in the other half of the molecules. So the whole crystal is racemic (Fig. 4). In the crystal packing, the weak C—H···O interactions play important roles. Neighboring molecules form a one dimensional chain through the weak C6—H6···O1ii, C8—H8b···O1ii and C12—H12···O1ii (ii: 1+x, y, z) interactions (Fig. 2). Furthermore, two neighboring chains are parallel to each other to form a double-stranded structure through the weak C14—H14C···O4i (i: 2-x, 1-y, 1-z) interactions (Fig. 3).