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The crystal structure of 5-fluoro-1-octanoyluracil [5-fluoro-1-octanoylpyrimidine-2,4(1H,3H)-dione, C12H17FN2O3], a lipophilic prodrug of 5-fluorouracil, is described. The 5-fluoropyrimidine-2,4(1H,3H)-dione moiety is similar to the known structure of 1-acetyl-5-fluorouracil. The 1-octanoyl group and the 5-fluorouracil moiety are essentially coplanar, with the octanoyl carbonyl group oriented towards the the ring C-H group and away from the nearer ring carbonyl group. The torsion angle C-N-C-O (from the ring CH group to the octanoyl carbonyl group) of 9.2 (2)° is similar to the corresponding torsion angles reported for 1-acetyl-5-fluorouracil (17.3 and 1.6°) and 1,3-diacetyl-5-fluorouracil (8.8°).
Supporting information
CCDC reference: 153946
Data collection: COLLECT (Nonius, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO-SMN (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997) and local programs.
5-fluoro-1-octanoylpyrimidine-2,4(1
H,3H)-dione
top
Crystal data top
C12H17FN2O3 | F(000) = 272 |
Mr = 256.28 | Dx = 1.347 Mg m−3 |
Triclinic, P1 | Melting point: 63–65°C K |
a = 5.4500 (11) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 9.7410 (19) Å | Cell parameters from 4236 reflections |
c = 12.307 (3) Å | θ = 1.0–25.4° |
α = 80.27 (3)° | µ = 0.11 mm−1 |
β = 85.97 (3)° | T = 173 K |
γ = 79.13 (3)° | Irregular plate-like fragment, colourless |
V = 631.9 (2) Å3 | 0.32 × 0.20 × 0.04 mm |
Z = 2 | |
Data collection top
Nonius KappaCCD diffractometer | 1562 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.034 |
Graphite monochromator | θmax = 25.2°, θmin = 1.7° |
Detector resolution: 18 pixels mm-1 | h = −6→6 |
ω scans at fixed χ = 55° | k = −11→11 |
4358 measured reflections | l = −14→14 |
2277 independent reflections | |
Refinement top
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)] = 0.041 | H-atom parameters constrained |
wR(F2) = 0.100 | w = 1/[σ2(Fo2) + (0.0424P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max < 0.001 |
2277 reflections | Δρmax = 0.21 e Å−3 |
165 parameters | Δρmin = −0.20 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.048 (5) |
Special details top
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 >
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. The torsion angle of methyl hydrogen atoms was assigned
via the SHELXL97 instruction AFIX 137. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
N1 | 0.4938 (2) | 0.88612 (13) | 0.40804 (10) | 0.0211 (3) | |
C2 | 0.7381 (3) | 0.81445 (17) | 0.38701 (13) | 0.0239 (4) | |
O2 | 0.8867 (2) | 0.86322 (12) | 0.32137 (9) | 0.0330 (3) | |
N3 | 0.7978 (2) | 0.68201 (13) | 0.44892 (10) | 0.0245 (4) | |
H3 | 0.9447 | 0.6327 | 0.4331 | 0.029* | |
C4 | 0.6582 (3) | 0.61694 (18) | 0.53204 (13) | 0.0256 (4) | |
O4 | 0.7347 (2) | 0.49871 (11) | 0.58329 (9) | 0.0331 (3) | |
C5 | 0.4169 (3) | 0.70182 (17) | 0.55021 (13) | 0.0252 (4) | |
F5 | 0.26729 (17) | 0.64464 (10) | 0.63032 (7) | 0.0384 (3) | |
C6 | 0.3404 (3) | 0.82681 (17) | 0.49141 (12) | 0.0240 (4) | |
H6 | 0.1780 | 0.8775 | 0.5060 | 0.029* | |
O7 | 0.1924 (2) | 1.08259 (11) | 0.38610 (8) | 0.0304 (3) | |
C7 | 0.3881 (3) | 1.02401 (17) | 0.34910 (13) | 0.0235 (4) | |
C8 | 0.5234 (3) | 1.08731 (17) | 0.24820 (12) | 0.0270 (4) | |
H8A | 0.5838 | 1.0138 | 0.2012 | 0.032* | |
H8B | 0.6708 | 1.1199 | 0.2706 | 0.032* | |
C9 | 0.3553 (3) | 1.21184 (17) | 0.18167 (13) | 0.0288 (4) | |
H9A | 0.2514 | 1.2691 | 0.2330 | 0.035* | |
H9B | 0.4609 | 1.2729 | 0.1351 | 0.035* | |
C10 | 0.1859 (3) | 1.16378 (17) | 0.10863 (13) | 0.0312 (4) | |
H10A | 0.0816 | 1.1025 | 0.1557 | 0.037* | |
H10B | 0.2909 | 1.1058 | 0.0581 | 0.037* | |
C11 | 0.0148 (3) | 1.28433 (17) | 0.04029 (13) | 0.0319 (4) | |
H11A | −0.1031 | 1.3361 | 0.0907 | 0.038* | |
H11B | 0.1173 | 1.3513 | −0.0009 | 0.038* | |
C12 | −0.1340 (3) | 1.23524 (17) | −0.04105 (13) | 0.0322 (5) | |
H12A | −0.0157 | 1.1829 | −0.0910 | 0.039* | |
H12B | −0.2364 | 1.1684 | 0.0004 | 0.039* | |
C13 | −0.3045 (3) | 1.35377 (18) | −0.11009 (13) | 0.0362 (5) | |
H13A | −0.2018 | 1.4180 | −0.1548 | 0.043* | |
H13B | −0.4180 | 1.4091 | −0.0604 | 0.043* | |
C14 | −0.4600 (3) | 1.3013 (2) | −0.18645 (14) | 0.0421 (5) | |
H14A | −0.3490 | 1.2472 | −0.2365 | 0.063* | |
H14B | −0.5645 | 1.3824 | −0.2295 | 0.063* | |
H14C | −0.5669 | 1.2404 | −0.1427 | 0.063* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.0153 (8) | 0.0227 (8) | 0.0238 (7) | 0.0000 (6) | 0.0011 (6) | −0.0041 (6) |
C2 | 0.0201 (10) | 0.0266 (10) | 0.0254 (9) | −0.0017 (8) | −0.0020 (8) | −0.0076 (8) |
O2 | 0.0213 (7) | 0.0362 (8) | 0.0360 (7) | −0.0001 (6) | 0.0051 (6) | 0.0012 (6) |
N3 | 0.0166 (7) | 0.0234 (8) | 0.0307 (8) | 0.0022 (6) | 0.0026 (6) | −0.0041 (7) |
C4 | 0.0216 (10) | 0.0259 (10) | 0.0291 (10) | −0.0022 (8) | −0.0012 (8) | −0.0061 (9) |
O4 | 0.0284 (7) | 0.0263 (7) | 0.0393 (7) | 0.0022 (6) | 0.0018 (6) | 0.0009 (6) |
C5 | 0.0208 (9) | 0.0272 (10) | 0.0262 (9) | −0.0048 (8) | 0.0055 (8) | −0.0029 (8) |
F5 | 0.0291 (6) | 0.0337 (6) | 0.0444 (6) | −0.0009 (5) | 0.0108 (5) | 0.0056 (5) |
C6 | 0.0169 (9) | 0.0278 (10) | 0.0272 (9) | −0.0012 (8) | 0.0015 (7) | −0.0084 (8) |
O7 | 0.0242 (7) | 0.0291 (7) | 0.0335 (7) | 0.0030 (6) | 0.0038 (5) | −0.0030 (6) |
C7 | 0.0209 (9) | 0.0242 (10) | 0.0255 (9) | −0.0021 (8) | −0.0041 (8) | −0.0051 (8) |
C8 | 0.0258 (10) | 0.0266 (10) | 0.0275 (9) | −0.0026 (8) | 0.0000 (7) | −0.0038 (8) |
C9 | 0.0286 (10) | 0.0284 (10) | 0.0266 (9) | −0.0026 (8) | 0.0016 (8) | 0.0000 (8) |
C10 | 0.0321 (10) | 0.0282 (10) | 0.0314 (10) | −0.0039 (8) | −0.0015 (8) | −0.0009 (8) |
C11 | 0.0329 (10) | 0.0315 (10) | 0.0300 (10) | −0.0036 (8) | −0.0020 (8) | −0.0037 (8) |
C12 | 0.0318 (10) | 0.0329 (11) | 0.0309 (10) | −0.0038 (9) | 0.0003 (8) | −0.0052 (8) |
C13 | 0.0393 (11) | 0.0367 (11) | 0.0322 (10) | −0.0060 (9) | −0.0063 (9) | −0.0029 (9) |
C14 | 0.0409 (12) | 0.0516 (13) | 0.0350 (11) | −0.0102 (10) | −0.0057 (9) | −0.0063 (9) |
Geometric parameters (Å, º) top
N1—C6 | 1.3950 (19) | C5—F5 | 1.3490 (18) |
N1—C2 | 1.410 (2) | O7—C7 | 1.2084 (18) |
N1—C7 | 1.449 (2) | C7—C8 | 1.500 (2) |
C2—O2 | 1.2074 (18) | C8—C9 | 1.527 (2) |
C2—N3 | 1.3766 (19) | C9—C10 | 1.517 (2) |
N3—C4 | 1.3714 (19) | C10—C11 | 1.523 (2) |
C4—O4 | 1.2282 (18) | C11—C12 | 1.520 (2) |
C4—C5 | 1.440 (2) | C12—C13 | 1.514 (2) |
C5—C6 | 1.316 (2) | C13—C14 | 1.517 (2) |
| | | |
C6—N1—C2 | 120.36 (14) | F5—C5—C4 | 116.15 (14) |
C6—N1—C7 | 115.90 (13) | C5—C6—N1 | 121.15 (15) |
C2—N1—C7 | 123.71 (13) | O7—C7—N1 | 116.73 (14) |
O2—C2—N3 | 121.57 (14) | O7—C7—C8 | 123.48 (15) |
O2—C2—N1 | 124.02 (15) | N1—C7—C8 | 119.78 (14) |
N3—C2—N1 | 114.41 (14) | C7—C8—C9 | 111.77 (14) |
C4—N3—C2 | 128.42 (14) | C10—C9—C8 | 112.19 (13) |
O4—C4—N3 | 122.42 (15) | C9—C10—C11 | 114.19 (14) |
O4—C4—C5 | 125.06 (16) | C12—C11—C10 | 113.52 (14) |
N3—C4—C5 | 112.53 (15) | C13—C12—C11 | 114.28 (14) |
C6—C5—F5 | 120.89 (14) | C12—C13—C14 | 113.15 (14) |
C6—C5—C4 | 122.95 (16) | | |
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