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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

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100013056/qa0395sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270100013056/qa0395Isup2.hkl
Contains datablock I

CCDC reference: 153946

Computing details top

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(1H,3H)-dione top
Crystal data top
C12H17FN2O3F(000) = 272
Mr = 256.28Dx = 1.347 Mg m3
Triclinic, P1Melting point: 63–65°C K
a = 5.4500 (11) ÅMo Kα radiation, λ = 0.71073 Å
b = 9.7410 (19) ÅCell parameters from 4236 reflections
c = 12.307 (3) Åθ = 1.0–25.4°
α = 80.27 (3)°µ = 0.11 mm1
β = 85.97 (3)°T = 173 K
γ = 79.13 (3)°Irregular plate-like fragment, colourless
V = 631.9 (2) Å30.32 × 0.20 × 0.04 mm
Z = 2
Data collection top
Nonius KappaCCD
diffractometer
1562 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.034
Graphite monochromatorθmax = 25.2°, θmin = 1.7°
Detector resolution: 18 pixels mm-1h = 66
ω scans at fixed χ = 55°k = 1111
4358 measured reflectionsl = 1414
2277 independent reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.041H-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 reflectionsΔρmax = 0.21 e Å3
165 parametersΔρmin = 0.20 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction 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
xyzUiso*/Ueq
N10.4938 (2)0.88612 (13)0.40804 (10)0.0211 (3)
C20.7381 (3)0.81445 (17)0.38701 (13)0.0239 (4)
O20.8867 (2)0.86322 (12)0.32137 (9)0.0330 (3)
N30.7978 (2)0.68201 (13)0.44892 (10)0.0245 (4)
H30.94470.63270.43310.029*
C40.6582 (3)0.61694 (18)0.53204 (13)0.0256 (4)
O40.7347 (2)0.49871 (11)0.58329 (9)0.0331 (3)
C50.4169 (3)0.70182 (17)0.55021 (13)0.0252 (4)
F50.26729 (17)0.64464 (10)0.63032 (7)0.0384 (3)
C60.3404 (3)0.82681 (17)0.49141 (12)0.0240 (4)
H60.17800.87750.50600.029*
O70.1924 (2)1.08259 (11)0.38610 (8)0.0304 (3)
C70.3881 (3)1.02401 (17)0.34910 (13)0.0235 (4)
C80.5234 (3)1.08731 (17)0.24820 (12)0.0270 (4)
H8A0.58381.01380.20120.032*
H8B0.67081.11990.27060.032*
C90.3553 (3)1.21184 (17)0.18167 (13)0.0288 (4)
H9A0.25141.26910.23300.035*
H9B0.46091.27290.13510.035*
C100.1859 (3)1.16378 (17)0.10863 (13)0.0312 (4)
H10A0.08161.10250.15570.037*
H10B0.29091.10580.05810.037*
C110.0148 (3)1.28433 (17)0.04029 (13)0.0319 (4)
H11A0.10311.33610.09070.038*
H11B0.11731.35130.00090.038*
C120.1340 (3)1.23524 (17)0.04105 (13)0.0322 (5)
H12A0.01571.18290.09100.039*
H12B0.23641.16840.00040.039*
C130.3045 (3)1.35377 (18)0.11009 (13)0.0362 (5)
H13A0.20181.41800.15480.043*
H13B0.41801.40910.06040.043*
C140.4600 (3)1.3013 (2)0.18645 (14)0.0421 (5)
H14A0.34901.24720.23650.063*
H14B0.56451.38240.22950.063*
H14C0.56691.24040.14270.063*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0153 (8)0.0227 (8)0.0238 (7)0.0000 (6)0.0011 (6)0.0041 (6)
C20.0201 (10)0.0266 (10)0.0254 (9)0.0017 (8)0.0020 (8)0.0076 (8)
O20.0213 (7)0.0362 (8)0.0360 (7)0.0001 (6)0.0051 (6)0.0012 (6)
N30.0166 (7)0.0234 (8)0.0307 (8)0.0022 (6)0.0026 (6)0.0041 (7)
C40.0216 (10)0.0259 (10)0.0291 (10)0.0022 (8)0.0012 (8)0.0061 (9)
O40.0284 (7)0.0263 (7)0.0393 (7)0.0022 (6)0.0018 (6)0.0009 (6)
C50.0208 (9)0.0272 (10)0.0262 (9)0.0048 (8)0.0055 (8)0.0029 (8)
F50.0291 (6)0.0337 (6)0.0444 (6)0.0009 (5)0.0108 (5)0.0056 (5)
C60.0169 (9)0.0278 (10)0.0272 (9)0.0012 (8)0.0015 (7)0.0084 (8)
O70.0242 (7)0.0291 (7)0.0335 (7)0.0030 (6)0.0038 (5)0.0030 (6)
C70.0209 (9)0.0242 (10)0.0255 (9)0.0021 (8)0.0041 (8)0.0051 (8)
C80.0258 (10)0.0266 (10)0.0275 (9)0.0026 (8)0.0000 (7)0.0038 (8)
C90.0286 (10)0.0284 (10)0.0266 (9)0.0026 (8)0.0016 (8)0.0000 (8)
C100.0321 (10)0.0282 (10)0.0314 (10)0.0039 (8)0.0015 (8)0.0009 (8)
C110.0329 (10)0.0315 (10)0.0300 (10)0.0036 (8)0.0020 (8)0.0037 (8)
C120.0318 (10)0.0329 (11)0.0309 (10)0.0038 (9)0.0003 (8)0.0052 (8)
C130.0393 (11)0.0367 (11)0.0322 (10)0.0060 (9)0.0063 (9)0.0029 (9)
C140.0409 (12)0.0516 (13)0.0350 (11)0.0102 (10)0.0057 (9)0.0063 (9)
Geometric parameters (Å, º) top
N1—C61.3950 (19)C5—F51.3490 (18)
N1—C21.410 (2)O7—C71.2084 (18)
N1—C71.449 (2)C7—C81.500 (2)
C2—O21.2074 (18)C8—C91.527 (2)
C2—N31.3766 (19)C9—C101.517 (2)
N3—C41.3714 (19)C10—C111.523 (2)
C4—O41.2282 (18)C11—C121.520 (2)
C4—C51.440 (2)C12—C131.514 (2)
C5—C61.316 (2)C13—C141.517 (2)
C6—N1—C2120.36 (14)F5—C5—C4116.15 (14)
C6—N1—C7115.90 (13)C5—C6—N1121.15 (15)
C2—N1—C7123.71 (13)O7—C7—N1116.73 (14)
O2—C2—N3121.57 (14)O7—C7—C8123.48 (15)
O2—C2—N1124.02 (15)N1—C7—C8119.78 (14)
N3—C2—N1114.41 (14)C7—C8—C9111.77 (14)
C4—N3—C2128.42 (14)C10—C9—C8112.19 (13)
O4—C4—N3122.42 (15)C9—C10—C11114.19 (14)
O4—C4—C5125.06 (16)C12—C11—C10113.52 (14)
N3—C4—C5112.53 (15)C13—C12—C11114.28 (14)
C6—C5—F5120.89 (14)C12—C13—C14113.15 (14)
C6—C5—C4122.95 (16)
 

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