In the title compound, C
6H
6N
2O
4, the planar carboxyl group makes a dihedral angle of 74.61 (2)° with the uracil plane. In the crystal structure, intermolecular N—H
O and O—H
O hydrogen bonds link the molecules into a three-dimensional network.
Supporting information
CCDC reference: 282306
Key indicators
- Single-crystal X-ray study
- T = 298 K
- Mean (C-C) = 0.010 Å
- R factor = 0.066
- wR factor = 0.148
- Data-to-parameter ratio = 8.3
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ... 10
PLAT731_ALERT_1_C Bond Calc 0.83(6), Rep 0.82(2) ...... 3.00 su-Rat
O4 -H4 1.555 1.555
PLAT731_ALERT_1_C Bond Calc 0.84(7), Rep 0.84(2) ...... 3.50 su-Rat
N2 -H2 1.555 1.555
PLAT735_ALERT_1_C D-H Calc 0.83(6), Rep 0.82(2) ...... 3.00 su-Rat
O4 -H4 1.555 1.555
PLAT735_ALERT_1_C D-H Calc 0.84(7), Rep 0.84(2) ...... 3.50 su-Rat
N2 -H2 1.555 1.555
PLAT736_ALERT_1_C H...A Calc 2.00(7), Rep 2.00(3) ...... 2.33 su-Rat
H2 -O3 1.555 2.564
Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
correct. If it is not, please give the correct count in the
_publ_section_exptl_refinement section of the submitted CIF.
From the CIF: _diffrn_reflns_theta_max 25.24
From the CIF: _reflns_number_total 621
Count of symmetry unique reflns 621
Completeness (_total/calc) 100.00%
TEST3: Check Friedels for noncentro structure
Estimate of Friedel pairs measured 0
Fraction of Friedel pairs measured 0.000
Are heavy atom types Z>Si present no
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
6 ALERT level C = Check and explain
1 ALERT level G = General alerts; check
5 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
0 ALERT type 2 Indicator that the structure model may be wrong or deficient
1 ALERT type 3 Indicator that the structure quality may be low
1 ALERT type 4 Improvement, methodology, query or suggestion
Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2002); software used to prepare material for publication: SHELXL97.
1-(Carboxymethyl)uracil
top
Crystal data top
C6H6N2O4 | F(000) = 176 |
Mr = 170.13 | Dx = 1.669 Mg m−3 |
Monoclinic, Pc | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P -2yc | Cell parameters from 861 reflections |
a = 5.0999 (8) Å | θ = 2.8–24.8° |
b = 4.6273 (8) Å | µ = 0.14 mm−1 |
c = 15.0106 (19) Å | T = 298 K |
β = 107.093 (5)° | Rod, colourless |
V = 338.58 (9) Å3 | 0.21 × 0.11 × 0.10 mm |
Z = 2 | |
Data collection top
Bruker APEX area-detector diffractometer | 621 independent reflections |
Radiation source: fine-focus sealed tube | 607 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.035 |
φ and ω scans | θmax = 25.2°, θmin = 2.8° |
Absorption correction: multi-scan (SADABS; Bruker, 2002) | h = −6→6 |
Tmin = 0.971, Tmax = 0.983 | k = −5→5 |
3071 measured reflections | l = −17→18 |
Refinement top
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)] = 0.066 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.148 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.27 | w = 1/[σ2(Fo2) + (0.0727P)2 + 0.2892P] where P = (Fo2 + 2Fc2)/3 |
621 reflections | (Δ/σ)max < 0.001 |
75 parameters | Δρmax = 0.30 e Å−3 |
4 restraints | Δρmin = −0.31 e Å−3 |
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 >
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.9156 (10) | 0.3732 (10) | 0.5139 (3) | 0.0398 (13) | |
O2 | 0.4403 (10) | 0.9587 (11) | 0.2833 (3) | 0.0396 (13) | |
O3 | 0.9652 (10) | 0.5312 (11) | 0.7798 (3) | 0.0373 (12) | |
O4 | 0.9946 (9) | 0.8467 (10) | 0.6727 (3) | 0.0341 (12) | |
N1 | 0.5691 (10) | 0.6351 (11) | 0.5402 (3) | 0.0252 (12) | |
N2 | 0.6688 (11) | 0.6708 (13) | 0.3997 (4) | 0.0292 (13) | |
C1 | 0.7309 (12) | 0.5479 (13) | 0.4864 (4) | 0.0246 (14) | |
C2 | 0.4686 (13) | 0.8753 (13) | 0.3631 (5) | 0.0275 (14) | |
C3 | 0.3159 (13) | 0.9613 (16) | 0.4239 (5) | 0.0297 (15) | |
H3 | 0.1790 | 1.1003 | 0.4051 | 0.036* | |
C4 | 0.3702 (12) | 0.8410 (14) | 0.5085 (5) | 0.0292 (15) | |
H4A | 0.2685 | 0.8998 | 0.5476 | 0.035* | |
C5 | 0.6290 (14) | 0.5115 (14) | 0.6334 (4) | 0.0306 (15) | |
H5A | 0.6522 | 0.3044 | 0.6290 | 0.037* | |
H5B | 0.4720 | 0.5430 | 0.6562 | 0.037* | |
C6 | 0.8787 (12) | 0.6316 (13) | 0.7031 (4) | 0.0231 (13) | |
H2 | 0.741 (14) | 0.593 (14) | 0.362 (4) | 0.028* | |
H4 | 1.139 (9) | 0.873 (15) | 0.715 (4) | 0.028* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.039 (3) | 0.037 (3) | 0.041 (3) | 0.013 (2) | 0.009 (2) | 0.007 (2) |
O2 | 0.043 (3) | 0.048 (3) | 0.030 (2) | 0.015 (3) | 0.014 (2) | 0.015 (3) |
O3 | 0.042 (3) | 0.041 (3) | 0.028 (2) | −0.009 (2) | 0.0091 (19) | 0.013 (2) |
O4 | 0.040 (3) | 0.032 (2) | 0.027 (2) | −0.015 (2) | 0.006 (2) | 0.003 (2) |
N1 | 0.026 (3) | 0.023 (3) | 0.027 (3) | −0.001 (2) | 0.008 (2) | −0.001 (2) |
N2 | 0.034 (3) | 0.036 (3) | 0.020 (3) | 0.008 (3) | 0.012 (2) | −0.003 (2) |
C1 | 0.019 (3) | 0.017 (3) | 0.031 (3) | 0.001 (3) | −0.002 (2) | −0.009 (3) |
C2 | 0.027 (3) | 0.021 (3) | 0.033 (4) | 0.001 (3) | 0.006 (3) | −0.002 (3) |
C3 | 0.026 (3) | 0.026 (3) | 0.038 (4) | 0.002 (3) | 0.011 (3) | 0.000 (3) |
C4 | 0.027 (4) | 0.029 (3) | 0.035 (3) | −0.010 (3) | 0.015 (3) | −0.008 (3) |
C5 | 0.039 (4) | 0.022 (3) | 0.032 (3) | −0.003 (3) | 0.012 (3) | 0.004 (3) |
C6 | 0.032 (3) | 0.017 (3) | 0.027 (3) | 0.003 (3) | 0.019 (3) | 0.007 (3) |
Geometric parameters (Å, º) top
O1—C1 | 1.217 (7) | N2—C2 | 1.382 (8) |
O2—C2 | 1.227 (8) | N2—H2 | 0.84 (2) |
O3—C6 | 1.199 (7) | C2—C3 | 1.419 (10) |
O4—C6 | 1.306 (7) | C3—C4 | 1.339 (10) |
O4—H4 | 0.82 (2) | C3—H3 | 0.9300 |
N1—C4 | 1.371 (8) | C4—H4A | 0.9300 |
N1—C1 | 1.374 (8) | C5—C6 | 1.497 (10) |
N1—C5 | 1.459 (8) | C5—H5A | 0.9700 |
N2—C1 | 1.369 (9) | C5—H5B | 0.9700 |
| | | |
C6—O4—H4 | 104 (5) | C4—C3—H3 | 120.2 |
C4—N1—C1 | 120.8 (5) | C2—C3—H3 | 120.2 |
C4—N1—C5 | 122.0 (5) | C3—C4—N1 | 122.9 (6) |
C1—N1—C5 | 117.1 (5) | C3—C4—H4A | 118.6 |
C1—N2—C2 | 126.9 (5) | N1—C4—H4A | 118.6 |
C1—N2—H2 | 116 (5) | N1—C5—C6 | 114.9 (5) |
C2—N2—H2 | 116 (5) | N1—C5—H5A | 108.6 |
O1—C1—N2 | 122.6 (6) | C6—C5—H5A | 108.6 |
O1—C1—N1 | 122.3 (6) | N1—C5—H5B | 108.6 |
N2—C1—N1 | 115.1 (5) | C6—C5—H5B | 108.6 |
O2—C2—N2 | 117.7 (6) | H5A—C5—H5B | 107.5 |
O2—C2—C3 | 127.6 (6) | O3—C6—O4 | 123.6 (6) |
N2—C2—C3 | 114.7 (6) | O3—C6—C5 | 121.7 (6) |
C4—C3—C2 | 119.6 (6) | O4—C6—C5 | 114.7 (5) |
| | | |
C2—N2—C1—O1 | −178.3 (6) | N2—C2—C3—C4 | −1.0 (9) |
C2—N2—C1—N1 | 1.9 (9) | C2—C3—C4—N1 | −0.1 (10) |
C4—N1—C1—O1 | 177.3 (6) | C1—N1—C4—C3 | 2.1 (9) |
C5—N1—C1—O1 | 0.7 (9) | C5—N1—C4—C3 | 178.6 (6) |
C4—N1—C1—N2 | −2.9 (8) | C4—N1—C5—C6 | −101.4 (7) |
C5—N1—C1—N2 | −179.5 (5) | C1—N1—C5—C6 | 75.2 (7) |
C1—N2—C2—O2 | −179.2 (7) | N1—C5—C6—O3 | −173.2 (5) |
C1—N2—C2—C3 | 0.0 (9) | N1—C5—C6—O4 | 5.4 (8) |
O2—C2—C3—C4 | 178.1 (7) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O4—H4···O2i | 0.82 (2) | 1.76 (3) | 2.553 (7) | 160 (7) |
N2—H2···O3ii | 0.84 (2) | 2.00 (3) | 2.828 (7) | 169 (7) |
Symmetry codes: (i) x+1, −y+2, z+1/2; (ii) x, −y+1, z−1/2. |