organic compounds
6-(2-Methylpropyl)-4-oxo-2-sulfanylidene-1,2,3,4-tetrahydropyrimidine-5-carbonitrile
aDepartment of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia, bDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia, and cChemistry Department, Faculty of Science, King Abdulaziz University, PO Box 80203 Jeddah, Saudi Arabia
*Correspondence e-mail: edward.tiekink@gmail.com
The title thiouracil derivative, C9H11N3OS, exists in the thione form. The six atoms comprising the ring are almost coplanar [r.m.s. deviation = 0.015 Å] and the 2-methylpropyl group lies approximately perpendicular to this plane [the N—C—C—C torsion angle is 72.88 (14)°]. Linear supramolecular chains along [001] sustained by N—H⋯O and N—H⋯S hydrogen bonding feature in the crystal packing.
Related literature
For the biological activity of uracil and pyrimidine derivatives see: Ding et al. (2006); Hawser et al., (2006); Brunelle et al. (2007); Al-Safarjalani et al. (2005); Al-Omar et al. (2010); Al-Abdullah et al. (2011); Al-Turkistani et al. (2011). For related uracil structures, see: Tiekink (1989); Nasir et al. (2010); El-Emam et al. (2011).
Experimental
Crystal data
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Refinement
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Data collection: CrysAlis PRO (Agilent, 2011); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).
Supporting information
10.1107/S1600536812005119/hg5174sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812005119/hg5174Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812005119/hg5174Isup3.cml
A mixture of 3-methylbutanal (8.61 g, 0.1 mol), ethyl cyanoacetate (11.31 g, 0.1 mol), thiourea (7.61 g, 0.1 mol) and potassium carbonate (13.8 g, 0.1 mol) was heated in in ethanol (300 ml) under reflux for 6 h. On cooling, the separated precipitate was filtered, washed with diethyl ether and dried. The obtained solid was added to water (200 ml) and the mixture was heated at 283–293 K until a clear solution was obtained. The solution was acidified with acetic acid and stirred for 30 min. The deposited precipitate was filtered, washed with cold water, dried and crystallized from acetic acid to yield 5.86 g (28%) of the title compound (I) as colourless crystals. m.p. 545–547. 1H NMR (DMSO-d6): δ 1.07 (d, 6H, CH3, J = 6.5 Hz), 2.18–2.24 (m, 1H, CH), 2.68 (d, 2H, CH2, J = 6.5 Hz), 13.08 (br. s, 2H, NH). 13C NMR: δ 21.50 (CH3), 29.40 (CH), 40.30 (CH2), 92.30 (Uracil C-5), 114.80 (CN), 158.60 (C═O), 163.90 (Uracil C-6), 176.75 (C═S).
Carbon-bound H atoms were placed in calculated positions [C—H = 0.95 to 1.00 Å, Uiso(H) = 1.2–1.5Ueq(C)] and were included in the
in the riding model approximation. The amide H atoms were located in a difference Fourier map, and were refined with a distance restraint of N—H = 0.88±0.01 Å; their Uiso values were refined.Data collection: CrysAlis PRO (Agilent, 2011); cell
CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).C9H11N3OS | F(000) = 880 |
Mr = 209.27 | Dx = 1.377 Mg m−3 |
Monoclinic, C2/c | Cu Kα radiation, λ = 1.54184 Å |
Hall symbol: -C 2yc | Cell parameters from 4317 reflections |
a = 25.8985 (6) Å | θ = 4.0–76.1° |
b = 7.0479 (2) Å | µ = 2.62 mm−1 |
c = 11.1811 (2) Å | T = 100 K |
β = 98.527 (2)° | Needle, colourless |
V = 2018.33 (8) Å3 | 0.35 × 0.20 × 0.03 mm |
Z = 8 |
Agilent SuperNova Dual diffractometer with Atlas detector | 2102 independent reflections |
Radiation source: SuperNova (Cu) X-ray Source | 1989 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.024 |
Detector resolution: 10.4041 pixels mm-1 | θmax = 76.3°, θmin = 6.5° |
ω scans | h = −31→32 |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011) | k = −8→8 |
Tmin = 0.461, Tmax = 0.926 | l = −14→10 |
6870 measured reflections |
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)] = 0.030 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.086 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0528P)2 + 1.3984P] where P = (Fo2 + 2Fc2)/3 |
2102 reflections | (Δ/σ)max = 0.002 |
135 parameters | Δρmax = 0.27 e Å−3 |
2 restraints | Δρmin = −0.28 e Å−3 |
C9H11N3OS | V = 2018.33 (8) Å3 |
Mr = 209.27 | Z = 8 |
Monoclinic, C2/c | Cu Kα radiation |
a = 25.8985 (6) Å | µ = 2.62 mm−1 |
b = 7.0479 (2) Å | T = 100 K |
c = 11.1811 (2) Å | 0.35 × 0.20 × 0.03 mm |
β = 98.527 (2)° |
Agilent SuperNova Dual diffractometer with Atlas detector | 2102 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011) | 1989 reflections with I > 2σ(I) |
Tmin = 0.461, Tmax = 0.926 | Rint = 0.024 |
6870 measured reflections |
R[F2 > 2σ(F2)] = 0.030 | 2 restraints |
wR(F2) = 0.086 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.27 e Å−3 |
2102 reflections | Δρmin = −0.28 e Å−3 |
135 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 | ||
S1 | 0.550100 (11) | 0.21184 (4) | 0.42164 (3) | 0.01651 (12) | |
O1 | 0.43446 (3) | 0.31829 (14) | 0.72665 (8) | 0.0189 (2) | |
N1 | 0.44705 (4) | 0.25643 (16) | 0.37760 (9) | 0.0154 (2) | |
N2 | 0.48422 (4) | 0.27666 (15) | 0.57730 (9) | 0.0143 (2) | |
N3 | 0.30186 (4) | 0.37646 (18) | 0.58639 (10) | 0.0225 (3) | |
C1 | 0.49111 (5) | 0.24972 (18) | 0.46022 (11) | 0.0144 (2) | |
C2 | 0.43658 (5) | 0.30269 (17) | 0.61833 (11) | 0.0146 (3) | |
C3 | 0.39202 (5) | 0.31030 (17) | 0.52342 (11) | 0.0150 (3) | |
C4 | 0.39788 (5) | 0.28817 (16) | 0.40487 (11) | 0.0151 (3) | |
C5 | 0.34180 (5) | 0.34614 (19) | 0.55782 (10) | 0.0166 (3) | |
C6 | 0.35440 (5) | 0.29348 (18) | 0.30154 (11) | 0.0165 (3) | |
H6A | 0.3644 | 0.3779 | 0.2381 | 0.020* | |
H6B | 0.3232 | 0.3490 | 0.3297 | 0.020* | |
C7 | 0.33981 (5) | 0.09633 (18) | 0.24532 (10) | 0.0160 (3) | |
H7 | 0.3698 | 0.0480 | 0.2073 | 0.019* | |
C8 | 0.29278 (5) | 0.1211 (2) | 0.14684 (12) | 0.0246 (3) | |
H8A | 0.3012 | 0.2133 | 0.0870 | 0.037* | |
H8B | 0.2629 | 0.1670 | 0.1831 | 0.037* | |
H8C | 0.2840 | −0.0010 | 0.1071 | 0.037* | |
C9 | 0.32809 (5) | −0.0459 (2) | 0.34028 (12) | 0.0221 (3) | |
H9A | 0.3589 | −0.0599 | 0.4022 | 0.033* | |
H9B | 0.3193 | −0.1689 | 0.3017 | 0.033* | |
H9C | 0.2986 | −0.0004 | 0.3780 | 0.033* | |
H1N | 0.4514 (7) | 0.243 (3) | 0.3021 (9) | 0.026 (4)* | |
H2N | 0.5113 (5) | 0.275 (3) | 0.6341 (13) | 0.023 (4)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.01253 (17) | 0.02143 (19) | 0.01565 (18) | 0.00095 (10) | 0.00231 (11) | 0.00078 (10) |
O1 | 0.0159 (4) | 0.0270 (5) | 0.0136 (4) | 0.0004 (4) | 0.0013 (3) | −0.0010 (3) |
N1 | 0.0141 (5) | 0.0193 (5) | 0.0125 (5) | −0.0002 (4) | 0.0014 (4) | −0.0001 (4) |
N2 | 0.0112 (5) | 0.0176 (5) | 0.0134 (5) | 0.0001 (4) | −0.0003 (4) | −0.0001 (4) |
N3 | 0.0173 (5) | 0.0264 (6) | 0.0232 (5) | 0.0018 (5) | 0.0018 (4) | −0.0033 (5) |
C1 | 0.0153 (6) | 0.0121 (5) | 0.0155 (6) | −0.0014 (4) | 0.0009 (4) | 0.0007 (4) |
C2 | 0.0137 (6) | 0.0130 (6) | 0.0168 (6) | −0.0004 (4) | 0.0016 (5) | 0.0000 (4) |
C3 | 0.0128 (6) | 0.0149 (6) | 0.0167 (6) | −0.0003 (4) | 0.0006 (4) | −0.0003 (4) |
C4 | 0.0139 (6) | 0.0122 (6) | 0.0186 (6) | −0.0003 (4) | 0.0009 (5) | 0.0006 (4) |
C5 | 0.0165 (6) | 0.0168 (6) | 0.0152 (5) | 0.0002 (5) | −0.0014 (4) | −0.0016 (4) |
C6 | 0.0150 (6) | 0.0183 (7) | 0.0152 (6) | 0.0013 (4) | −0.0012 (5) | −0.0003 (4) |
C7 | 0.0122 (5) | 0.0193 (6) | 0.0162 (5) | 0.0005 (4) | 0.0011 (4) | −0.0028 (5) |
C8 | 0.0230 (7) | 0.0251 (7) | 0.0224 (6) | 0.0030 (5) | −0.0075 (5) | −0.0055 (5) |
C9 | 0.0201 (6) | 0.0233 (7) | 0.0224 (6) | −0.0050 (5) | 0.0014 (5) | 0.0004 (5) |
S1—C1 | 1.6693 (13) | C6—C7 | 1.5486 (17) |
O1—C2 | 1.2254 (15) | C6—H6A | 0.9900 |
N1—C1 | 1.3583 (16) | C6—H6B | 0.9900 |
N1—C4 | 1.3711 (16) | C7—C9 | 1.5232 (18) |
N1—H1N | 0.873 (9) | C7—C8 | 1.5261 (16) |
N2—C1 | 1.3605 (16) | C7—H7 | 1.0000 |
N2—C2 | 1.3909 (16) | C8—H8A | 0.9800 |
N2—H2N | 0.874 (9) | C8—H8B | 0.9800 |
N3—C5 | 1.1470 (17) | C8—H8C | 0.9800 |
C2—C3 | 1.4482 (17) | C9—H9A | 0.9800 |
C3—C4 | 1.3653 (18) | C9—H9B | 0.9800 |
C3—C5 | 1.4323 (17) | C9—H9C | 0.9800 |
C4—C6 | 1.4895 (17) | ||
C1—N1—C4 | 124.66 (11) | C4—C6—H6B | 108.8 |
C1—N1—H1N | 116.1 (12) | C7—C6—H6B | 108.8 |
C4—N1—H1N | 119.2 (12) | H6A—C6—H6B | 107.7 |
C1—N2—C2 | 125.81 (10) | C9—C7—C8 | 110.98 (10) |
C1—N2—H2N | 119.4 (12) | C9—C7—C6 | 111.67 (10) |
C2—N2—H2N | 114.7 (12) | C8—C7—C6 | 108.10 (10) |
N1—C1—N2 | 115.64 (11) | C9—C7—H7 | 108.7 |
N1—C1—S1 | 122.58 (9) | C8—C7—H7 | 108.7 |
N2—C1—S1 | 121.77 (9) | C6—C7—H7 | 108.7 |
O1—C2—N2 | 120.65 (11) | C7—C8—H8A | 109.5 |
O1—C2—C3 | 124.98 (11) | C7—C8—H8B | 109.5 |
N2—C2—C3 | 114.37 (10) | H8A—C8—H8B | 109.5 |
C4—C3—C5 | 121.13 (11) | C7—C8—H8C | 109.5 |
C4—C3—C2 | 121.06 (11) | H8A—C8—H8C | 109.5 |
C5—C3—C2 | 117.79 (11) | H8B—C8—H8C | 109.5 |
N1—C4—C3 | 118.37 (11) | C7—C9—H9A | 109.5 |
N1—C4—C6 | 116.87 (11) | C7—C9—H9B | 109.5 |
C3—C4—C6 | 124.75 (12) | H9A—C9—H9B | 109.5 |
N3—C5—C3 | 179.16 (14) | C7—C9—H9C | 109.5 |
C4—C6—C7 | 113.78 (10) | H9A—C9—H9C | 109.5 |
C4—C6—H6A | 108.8 | H9B—C9—H9C | 109.5 |
C7—C6—H6A | 108.8 | ||
C4—N1—C1—N2 | 0.16 (19) | C1—N1—C4—C3 | −1.67 (19) |
C4—N1—C1—S1 | −179.61 (10) | C1—N1—C4—C6 | 179.07 (12) |
C2—N2—C1—N1 | 2.54 (19) | C5—C3—C4—N1 | 179.23 (11) |
C2—N2—C1—S1 | −177.70 (9) | C2—C3—C4—N1 | 0.68 (18) |
C1—N2—C2—O1 | 177.06 (12) | C5—C3—C4—C6 | −1.58 (19) |
C1—N2—C2—C3 | −3.35 (18) | C2—C3—C4—C6 | 179.87 (11) |
O1—C2—C3—C4 | −178.83 (12) | N1—C4—C6—C7 | 72.88 (14) |
N2—C2—C3—C4 | 1.60 (17) | C3—C4—C6—C7 | −106.32 (14) |
O1—C2—C3—C5 | 2.58 (19) | C4—C6—C7—C9 | 53.98 (14) |
N2—C2—C3—C5 | −176.99 (11) | C4—C6—C7—C8 | 176.33 (11) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N···S1i | 0.87 (1) | 2.51 (1) | 3.3723 (11) | 172 (2) |
N2—H2N···O1ii | 0.87 (1) | 1.96 (1) | 2.8210 (14) | 168 (2) |
Symmetry codes: (i) −x+1, y, −z+1/2; (ii) −x+1, y, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | C9H11N3OS |
Mr | 209.27 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 100 |
a, b, c (Å) | 25.8985 (6), 7.0479 (2), 11.1811 (2) |
β (°) | 98.527 (2) |
V (Å3) | 2018.33 (8) |
Z | 8 |
Radiation type | Cu Kα |
µ (mm−1) | 2.62 |
Crystal size (mm) | 0.35 × 0.20 × 0.03 |
Data collection | |
Diffractometer | Agilent SuperNova Dual diffractometer with Atlas detector |
Absorption correction | Multi-scan (CrysAlis PRO; Agilent, 2011) |
Tmin, Tmax | 0.461, 0.926 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6870, 2102, 1989 |
Rint | 0.024 |
(sin θ/λ)max (Å−1) | 0.630 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.030, 0.086, 1.03 |
No. of reflections | 2102 |
No. of parameters | 135 |
No. of restraints | 2 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.27, −0.28 |
Computer programs: CrysAlis PRO (Agilent, 2011), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N···S1i | 0.873 (9) | 2.506 (10) | 3.3723 (11) | 171.8 (16) |
N2—H2N···O1ii | 0.874 (9) | 1.960 (10) | 2.8210 (14) | 168.2 (17) |
Symmetry codes: (i) −x+1, y, −z+1/2; (ii) −x+1, y, −z+3/2. |
Footnotes
‡Additional correspondence author, e-mail: elemam5@hotmail.com.
Acknowledgements
The financial support of the Deanship of Scientific Research and the Research Center of the College of Pharmacy, King Saud University, is greatly appreciated. We also thank the Ministry of Higher Education (Malaysia) for funding structural studies through the High-Impact Research Scheme (grant No. UM.C/HIR/MOHE/SC/12).
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The chemotherapeutic efficacy of uracil derivatives is related to their ability to inhibit vital enzymes responsible for DNA biosynthesis. Thus, several uracil and pyrimidine non-nucleoside derivatives exhibited anti-cancer (Al-Safarjalani et al., 2005), anti-viral (Brunelle et al., 2007; Ding et al., 2006) and anti-bacterial activities (Hawser et al., 2006; Al-Abdullah et al., 2011). In continuation to our interest in the chemical and pharmacological properties of uracil and pyrimidine derivatives (Al-Omar et al., 2010; Al-Turkistani et al., 2011), and as part of on-going structural studies of uracil and pyrimidine derivatives (Nasir et al., 2010; El-Emam et al. 2011), we synthesized the title compound 6-(2-methylpropyl)-2-thiouracil-5-carbonitrile (I) as a precursor for potential chemotherapeutic agents.
The thiouracil derivative (I), Fig. 1, exists in the thione form with the C1═S1 bond length of 1.6693 (13) Å being shorter than the equivalent bond in the parent 2-thiouracil compound, i.e. 1.683 (3) Å (Tiekink, 1989). The six atoms comprising the ring are co-planar, having a r.m.s. deviation = 0.015 Å. The 2-methylpropyl group lies to one side of the central plane with the N1—C4—C6—C7 torsion angle being 72.88 (14)°.
The crystal packing features N—H···O and N—H···S hydrogen bonding involving both amide-H and the oxo and thione atoms, Table 1. The result of these hydrogen bonds is the formation of linear supramolecular chains along the c axis featuring alternating eight-membered {···HNCO}2 and {···HNCS}2 synthons, Fig. 2. The chains stack in the crystal structure with no specific intermolecular interactions between them, Fig. 3.