organic compounds
7-(5-Methylsulfanyl-β-D-erythrofuranosyl)-7H-pyrrolo[2,3-d]pyrimidin-4-amine monohydrate (MT-tubercidin·H2O)
aCarbohydrate Chemistry Group, Industrial Research Limited, PO Box 31-310, Lower Hutt 5040, New Zealand
*Correspondence e-mail: g.gainsford@irl.cri.nz
The title compound, C12H16N4O3S·H2O, which has potential as a possible antimalarial drug, was studied when small deviations in melting points, for two differently aged preparations, were observed. The unexpected existence of a water molecule of crystallization is considered to be the cause of this variation. The 7H-pyrrolo[2,3-d]pyrimidine unit is very slightly puckered with a total puckering amplitude of 0.035 (2) Å; its mean plane makes an angle of 88.40 (12)° with the mean plane through the ribofuranosyl unit. In the crystal, the molecules are bound by strong O—H⋯N and N—H⋯O hydrogen bonds, utilizing all available protons and linking mainly through the water of crystallization.
Related literature
For details of the synthesis of and for background to the title compound, see: Riegelhaupt et al. (2010). For related structures, see: Seela et al. (2007); Abola & Sundaralingam (1973). For ring conformations, see: Cremer & Pople (1975). For hydrogen-bond motifs, see: Etter et al. (1990); Bernstein et al. (1995).
Experimental
Crystal data
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Data collection: CrystalClear (Rigaku Americas, 2005); cell FSProcess in PROCESS-AUTO (Rigaku, 1998); data reduction: FSProcess in PROCESS-AUTO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP in WinGX (Farrugia, 1999) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009).
Supporting information
10.1107/S1600536810020179/kp2257sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536810020179/kp2257Isup2.hkl
The title compound was prepared as described in the supplementary data section (compound 10) by Riegelhaupt et al. (2010).
The H atoms of the ordered hydroxyl, water and amine atoms were placed in the positions indicated by a difference
and their positions were allowed to refine with Uiso(H) = 1.5Ueq(O,N). The water H atoms were restrained to an O–H distance of 0.82 (2) Å. The methyl H atoms were constrained to an ideal geometry (C—H = 0.98 Å) with Uiso(H) = 1.5Ueq(C), but were allowed to rotate freely about the adjacent C—C bonds. All other H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C—H distances of 0.95 (aromatic), 0.99 (methylene) or 1.00 (tertiary) Å with Uiso(H) = 1.2Ueq(C,N). Thirty-four high angle outlier reflections identified by having Fo>>Fc and collected in the same area of (and with ΔFo**2/e.s.d. > 5) were omitted from the final cycles of based on the lack of backstop mask corrections.Data collection: CrystalClear (Rigaku Americas, 2005); cell
FSProcess in PROCESS-AUTO (Rigaku, 1998); data reduction: FSProcess in PROCESS-AUTO (Rigaku, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP in WinGX (Farrugia, 1999) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).Fig. 1. An ORTEP (Farrugia, 1999) view showing the asymmetric unit of (I) with 50% probabilility ellipsoids. The dotted lines represents an intermolecular hydrogen bond. | |
Fig. 2. Mercury cell packing view (Macrae et al., 2006) emphasizing the links with the water of crystallization: conventional hydrogen bonds not running up the a axis are shown (dotted lines).For the complete hydrogen bonding set see Table 1. Contact atoms are shown in ball mode; H atoms are omitted for clarity. Symmetry operations: (i) 1 - x, y - 1/2, 3/2 - z (ii) 1/2 - x, 1 - y, 1/2 + z. |
C12H16N4O3S·H2O | F(000) = 664 |
Mr = 314.36 | Dx = 1.456 Mg m−3 |
Orthorhombic, P212121 | Cu Kα radiation, λ = 1.54178 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 1322 reflections |
a = 4.790 (1) Å | θ = 10.7–72.1° |
b = 16.610 (3) Å | µ = 2.22 mm−1 |
c = 18.020 (4) Å | T = 100 K |
V = 1433.7 (5) Å3 | Needle, colourless |
Z = 4 | 0.50 × 0.02 × 0.02 mm |
Rigaku Spider diffractometer | 2582 independent reflections |
Radiation source: Rigaku MM007 rotating anode | 2422 reflections with I > 2σ(I) |
Rigaku VariMax-HF Confocal Optical System monochromator | Rint = 0.045 |
Detector resolution: 10 pixels mm-1 | θmax = 71.9°, θmin = 7.3° |
ω–scans | h = −5→2 |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | k = −20→20 |
Tmin = 0.712, Tmax = 1.0 | l = −21→19 |
8013 measured reflections |
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)] = 0.039 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.091 | w = 1/[σ2(Fo2) + (0.031P)2 + 0.7234P] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max < 0.001 |
2582 reflections | Δρmax = 0.29 e Å−3 |
209 parameters | Δρmin = −0.33 e Å−3 |
2 restraints | Absolute structure: Flack (1983), 986 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.02 (2) |
C12H16N4O3S·H2O | V = 1433.7 (5) Å3 |
Mr = 314.36 | Z = 4 |
Orthorhombic, P212121 | Cu Kα radiation |
a = 4.790 (1) Å | µ = 2.22 mm−1 |
b = 16.610 (3) Å | T = 100 K |
c = 18.020 (4) Å | 0.50 × 0.02 × 0.02 mm |
Rigaku Spider diffractometer | 2582 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 2422 reflections with I > 2σ(I) |
Tmin = 0.712, Tmax = 1.0 | Rint = 0.045 |
8013 measured reflections |
R[F2 > 2σ(F2)] = 0.039 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.091 | Δρmax = 0.29 e Å−3 |
S = 1.08 | Δρmin = −0.33 e Å−3 |
2582 reflections | Absolute structure: Flack (1983), 986 Friedel pairs |
209 parameters | Absolute structure parameter: 0.02 (2) |
2 restraints |
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 | 0.97214 (14) | 0.38389 (4) | 0.36963 (3) | 0.01889 (16) | |
O1W | 0.2297 (5) | 0.66101 (10) | 0.58560 (11) | 0.0210 (4) | |
H1A | 0.363 (5) | 0.6337 (16) | 0.5723 (16) | 0.032* | |
H1B | 0.110 (6) | 0.6336 (16) | 0.6041 (16) | 0.032* | |
O2' | 0.8902 (4) | 0.53482 (10) | 0.64314 (9) | 0.0155 (4) | |
H2'O | 0.971 (7) | 0.5148 (17) | 0.6768 (15) | 0.023* | |
O3' | 0.6026 (4) | 0.56178 (10) | 0.51450 (10) | 0.0171 (4) | |
H3'O | 0.553 (7) | 0.5708 (17) | 0.4704 (16) | 0.026* | |
O4' | 0.4719 (4) | 0.38417 (10) | 0.55162 (8) | 0.0166 (4) | |
N1 | 0.1518 (5) | 0.40830 (11) | 0.87950 (11) | 0.0148 (5) | |
C2 | 0.0798 (6) | 0.45356 (14) | 0.82094 (13) | 0.0152 (5) | |
H2 | −0.0681 | 0.4906 | 0.8293 | 0.018* | |
N3 | 0.1866 (5) | 0.45398 (11) | 0.75258 (11) | 0.0132 (4) | |
C4 | 0.3891 (6) | 0.39748 (13) | 0.74463 (13) | 0.0126 (5) | |
C5 | 0.4795 (6) | 0.34442 (13) | 0.79930 (13) | 0.0130 (5) | |
C6 | 0.3551 (5) | 0.35230 (14) | 0.87012 (13) | 0.0144 (5) | |
N6 | 0.4318 (5) | 0.30707 (13) | 0.92757 (12) | 0.0188 (5) | |
H6A | 0.355 (7) | 0.3126 (17) | 0.9726 (16) | 0.028* | |
H6B | 0.552 (7) | 0.2722 (17) | 0.9214 (17) | 0.028* | |
C7 | 0.6937 (6) | 0.29487 (14) | 0.76725 (14) | 0.0155 (5) | |
H7 | 0.7949 | 0.2532 | 0.7913 | 0.019* | |
C8 | 0.7228 (6) | 0.31939 (14) | 0.69593 (14) | 0.0141 (5) | |
H8 | 0.8501 | 0.2971 | 0.6611 | 0.017* | |
N9 | 0.5374 (4) | 0.38247 (11) | 0.68120 (10) | 0.0128 (4) | |
C1' | 0.5393 (6) | 0.43227 (14) | 0.61535 (12) | 0.0139 (5) | |
H1' | 0.3971 | 0.4760 | 0.6208 | 0.017* | |
C2' | 0.8210 (6) | 0.46963 (14) | 0.59653 (13) | 0.0133 (5) | |
H2' | 0.9698 | 0.4276 | 0.5998 | 0.016* | |
C3' | 0.7750 (6) | 0.49214 (14) | 0.51606 (14) | 0.0138 (5) | |
H3' | 0.9552 | 0.5009 | 0.4892 | 0.017* | |
C4' | 0.6191 (6) | 0.41680 (15) | 0.48763 (13) | 0.0139 (5) | |
H4' | 0.4815 | 0.4328 | 0.4486 | 0.017* | |
C5' | 0.8164 (6) | 0.35258 (16) | 0.45686 (13) | 0.0188 (6) | |
H5'A | 0.7116 | 0.3019 | 0.4492 | 0.023* | |
H5'B | 0.9660 | 0.3419 | 0.4935 | 0.023* | |
C6' | 0.7305 (6) | 0.34328 (16) | 0.30226 (15) | 0.0219 (6) | |
H6'A | 0.7358 | 0.2843 | 0.3041 | 0.033* | |
H6'B | 0.7835 | 0.3615 | 0.2525 | 0.033* | |
H6'C | 0.5412 | 0.3620 | 0.3137 | 0.033* |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1 | 0.0145 (4) | 0.0267 (3) | 0.0155 (3) | −0.0023 (3) | 0.0037 (3) | −0.0050 (3) |
O1W | 0.0206 (12) | 0.0217 (9) | 0.0208 (10) | −0.0034 (8) | 0.0045 (8) | 0.0000 (8) |
O2' | 0.0170 (10) | 0.0174 (8) | 0.0120 (9) | −0.0004 (7) | −0.0028 (8) | −0.0007 (7) |
O3' | 0.0200 (11) | 0.0205 (9) | 0.0108 (8) | 0.0075 (8) | −0.0027 (8) | 0.0023 (7) |
O4' | 0.0138 (10) | 0.0262 (9) | 0.0096 (8) | −0.0044 (9) | 0.0006 (8) | −0.0020 (7) |
N1 | 0.0160 (12) | 0.0172 (10) | 0.0113 (10) | 0.0002 (8) | −0.0001 (9) | 0.0006 (8) |
C2 | 0.0135 (14) | 0.0164 (11) | 0.0157 (12) | 0.0007 (10) | −0.0020 (11) | −0.0023 (10) |
N3 | 0.0108 (11) | 0.0172 (9) | 0.0117 (11) | 0.0010 (8) | −0.0005 (9) | −0.0015 (9) |
C4 | 0.0102 (13) | 0.0155 (11) | 0.0121 (12) | −0.0032 (9) | −0.0034 (10) | −0.0014 (10) |
C5 | 0.0113 (14) | 0.0155 (10) | 0.0123 (11) | −0.0002 (10) | 0.0009 (11) | 0.0012 (9) |
C6 | 0.0153 (14) | 0.0157 (11) | 0.0121 (11) | −0.0018 (10) | −0.0028 (11) | −0.0004 (10) |
N6 | 0.0235 (15) | 0.0226 (10) | 0.0104 (10) | 0.0066 (10) | 0.0018 (10) | 0.0015 (9) |
C7 | 0.0130 (14) | 0.0162 (11) | 0.0174 (12) | 0.0012 (10) | −0.0002 (12) | 0.0008 (10) |
C8 | 0.0105 (14) | 0.0158 (11) | 0.0160 (13) | 0.0017 (10) | 0.0025 (11) | −0.0035 (10) |
N9 | 0.0104 (11) | 0.0170 (9) | 0.0110 (10) | −0.0010 (9) | 0.0025 (9) | 0.0006 (8) |
C1' | 0.0133 (15) | 0.0196 (11) | 0.0089 (11) | 0.0001 (10) | −0.0008 (10) | −0.0001 (9) |
C2' | 0.0077 (13) | 0.0178 (11) | 0.0142 (12) | −0.0002 (10) | −0.0020 (11) | 0.0008 (10) |
C3' | 0.0110 (14) | 0.0174 (11) | 0.0131 (12) | 0.0020 (10) | 0.0011 (11) | 0.0001 (10) |
C4' | 0.0098 (14) | 0.0227 (12) | 0.0091 (11) | 0.0009 (10) | −0.0027 (10) | 0.0029 (10) |
C5' | 0.0184 (15) | 0.0227 (12) | 0.0153 (12) | 0.0002 (12) | −0.0011 (12) | −0.0042 (11) |
C6' | 0.0177 (16) | 0.0283 (14) | 0.0197 (14) | −0.0005 (12) | −0.0007 (12) | −0.0054 (12) |
S1—C6' | 1.808 (3) | N6—H6A | 0.90 (3) |
S1—C5' | 1.816 (3) | N6—H6B | 0.82 (3) |
O1W—H1A | 0.820 (18) | C7—C8 | 1.355 (3) |
O1W—H1B | 0.805 (18) | C7—H7 | 0.9500 |
O2'—C2' | 1.410 (3) | C8—N9 | 1.399 (3) |
O2'—H2'O | 0.79 (3) | C8—H8 | 0.9500 |
O3'—C3' | 1.422 (3) | N9—C1' | 1.446 (3) |
O3'—H3'O | 0.84 (3) | C1'—C2' | 1.523 (4) |
O4'—C1' | 1.436 (3) | C1'—H1' | 1.0000 |
O4'—C4' | 1.456 (3) | C2'—C3' | 1.514 (3) |
N1—C2 | 1.341 (3) | C2'—H2' | 1.0000 |
N1—C6 | 1.357 (3) | C3'—C4' | 1.545 (3) |
C2—N3 | 1.334 (3) | C3'—H3' | 1.0000 |
C2—H2 | 0.9500 | C4'—C5' | 1.529 (3) |
N3—C4 | 1.357 (3) | C4'—H4' | 1.0000 |
C4—N9 | 1.369 (3) | C5'—H5'A | 0.9900 |
C4—C5 | 1.391 (3) | C5'—H5'B | 0.9900 |
C5—C6 | 1.415 (3) | C6'—H6'A | 0.9800 |
C5—C7 | 1.436 (3) | C6'—H6'B | 0.9800 |
C6—N6 | 1.331 (3) | C6'—H6'C | 0.9800 |
C6'—S1—C5' | 102.20 (14) | O4'—C1'—H1' | 109.2 |
H1A—O1W—H1B | 111 (3) | N9—C1'—H1' | 109.2 |
C2'—O2'—H2'O | 104 (2) | C2'—C1'—H1' | 109.2 |
C3'—O3'—H3'O | 109 (2) | O2'—C2'—C3' | 114.53 (19) |
C1'—O4'—C4' | 108.50 (17) | O2'—C2'—C1' | 112.9 (2) |
C2—N1—C6 | 118.1 (2) | C3'—C2'—C1' | 100.7 (2) |
N3—C2—N1 | 129.2 (2) | O2'—C2'—H2' | 109.5 |
N3—C2—H2 | 115.4 | C3'—C2'—H2' | 109.5 |
N1—C2—H2 | 115.4 | C1'—C2'—H2' | 109.5 |
C2—N3—C4 | 111.6 (2) | O3'—C3'—C2' | 107.7 (2) |
N3—C4—N9 | 125.8 (2) | O3'—C3'—C4' | 111.8 (2) |
N3—C4—C5 | 125.9 (2) | C2'—C3'—C4' | 100.83 (19) |
N9—C4—C5 | 108.3 (2) | O3'—C3'—H3' | 112.0 |
C4—C5—C6 | 116.7 (2) | C2'—C3'—H3' | 112.0 |
C4—C5—C7 | 107.5 (2) | C4'—C3'—H3' | 112.0 |
C6—C5—C7 | 135.8 (2) | O4'—C4'—C5' | 109.07 (19) |
N6—C6—N1 | 119.2 (2) | O4'—C4'—C3' | 105.84 (19) |
N6—C6—C5 | 122.2 (2) | C5'—C4'—C3' | 112.7 (2) |
N1—C6—C5 | 118.6 (2) | O4'—C4'—H4' | 109.7 |
C6—N6—H6A | 122 (2) | C5'—C4'—H4' | 109.7 |
C6—N6—H6B | 119 (2) | C3'—C4'—H4' | 109.7 |
H6A—N6—H6B | 119 (3) | C4'—C5'—S1 | 111.59 (18) |
C8—C7—C5 | 106.4 (2) | C4'—C5'—H5'A | 109.3 |
C8—C7—H7 | 126.8 | S1—C5'—H5'A | 109.3 |
C5—C7—H7 | 126.8 | C4'—C5'—H5'B | 109.3 |
C7—C8—N9 | 109.9 (2) | S1—C5'—H5'B | 109.3 |
C7—C8—H8 | 125.1 | H5'A—C5'—H5'B | 108.0 |
N9—C8—H8 | 125.1 | S1—C6'—H6'A | 109.5 |
C4—N9—C8 | 107.91 (19) | S1—C6'—H6'B | 109.5 |
C4—N9—C1' | 125.7 (2) | H6'A—C6'—H6'B | 109.5 |
C8—N9—C1' | 125.5 (2) | S1—C6'—H6'C | 109.5 |
O4'—C1'—N9 | 109.66 (18) | H6'A—C6'—H6'C | 109.5 |
O4'—C1'—C2' | 104.34 (19) | H6'B—C6'—H6'C | 109.5 |
N9—C1'—C2' | 114.9 (2) | ||
C6—N1—C2—N3 | −2.3 (4) | C4'—O4'—C1'—N9 | −148.2 (2) |
N1—C2—N3—C4 | 2.3 (4) | C4'—O4'—C1'—C2' | −24.6 (2) |
C2—N3—C4—N9 | 179.6 (2) | C4—N9—C1'—O4' | −126.6 (2) |
C2—N3—C4—C5 | 0.3 (3) | C8—N9—C1'—O4' | 65.6 (3) |
N3—C4—C5—C6 | −2.4 (4) | C4—N9—C1'—C2' | 116.2 (3) |
N9—C4—C5—C6 | 178.2 (2) | C8—N9—C1'—C2' | −51.6 (3) |
N3—C4—C5—C7 | 179.5 (2) | O4'—C1'—C2'—O2' | 164.56 (18) |
N9—C4—C5—C7 | 0.1 (3) | N9—C1'—C2'—O2' | −75.3 (3) |
C2—N1—C6—N6 | 179.5 (2) | O4'—C1'—C2'—C3' | 42.0 (2) |
C2—N1—C6—C5 | −0.2 (3) | N9—C1'—C2'—C3' | 162.11 (19) |
C4—C5—C6—N6 | −177.4 (2) | O2'—C2'—C3'—O3' | −45.9 (3) |
C7—C5—C6—N6 | 0.1 (5) | C1'—C2'—C3'—O3' | 75.5 (2) |
C4—C5—C6—N1 | 2.2 (3) | O2'—C2'—C3'—C4' | −163.2 (2) |
C7—C5—C6—N1 | 179.7 (3) | C1'—C2'—C3'—C4' | −41.8 (2) |
C4—C5—C7—C8 | −0.1 (3) | C1'—O4'—C4'—C5' | 119.1 (2) |
C6—C5—C7—C8 | −177.8 (3) | C1'—O4'—C4'—C3' | −2.5 (2) |
C5—C7—C8—N9 | 0.2 (3) | O3'—C3'—C4'—O4' | −85.9 (2) |
N3—C4—N9—C8 | −179.4 (2) | C2'—C3'—C4'—O4' | 28.4 (2) |
C5—C4—N9—C8 | 0.0 (3) | O3'—C3'—C4'—C5' | 155.0 (2) |
N3—C4—N9—C1' | 11.0 (4) | C2'—C3'—C4'—C5' | −90.8 (2) |
C5—C4—N9—C1' | −169.5 (2) | O4'—C4'—C5'—S1 | 172.20 (16) |
C7—C8—N9—C4 | −0.1 (3) | C3'—C4'—C5'—S1 | −70.5 (2) |
C7—C8—N9—C1' | 169.5 (2) | C6'—S1—C5'—C4' | −91.9 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2′—H2′O···N3i | 0.79 (3) | 1.99 (3) | 2.776 (3) | 173 (3) |
O1W—H1A···O3′ | 0.82 (3) | 1.96 (3) | 2.748 (3) | 162 (3) |
O1W—H1B···O2′ii | 0.80 (3) | 2.07 (3) | 2.848 (3) | 162 (3) |
O3′—H3′O···N1iii | 0.84 (3) | 1.94 (3) | 2.766 (3) | 166 (3) |
N6—H6A···O1Wiv | 0.90 (3) | 2.12 (3) | 2.998 (3) | 166 (3) |
N6—H6B···O1Wv | 0.82 (3) | 2.13 (3) | 2.928 (3) | 164 (3) |
Symmetry codes: (i) x+1, y, z; (ii) x−1, y, z; (iii) −x+1/2, −y+1, z−1/2; (iv) −x+1/2, −y+1, z+1/2; (v) −x+1, y−1/2, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | C12H16N4O3S·H2O |
Mr | 314.36 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 100 |
a, b, c (Å) | 4.790 (1), 16.610 (3), 18.020 (4) |
V (Å3) | 1433.7 (5) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 2.22 |
Crystal size (mm) | 0.50 × 0.02 × 0.02 |
Data collection | |
Diffractometer | Rigaku Spider diffractometer |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.712, 1.0 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8013, 2582, 2422 |
Rint | 0.045 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.039, 0.091, 1.08 |
No. of reflections | 2582 |
No. of parameters | 209 |
No. of restraints | 2 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.29, −0.33 |
Absolute structure | Flack (1983), 986 Friedel pairs |
Absolute structure parameter | 0.02 (2) |
Computer programs: CrystalClear (Rigaku Americas, 2005), FSProcess in PROCESS-AUTO (Rigaku, 1998), SHELXS97 (Sheldrick, 2008), ORTEP in WinGX (Farrugia, 1999) and Mercury (Macrae et al., 2006), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
O2'—H2'O···N3i | 0.79 (3) | 1.99 (3) | 2.776 (3) | 173 (3) |
O1W—H1A···O3' | 0.82 (3) | 1.96 (3) | 2.748 (3) | 162 (3) |
O1W—H1B···O2'ii | 0.80 (3) | 2.07 (3) | 2.848 (3) | 162 (3) |
O3'—H3'O···N1iii | 0.84 (3) | 1.94 (3) | 2.766 (3) | 166 (3) |
N6—H6A···O1Wiv | 0.90 (3) | 2.12 (3) | 2.998 (3) | 166 (3) |
N6—H6B···O1Wv | 0.82 (3) | 2.13 (3) | 2.928 (3) | 164 (3) |
Symmetry codes: (i) x+1, y, z; (ii) x−1, y, z; (iii) −x+1/2, −y+1, z−1/2; (iv) −x+1/2, −y+1, z+1/2; (v) −x+1, y−1/2, −z+3/2. |
Acknowledgements
We thank the MacDiarmid Institute for Advanced Materials and Nanotechnology for funding of the diffractometer equipment.
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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 title compound was prepared as part of a study of purine transport or purine salvage pathway inhibitors with potential as alternative anti-malarial drugs (Riegelhaupt et al., 2010). Its common name is 7-(5'Methylthio-β-D-erythrofuranosyl)-7H-pyrrolo[2,3-d]pyrimidin-2-amine monohydrate usually shortened to MT-tubercidin.H2O while the conventional name is 2-(4-Amino-pyrrolo[2,3-d]pyrimidin-7-yl)-5-methylsulfanylmethyl -tetrahydrofuran-3,4-diol monohydrate. The structural solution showed that in both batches there was an unexpected water molecule of crystallization, a likely cause of the variation in melting points with differently aged samples. The results for the better crystals are presented here. The asymmetric unit contents are shown in Figure 1.
The absolute configuration is defined as C1'(R), C2'(R), C3'(S) and C4'(S) with the ribofuranosyl unit adopting an (C2'-)endo-envelope Δ conformation (Q(2) 0.434 (3) Å, ϕ(2) 76.3 (3)°, Cremer & Pople (1975)). The 7H-pyrrolo[2,3-d]pyrimidine unit is very slightly puckered with total puckering amplitude of 0.035 (2) Å: its mean plane makes an angle of 88.40 (12)° with the mean plane through the ribofuranosyl unit. The orientation of the C4'–C5' bond is slightly different (with O4'-C1'-N9—C4 torsion angle of -126.6 (2)°) to that found in the related compounds 2'-Deoxy-2-fluorotubercidin (-110.2 (3)°, Seela et al., 2007) and tubercidin (-112.8 (4)°, Abola & Sundaralingam, 1973). Other dimensions are normal.
The molecules are packed in three dimensions using 6 strong hydrogen bonds of the O–H···O and N–H···O types (Table 1). The graph set motifs (Etter et al., 1990; Bernstein et al., 1995) are extensive at the binary level: C22(7), C22(9), C22(11), C22(12), C22(17), D33(10), D33(13), D33(14), D33(15), D33(17) and D33(18) types are found being based mainly on linked chains through the included water molecule (the latter feature is shown in Figure 2). The C–H···π interaction involving the methyl hydrogen H6'A and the 5-membered pyrrolo ring (at 2.80 Å) is considered fortuitous but noted here for completeness.