Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807047940/kj2066sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807047940/kj2066Isup2.hkl |
CCDC reference: 669132
7-formylpterin dimethyl acetal (500 mg, 2.11 mmol) and 4-(dimethylamino)-pyridine (50 mg) dissolved in pivalic anhydride (5 ml) were heated at reflux under nitrogen until all of the starting material went into solution (6 h). The excess pivalic anhydride and pivalic acid were removed carefully through short-path distillation under reduced pressure. The brown product was washed well with sodium carbonate followed by water and then extracted with chloroform. The organic layer was evaporated under reduced pressure. The product was purified by silica gel (100–200 mesh) column chromatography eluting with methanol in chloroform (5%) which yielded pure yellow crystalline solid of the title compound (492 mg, 66%, m.p. 396–397 K).
Water H and H atoms attached to N were located in a difference map and their positions and isotropic displacement factors were refined. The remaining H atoms were positioned geometrically and allowed to ride on their parent atoms, with C—H distances in the range 0.93–0.98 Å. The Uiso values were constrained to be 1.5Ueq of the carrier atom for methyl H atoms and 1.2Ueq for the remaining H atoms. A rotating group model was used for the methyl groups.
6-Formylpterin is a useful precursor to the nutrient cofactor folic acid, anticancer drug methotrexate (Piper & Montgomery, 1977) and related pteridines like biopterin, neopterin, monapterin, umanopterin as well as precursor Z of molybdenum cofactor or Moco (Pateman et al., 1964; Hille, 1996). These naturally occurring pteridine derivatives are mostly found in human urine and plasma, toad skins, germinating potatoes and various micro-organisms. All compounds of these heterocyclic ring systems found in nature so far, are derivatives of pterin and lumazine carrying different substituents in the 6- and/or 7- positions. One interesting aspect of the pterin system besides its biological importance is that pterins are fluorescent and thus fluorescence assay makes them detectable in biological systems even in trace amounts. We report here the hydrogen-bonding network in the crystal structure of the title compound, as an example of a 7-substituted soluble pterin derivative. We have previously reported the crystal structures of pivaloyl halopterins (Goswami et al., 2000; Shanmuga Sundara Raj et al., 2000), as part of our research program on solubilizing pterins and establish their X-ray structures to investigate their supramolecular network. The first general and unequivocal multistep 7-formylpterin dimethyl acetal was elegantly synthesized by Taylor (Taylor & Dumas, 1981).
In the molecules of the title compound (Fig. 1), the 3,4-dihydropteridine ring (N2–N5/C1–C6) deviates significantly from planarity with the largest deviations found for atoms N2 and N5 [0.0824 (17) and -0.0472 (16) Å, respectively], and the total puckering parameter Q = 0.144 (2) Å (Cremer & Pople, 1975). The dihedral angle between the mean planes of the two rings in the molecular structure is 3.93 (9)°. The 2,2-dimethylpropionamide substituent (O1/N1/C7–C11) is attached at atom C6, the dihedral angle between the mean plane of O1/N1/C6/C7/C8 group and the attached ring is 23.80 (9)°. The orientation of the two dimethoxymethyl groups can be indicated by the torsion angles C13—O3—C12—C4 = 168.57 (16)° and C14—O4—C12—C4 = 57.4 (2)°. The intramolecular N—H···O hydrogen bond generates an S(6) ring motif (Bernstein et al., 1995). The water molecule forms intramolecular O—H···O and O—H···N hydrogen bonds with the 3,4-dihydro-pteridine (Table 1). In the crystal (Fig. 2), the substituted-pteridine molecules are linked by N—H···N hydrogen bonds (N2—H1N2···N3) into chains running along the c direction. These chains are further connected to the water molecules by N—H···O, O—H···O and O—H···N hydrogen bonds to form two-dimemsional networks parallel to the bc plane. The crystal is stabilized by intra- and intermolecular N—H···O, N—H···N, O—H···O and O—H···N hydrogen bonds together with weak C—H···O and C—H···N intra- and intermolecular interactions. C—H···π interactions further stabilized the crystal (Table 1); Cg1 and Cg2 are the centroids of the C1/C2/C5/N3/C6/N2 and N5/C3/C4/N4/C5/C2 rings, respectively.
For related literature on the chemistry and applications of pteridine derivatives, see: e.g. Pateman et al. (1964); Piper & Montgomery (1977); Hille (1996); Taylor & Dumas (1981). For related structures, see: e.g. Goswami et al. (2000); Shanmuga Sundara Raj et al. (2000).
For related literature, see: Bernstein et al. (1995); Cremer & Pople (1975).
Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 1998); program(s) used to refine structure: SHELXTL (Sheldrick, 1998); molecular graphics: SHELXTL (Sheldrick, 1998); software used to prepare material for publication: SHELXTL (Sheldrick, 1998) and PLATON (Spek, 2003).
C14H19N5O4·H2O | F(000) = 720 |
Mr = 339.36 | Dx = 1.346 Mg m−3 |
Monoclinic, P21/c | Melting point = 396–397 K |
Hall symbol: -P 2ybc | Mo Kα radiation, λ = 0.71073 Å |
a = 11.9683 (5) Å | Cell parameters from 4876 reflections |
b = 15.7252 (6) Å | θ = 2.6–30.0° |
c = 8.9289 (3) Å | µ = 0.10 mm−1 |
β = 94.998 (2)° | T = 100 K |
V = 1674.06 (11) Å3 | Needle, brown |
Z = 4 | 0.57 × 0.09 × 0.08 mm |
Bruker SMART APEXII CCD area-detector diffractometer | 4876 independent reflections |
Radiation source: fine-focus sealed tube | 2723 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.061 |
Detector resolution: 8.33 pixels mm-1 | θmax = 30.0°, θmin = 2.6° |
ω scans | h = −16→14 |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | k = −17→22 |
Tmin = 0.943, Tmax = 0.992 | l = −12→12 |
21832 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)] = 0.061 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.166 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0731P)2] where P = (Fo2 + 2Fc2)/3 |
4876 reflections | (Δ/σ)max < 0.001 |
238 parameters | Δρmax = 0.32 e Å−3 |
0 restraints | Δρmin = −0.36 e Å−3 |
C14H19N5O4·H2O | V = 1674.06 (11) Å3 |
Mr = 339.36 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 11.9683 (5) Å | µ = 0.10 mm−1 |
b = 15.7252 (6) Å | T = 100 K |
c = 8.9289 (3) Å | 0.57 × 0.09 × 0.08 mm |
β = 94.998 (2)° |
Bruker SMART APEXII CCD area-detector diffractometer | 4876 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | 2723 reflections with I > 2σ(I) |
Tmin = 0.943, Tmax = 0.992 | Rint = 0.061 |
21832 measured reflections |
R[F2 > 2σ(F2)] = 0.061 | 0 restraints |
wR(F2) = 0.166 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | Δρmax = 0.32 e Å−3 |
4876 reflections | Δρmin = −0.36 e Å−3 |
238 parameters |
Experimental. The data was collected with the Oxford Cyrosystem Cobra low-temperature attachment. |
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 | ||
O1W | 0.33669 (13) | 0.55171 (10) | 0.83417 (19) | 0.0319 (4) | |
H2W | 0.3765 (19) | 0.5502 (14) | 0.916 (3) | 0.041 (7)* | |
H1W | 0.375 (2) | 0.5259 (17) | 0.776 (3) | 0.064 (9)* | |
N1 | 0.74698 (13) | 0.21118 (11) | 0.76942 (17) | 0.0226 (4) | |
H1N1 | 0.7338 (16) | 0.1598 (14) | 0.731 (2) | 0.030 (6)* | |
N2 | 0.65491 (14) | 0.33999 (10) | 0.80582 (17) | 0.0231 (4) | |
H1N2 | 0.6955 (18) | 0.3425 (13) | 0.887 (2) | 0.036 (6)* | |
N3 | 0.61656 (13) | 0.25861 (10) | 0.58549 (16) | 0.0224 (4) | |
N4 | 0.48333 (13) | 0.30708 (10) | 0.40139 (16) | 0.0235 (4) | |
N5 | 0.42175 (13) | 0.43870 (10) | 0.59176 (17) | 0.0280 (4) | |
O1 | 0.85318 (11) | 0.29207 (9) | 0.93866 (15) | 0.0299 (3) | |
O2 | 0.55239 (12) | 0.45420 (9) | 0.86810 (15) | 0.0358 (4) | |
O3 | 0.24515 (11) | 0.40072 (9) | 0.20062 (14) | 0.0320 (4) | |
O4 | 0.32505 (11) | 0.26822 (9) | 0.15833 (14) | 0.0301 (3) | |
C1 | 0.56955 (16) | 0.39795 (12) | 0.7781 (2) | 0.0255 (4) | |
C2 | 0.50631 (16) | 0.38486 (12) | 0.6321 (2) | 0.0236 (4) | |
C3 | 0.36985 (17) | 0.42572 (13) | 0.4568 (2) | 0.0289 (5) | |
H3A | 0.3100 | 0.4607 | 0.4241 | 0.035* | |
C4 | 0.40165 (16) | 0.36134 (13) | 0.3615 (2) | 0.0251 (4) | |
C5 | 0.53529 (15) | 0.31760 (12) | 0.54104 (19) | 0.0219 (4) | |
C6 | 0.66998 (15) | 0.27179 (11) | 0.7166 (2) | 0.0213 (4) | |
C7 | 0.83548 (15) | 0.22343 (12) | 0.8770 (2) | 0.0235 (4) | |
C8 | 0.90800 (16) | 0.14517 (12) | 0.9143 (2) | 0.0249 (4) | |
C9 | 1.00897 (17) | 0.17112 (14) | 1.0194 (2) | 0.0373 (5) | |
H9A | 1.0516 | 0.2132 | 0.9712 | 0.056* | |
H9B | 1.0551 | 0.1222 | 1.0433 | 0.056* | |
H9C | 0.9839 | 0.1944 | 1.1101 | 0.056* | |
C10 | 0.94675 (17) | 0.10571 (13) | 0.7706 (2) | 0.0327 (5) | |
H10A | 0.9829 | 0.1484 | 0.7149 | 0.049* | |
H10B | 0.8830 | 0.0836 | 0.7102 | 0.049* | |
H10C | 0.9986 | 0.0604 | 0.7967 | 0.049* | |
C11 | 0.83748 (17) | 0.08041 (13) | 0.9936 (2) | 0.0329 (5) | |
H11A | 0.8156 | 0.1045 | 1.0854 | 0.049* | |
H11B | 0.8810 | 0.0300 | 1.0158 | 0.049* | |
H11C | 0.7717 | 0.0662 | 0.9291 | 0.049* | |
C12 | 0.34396 (16) | 0.35271 (13) | 0.2031 (2) | 0.0273 (5) | |
H12A | 0.3924 | 0.3790 | 0.1332 | 0.033* | |
C13 | 0.19087 (18) | 0.41344 (14) | 0.0531 (2) | 0.0364 (5) | |
H13A | 0.1329 | 0.4554 | 0.0572 | 0.055* | |
H13B | 0.1585 | 0.3608 | 0.0161 | 0.055* | |
H13C | 0.2448 | 0.4327 | −0.0128 | 0.055* | |
C14 | 0.25935 (18) | 0.22090 (15) | 0.2566 (2) | 0.0375 (5) | |
H14A | 0.2477 | 0.1643 | 0.2182 | 0.056* | |
H14B | 0.1882 | 0.2484 | 0.2620 | 0.056* | |
H14C | 0.2983 | 0.2184 | 0.3551 | 0.056* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1W | 0.0349 (9) | 0.0347 (9) | 0.0253 (8) | 0.0079 (7) | −0.0017 (7) | −0.0030 (7) |
N1 | 0.0278 (9) | 0.0197 (9) | 0.0194 (8) | 0.0041 (7) | −0.0026 (7) | −0.0009 (7) |
N2 | 0.0275 (9) | 0.0260 (9) | 0.0152 (8) | 0.0036 (7) | −0.0014 (7) | −0.0015 (7) |
N3 | 0.0236 (8) | 0.0265 (9) | 0.0169 (8) | 0.0025 (7) | 0.0012 (6) | 0.0006 (6) |
N4 | 0.0243 (9) | 0.0282 (9) | 0.0179 (8) | 0.0028 (7) | 0.0009 (7) | 0.0015 (6) |
N5 | 0.0304 (9) | 0.0308 (9) | 0.0223 (8) | 0.0070 (7) | 0.0005 (7) | −0.0010 (7) |
O1 | 0.0286 (8) | 0.0287 (8) | 0.0311 (8) | 0.0001 (6) | −0.0044 (6) | −0.0038 (6) |
O2 | 0.0457 (9) | 0.0352 (8) | 0.0248 (7) | 0.0134 (7) | −0.0058 (7) | −0.0096 (6) |
O3 | 0.0315 (8) | 0.0410 (9) | 0.0227 (7) | 0.0111 (6) | −0.0014 (6) | 0.0005 (6) |
O4 | 0.0330 (8) | 0.0352 (9) | 0.0218 (7) | 0.0027 (6) | 0.0016 (6) | −0.0023 (6) |
C1 | 0.0289 (11) | 0.0260 (11) | 0.0214 (9) | 0.0022 (8) | 0.0014 (8) | 0.0014 (8) |
C2 | 0.0267 (10) | 0.0230 (10) | 0.0209 (9) | 0.0025 (8) | 0.0013 (8) | 0.0019 (8) |
C3 | 0.0328 (11) | 0.0317 (12) | 0.0213 (10) | 0.0080 (9) | −0.0024 (8) | 0.0002 (8) |
C4 | 0.0248 (10) | 0.0302 (11) | 0.0203 (9) | 0.0000 (8) | 0.0027 (8) | 0.0009 (8) |
C5 | 0.0232 (10) | 0.0244 (10) | 0.0187 (9) | −0.0006 (8) | 0.0041 (7) | 0.0008 (8) |
C6 | 0.0221 (10) | 0.0210 (10) | 0.0212 (9) | −0.0009 (8) | 0.0045 (8) | 0.0025 (7) |
C7 | 0.0240 (10) | 0.0278 (11) | 0.0192 (9) | −0.0003 (8) | 0.0039 (8) | 0.0020 (8) |
C8 | 0.0247 (10) | 0.0278 (11) | 0.0218 (9) | 0.0024 (8) | −0.0010 (8) | 0.0024 (8) |
C9 | 0.0322 (12) | 0.0365 (13) | 0.0409 (13) | 0.0046 (10) | −0.0098 (10) | −0.0030 (10) |
C10 | 0.0330 (12) | 0.0367 (12) | 0.0281 (11) | 0.0103 (9) | 0.0021 (9) | −0.0002 (9) |
C11 | 0.0339 (12) | 0.0317 (12) | 0.0327 (11) | 0.0034 (10) | 0.0011 (9) | 0.0069 (9) |
C12 | 0.0282 (11) | 0.0300 (11) | 0.0236 (10) | 0.0031 (9) | 0.0009 (8) | 0.0006 (8) |
C13 | 0.0358 (12) | 0.0491 (14) | 0.0229 (10) | 0.0087 (11) | −0.0044 (9) | 0.0077 (10) |
C14 | 0.0374 (13) | 0.0434 (14) | 0.0310 (12) | −0.0070 (10) | −0.0004 (10) | 0.0015 (10) |
O1W—H2W | 0.84 (2) | C3—H3A | 0.9300 |
O1W—H1W | 0.83 (3) | C4—C12 | 1.525 (3) |
N1—C7 | 1.380 (2) | C7—C8 | 1.526 (3) |
N1—C6 | 1.380 (2) | C8—C9 | 1.520 (3) |
N1—H1N1 | 0.89 (2) | C8—C10 | 1.533 (3) |
N2—C6 | 1.358 (2) | C8—C11 | 1.534 (3) |
N2—C1 | 1.375 (2) | C9—H9A | 0.9600 |
N2—H1N2 | 0.84 (2) | C9—H9B | 0.9600 |
N3—C6 | 1.300 (2) | C9—H9C | 0.9600 |
N3—C5 | 1.377 (2) | C10—H10A | 0.9600 |
N4—C4 | 1.323 (2) | C10—H10B | 0.9600 |
N4—C5 | 1.354 (2) | C10—H10C | 0.9600 |
N5—C3 | 1.323 (2) | C11—H11A | 0.9600 |
N5—C2 | 1.344 (2) | C11—H11B | 0.9600 |
O1—C7 | 1.222 (2) | C11—H11C | 0.9600 |
O2—C1 | 1.224 (2) | C12—H12A | 0.9800 |
O3—C12 | 1.402 (2) | C13—H13A | 0.9600 |
O3—C13 | 1.431 (2) | C13—H13B | 0.9600 |
O4—C12 | 1.400 (2) | C13—H13C | 0.9600 |
O4—C14 | 1.436 (2) | C14—H14A | 0.9600 |
C1—C2 | 1.464 (3) | C14—H14B | 0.9600 |
C2—C5 | 1.396 (3) | C14—H14C | 0.9600 |
C3—C4 | 1.396 (3) | ||
H2W—O1W—H1W | 104 (2) | C10—C8—C11 | 109.64 (17) |
C7—N1—C6 | 126.22 (17) | C8—C9—H9A | 109.5 |
C7—N1—H1N1 | 119.8 (13) | C8—C9—H9B | 109.5 |
C6—N1—H1N1 | 113.9 (13) | H9A—C9—H9B | 109.5 |
C6—N2—C1 | 123.54 (16) | C8—C9—H9C | 109.5 |
C6—N2—H1N2 | 116.6 (15) | H9A—C9—H9C | 109.5 |
C1—N2—H1N2 | 119.4 (15) | H9B—C9—H9C | 109.5 |
C6—N3—C5 | 115.57 (16) | C8—C10—H10A | 109.5 |
C4—N4—C5 | 116.01 (16) | C8—C10—H10B | 109.5 |
C3—N5—C2 | 115.46 (16) | H10A—C10—H10B | 109.5 |
C12—O3—C13 | 113.87 (15) | C8—C10—H10C | 109.5 |
C12—O4—C14 | 113.63 (15) | H10A—C10—H10C | 109.5 |
O2—C1—N2 | 121.69 (17) | H10B—C10—H10C | 109.5 |
O2—C1—C2 | 125.64 (17) | C8—C11—H11A | 109.5 |
N2—C1—C2 | 112.66 (16) | C8—C11—H11B | 109.5 |
N5—C2—C5 | 122.71 (17) | H11A—C11—H11B | 109.5 |
N5—C2—C1 | 117.96 (16) | C8—C11—H11C | 109.5 |
C5—C2—C1 | 119.33 (17) | H11A—C11—H11C | 109.5 |
N5—C3—C4 | 122.39 (18) | H11B—C11—H11C | 109.5 |
N5—C3—H3A | 118.8 | O4—C12—O3 | 113.05 (15) |
C4—C3—H3A | 118.8 | O4—C12—C4 | 113.46 (16) |
N4—C4—C3 | 122.53 (17) | O3—C12—C4 | 106.26 (15) |
N4—C4—C12 | 117.17 (16) | O4—C12—H12A | 107.9 |
C3—C4—C12 | 120.28 (17) | O3—C12—H12A | 107.9 |
N4—C5—N3 | 116.06 (16) | C4—C12—H12A | 107.9 |
N4—C5—C2 | 120.76 (17) | O3—C13—H13A | 109.5 |
N3—C5—C2 | 123.19 (16) | O3—C13—H13B | 109.5 |
N3—C6—N2 | 125.05 (17) | H13A—C13—H13B | 109.5 |
N3—C6—N1 | 117.33 (16) | O3—C13—H13C | 109.5 |
N2—C6—N1 | 117.62 (16) | H13A—C13—H13C | 109.5 |
O1—C7—N1 | 121.97 (17) | H13B—C13—H13C | 109.5 |
O1—C7—C8 | 122.73 (17) | O4—C14—H14A | 109.5 |
N1—C7—C8 | 115.29 (16) | O4—C14—H14B | 109.5 |
C9—C8—C7 | 108.96 (16) | H14A—C14—H14B | 109.5 |
C9—C8—C10 | 110.07 (17) | O4—C14—H14C | 109.5 |
C7—C8—C10 | 110.55 (15) | H14A—C14—H14C | 109.5 |
C9—C8—C11 | 109.47 (16) | H14B—C14—H14C | 109.5 |
C7—C8—C11 | 108.11 (15) | ||
C6—N2—C1—O2 | 173.22 (18) | C5—N3—C6—N1 | 175.91 (15) |
C6—N2—C1—C2 | −7.8 (3) | C1—N2—C6—N3 | 9.6 (3) |
C3—N5—C2—C5 | −2.4 (3) | C1—N2—C6—N1 | −169.62 (16) |
C3—N5—C2—C1 | 177.85 (17) | C7—N1—C6—N3 | 158.04 (17) |
O2—C1—C2—N5 | −0.1 (3) | C7—N1—C6—N2 | −22.7 (3) |
N2—C1—C2—N5 | −178.98 (16) | C6—N1—C7—O1 | 0.9 (3) |
O2—C1—C2—C5 | −179.84 (19) | C6—N1—C7—C8 | −179.91 (16) |
N2—C1—C2—C5 | 1.2 (3) | O1—C7—C8—C9 | −7.5 (3) |
C2—N5—C3—C4 | −0.9 (3) | N1—C7—C8—C9 | 173.27 (16) |
C5—N4—C4—C3 | −0.2 (3) | O1—C7—C8—C10 | −128.64 (19) |
C5—N4—C4—C12 | 178.21 (16) | N1—C7—C8—C10 | 52.2 (2) |
N5—C3—C4—N4 | 2.3 (3) | O1—C7—C8—C11 | 111.3 (2) |
N5—C3—C4—C12 | −176.04 (18) | N1—C7—C8—C11 | −67.8 (2) |
C4—N4—C5—N3 | 176.92 (16) | C14—O4—C12—O3 | −63.6 (2) |
C4—N4—C5—C2 | −3.0 (3) | C14—O4—C12—C4 | 57.4 (2) |
C6—N3—C5—N4 | 176.56 (16) | C13—O3—C12—O4 | −66.3 (2) |
C6—N3—C5—C2 | −3.5 (3) | C13—O3—C12—C4 | 168.57 (16) |
N5—C2—C5—N4 | 4.6 (3) | N4—C4—C12—O4 | 40.6 (2) |
C1—C2—C5—N4 | −175.67 (17) | C3—C4—C12—O4 | −140.96 (18) |
N5—C2—C5—N3 | −175.38 (17) | N4—C4—C12—O3 | 165.42 (16) |
C1—C2—C5—N3 | 4.4 (3) | C3—C4—C12—O3 | −16.1 (2) |
C5—N3—C6—N2 | −3.3 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1W···O2 | 0.83 (3) | 2.48 (2) | 2.995 (2) | 121 (2) |
O1W—H1W···N5 | 0.83 (3) | 2.25 (3) | 3.044 (2) | 161 (2) |
O1W—H2W···O2i | 0.84 (3) | 2.04 (3) | 2.868 (2) | 170 (2) |
N1—H1N1···O1Wii | 0.89 (2) | 1.96 (2) | 2.826 (2) | 164.0 (18) |
N2—H1N2···O1 | 0.838 (19) | 2.06 (2) | 2.667 (2) | 128.8 (18) |
N2—H1N2···N3iii | 0.838 (19) | 2.62 (2) | 3.008 (2) | 109.9 (17) |
C3—H3A···O3 | 0.93 | 2.28 | 2.649 (2) | 103 |
C11—H11C···O1Wii | 0.96 | 2.59 | 3.471 (2) | 152 |
C14—H14C···N4 | 0.96 | 2.62 | 3.176 (3) | 117 |
C11—H11A···Cg1iv | 0.96 | 3.05 | 3.766 (2) | 132 |
C14—H14A···Cg2v | 0.96 | 3.33 | 3.718 (2) | 106 |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) −x+1, y−1/2, −z+3/2; (iii) x, −y+1/2, z+1/2; (iv) x, −y−1/2, z−1/2; (v) x, −y−1/2, z−3/2. |
Experimental details
Crystal data | |
Chemical formula | C14H19N5O4·H2O |
Mr | 339.36 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 100 |
a, b, c (Å) | 11.9683 (5), 15.7252 (6), 8.9289 (3) |
β (°) | 94.998 (2) |
V (Å3) | 1674.06 (11) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.57 × 0.09 × 0.08 |
Data collection | |
Diffractometer | Bruker SMART APEXII CCD area-detector |
Absorption correction | Multi-scan (SADABS; Bruker, 2005) |
Tmin, Tmax | 0.943, 0.992 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 21832, 4876, 2723 |
Rint | 0.061 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.061, 0.166, 1.05 |
No. of reflections | 4876 |
No. of parameters | 238 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.32, −0.36 |
Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 1998) and PLATON (Spek, 2003).
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1W···O2 | 0.83 (3) | 2.48 (2) | 2.995 (2) | 121 (2) |
O1W—H1W···N5 | 0.83 (3) | 2.25 (3) | 3.044 (2) | 161 (2) |
O1W—H2W···O2i | 0.84 (3) | 2.04 (3) | 2.868 (2) | 170 (2) |
N1—H1N1···O1Wii | 0.89 (2) | 1.96 (2) | 2.826 (2) | 164.0 (18) |
N2—H1N2···O1 | 0.838 (19) | 2.06 (2) | 2.667 (2) | 128.8 (18) |
N2—H1N2···N3iii | 0.838 (19) | 2.62 (2) | 3.008 (2) | 109.9 (17) |
C3—H3A···O3 | 0.93 | 2.2812 | 2.649 (2) | 103 |
C11—H11C···O1Wii | 0.96 | 2.5941 | 3.471 (2) | 152 |
C14—H14C···N4 | 0.96 | 2.6192 | 3.176 (3) | 117 |
C11—H11A···Cg1iv | 0.96 | 3.0508 | 3.766 (2) | 132 |
C14—H14A···Cg2v | 0.96 | 3.3324 | 3.718 (2) | 106 |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) −x+1, y−1/2, −z+3/2; (iii) x, −y+1/2, z+1/2; (iv) x, −y−1/2, z−1/2; (v) x, −y−1/2, z−3/2. |
6-Formylpterin is a useful precursor to the nutrient cofactor folic acid, anticancer drug methotrexate (Piper & Montgomery, 1977) and related pteridines like biopterin, neopterin, monapterin, umanopterin as well as precursor Z of molybdenum cofactor or Moco (Pateman et al., 1964; Hille, 1996). These naturally occurring pteridine derivatives are mostly found in human urine and plasma, toad skins, germinating potatoes and various micro-organisms. All compounds of these heterocyclic ring systems found in nature so far, are derivatives of pterin and lumazine carrying different substituents in the 6- and/or 7- positions. One interesting aspect of the pterin system besides its biological importance is that pterins are fluorescent and thus fluorescence assay makes them detectable in biological systems even in trace amounts. We report here the hydrogen-bonding network in the crystal structure of the title compound, as an example of a 7-substituted soluble pterin derivative. We have previously reported the crystal structures of pivaloyl halopterins (Goswami et al., 2000; Shanmuga Sundara Raj et al., 2000), as part of our research program on solubilizing pterins and establish their X-ray structures to investigate their supramolecular network. The first general and unequivocal multistep 7-formylpterin dimethyl acetal was elegantly synthesized by Taylor (Taylor & Dumas, 1981).
In the molecules of the title compound (Fig. 1), the 3,4-dihydropteridine ring (N2–N5/C1–C6) deviates significantly from planarity with the largest deviations found for atoms N2 and N5 [0.0824 (17) and -0.0472 (16) Å, respectively], and the total puckering parameter Q = 0.144 (2) Å (Cremer & Pople, 1975). The dihedral angle between the mean planes of the two rings in the molecular structure is 3.93 (9)°. The 2,2-dimethylpropionamide substituent (O1/N1/C7–C11) is attached at atom C6, the dihedral angle between the mean plane of O1/N1/C6/C7/C8 group and the attached ring is 23.80 (9)°. The orientation of the two dimethoxymethyl groups can be indicated by the torsion angles C13—O3—C12—C4 = 168.57 (16)° and C14—O4—C12—C4 = 57.4 (2)°. The intramolecular N—H···O hydrogen bond generates an S(6) ring motif (Bernstein et al., 1995). The water molecule forms intramolecular O—H···O and O—H···N hydrogen bonds with the 3,4-dihydro-pteridine (Table 1). In the crystal (Fig. 2), the substituted-pteridine molecules are linked by N—H···N hydrogen bonds (N2—H1N2···N3) into chains running along the c direction. These chains are further connected to the water molecules by N—H···O, O—H···O and O—H···N hydrogen bonds to form two-dimemsional networks parallel to the bc plane. The crystal is stabilized by intra- and intermolecular N—H···O, N—H···N, O—H···O and O—H···N hydrogen bonds together with weak C—H···O and C—H···N intra- and intermolecular interactions. C—H···π interactions further stabilized the crystal (Table 1); Cg1 and Cg2 are the centroids of the C1/C2/C5/N3/C6/N2 and N5/C3/C4/N4/C5/C2 rings, respectively.