organic compounds
4-Hydrazino-1-methylpyrazolo[3,4-d]pyrimidine
aDepartment of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore, and bDepartment of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
*Correspondence e-mail: phada@nus.edu.sg
The title compound, C6H8N6, crystallizes as an N—H⋯N hydrogen-bond-linked dimer of two almost identical molecules in the Both of the molecules are almost planar (rms deviations of 0.0186 and 0.0296 Å in the two molecules) and their hydrazino groups are turned towards the pyrazole rings. The dimers are arranged into chains via intermolecular N—H⋯N hydrogen bonds between the hydrazino groups and the N atoms of the pyrimidine rings of both types of the molecules, linking the molecules into a C(7) graph-set motif along [100]. The methyl groups and the N atoms of the pyrazole rings form weak C—H⋯N hydrogen bonds, which connect chains of the dimers in a C(4) motif parallel to [100].
Related literature
For recent reviews on the synthesis and biological activity of pyrazolo[3,4-d]pyrimidines, see: Caravatti et al. (2001); Dang (2002); Schenone et al. (2007); Schenone et al. (2008). The synthesis of the title compound was performed according to the procedure reported by Taylor & Loeffler (1960). For the of 1-methyl-4-(2-methylhydrazino)pyrazolo[3,4-d]pyrimidine, see: Hosmane et al. (1988). For the graph-set analysis of hydrogen bonding, see: Bernstein et al. (1995).
Experimental
Crystal data
|
Refinement
|
Data collection: SMART (Bruker, 2001); cell SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S1600536809023952/jh2082sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809023952/jh2082Isup2.hkl
4-Hydrazino-1-methylpyrazolo[3,4-d]pyrimidine was synthesized by cyclocondensation of 4-cyano-5-[(ethoxymethylene)amino]-1-methylpyrazole with hydrazine according to the procedure reported by Taylor and Loeffler (1960). Single crystals suitable for crystallographic analysis were grown by recrystallization from ethanol.
All the H atoms attached to the carbon atoms were constrained in a riding motion approximation [0.94 Å for Caryl—H and 0.97 Å for methyl groups; Uiso(H) =1.2Ueq(Caryl) and Uiso(H) =1.5Ueq(Cmethyl)] while the N-bound H atoms were located in a difference map and refined freely. Friedel pairs were merged.
Data collection: SMART (Bruker, 2001); cell
SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).Fig. 1. The synthesis of 4-hydrazino-1-methylpyrazolo[3,4-d]pyrimidine | |
Fig. 2. The hydrazino-hydrazono tautomerism in the title compound | |
Fig. 3. The molecular structure of 4-hydrazino-1-methylpyrazolo[3,4-d]pyrimidine with the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. | |
Fig. 4. Molecular parking in the crystal, viewed along the b axis. |
C6H8N6 | Dx = 1.465 Mg m−3 |
Mr = 164.18 | Melting point: 514 K |
Orthorhombic, Pna21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2c -2n | Cell parameters from 3657 reflections |
a = 14.086 (4) Å | θ = 2.9–27.2° |
b = 3.8756 (12) Å | µ = 0.10 mm−1 |
c = 27.271 (8) Å | T = 223 K |
V = 1488.8 (8) Å3 | Block, colourless |
Z = 8 | 0.58 × 0.26 × 0.10 mm |
F(000) = 688 |
Bruker SMART APEX CCD diffractometer | 1715 independent reflections |
Radiation source: fine-focus sealed tube | 1652 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.051 |
ϕ and ω scans | θmax = 27.5°, θmin = 1.5° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | h = −18→18 |
Tmin = 0.943, Tmax = 0.990 | k = −5→4 |
8939 measured reflections | l = −24→35 |
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)] = 0.065 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.159 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.21 | w = 1/[σ2(Fo2) + (0.0699P)2 + 1.3392P] where P = (Fo2 + 2Fc2)/3 |
1715 reflections | (Δ/σ)max < 0.001 |
243 parameters | Δρmax = 0.29 e Å−3 |
1 restraint | Δρmin = −0.28 e Å−3 |
C6H8N6 | V = 1488.8 (8) Å3 |
Mr = 164.18 | Z = 8 |
Orthorhombic, Pna21 | Mo Kα radiation |
a = 14.086 (4) Å | µ = 0.10 mm−1 |
b = 3.8756 (12) Å | T = 223 K |
c = 27.271 (8) Å | 0.58 × 0.26 × 0.10 mm |
Bruker SMART APEX CCD diffractometer | 1715 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | 1652 reflections with I > 2σ(I) |
Tmin = 0.943, Tmax = 0.990 | Rint = 0.051 |
8939 measured reflections |
R[F2 > 2σ(F2)] = 0.065 | 1 restraint |
wR(F2) = 0.159 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.21 | Δρmax = 0.29 e Å−3 |
1715 reflections | Δρmin = −0.28 e Å−3 |
243 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 | ||
N1 | 0.4891 (3) | 0.4783 (12) | 0.43889 (16) | 0.0351 (9) | |
N2 | 0.4203 (3) | 0.6408 (11) | 0.46578 (15) | 0.0307 (9) | |
N3 | 0.3922 (2) | 0.8124 (10) | 0.54938 (15) | 0.0273 (9) | |
N4 | 0.5189 (3) | 0.6416 (10) | 0.60298 (15) | 0.0281 (8) | |
N5 | 0.6553 (3) | 0.3740 (12) | 0.57903 (17) | 0.0321 (9) | |
H5N | 0.668 (4) | 0.343 (14) | 0.609 (2) | 0.030 (14)* | |
N6 | 0.7119 (3) | 0.2094 (13) | 0.54313 (18) | 0.0348 (10) | |
H6NA | 0.764 (5) | 0.32 (2) | 0.549 (3) | 0.05 (2)* | |
H6NB | 0.731 (4) | 0.007 (19) | 0.555 (2) | 0.037 (16)* | |
N7 | 0.7580 (3) | 0.6324 (11) | 0.84251 (15) | 0.0335 (9) | |
N8 | 0.8271 (3) | 0.4576 (10) | 0.81702 (14) | 0.0297 (9) | |
N9 | 0.8504 (2) | 0.2236 (10) | 0.73690 (15) | 0.0274 (9) | |
N10 | 0.7183 (3) | 0.3347 (11) | 0.68245 (15) | 0.0281 (8) | |
N11 | 0.5809 (2) | 0.5994 (12) | 0.70605 (16) | 0.0300 (9) | |
H11N | 0.566 (4) | 0.587 (14) | 0.676 (2) | 0.025 (13)* | |
N12 | 0.5243 (3) | 0.7763 (12) | 0.74061 (17) | 0.0292 (9) | |
H12D | 0.469 (4) | 0.656 (15) | 0.743 (2) | 0.030 (14)* | |
H12E | 0.518 (4) | 1.019 (18) | 0.732 (2) | 0.037 (15)* | |
C1 | 0.5567 (3) | 0.3971 (14) | 0.47002 (17) | 0.0310 (10) | |
H1 | 0.6128 | 0.2804 | 0.4616 | 0.037* | |
C2 | 0.5337 (3) | 0.5087 (12) | 0.51798 (17) | 0.0242 (9) | |
C3 | 0.4448 (3) | 0.6664 (12) | 0.51286 (17) | 0.0247 (9) | |
C4 | 0.4345 (3) | 0.7879 (13) | 0.59211 (18) | 0.0280 (10) | |
H4 | 0.4016 | 0.8853 | 0.6187 | 0.034* | |
C5 | 0.5701 (3) | 0.5040 (12) | 0.56624 (17) | 0.0253 (9) | |
C6 | 0.3354 (4) | 0.7825 (17) | 0.4417 (2) | 0.0425 (13) | |
H6A | 0.3540 | 0.9659 | 0.4195 | 0.064* | |
H6B | 0.2925 | 0.8736 | 0.4663 | 0.064* | |
H6C | 0.3038 | 0.6013 | 0.4234 | 0.064* | |
C9 | 0.7999 (3) | 0.3896 (12) | 0.77082 (18) | 0.0242 (9) | |
C7 | 0.6873 (3) | 0.6765 (13) | 0.81121 (18) | 0.0309 (10) | |
H7 | 0.6305 | 0.7923 | 0.8187 | 0.037* | |
C8 | 0.7076 (3) | 0.5295 (12) | 0.76570 (18) | 0.0239 (9) | |
C10 | 0.8039 (3) | 0.2142 (13) | 0.69443 (18) | 0.0282 (10) | |
H10 | 0.8367 | 0.1051 | 0.6687 | 0.034* | |
C11 | 0.6678 (3) | 0.4953 (12) | 0.71848 (16) | 0.0242 (9) | |
C12 | 0.9129 (4) | 0.3412 (17) | 0.8420 (2) | 0.0430 (14) | |
H12A | 0.9554 | 0.2352 | 0.8184 | 0.065* | |
H12B | 0.8962 | 0.1739 | 0.8670 | 0.065* | |
H12C | 0.9442 | 0.5369 | 0.8571 | 0.065* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0288 (19) | 0.046 (2) | 0.031 (2) | −0.0051 (18) | 0.0019 (17) | −0.0057 (19) |
N2 | 0.0226 (18) | 0.042 (2) | 0.027 (2) | −0.0047 (16) | −0.0017 (15) | 0.0028 (18) |
N3 | 0.0193 (16) | 0.030 (2) | 0.032 (2) | 0.0040 (15) | −0.0007 (16) | −0.0014 (16) |
N4 | 0.0202 (18) | 0.034 (2) | 0.030 (2) | −0.0008 (15) | −0.0005 (14) | −0.0005 (17) |
N5 | 0.0208 (17) | 0.046 (3) | 0.029 (2) | 0.0086 (17) | −0.0004 (16) | 0.0020 (19) |
N6 | 0.0206 (19) | 0.036 (3) | 0.048 (3) | 0.0011 (18) | 0.0044 (18) | −0.001 (2) |
N7 | 0.0301 (19) | 0.039 (2) | 0.031 (2) | 0.0009 (18) | −0.0001 (16) | 0.0056 (18) |
N8 | 0.0227 (17) | 0.035 (2) | 0.031 (2) | −0.0009 (15) | −0.0055 (16) | 0.0078 (17) |
N9 | 0.0163 (16) | 0.0300 (19) | 0.036 (2) | −0.0027 (15) | 0.0012 (15) | 0.0041 (17) |
N10 | 0.0222 (17) | 0.035 (2) | 0.0272 (19) | 0.0039 (15) | −0.0023 (15) | 0.0049 (17) |
N11 | 0.0158 (17) | 0.046 (2) | 0.028 (2) | 0.0042 (16) | −0.0029 (15) | −0.0013 (18) |
N12 | 0.0126 (16) | 0.036 (2) | 0.039 (2) | 0.0009 (16) | −0.0018 (15) | −0.0010 (19) |
C1 | 0.023 (2) | 0.043 (3) | 0.027 (2) | −0.005 (2) | 0.0039 (19) | 0.002 (2) |
C2 | 0.0166 (18) | 0.028 (2) | 0.029 (2) | −0.0044 (17) | 0.0037 (16) | 0.0003 (18) |
C3 | 0.020 (2) | 0.025 (2) | 0.029 (2) | −0.0086 (16) | −0.0021 (17) | 0.0052 (18) |
C4 | 0.0210 (19) | 0.035 (3) | 0.029 (2) | 0.0055 (18) | 0.0048 (18) | 0.0001 (18) |
C5 | 0.0191 (17) | 0.024 (2) | 0.033 (2) | −0.0056 (15) | 0.0011 (16) | 0.0043 (17) |
C6 | 0.032 (3) | 0.058 (4) | 0.037 (3) | 0.001 (2) | −0.015 (2) | −0.001 (3) |
C9 | 0.0162 (17) | 0.023 (2) | 0.033 (2) | −0.0034 (16) | −0.0032 (17) | 0.0062 (18) |
C7 | 0.0192 (19) | 0.039 (3) | 0.035 (2) | −0.0018 (18) | −0.0007 (19) | 0.006 (2) |
C8 | 0.0158 (17) | 0.025 (2) | 0.031 (2) | −0.0027 (15) | 0.0003 (17) | 0.0072 (18) |
C10 | 0.022 (2) | 0.035 (2) | 0.028 (2) | −0.0029 (18) | 0.0048 (18) | 0.0010 (19) |
C11 | 0.0145 (17) | 0.031 (2) | 0.027 (2) | −0.0012 (16) | −0.0001 (16) | 0.0029 (18) |
C12 | 0.029 (2) | 0.056 (3) | 0.044 (3) | 0.005 (2) | −0.018 (2) | 0.010 (3) |
N1—C1 | 1.314 (7) | N11—C11 | 1.332 (5) |
N1—N2 | 1.369 (6) | N11—N12 | 1.412 (6) |
N2—C3 | 1.333 (6) | N11—H11N | 0.85 (6) |
N2—C6 | 1.470 (6) | N12—H12D | 0.91 (6) |
N3—C4 | 1.312 (6) | N12—H12E | 0.97 (7) |
N3—C3 | 1.364 (6) | C1—C2 | 1.415 (7) |
N4—C5 | 1.345 (6) | C1—H1 | 0.9400 |
N4—C4 | 1.350 (6) | C2—C3 | 1.401 (6) |
N5—C5 | 1.348 (6) | C2—C5 | 1.413 (6) |
N5—N6 | 1.415 (6) | C4—H4 | 0.9400 |
N5—H5N | 0.84 (7) | C6—H6A | 0.9700 |
N6—H6NA | 0.86 (7) | C6—H6B | 0.9700 |
N6—H6NB | 0.89 (7) | C6—H6C | 0.9700 |
N7—C7 | 1.322 (6) | C9—C8 | 1.415 (5) |
N7—N8 | 1.375 (6) | C7—C8 | 1.395 (7) |
N8—C9 | 1.343 (6) | C7—H7 | 0.9400 |
N8—C12 | 1.458 (6) | C8—C11 | 1.411 (6) |
N9—C10 | 1.331 (6) | C10—H10 | 0.9400 |
N9—C9 | 1.332 (6) | C12—H12A | 0.9700 |
N10—C10 | 1.334 (6) | C12—H12B | 0.9700 |
N10—C11 | 1.364 (6) | C12—H12C | 0.9700 |
C1—N1—N2 | 106.1 (4) | N3—C4—N4 | 128.7 (4) |
C3—N2—N1 | 111.5 (4) | N3—C4—H4 | 115.7 |
C3—N2—C6 | 127.8 (4) | N4—C4—H4 | 115.7 |
N1—N2—C6 | 120.5 (4) | N4—C5—N5 | 115.7 (4) |
C4—N3—C3 | 111.9 (4) | N4—C5—C2 | 119.6 (4) |
C5—N4—C4 | 118.4 (4) | N5—C5—C2 | 124.7 (4) |
C5—N5—N6 | 119.4 (4) | N2—C6—H6A | 109.5 |
C5—N5—H5N | 120 (4) | N2—C6—H6B | 109.5 |
N6—N5—H5N | 119 (4) | H6A—C6—H6B | 109.5 |
N5—N6—H6NA | 97 (5) | N2—C6—H6C | 109.5 |
N5—N6—H6NB | 108 (4) | H6A—C6—H6C | 109.5 |
H6NA—N6—H6NB | 97 (6) | H6B—C6—H6C | 109.5 |
C7—N7—N8 | 105.7 (4) | N9—C9—N8 | 126.4 (4) |
C9—N8—N7 | 111.6 (4) | N9—C9—C8 | 127.3 (4) |
C9—N8—C12 | 127.8 (4) | N8—C9—C8 | 106.2 (4) |
N7—N8—C12 | 120.2 (4) | N7—C7—C8 | 111.6 (4) |
C10—N9—C9 | 110.8 (4) | N7—C7—H7 | 124.2 |
C10—N10—C11 | 117.1 (4) | C8—C7—H7 | 124.2 |
C11—N11—N12 | 119.7 (4) | C7—C8—C11 | 140.2 (4) |
C11—N11—H11N | 118 (3) | C7—C8—C9 | 104.9 (4) |
N12—N11—H11N | 122 (4) | C11—C8—C9 | 114.8 (4) |
N11—N12—H12D | 107 (4) | N9—C10—N10 | 130.4 (5) |
N11—N12—H12E | 111 (4) | N9—C10—H10 | 114.8 |
H12D—N12—H12E | 116 (5) | N10—C10—H10 | 114.8 |
N1—C1—C2 | 111.0 (4) | N11—C11—N10 | 115.7 (4) |
N1—C1—H1 | 124.5 | N11—C11—C8 | 124.7 (4) |
C2—C1—H1 | 124.5 | N10—C11—C8 | 119.5 (4) |
C3—C2—C5 | 115.0 (4) | N8—C12—H12A | 109.5 |
C3—C2—C1 | 104.2 (4) | N8—C12—H12B | 109.5 |
C5—C2—C1 | 140.7 (4) | H12A—C12—H12B | 109.5 |
N2—C3—N3 | 126.4 (4) | N8—C12—H12C | 109.5 |
N2—C3—C2 | 107.2 (4) | H12A—C12—H12C | 109.5 |
N3—C3—C2 | 126.4 (4) | H12B—C12—H12C | 109.5 |
C1—N1—N2—C3 | 1.0 (5) | C3—C2—C5—N5 | −178.1 (4) |
C1—N1—N2—C6 | 177.0 (4) | C1—C2—C5—N5 | 3.4 (9) |
C7—N7—N8—C9 | −0.8 (5) | C10—N9—C9—N8 | −177.2 (4) |
C7—N7—N8—C12 | −175.0 (4) | C10—N9—C9—C8 | 2.7 (6) |
N2—N1—C1—C2 | −0.6 (6) | N7—N8—C9—N9 | −179.8 (4) |
N1—C1—C2—C3 | 0.1 (6) | C12—N8—C9—N9 | −6.0 (7) |
N1—C1—C2—C5 | 178.6 (5) | N7—N8—C9—C8 | 0.3 (5) |
N1—N2—C3—N3 | −179.7 (4) | C12—N8—C9—C8 | 174.0 (5) |
C6—N2—C3—N3 | 4.7 (8) | N8—N7—C7—C8 | 1.0 (6) |
N1—N2—C3—C2 | −0.9 (5) | N7—C7—C8—C11 | −177.1 (5) |
C6—N2—C3—C2 | −176.6 (5) | N7—C7—C8—C9 | −0.8 (6) |
C4—N3—C3—N2 | 178.0 (4) | N9—C9—C8—C7 | −179.7 (4) |
C4—N3—C3—C2 | −0.5 (6) | N8—C9—C8—C7 | 0.3 (5) |
C5—C2—C3—N2 | −178.5 (4) | N9—C9—C8—C11 | −2.3 (7) |
C1—C2—C3—N2 | 0.5 (5) | N8—C9—C8—C11 | 177.7 (4) |
C5—C2—C3—N3 | 0.3 (6) | C9—N9—C10—N10 | −1.5 (7) |
C1—C2—C3—N3 | 179.3 (4) | C11—N10—C10—N9 | 0.0 (7) |
C3—N3—C4—N4 | −0.3 (7) | N12—N11—C11—N10 | −178.3 (4) |
C5—N4—C4—N3 | 1.3 (8) | N12—N11—C11—C8 | 4.0 (7) |
C4—N4—C5—N5 | 177.5 (4) | C10—N10—C11—N11 | −177.1 (4) |
C4—N4—C5—C2 | −1.5 (6) | C10—N10—C11—C8 | 0.6 (6) |
N6—N5—C5—N4 | 176.9 (4) | C7—C8—C11—N11 | −6.0 (9) |
N6—N5—C5—C2 | −4.1 (7) | C9—C8—C11—N11 | 177.9 (4) |
C3—C2—C5—N4 | 0.8 (6) | C7—C8—C11—N10 | 176.4 (5) |
C1—C2—C5—N4 | −177.7 (6) | C9—C8—C11—N10 | 0.4 (6) |
D—H···A | D—H | H···A | D···A | D—H···A |
C12—H12B···N1i | 0.97 | 2.65 | 3.297 (7) | 124 |
C6—H6C···N7ii | 0.97 | 2.54 | 3.410 (7) | 150 |
N11—H11N···N4 | 0.85 (6) | 2.11 (6) | 2.948 (6) | 170 (5) |
N5—H5N···N10 | 0.84 (7) | 2.13 (7) | 2.961 (6) | 170 (5) |
N12—H12E···N9iii | 0.97 (7) | 2.56 (6) | 3.125 (5) | 117 (4) |
N12—H12D···N9iv | 0.91 (6) | 2.24 (6) | 3.125 (6) | 166 (5) |
N6—H6NB···N3v | 0.89 (7) | 2.59 (6) | 3.251 (6) | 131 (5) |
N6—H6NA···N3vi | 0.86 (7) | 2.30 (7) | 3.149 (6) | 168 (7) |
Symmetry codes: (i) −x+3/2, y−1/2, z+1/2; (ii) −x+1, −y+1, z−1/2; (iii) x−1/2, −y+3/2, z; (iv) x−1/2, −y+1/2, z; (v) x+1/2, −y+1/2, z; (vi) x+1/2, −y+3/2, z. |
Experimental details
Crystal data | |
Chemical formula | C6H8N6 |
Mr | 164.18 |
Crystal system, space group | Orthorhombic, Pna21 |
Temperature (K) | 223 |
a, b, c (Å) | 14.086 (4), 3.8756 (12), 27.271 (8) |
V (Å3) | 1488.8 (8) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.58 × 0.26 × 0.10 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2001) |
Tmin, Tmax | 0.943, 0.990 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8939, 1715, 1652 |
Rint | 0.051 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.065, 0.159, 1.21 |
No. of reflections | 1715 |
No. of parameters | 243 |
No. of restraints | 1 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.29, −0.28 |
Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C12—H12B···N1i | 0.97 | 2.65 | 3.297 (7) | 124.3 |
C6—H6C···N7ii | 0.97 | 2.54 | 3.410 (7) | 149.7 |
N11—H11N···N4 | 0.85 (6) | 2.11 (6) | 2.948 (6) | 170 (5) |
N5—H5N···N10 | 0.84 (7) | 2.13 (7) | 2.961 (6) | 170 (5) |
N12—H12E···N9iii | 0.97 (7) | 2.56 (6) | 3.125 (5) | 117 (4) |
N12—H12D···N9iv | 0.91 (6) | 2.24 (6) | 3.125 (6) | 166 (5) |
N6—H6NB···N3v | 0.89 (7) | 2.59 (6) | 3.251 (6) | 131 (5) |
N6—H6NA···N3vi | 0.86 (7) | 2.30 (7) | 3.149 (6) | 168 (7) |
Symmetry codes: (i) −x+3/2, y−1/2, z+1/2; (ii) −x+1, −y+1, z−1/2; (iii) x−1/2, −y+3/2, z; (iv) x−1/2, −y+1/2, z; (v) x+1/2, −y+1/2, z; (vi) x+1/2, −y+3/2, z. |
Acknowledgements
This work was supported by the National Medical Research Council, Singapore (NMRC/NIG/0020/2008) and the National University of Singapore (R-148–050-091–101/133).
References
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Bruker (2001). SMART and SAINT. Bruker AXS GmbH, Karlsruhe, Germany. Google Scholar
Caravatti, G., Bruggen, J., Buchdunger, E., Cozens, R., Furet, P., Lydon, N., O'Reilly, T. & Traxler, P. (2001). ACS Symp. Ser. 796, 231–244. CrossRef CAS Google Scholar
Dang, Q. (2002). Recent Res. Dev. Org. Chem. 6, 431–447. CAS Google Scholar
Hosmane, R. S., Lim, B. B., Summers, M. F., Siriwardane, U., Hosmane, N. S. & Chu, S. S. C. (1988). J. Org. Chem. 53, 5309–5315. CSD CrossRef CAS Web of Science Google Scholar
Schenone, S., Radi, M. & Botta, M. (2007). Targets Heterocycl. Syst. 11, 44–69. CAS Google Scholar
Schenone, S., Zanoli, S., Brullo, C., Crespan, E. & Maga, G. (2008). Curr. Drug Ther. 3, 158–176. CrossRef CAS Google Scholar
Sheldrick, G. M. (2001). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Taylor, E. C. Jr & Loeffler, P. K. (1960). J. Am. Chem. Soc. 82, 3147–3151. CrossRef CAS Web of Science Google Scholar
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 pyrazolo[3,4-d]pyrimidine heterocyclic system is known to be a bioisoster of purine. Therefore, chemistry of pyrazolo[3,4-d]pyrimidines has received significant attention, particularly for the development of new biologically active substances (Caravatti et al., 2001; Dang, 2002; Schenone et al., 2007; Schenone et al., 2008).
Herein, we report the crystal structure of 4-hydrazino-1-methylpyrazolo[3,4-d]pyrimidine, which was prepared via a reaction of 4-cyano-5-[(ethoxymethylene)amino]-1-methylpyrazole with hydrazine according to Taylor and Loeffler (1960) (Fig. 1). Theoretically, the compound might be involved in tautomerism with three tautomeric forms (Fig. 2). However, only one tautomeric form, similarly to previously reported 1-methyl-4-(2-methylhydrazino)pyrazolo[3,4-d]pyrimidine (Hosmane et al., 1988), was found in the crystal.
The title compound crystallizes in asymmetric unit as a dimer of two almost identical molecules (Fig. 3). Both molecules are essentially planar except for the hydrazino groups, which are turned towards pyrazole ring making the torsion angles C2—C5—N5—N6 and C8—C11—N11—N12 equal to 4.1 (7)° and 4.0 (7)°, respectively. The geometry of the molecule as well as 1.348 (6) Å and 1.332 (5) Å distances of C5—N5 and C11—N11 bonds indicate delocalization of the electron pairs of N5 and N11 with the pyrazolo[3,4-d]pyrimidine aromatic system.
In the crystal, the dimer molecules are linked in a R22(8) graph-set motif (Bernstein et al., 1995) by the N—H···N hydrogen bonds (Fig. 4, Table 1). The dimers are arranged into chains via intermolecular N—H···N hydrogen bonds between the hydrazino groups and the nitrogen atoms of the pyrimidine rings of both type of the molecules linking them with symmetry-related molecules in a C(7) graph-set motif along the [100] direction. The interactions between pyrimidine rings and hydrazino groups make a R44(14) hydrogen bond motif of the fourth order. The methyl groups and the nitrogen atoms of the pyrazole rings form weak C—H···N hydrogen bonds connecting chains of the dimers in a C(4) motif parallel to the [100]) direction.