5-tert-Butyl 1-ethyl 3-amino-1,4,5,6-tetra­hydro­pyrrolo­[3,4-c]pyrazole-1,5-dicarboxyl­ate

Wen-Bin Xia; Xiao-Guang Bai; Hong-Tao Liu; Ju-Xian Wang

doi:10.1107/S1600536811013444

. 2011 Apr 16;67(Pt 5):o1150. doi: 10.1107/S1600536811013444

5-tert-Butyl 1-ethyl 3-amino-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-1,5-dicarboxylate

Wen-Bin Xia ^a, Xiao-Guang Bai ^b, Hong-Tao Liu ^b, Ju-Xian Wang ^b,^*

PMCID: PMC3089316 PMID: 21754458

Abstract

The asymmetric unit of the title compound, C₁₃H₂₀N₄O₄, contains two crystallographically independent molecules in which the dihedral angles between the fused pyrrole and pyrazole rings are 5.06 (8) and 1.12 (8)°. In the crystal, molecules are linked by intermolecular N—H⋯O and N—H⋯N hydrogen bonds into chains parallel to the b axis.

Related literature

For general background to potential anticancer kinase inhibitors, see: Fancelli et al. (2005 ▶); Gadekar et al. (1968 ▶). For the structure of a related compound synthesized by our group, see: Guo et al. (2010 ▶).

Experimental

Crystal data

C₁₃H₂₀N₄O₄
M _r = 296.33
Triclinic,
a = 10.772 (3) Å
b = 12.180 (4) Å
c = 12.986 (4) Å
α = 70.845 (5)°
β = 65.875 (4)°
γ = 85.821 (5)°
V = 1465.2 (7) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 296 K
0.06 × 0.05 × 0.04 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.994, T _max = 0.996
7444 measured reflections
5102 independent reflections
3915 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.128
S = 1.03
5102 reflections
387 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); 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.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811013444/rz2580sup1.cif

e-67-o1150-sup1.cif^{(27.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811013444/rz2580Isup2.hkl

e-67-o1150-Isup2.hkl^{(249.8KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N8—H8"⋯O4ⁱ	0.86	2.25	3.069 (3)	160
N8—H8′⋯N2ⁱⁱ	0.86	2.26	3.087 (3)	163
N4—H4′⋯N6ⁱⁱⁱ	0.90	2.25	3.104 (3)	157
N4—H4"⋯O8^iv	0.90	2.36	3.233 (3)	163

Open in a new tab

Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

This work was supported by the National Natural Science Foundation (81072577).

supplementary crystallographic information

Comment

As an extension of our work (Guo et al., 2010) on the development of potential anticancer kinase inhibitors (Fancelli et al., 2005; Gadekar et al., 1968), we have synthesized the title compound and report its crystal structure herein.

The asymmetric unit of the title compound (Fig. 1) contains two crystallographically independent molecules. All bond lengths and angles have normal values. The dihedral angles between the fused pyrrole and pyrazole rings are 5.06 (8) and 1.12 (8)°. The C6/O1/O2/C7 and C9/O4/O3/C10 mean planes form dihedral angles of 5.83(0.09)° and 14.86(0.10) °, respectively, with the mean plane through N1/N2/C2/C1/C3/C4/C5/N3, whereas the O8/C22/O7/C23 and C18/O5/O6/C17 mean planes form dihedral angles of 6.20(0.12) ° and 5.12(0.13) °, respectively, with the N5/N6/C14/C15/C16/C20/C21/N7 mean plane. In the crystal structure (Fig.2), molecules are linked by intermolecular N—H···O and N—H···N hydrogen bonds (Table 1) to form chains running parallel to the b axis.

Experimental

A solution of ethyl chlorocarbonate (2.90 g, 12 mmol) in THF (30 ml) was slowly added dropwise to a mixture of tert-butyl 3-aminopyrrolo[3,4-c]pyrazole-5(1H,4H,6H)-carboxylate (3.3 g, 11 mmol) and DIEA (8.54 g, 66 mmol) in THF (60 ml) at 0~5 °C. The reaction was kept at the same temperature for 2 h, allowed to reach r.t., and stirred overnight. The obtained mixture was evaporated to dryness and the resulting residue extracted with AcOEt and water. The organic layer was separated, dried over sodium sulfate, and evaporated to dryness. The residue was purified by flash chromatography to give 1.8 g (55%) of the title compound as a white solid. Colourless block crystals suitable for X-ray diffraction were obtained in 2 days by slow evaporation of a methanol solution.