Di-tert-butyl 3,5-dimethyl-1H-pyrrole-2,4-dicarboxyl­ate

Zhao-Po Zhang; Wei-Na Wu

doi:10.1107/S1600536812026700

. 2012 Jun 20;68(Pt 7):o2133. doi: 10.1107/S1600536812026700

Di-tert-butyl 3,5-dimethyl-1H-pyrrole-2,4-dicarboxylate

Zhao-Po Zhang ^a, Wei-Na Wu ^a,^*

PMCID: PMC3393944 PMID: 22798809

Abstract

In the title molecule, C₁₆H₂₅NO₄, the non-H atoms, except for the two tert-butyl groups, are roughly planar (r.m.s. deviation of the non-H atoms = 0.086 Å). In the crystal, molecules are linked into inversion dimers by pairs of N—H⋯O hydrogen bonds, forming R ₂ ²(10) ring motifs.

Related literature

For complexes of Schiff bases containing a pyrrole unit, see: Wu et al. (2003 ▶); Wang et al. (2008 ▶). For the synthesis of the title compound, see: Sun et al. (2003 ▶).

Experimental

Crystal data

C₁₆H₂₅NO₄
M _r = 295.37
Triclinic,
a = 5.8976 (10) Å
b = 11.511 (2) Å
c = 13.460 (2) Å
α = 103.956 (4)°
β = 90.078 (3)°
γ = 104.804 (3)°
V = 855.5 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 296 K
0.21 × 0.19 × 0.16 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶) T _min = 0.983, T _max = 0.987
4496 measured reflections
2989 independent reflections
1704 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.058
wR(F ²) = 0.150
S = 1.04
2989 reflections
191 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); 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 datablock(s) I, global. DOI: 10.1107/S1600536812026700/vm2177sup1.cif

e-68-o2133-sup1.cif^{(19KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812026700/vm2177Isup2.hkl

e-68-o2133-Isup2.hkl^{(146.7KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812026700/vm2177Isup3.cml

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
N1—H1A⋯O1ⁱ	0.873 (17)	2.087 (18)	2.933 (3)	163.2 (12)

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors are grateful for financial support by the Doctoral Foundation of Henan Polytechnic University (B2009–70 648364).

supplementary crystallographic information

Comment

Schiff bases containing pyrrole units have been extensively investigated due to their excellent coordination abilities (Wu et al., 2003; Wang et al., 2008). However, tert-butyl pyrrole-2-carboxylate derivatives are important intermediates to form 2-formyl pyrroles (Sun et al., 2003). As part of our studies on bis(pyrrol-2-yl-methyleneamine) ligands, the crystal structure of the title compound is reported here.

In the title molecule (Fig. 1), except for the two tert-butyl groups, the non-hydrogen atoms are situated in a fair plane (r.m.s. deviation of the non-hydrogen atoms being 0.2542 Å). In the crystal, the molecules are linked into a centrosymmetric dimer by two intermolecular N—H···O hydrogen bonds (Table 1), forming a R₂²(10) ring motif (Fig. 2).

Experimental

The di-tert-butyl 3,5-dimethyl-1H-pyrrole-2,4-dicarboxylate was prepared by a Knorr-type reaction from the condensation of tert-butyl acetoacetate and tert-butyl oximinoacetoacetate according to literature (Sun et al., 2003).