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

Zhang, Z.-P.; Wu, W.-N.

doi:10.1107/S1600536812026700

organic compounds

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ISSN: 2056-9890

Volume 68| Part 7| July 2012| Page o2133

https://doi.org/10.1107/S1600536812026700

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

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

^aDepartment of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000, People's Republic of China
^*Correspondence e-mail: wuwn08@hpu.edu.cn

(Received 15 May 2012; accepted 13 June 2012; online 20 June 2012)

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 R₂²(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, $[P \overline 1]$
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[F² > 2σ(F²)] = 0.058
wR(F²) = 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

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)
Symmetry code: (i) -x-1, -y, -z.

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.

Supporting information

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S1600536812026700/vm2177sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812026700/vm2177Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S1600536812026700/vm2177Isup3.cml

checkCIF report

Comment top

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).

Related literature top

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 top

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).

Structure description top

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).

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); 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).

Figures top

	Fig. 1. The molecular structure shown with 30% probability displacement ellipsoids.
	Fig. 2. The dimer of the title compounds formed via N—H···O hydrogen bonds shown as dashed lines. Unlabelled atoms are related with the labelled ones by symmetry operation -1 - x, -y, -z.

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

Crystal data top

C₁₆H₂₅NO₄	Z = 2
M_r = 295.37	F(000) = 320
Triclinic, P1	D_x = 1.147 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.8976 (10) Å	Cell parameters from 771 reflections
b = 11.511 (2) Å	θ = 3.2–20.5°
c = 13.460 (2) Å	µ = 0.08 mm⁻¹
α = 103.956 (4)°	T = 296 K
β = 90.078 (3)°	Plate, colorless
γ = 104.804 (3)°	0.21 × 0.19 × 0.16 mm
V = 855.5 (3) Å³

Data collection top

Bruker SMART CCD diffractometer	2989 independent reflections
Radiation source: fine-focus sealed tube	1704 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.023
φ and ω scans	θ_max = 25.0°, θ_min = 1.9°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −6→6
T_min = 0.983, T_max = 0.987	k = −13→13
4496 measured reflections	l = −16→13

Refinement top

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)] = 0.058	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.150	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ²(F_o²) + (0.0557P)² + 0.202P] where P = (F_o² + 2F_c²)/3
2989 reflections	(Δ/σ)_max < 0.001
191 parameters	Δρ_max = 0.27 e Å⁻³
0 restraints	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₁₆H₂₅NO₄	γ = 104.804 (3)°
M_r = 295.37	V = 855.5 (3) Å³
Triclinic, P1	Z = 2
a = 5.8976 (10) Å	Mo Kα radiation
b = 11.511 (2) Å	µ = 0.08 mm⁻¹
c = 13.460 (2) Å	T = 296 K
α = 103.956 (4)°	0.21 × 0.19 × 0.16 mm
β = 90.078 (3)°

Data collection top

Bruker SMART CCD diffractometer	2989 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2007)	1704 reflections with I > 2σ(I)
T_min = 0.983, T_max = 0.987	R_int = 0.023
4496 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.058	0 restraints
wR(F²) = 0.150	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	Δρ_max = 0.27 e Å⁻³
2989 reflections	Δρ_min = −0.21 e Å⁻³
191 parameters

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1	−0.2311 (4)	0.1845 (2)	−0.08222 (19)	0.0471 (7)
C2	−0.1610 (4)	0.2579 (2)	−0.14921 (19)	0.0476 (7)
C3	−0.3401 (5)	0.2180 (2)	−0.23018 (19)	0.0478 (7)
C4	−0.5147 (5)	0.1215 (2)	−0.2090 (2)	0.0484 (7)
C5	0.0637 (5)	0.3586 (3)	−0.1403 (2)	0.0673 (9)
H5A	0.1527	0.3670	−0.0781	0.101*
H5B	0.0276	0.4356	−0.1393	0.101*
H5C	0.1540	0.3375	−0.1980	0.101*
C6	−0.7463 (5)	0.0472 (3)	−0.2626 (2)	0.0691 (9)
H6A	−0.8212	−0.0121	−0.2255	0.104*
H6B	−0.7229	0.0045	−0.3308	0.104*
H6C	−0.8440	0.1015	−0.2660	0.104*
C7	−0.1316 (4)	0.1787 (2)	0.0145 (2)	0.0479 (7)
C8	0.1962 (5)	0.2870 (3)	0.1451 (2)	0.0537 (7)
C9	0.2769 (5)	0.1727 (3)	0.1469 (2)	0.0726 (9)
H9A	0.3721	0.1553	0.0903	0.109*
H9B	0.1424	0.1032	0.1415	0.109*
H9C	0.3674	0.1870	0.2101	0.109*
C10	0.0441 (5)	0.3201 (3)	0.2315 (2)	0.0693 (9)
H10A	−0.0005	0.3935	0.2274	0.104*
H10B	0.1301	0.3351	0.2960	0.104*
H10C	−0.0944	0.2529	0.2263	0.104*
C11	0.4029 (6)	0.3960 (3)	0.1429 (3)	0.0819 (10)
H11A	0.3469	0.4670	0.1417	0.123*
H11B	0.4861	0.3754	0.0827	0.123*
H11C	0.5067	0.4147	0.2030	0.123*
C12	−0.3408 (5)	0.2728 (3)	−0.3174 (2)	0.0549 (7)
C13	−0.5671 (6)	0.2464 (3)	−0.4787 (2)	0.0673 (9)
C14	−0.3574 (7)	0.2685 (4)	−0.5428 (3)	0.1043 (13)
H14A	−0.3103	0.1930	−0.5657	0.156*
H14B	−0.2298	0.3317	−0.5022	0.156*
H14C	−0.3990	0.2948	−0.6012	0.156*
C15	−0.6498 (7)	0.3616 (4)	−0.4426 (3)	0.1023 (13)
H15A	−0.7827	0.3448	−0.4023	0.153*
H15B	−0.6943	0.3873	−0.5009	0.153*
H15C	−0.5252	0.4265	−0.4017	0.153*
C16	−0.7630 (8)	0.1391 (4)	−0.5360 (3)	0.1329 (19)
H16A	−0.8932	0.1267	−0.4935	0.199*
H16B	−0.7085	0.0654	−0.5536	0.199*
H16C	−0.8123	0.1567	−0.5976	0.199*
N1	−0.4459 (4)	0.10303 (19)	−0.12068 (16)	0.0492 (6)
H1A	−0.526 (2)	0.0471 (17)	−0.0913 (9)	0.059*
O1	−0.2209 (3)	0.10146 (17)	0.06093 (14)	0.0565 (5)
O2	0.0654 (3)	0.26788 (16)	0.04613 (13)	0.0594 (6)
O3	−0.2064 (4)	0.3672 (2)	−0.32547 (15)	0.0789 (7)
O4	−0.5120 (4)	0.20430 (18)	−0.38930 (14)	0.0728 (7)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0392 (15)	0.0471 (16)	0.0494 (16)	0.0026 (13)	−0.0034 (13)	0.0109 (13)
C2	0.0431 (16)	0.0459 (16)	0.0501 (16)	0.0040 (13)	0.0011 (13)	0.0133 (13)
C3	0.0487 (17)	0.0433 (15)	0.0484 (16)	0.0059 (13)	−0.0017 (13)	0.0123 (12)
C4	0.0481 (17)	0.0447 (16)	0.0490 (16)	0.0062 (13)	−0.0060 (13)	0.0117 (13)
C5	0.0580 (19)	0.069 (2)	0.066 (2)	−0.0086 (16)	−0.0064 (16)	0.0271 (16)
C6	0.062 (2)	0.065 (2)	0.068 (2)	−0.0084 (16)	−0.0152 (16)	0.0191 (16)
C7	0.0364 (15)	0.0501 (16)	0.0511 (16)	0.0022 (13)	−0.0015 (13)	0.0109 (14)
C8	0.0435 (16)	0.0598 (18)	0.0503 (17)	0.0019 (14)	−0.0090 (13)	0.0121 (14)
C9	0.056 (2)	0.088 (2)	0.078 (2)	0.0266 (18)	−0.0060 (16)	0.0190 (18)
C10	0.068 (2)	0.070 (2)	0.064 (2)	0.0160 (17)	0.0038 (17)	0.0075 (16)
C11	0.058 (2)	0.089 (2)	0.079 (2)	−0.0151 (18)	−0.0104 (17)	0.0205 (18)
C12	0.0551 (18)	0.0514 (18)	0.0541 (17)	0.0048 (15)	−0.0033 (15)	0.0152 (14)
C13	0.067 (2)	0.075 (2)	0.0572 (19)	0.0036 (17)	−0.0113 (17)	0.0290 (16)
C14	0.103 (3)	0.154 (4)	0.063 (2)	0.040 (3)	0.009 (2)	0.033 (2)
C15	0.105 (3)	0.133 (4)	0.092 (3)	0.050 (3)	0.004 (2)	0.050 (2)
C16	0.137 (4)	0.125 (3)	0.107 (3)	−0.041 (3)	−0.073 (3)	0.053 (3)
N1	0.0457 (14)	0.0490 (13)	0.0491 (13)	0.0005 (11)	−0.0029 (11)	0.0181 (11)
O1	0.0495 (12)	0.0582 (12)	0.0572 (12)	−0.0030 (9)	−0.0060 (9)	0.0240 (10)
O2	0.0486 (12)	0.0636 (13)	0.0566 (12)	−0.0083 (10)	−0.0105 (9)	0.0220 (9)
O3	0.0853 (16)	0.0726 (15)	0.0676 (14)	−0.0133 (13)	−0.0132 (12)	0.0327 (11)
O4	0.0795 (15)	0.0684 (14)	0.0620 (13)	−0.0075 (11)	−0.0240 (11)	0.0292 (11)

Geometric parameters (Å, º) top

C1—C2	1.375 (3)	C9—H9C	0.9600
C1—N1	1.381 (3)	C10—H10A	0.9600
C1—C7	1.450 (4)	C10—H10B	0.9600
C2—C3	1.422 (3)	C10—H10C	0.9600
C2—C5	1.504 (3)	C11—H11A	0.9600
C3—C4	1.394 (3)	C11—H11B	0.9600
C3—C12	1.462 (4)	C11—H11C	0.9600
C4—N1	1.337 (3)	C12—O3	1.200 (3)
C4—C6	1.490 (3)	C12—O4	1.342 (3)
C5—H5A	0.9600	C13—O4	1.466 (3)
C5—H5B	0.9600	C13—C15	1.502 (5)
C5—H5C	0.9600	C13—C16	1.505 (4)
C6—H6A	0.9600	C13—C14	1.512 (5)
C6—H6B	0.9600	C14—H14A	0.9600
C6—H6C	0.9600	C14—H14B	0.9600
C7—O1	1.220 (3)	C14—H14C	0.9600
C7—O2	1.328 (3)	C15—H15A	0.9600
C8—O2	1.479 (3)	C15—H15B	0.9600
C8—C10	1.506 (4)	C15—H15C	0.9600
C8—C9	1.514 (4)	C16—H16A	0.9600
C8—C11	1.516 (4)	C16—H16B	0.9600
C9—H9A	0.9600	C16—H16C	0.9600
C9—H9B	0.9600	N1—H1A	0.873 (17)

C2—C1—N1	107.7 (2)	C8—C10—H10C	109.5
C2—C1—C7	134.1 (2)	H10A—C10—H10C	109.5
N1—C1—C7	118.2 (2)	H10B—C10—H10C	109.5
C1—C2—C3	106.5 (2)	C8—C11—H11A	109.5
C1—C2—C5	126.9 (2)	C8—C11—H11B	109.5
C3—C2—C5	126.6 (2)	H11A—C11—H11B	109.5
C4—C3—C2	107.8 (2)	C8—C11—H11C	109.5
C4—C3—C12	127.0 (2)	H11A—C11—H11C	109.5
C2—C3—C12	125.2 (2)	H11B—C11—H11C	109.5
N1—C4—C3	107.2 (2)	O3—C12—O4	123.1 (3)
N1—C4—C6	120.3 (2)	O3—C12—C3	125.1 (3)
C3—C4—C6	132.5 (2)	O4—C12—C3	111.8 (2)
C2—C5—H5A	109.5	O4—C13—C15	108.9 (3)
C2—C5—H5B	109.5	O4—C13—C16	102.4 (2)
H5A—C5—H5B	109.5	C15—C13—C16	111.3 (3)
C2—C5—H5C	109.5	O4—C13—C14	111.3 (3)
H5A—C5—H5C	109.5	C15—C13—C14	111.4 (3)
H5B—C5—H5C	109.5	C16—C13—C14	111.2 (3)
C4—C6—H6A	109.5	C13—C14—H14A	109.5
C4—C6—H6B	109.5	C13—C14—H14B	109.5
H6A—C6—H6B	109.5	H14A—C14—H14B	109.5
C4—C6—H6C	109.5	C13—C14—H14C	109.5
H6A—C6—H6C	109.5	H14A—C14—H14C	109.5
H6B—C6—H6C	109.5	H14B—C14—H14C	109.5
O1—C7—O2	124.6 (2)	C13—C15—H15A	109.5
O1—C7—C1	123.5 (2)	C13—C15—H15B	109.5
O2—C7—C1	111.9 (2)	H15A—C15—H15B	109.5
O2—C8—C10	109.2 (2)	C13—C15—H15C	109.5
O2—C8—C9	109.9 (2)	H15A—C15—H15C	109.5
C10—C8—C9	112.8 (2)	H15B—C15—H15C	109.5
O2—C8—C11	101.8 (2)	C13—C16—H16A	109.5
C10—C8—C11	111.4 (2)	C13—C16—H16B	109.5
C9—C8—C11	111.2 (3)	H16A—C16—H16B	109.5
C8—C9—H9A	109.5	C13—C16—H16C	109.5
C8—C9—H9B	109.5	H16A—C16—H16C	109.5
H9A—C9—H9B	109.5	H16B—C16—H16C	109.5
C8—C9—H9C	109.5	C4—N1—C1	110.9 (2)
H9A—C9—H9C	109.5	C4—N1—H1A	124.5 (8)
H9B—C9—H9C	109.5	C1—N1—H1A	124.6 (8)
C8—C10—H10A	109.5	C7—O2—C8	122.9 (2)
C8—C10—H10B	109.5	C12—O4—C13	122.3 (2)
H10A—C10—H10B	109.5

N1—C1—C2—C3	−0.3 (3)	C2—C3—C12—O3	−9.7 (5)
C7—C1—C2—C3	−179.0 (3)	C4—C3—C12—O4	−12.0 (4)
N1—C1—C2—C5	−178.9 (2)	C2—C3—C12—O4	170.3 (2)
C7—C1—C2—C5	2.5 (5)	C3—C4—N1—C1	0.2 (3)
C1—C2—C3—C4	0.4 (3)	C6—C4—N1—C1	−177.7 (2)
C5—C2—C3—C4	179.0 (3)	C2—C1—N1—C4	0.1 (3)
C1—C2—C3—C12	178.5 (3)	C7—C1—N1—C4	179.0 (2)
C5—C2—C3—C12	−3.0 (4)	O1—C7—O2—C8	−2.5 (4)
C2—C3—C4—N1	−0.3 (3)	C1—C7—O2—C8	176.8 (2)
C12—C3—C4—N1	−178.3 (3)	C10—C8—O2—C7	−63.0 (3)
C2—C3—C4—C6	177.1 (3)	C9—C8—O2—C7	61.2 (3)
C12—C3—C4—C6	−0.9 (5)	C11—C8—O2—C7	179.2 (2)
C2—C1—C7—O1	−177.3 (3)	O3—C12—O4—C13	−7.2 (5)
N1—C1—C7—O1	4.1 (4)	C3—C12—O4—C13	172.8 (3)
C2—C1—C7—O2	3.3 (4)	C15—C13—O4—C12	−63.2 (4)
N1—C1—C7—O2	−175.2 (2)	C16—C13—O4—C12	178.9 (3)
C4—C3—C12—O3	168.0 (3)	C14—C13—O4—C12	60.0 (4)

Hydrogen-bond geometry (Å, º) top

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)

Symmetry code: (i) −x−1, −y, −z.

Experimental details

Crystal data
Chemical formula	C₁₆H₂₅NO₄
M_r	295.37
Crystal system, space group	Triclinic, P1
Temperature (K)	296
a, b, c (Å)	5.8976 (10), 11.511 (2), 13.460 (2)
α, β, γ (°)	103.956 (4), 90.078 (3), 104.804 (3)
V (Å³)	855.5 (3)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.21 × 0.19 × 0.16

Data collection
Diffractometer	Bruker SMART CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2007)
T_min, T_max	0.983, 0.987
No. of measured, independent and observed [I > 2σ(I)] reflections	4496, 2989, 1704
R_int	0.023
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.058, 0.150, 1.04
No. of reflections	2989
No. of parameters	191
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.27, −0.21

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

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)

Symmetry code: (i) −x−1, −y, −z.

Acknowledgements

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

References

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