4-Bromo-1H-pyrrole-2-carb­oxy­lic acid

Zheng, L.; Hu, F.; Zeng, X.C.; Li, K.P.

doi:10.1107/S1600536812034800

organic compounds

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ISSN: 2056-9890

Volume 68| Part 9| September 2012| Page o2689

doi:10.1107/S1600536812034800

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4-Bromo-1H-pyrrole-2-carboxylic acid

Le Zheng,^a Fang Hu,^a Xiang Chao Zeng ^a ^* and Kai Ping Li ^a

^aDepartment of Chemistry, Jinan University, Guangzhou, Guangdong 510632, People's Republic of China
^*Correspondence e-mail: xczeng@126.com

(Received 26 June 2012; accepted 6 August 2012; online 11 August 2012)

In the title compound, C₅H₄BrNO₂, the non-H atoms of the pyrrole ring and the Br atom are approximately coplanar, with an r.m.s. deviation from the best fit plane of 0.025 (6) Å;. The dihedral angle between the plane of the carboxy group and this plane is 14.1 (2)°. In the crystal, O—H⋯O hydrogen bonds link the molecules together, forming corrugated sheets parallel to the bc plane.

Related literature

For pyrrole compounds obtained from marine organisms, see: Liu et al. (2005 ); Faulkner (2002 ). For the bioactivity of pyrrole derivatives, see: Banwell et al. (2006 ); Sosa et al. (2002 ). For related structures, see: Zeng et al. (2007 ); Tang et al. (2008 ).

Experimental

Crystal data

C₅H₄BrNO₂
M_r = 190.00
Monoclinic, P 2₁ /c
a = 16.0028 (13) Å
b = 4.9046 (6) Å
c = 8.2367 (7) Å
β = 93.199 (7)°
V = 645.47 (11) Å³
Z = 4
Mo Kα radiation
μ = 6.29 mm⁻¹
T = 293 K
0.24 × 0.20 × 0.14 mm

Data collection

Oxford Gemini S Ultra area-detector diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010 $[Oxford Diffraction (2010). CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.]$ ) T_min = 0.314, T_max = 0.473
2436 measured reflections
1387 independent reflections
1081 reflections with I > 2σ(I)
R_int = 0.021

Refinement

R[F² > 2σ(F²)] = 0.034
wR(F²) = 0.081
S = 1.10
1387 reflections
85 parameters
H-atom parameters constrained
Δρ_max = 0.39 e Å⁻³
Δρ_min = −0.45 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2′⋯O1ⁱ	1.07	1.86	2.914 (4)	166
O2—H2⋯O1ⁱⁱ	0.82	2.28	3.030 (4)	153
Symmetry codes: (i) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) $[x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]$ .

Data collection: CrysAlis PRO (Oxford Diffraction, 2010 $[Oxford Diffraction (2010). CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.]$ ); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; 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: 10.1107/S1600536812034800/fj2579sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812034800/fj2579Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812034800/fj2579Isup3.cml

checkCIF report

Comment top

Pyrrole derivatives are well known in many marine organisms (Faulkner, 2002), some show important bioactivities, such as antitumor activity (Banwell et al., 2006) and protein kinase inhibiting activity (Sosa et al., 2002). These are the reasons why they have attracted our interest. This study is relevant to our previous studies on Methyl 2-(4,5-dibromo-1H-pyrrole-2-carboxamido)propionate (Zeng et al., 2007) and 1H-Pyrrole-2-carboxylic acid (Tang et al., 2008).

In the title molecule, bond lengths and angles are unexceptional. The non-H atoms of the pyrrole ring and Br atom are approximately coplanar (plane 1), with r.m.s. deviation from the best fit plane of 0.025 (6)°, the dihedral angle between the carboxy plane and Plane 1 is 14.1 (2)°. The OH hydrogen atom is disordered over two positions (shown as in Fig. 1), which form weak intermolecular O2—H2···O1 hydrogen bonds respectively (Table 1). In the crystal, the above hydrogen bonds link the molecules into corrugated sheets parallel to the bc plane (shown as in Fig. 2 and Fig. 3).

Related literature top

For pyrrole compounds obtained from marine organisms, see: Liu et al. (2005); Faulkner (2002). For the bioactivity of pyrrole derivatives, see: Banwell et al. (2006); Sosa et al. (2002). For related structures, see: Zeng et al. (2007); Tang et al. (2008).

Experimental top

The methyl 4-bromopyrrole-2-carbonylaminoacetate (1.30 g, 5 mmol) and potassium carbonate (1.38 g, 10 mmol) were added to acetonitrile (20 ml), the mixture was stirred at reflux for 24 h. After the reaction mixture was cooled and filtered, the filtrate was evaporated in vacuo, and then the residue was chromatographed over Si gel 60 using EtOAc-petroleum ether (1:2.5) as eluting solvent and the title compound (I) was obtained (55.2% yield). Light yellow monoclinic crystals suitable for X-ray analysis (m.p. 424 K) grew over a period of one week when the EtOH solution of I was exposed to the air at room temperature.

Computing details top

Data collection: CrysAlis PRO (Oxford Diffraction, 2010); cell refinement: CrysAlis PRO (Oxford Diffraction, 2010); data reduction: CrysAlis PRO (Oxford Diffraction, 2010); 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 of the title compound, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. The crystal packing. Dashed lines indicate hydrogen bonds.
	Fig. 3. sheet formed by weak hydrogen bonds (dashed lines).

4-Bromo-1H-pyrrole-2-carboxylic acid top

Crystal data top

C₅H₄BrNO₂	F(000) = 368
M_r = 190.00	D_x = 1.955 Mg m⁻³
Monoclinic, P2₁/c	Melting point < 424 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 16.0028 (13) Å	Cell parameters from 950 reflections
b = 4.9046 (6) Å	θ = 3.5–29.1°
c = 8.2367 (7) Å	µ = 6.29 mm⁻¹
β = 93.199 (7)°	T = 293 K
V = 645.47 (11) Å³	Block, light yellow
Z = 4	0.24 × 0.20 × 0.14 mm

Data collection top

Oxford Gemini S Ultra area-detector diffractometer	1387 independent reflections
Radiation source: fine-focus sealed tube	1081 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.021
ϕ and ω scans	θ_max = 27.0°, θ_min = 3.8°
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010)	h = −20→12
T_min = 0.314, T_max = 0.473	k = −5→6
2436 measured reflections	l = −10→10

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.081	H-atom parameters constrained
S = 1.10	w = 1/[σ²(F_o²) + (0.034P)² + 0.2705P] where P = (F_o² + 2F_c²)/3
1387 reflections	(Δ/σ)_max < 0.001
85 parameters	Δρ_max = 0.39 e Å⁻³
0 restraints	Δρ_min = −0.45 e Å⁻³

Crystal data top

C₅H₄BrNO₂	V = 645.47 (11) Å³
M_r = 190.00	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 16.0028 (13) Å	µ = 6.29 mm⁻¹
b = 4.9046 (6) Å	T = 293 K
c = 8.2367 (7) Å	0.24 × 0.20 × 0.14 mm
β = 93.199 (7)°

Data collection top

Oxford Gemini S Ultra area-detector diffractometer	1387 independent reflections
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010)	1081 reflections with I > 2σ(I)
T_min = 0.314, T_max = 0.473	R_int = 0.021
2436 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.034	0 restraints
wR(F²) = 0.081	H-atom parameters constrained
S = 1.10	Δρ_max = 0.39 e Å⁻³
1387 reflections	Δρ_min = −0.45 e Å⁻³
85 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	Occ. (<1)
Br1	0.07690 (2)	0.68153 (9)	−0.16395 (4)	0.04763 (17)
N1	0.24925 (19)	0.3185 (6)	0.1354 (4)	0.0400 (7)
H1	0.2653	0.1983	0.2065	0.048*
C3	0.2505 (2)	0.6756 (8)	−0.0297 (4)	0.0321 (7)
H3	0.2674	0.8285	−0.0861	0.039*
O1	0.40382 (15)	0.4281 (6)	0.2816 (3)	0.0514 (7)
C4	0.29799 (19)	0.5248 (7)	0.0817 (4)	0.0321 (8)
C2	0.17094 (19)	0.5519 (8)	−0.0414 (4)	0.0327 (8)
O2	0.4311 (2)	0.7498 (8)	0.0940 (4)	0.0731 (10)
H2	0.4079	0.8099	0.0102	0.013 (15)*	0.50
H2'	0.4898	0.7973	0.1562	0.009 (13)*	0.50
C1	0.1716 (2)	0.3316 (8)	0.0598 (5)	0.0421 (9)
H1A	0.1274	0.2128	0.0743	0.050*
C5	0.3821 (2)	0.5608 (9)	0.1583 (4)	0.0373 (8)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0310 (2)	0.0638 (3)	0.0466 (2)	0.00130 (19)	−0.01071 (15)	0.0010 (2)
N1	0.0398 (17)	0.0338 (17)	0.0453 (16)	0.0004 (15)	−0.0077 (13)	0.0041 (15)
C3	0.0309 (17)	0.037 (2)	0.0284 (15)	−0.0035 (16)	−0.0004 (12)	0.0005 (16)
O1	0.0376 (14)	0.0662 (19)	0.0487 (14)	0.0089 (14)	−0.0119 (11)	0.0072 (15)
C4	0.0274 (15)	0.036 (2)	0.0329 (15)	0.0019 (15)	−0.0013 (12)	−0.0050 (16)
C2	0.0279 (16)	0.041 (2)	0.0289 (15)	0.0017 (16)	−0.0025 (12)	−0.0053 (17)
O2	0.052 (2)	0.097 (3)	0.069 (2)	−0.0130 (18)	−0.0158 (16)	0.004 (2)
C1	0.0357 (19)	0.042 (2)	0.048 (2)	−0.0074 (17)	−0.0006 (16)	−0.0045 (19)
C5	0.0278 (17)	0.048 (2)	0.0357 (17)	0.0020 (18)	−0.0038 (13)	−0.0053 (19)

Geometric parameters (Å, º) top

Br1—C2	1.876 (3)	O1—C5	1.239 (4)
N1—C1	1.360 (5)	C4—C5	1.465 (4)
N1—C4	1.366 (4)	C2—C1	1.364 (5)
N1—H1	0.8600	O2—C5	1.342 (5)
C3—C4	1.375 (5)	O2—H2	0.8200
C3—C2	1.408 (4)	O2—H2'	1.0702
C3—H3	0.9300	C1—H1A	0.9300

C1—N1—C4	109.9 (3)	C3—C2—Br1	125.8 (3)
C1—N1—H1	125.1	C5—O2—H2	109.5
C4—N1—H1	125.1	C5—O2—H2'	118.5
C4—C3—C2	106.1 (3)	H2—O2—H2'	132.0
C4—C3—H3	126.9	N1—C1—C2	107.1 (3)
C2—C3—H3	126.9	N1—C1—H1A	126.5
N1—C4—C3	108.1 (3)	C2—C1—H1A	126.5
N1—C4—C5	118.5 (3)	O1—C5—O2	122.9 (3)
C3—C4—C5	133.1 (3)	O1—C5—C4	119.9 (3)
C1—C2—C3	108.8 (3)	O2—C5—C4	117.1 (3)
C1—C2—Br1	125.2 (3)

C1—N1—C4—C3	0.6 (4)	C3—C2—C1—N1	0.8 (4)
C1—N1—C4—C5	175.0 (3)	Br1—C2—C1—N1	−175.1 (2)
C2—C3—C4—N1	−0.1 (4)	N1—C4—C5—O1	−8.7 (5)
C2—C3—C4—C5	−173.3 (3)	C3—C4—C5—O1	163.9 (4)
C4—C3—C2—C1	−0.5 (4)	N1—C4—C5—O2	174.5 (3)
C4—C3—C2—Br1	175.4 (2)	C3—C4—C5—O2	−12.8 (6)
C4—N1—C1—C2	−0.9 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2′···O1ⁱ	1.07	1.86	2.914 (4)	166
O2—H2···O1ⁱⁱ	0.82	2.28	3.030 (4)	153

Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) x, −y+3/2, z−1/2.

Experimental details

Crystal data
Chemical formula	C₅H₄BrNO₂
M_r	190.00
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	16.0028 (13), 4.9046 (6), 8.2367 (7)
β (°)	93.199 (7)
V (Å³)	645.47 (11)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	6.29
Crystal size (mm)	0.24 × 0.20 × 0.14

Data collection
Diffractometer	Oxford Gemini S Ultra area-detector diffractometer
Absorption correction	Multi-scan (CrysAlis PRO; Oxford Diffraction, 2010)
T_min, T_max	0.314, 0.473
No. of measured, independent and observed [I > 2σ(I)] reflections	2436, 1387, 1081
R_int	0.021
(sin θ/λ)_max (Å⁻¹)	0.639

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.034, 0.081, 1.10
No. of reflections	1387
No. of parameters	85
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.39, −0.45

Computer programs: CrysAlis PRO (Oxford Diffraction, 2010), 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
O2—H2'···O1ⁱ	1.07	1.86	2.914 (4)	166
O2—H2···O1ⁱⁱ	0.82	2.28	3.030 (4)	153

Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) x, −y+3/2, z−1/2.

Acknowledgements

We thank the Natural Science Foundation of Guangdong Province, China (No. 06300581) for generously supporting this study.

References

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