1H-Pyrrole-2-carboxylic acid

Tang, G.H.; Li, D.D.; Huang, G.; Xu, X.Y.; Zeng, X.C.

doi:10.1107/S1600536809014044

organic compounds

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ISSN: 2056-9890

Volume 65| Part 5| May 2009| Page o1121

doi:10.1107/S1600536809014044

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1H-Pyrrole-2-carboxylic acid

Gui Hong Tang,^a Dong Dong Li,^a Gang Huang,^a Xing Yan Xu ^a and Xiang Chao Zeng ^a ^*

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

(Received 27 March 2009; accepted 15 April 2009; online 25 April 2009)

In the title compound, C₅H₅NO₂, the pyrrole ring and its carboxyl substituent are close to coplanar, with a dihedral angle of 11.7 (3)° between the planes. In the crystal structure, adjacent molecules are linked by pairs of O—H⋯O hydrogen bonds to form inversion dimers. Additional N—H⋯O hydrogen bonds link these dimers into chains extending along the a axis.

Related literature

For pyrroles sourced from marine organisms, see: Faulkner (2002 ). For the bioactivity of pyrrole derivatives, see: Banwell et al. (2006 ); Sosa et al. (2002 ). For related structures, see: Zeng (2006 ); Zeng et al. (2007 ). For graph-set motifs, see: Bernstein et al. (1995 ).

Experimental

Crystal data

C₅H₅NO₂
M_r = 111.10
Monoclinic, C 2/c
a = 14.080 (3) Å
b = 5.0364 (10) Å
c = 14.613 (3) Å
β = 98.969 (3)°
V = 1023.6 (3) Å³
Z = 8
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 173 K
0.42 × 0.40 × 0.37 mm

Data collection

Bruker SMART 1K CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.954, T_max = 0.959
2277 measured reflections
1006 independent reflections
875 reflections with I > 2σ(I)
R_int = 0.015

Refinement

R[F² > 2σ(F²)] = 0.063
wR(F²) = 0.191
S = 1.06
1006 reflections
74 parameters
H-atom parameters constrained
Δρ_max = 0.74 e Å⁻³
Δρ_min = −0.73 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O1ⁱ	0.88	2.22	2.951 (3)	141
O2—H2A⋯O1ⁱⁱ	0.84	2.16	2.986 (3)	166
Symmetry codes: (i) $[-x+{\script{1\over 2}}, -y+{\script{5\over 2}}, -z+1]$ ; (ii) -x, -y+2, -z+1.

Data collection: SMART (Bruker,1999 ); cell refinement: SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus; 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/S1600536809014044/sj2604sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809014044/sj2604Isup2.hkl

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). This is the reason they have attracted our interest. This study is related to our previous structural investigations of methyl 2-(4,5-dibromo-1H-pyrrole-2-carboxamido)propionate (Zeng et al., 2007) and 3-bromo-1-methyl-6,7-dihydropyrrolo[2,3-c]azepine- 4,8(1H,5H)-dione (Zeng, 2006). In the crystal structure, molecules of the title compound are linked through N1—H1···O1ⁱ hydrogen bonds to form centrosymmetric dimers (Fig. 2) of graph-set motif R₂²(10) (Bernstein et al., 1995), which are linked by O2—H2···O1ⁱⁱ hydrogen bonds (another kind of centrosymmetric dimers of graph-set motif R₂²(8) are formed), generating chains extending to the a axis (also shown in Fig. 2).

Related literature top

For pyrroles sourced from marine organisms, see: Faulkner (2002). For the bioactivity of pyrrole derivatives, see: Banwell et al. (2006); Sosa et al. (2002). For related structures, see: Zeng (2006); Zeng et al. (2007). For graph-set motifs, see: Bernstein et al. (1995).

Experimental top

The commercially available 1H-pyrrole-2-carboxylic acid was dissolved in the mixture of EtOH (80%) and ethyl acetate (20%). Colorless monoclinic crystals suitable for X-ray analysis were obtained when the solution was exposed to the air at room temperature for about 5 d.

Computing details top

Data collection: SMART (Bruker,1999); cell refinement: SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus (Bruker, 1999); 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. Crystal packing of (I) showing the chains formed by hydrogen bonds (dashed lines).

1H-Pyrrole-2-carboxylic acid top

Crystal data top

C₅H₅NO₂	F(000) = 464
M_r = 111.10	D_x = 1.442 Mg m⁻³
Monoclinic, C2/c	Melting point: 480 K
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 14.080 (3) Å	Cell parameters from 1751 reflections
b = 5.0364 (10) Å	θ = 2.8–27.0°
c = 14.613 (3) Å	µ = 0.11 mm⁻¹
β = 98.969 (3)°	T = 173 K
V = 1023.6 (3) Å³	Block, colorless
Z = 8	0.42 × 0.40 × 0.37 mm

Data collection top

Bruker SMART 1K CCD area-detector diffractometer	1006 independent reflections
Radiation source: fine-focus sealed tube	875 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.015
ϕ and ω scans	θ_max = 26.0°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −17→13
T_min = 0.954, T_max = 0.959	k = −6→6
2277 measured reflections	l = −14→18

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)] = 0.063	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.191	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.1108P)² + 3.3345P] where P = (F_o² + 2F_c²)/3
1006 reflections	(Δ/σ)_max = 0.001
74 parameters	Δρ_max = 0.74 e Å⁻³
0 restraints	Δρ_min = −0.73 e Å⁻³

Crystal data top

C₅H₅NO₂	V = 1023.6 (3) Å³
M_r = 111.10	Z = 8
Monoclinic, C2/c	Mo Kα radiation
a = 14.080 (3) Å	µ = 0.11 mm⁻¹
b = 5.0364 (10) Å	T = 173 K
c = 14.613 (3) Å	0.42 × 0.40 × 0.37 mm
β = 98.969 (3)°

Data collection top

Bruker SMART 1K CCD area-detector diffractometer	1006 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	875 reflections with I > 2σ(I)
T_min = 0.954, T_max = 0.959	R_int = 0.015
2277 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.063	0 restraints
wR(F²) = 0.191	H-atom parameters constrained
S = 1.06	Δρ_max = 0.74 e Å⁻³
1006 reflections	Δρ_min = −0.73 e Å⁻³
74 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
O1	0.12435 (12)	1.1503 (3)	0.53422 (12)	0.0223 (5)
C4	0.23786 (16)	0.8483 (5)	0.61313 (15)	0.0176 (6)
O2	0.07382 (14)	0.7350 (4)	0.56343 (15)	0.0373 (6)
H2A	0.0220	0.7923	0.5336	0.056*
N1	0.31542 (14)	1.0100 (4)	0.61094 (15)	0.0216 (6)
H1A	0.3144	1.1614	0.5808	0.026*
C3	0.26837 (17)	0.6325 (5)	0.66849 (17)	0.0208 (6)
H3	0.2299	0.4879	0.6828	0.025*
C5	0.14189 (16)	0.9228 (5)	0.56657 (15)	0.0173 (6)
C2	0.36767 (18)	0.6681 (5)	0.69974 (17)	0.0245 (6)
H2	0.4085	0.5521	0.7393	0.029*
C1	0.39405 (17)	0.9010 (6)	0.66242 (18)	0.0251 (6)
H1	0.4570	0.9740	0.6712	0.030*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0198 (9)	0.0190 (10)	0.0273 (10)	−0.0004 (7)	0.0008 (7)	0.0048 (7)
C4	0.0184 (12)	0.0182 (12)	0.0167 (11)	−0.0004 (9)	0.0039 (9)	−0.0005 (9)
O2	0.0298 (11)	0.0331 (12)	0.0472 (13)	−0.0029 (9)	0.0002 (10)	0.0044 (10)
N1	0.0191 (10)	0.0196 (11)	0.0253 (11)	−0.0027 (8)	0.0013 (8)	0.0062 (8)
C3	0.0210 (12)	0.0198 (12)	0.0216 (12)	0.0003 (9)	0.0035 (9)	0.0020 (9)
C5	0.0192 (12)	0.0164 (11)	0.0167 (11)	−0.0002 (9)	0.0042 (9)	−0.0008 (9)
C2	0.0220 (13)	0.0291 (14)	0.0215 (12)	0.0052 (10)	0.0009 (9)	0.0038 (10)
C1	0.0174 (12)	0.0318 (14)	0.0256 (13)	−0.0013 (10)	0.0019 (9)	0.0030 (11)

Geometric parameters (Å, º) top

O1—C5	1.250 (3)	N1—H1A	0.8800
C4—N1	1.367 (3)	C3—C2	1.413 (3)
C4—C3	1.383 (3)	C3—H3	0.9500
C4—C5	1.464 (3)	C2—C1	1.369 (4)
O2—C5	1.342 (3)	C2—H2	0.9500
O2—H2A	0.8400	C1—H1	0.9500
N1—C1	1.354 (3)

N1—C4—C3	107.8 (2)	O1—C5—O2	122.4 (2)
N1—C4—C5	121.3 (2)	O1—C5—C4	121.6 (2)
C3—C4—C5	130.8 (2)	O2—C5—C4	116.0 (2)
C5—O2—H2A	109.5	C1—C2—C3	107.2 (2)
C1—N1—C4	109.4 (2)	C1—C2—H2	126.4
C1—N1—H1A	125.3	C3—C2—H2	126.4
C4—N1—H1A	125.3	N1—C1—C2	108.6 (2)
C4—C3—C2	106.9 (2)	N1—C1—H1	125.7
C4—C3—H3	126.5	C2—C1—H1	125.7
C2—C3—H3	126.5

C3—C4—N1—C1	0.7 (3)	N1—C4—C5—O2	171.9 (2)
C5—C4—N1—C1	177.3 (2)	C3—C4—C5—O2	−12.3 (4)
N1—C4—C3—C2	−0.2 (3)	C4—C3—C2—C1	−0.3 (3)
C5—C4—C3—C2	−176.4 (2)	C4—N1—C1—C2	−0.9 (3)
N1—C4—C5—O1	−10.0 (3)	C3—C2—C1—N1	0.7 (3)
C3—C4—C5—O1	165.7 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1ⁱ	0.88	2.22	2.951 (3)	141
O2—H2A···O1ⁱⁱ	0.84	2.16	2.986 (3)	166

Symmetry codes: (i) −x+1/2, −y+5/2, −z+1; (ii) −x, −y+2, −z+1.

Experimental details

Crystal data
Chemical formula	C₅H₅NO₂
M_r	111.10
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	173
a, b, c (Å)	14.080 (3), 5.0364 (10), 14.613 (3)
β (°)	98.969 (3)
V (Å³)	1023.6 (3)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.11
Crystal size (mm)	0.42 × 0.40 × 0.37

Data collection
Diffractometer	Bruker SMART 1K CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.954, 0.959
No. of measured, independent and observed [I > 2σ(I)] reflections	2277, 1006, 875
R_int	0.015
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.063, 0.191, 1.06
No. of reflections	1006
No. of parameters	74
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.74, −0.73

Computer programs: SMART (Bruker,1999), SAINT-Plus (Bruker, 1999), 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	0.88	2.22	2.951 (3)	140.6
O2—H2A···O1ⁱⁱ	0.84	2.16	2.986 (3)	166.4

Symmetry codes: (i) −x+1/2, −y+5/2, −z+1; (ii) −x, −y+2, −z+1.

Acknowledgements

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

References

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