Methyl 3-(3,4,5-tribromo-1H-pyrrol-2-ylcarboxamido)propionate

In the crystal structure of the title compound, C₉H₉Br₃N₂O₃, mol­ecules are linked by N—H...O hydrogen bonds to form centrosymmetric dimers of graph-set motif R₂²(10).

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.037
• wR factor = 0.107
• Data-to-parameter ratio = 16.0

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT431_ALERT_2_B Short Inter HL..A Contact  Br2    ..  O2      ..       2.97 Ang.

Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.17
PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          7
PLAT431_ALERT_2_C Short Inter HL..A Contact  Br3    ..  O3      ..       3.21 Ang.

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

S1. Comment

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 why they have attracted our interest. This study follows our previous studies on 3-[(3,4,5-tribromo-1H-pyrrol-2-ylcarbonyl)amino]propanoic acid (Zeng et al., 2006) 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 N—H···O hydrogen bonds (Table 1) to form centrosymmetric dimers (Fig. 2) of graph-set motif R₂²(10) (Bernstein et al., 1995). Bond lengths and angles are unexceptional.

Related literature

For related literature, see: Banwell et al. (2006); Bernstein et al. (1995); Faulkner (2002); Sosa et al. (2002); Zeng (2006); Zeng et al. (2006).

S2. Experimental

The hydrochloric acid salt of beta-alanine methyl ester (0.70 g, 5 mmol) and 3,4,5-tribromo-2-trichloroacetylpyrrole (2.25 g, 5 mmol) were added to acetonitrile (12 ml), followed by the dropwise addition of triethylamine (1.4 ml). The mixture was stirred at room temperature for 12 h and then poured into water. After filtration, the precipitate was collected as a yellow solid. The impure product was dissolved in EtOH at room temperature. Colourless monoclinic crystals suitable for X-ray analysis (m.p. 456 K, 90.3% yield) grew over a period of one week when the solution was exposed to the air. Analysis calculated for C₉H₉Br₃N₂O₃: C 24.97, H 2.09, N 6.47%. Found: C 24.82, H 2.15, N 6.54%.

S3. Refinement

The H atoms were positioned geometrically [C—H = 0.99 Å for CH₂, 0.98 Å for CH₃, and N—H = 0.88 Å] and refined using a riding model, with U_iso(H) = 1.2U_eq (1.5U_eq for the methyl group) of the parent atom.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SAINT-Plus (Bruker, 1999); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

Figures

	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. Dimers formed by hydrogen bonds (dashed lines).

Methyl 3-(3,4,5-tribromo-1H-pyrrol-2-ylcarboxamido)propionate

Crystal data

C9H9Br3N2O3	F(000) = 824
Mr = 432.91	Dx = 2.265 Mg m^−3
Monoclinic, P21/c	Melting point: 456 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 8.7032 (12) Å	Cell parameters from 2696 reflections
b = 8.6376 (12) Å	θ = 2.6–22.7°
c = 16.962 (2) Å	µ = 9.53 mm^−1
β = 95.341 (2)°	T = 173 K
V = 1269.6 (3) Å^3	Prism, colourless
Z = 4	0.44 × 0.31 × 0.25 mm

Data collection

Bruker SMART 1K CCD area-detector diffractometer	2484 independent reflections
Radiation source: fine-focus sealed tube	2097 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
φ and ω scans	θmax = 26.0°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→10
Tmin = 0.040, Tmax = 0.092	k = −9→10
7442 measured reflections	l = −18→20

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.107	H-atom parameters constrained
S = 1.14	w = 1/[σ^2(Fo^2) + (0.0438P)^2 + 6.1964P] where P = (Fo^2 + 2Fc^2)/3
2484 reflections	(Δ/σ)max = 0.001
155 parameters	Δρmax = 0.77 e Å^−3
0 restraints	Δρmin = −1.86 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Br2	0.33602 (6)	0.27122 (7)	0.89835 (3)	0.02380 (18)
Br1	0.61311 (6)	0.24109 (7)	1.07246 (3)	0.02411 (18)
C9	1.1909 (7)	0.4604 (9)	0.5581 (4)	0.0341 (15)
H9A	1.1514	0.5392	0.5199	0.051*
H9B	1.1172	0.3746	0.5579	0.051*
H9C	1.2902	0.4215	0.5434	0.051*
C4	0.7555 (6)	0.4767 (6)	0.8898 (3)	0.0157 (10)
C3	0.6101 (6)	0.4372 (7)	0.8553 (3)	0.0164 (11)
O1	1.0017 (4)	0.5867 (5)	0.9124 (2)	0.0272 (10)
N2	0.8719 (5)	0.6408 (5)	0.7957 (3)	0.0176 (9)
H2	0.7916	0.6209	0.7618	0.021*
N1	0.7698 (5)	0.4137 (5)	0.9641 (3)	0.0168 (9)
H1	0.8523	0.4207	0.9981	0.020*
O3	1.2117 (4)	0.5281 (5)	0.6367 (2)	0.0260 (9)
C6	0.9914 (6)	0.7501 (6)	0.7736 (3)	0.0188 (11)
H6A	1.0287	0.8119	0.8207	0.023*
H6B	0.9446	0.8224	0.7329	0.023*
O2	0.9712 (4)	0.6185 (5)	0.6209 (2)	0.0293 (10)
C1	0.6386 (6)	0.3391 (6)	0.9774 (3)	0.0156 (11)
C7	1.1278 (6)	0.6691 (6)	0.7418 (3)	0.0170 (11)
H7A	1.2142	0.7435	0.7411	0.020*
H7B	1.1623	0.5836	0.7781	0.020*
C2	0.5355 (6)	0.3512 (6)	0.9103 (3)	0.0157 (11)
C8	1.0915 (6)	0.6051 (6)	0.6604 (3)	0.0174 (11)
C5	0.8841 (6)	0.5724 (6)	0.8659 (3)	0.0170 (11)
Br3	0.51990 (6)	0.48619 (7)	0.75407 (3)	0.02589 (18)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br2	0.0114 (3)	0.0376 (4)	0.0222 (3)	−0.0095 (2)	0.0003 (2)	−0.0027 (2)
Br1	0.0206 (3)	0.0334 (4)	0.0184 (3)	−0.0073 (2)	0.0021 (2)	0.0047 (2)
C9	0.028 (3)	0.050 (4)	0.025 (3)	0.007 (3)	0.004 (3)	−0.017 (3)
C4	0.011 (2)	0.022 (3)	0.014 (2)	0.001 (2)	0.0006 (18)	0.002 (2)
C3	0.010 (2)	0.027 (3)	0.011 (2)	0.003 (2)	−0.0012 (19)	−0.001 (2)
O1	0.0143 (19)	0.044 (3)	0.022 (2)	−0.0086 (18)	−0.0054 (16)	0.0083 (19)
N2	0.011 (2)	0.026 (3)	0.015 (2)	−0.0033 (18)	0.0004 (17)	0.0028 (19)
N1	0.009 (2)	0.021 (2)	0.019 (2)	−0.0011 (17)	−0.0033 (17)	−0.0017 (19)
O3	0.0174 (19)	0.041 (3)	0.019 (2)	0.0071 (18)	0.0013 (15)	−0.0054 (18)
C6	0.016 (3)	0.020 (3)	0.021 (3)	−0.004 (2)	0.003 (2)	0.003 (2)
O2	0.019 (2)	0.045 (3)	0.022 (2)	0.0105 (19)	−0.0062 (16)	−0.0085 (19)
C1	0.011 (2)	0.020 (3)	0.015 (3)	−0.002 (2)	0.0006 (19)	−0.001 (2)
C7	0.012 (2)	0.019 (3)	0.021 (3)	−0.001 (2)	0.003 (2)	0.001 (2)
C2	0.008 (2)	0.021 (3)	0.018 (3)	−0.002 (2)	0.0002 (19)	−0.003 (2)
C8	0.014 (3)	0.021 (3)	0.018 (3)	−0.001 (2)	0.004 (2)	0.005 (2)
C5	0.008 (2)	0.021 (3)	0.022 (3)	−0.002 (2)	0.002 (2)	−0.003 (2)
Br3	0.0185 (3)	0.0375 (4)	0.0206 (3)	0.0007 (2)	−0.0034 (2)	0.0017 (2)

Geometric parameters (Å, º)

Br2—C2	1.862 (5)	N2—C6	1.479 (7)
Br1—C1	1.852 (5)	N2—H2	0.8800
C9—O3	1.453 (7)	N1—C1	1.349 (7)
C9—H9A	0.9800	N1—H1	0.8800
C9—H9B	0.9800	O3—C8	1.332 (6)
C9—H9C	0.9800	C6—C7	1.520 (7)
C4—N1	1.368 (7)	C6—H6A	0.9900
C4—C3	1.386 (7)	C6—H6B	0.9900
C4—C5	1.478 (7)	O2—C8	1.196 (6)
C3—C2	1.398 (7)	C1—C2	1.387 (7)
C3—Br3	1.869 (5)	C7—C8	1.493 (7)
O1—C5	1.239 (6)	C7—H7A	0.9900
N2—C5	1.324 (7)	C7—H7B	0.9900
O3—C9—H9A	109.5	N2—C6—H6B	109.0
O3—C9—H9B	109.5	C7—C6—H6B	109.0
H9A—C9—H9B	109.5	H6A—C6—H6B	107.8
O3—C9—H9C	109.5	N1—C1—C2	108.6 (5)
H9A—C9—H9C	109.5	N1—C1—Br1	122.5 (4)
H9B—C9—H9C	109.5	C2—C1—Br1	128.9 (4)
N1—C4—C3	107.0 (4)	C8—C7—C6	113.2 (4)
N1—C4—C5	117.9 (4)	C8—C7—H7A	108.9
C3—C4—C5	135.0 (5)	C6—C7—H7A	108.9
C4—C3—C2	108.2 (4)	C8—C7—H7B	108.9
C4—C3—Br3	128.4 (4)	C6—C7—H7B	108.9
C2—C3—Br3	123.5 (4)	H7A—C7—H7B	107.7
C5—N2—C6	120.9 (4)	C1—C2—C3	106.4 (4)
C5—N2—H2	119.6	C1—C2—Br2	125.9 (4)
C6—N2—H2	119.6	C3—C2—Br2	127.7 (4)
C1—N1—C4	109.8 (4)	O2—C8—O3	123.4 (5)
C1—N1—H1	125.1	O2—C8—C7	125.5 (5)
C4—N1—H1	125.1	O3—C8—C7	111.1 (4)
C8—O3—C9	116.4 (4)	O1—C5—N2	121.3 (5)
N2—C6—C7	112.8 (4)	O1—C5—C4	118.9 (5)
N2—C6—H6A	109.0	N2—C5—C4	119.8 (4)
C7—C6—H6A	109.0
N1—C4—C3—C2	0.9 (6)	C4—C3—C2—C1	−0.4 (6)
C5—C4—C3—C2	−175.4 (6)	Br3—C3—C2—C1	179.9 (4)
N1—C4—C3—Br3	−179.5 (4)	C4—C3—C2—Br2	178.3 (4)
C5—C4—C3—Br3	4.3 (10)	Br3—C3—C2—Br2	−1.4 (7)
C3—C4—N1—C1	−1.0 (6)	C9—O3—C8—O2	0.7 (8)
C5—C4—N1—C1	176.0 (5)	C9—O3—C8—C7	−179.9 (5)
C5—N2—C6—C7	83.9 (6)	C6—C7—C8—O2	2.8 (8)
C4—N1—C1—C2	0.7 (6)	C6—C7—C8—O3	−176.7 (4)
C4—N1—C1—Br1	−179.1 (4)	C6—N2—C5—O1	−6.5 (8)
N2—C6—C7—C8	73.0 (6)	C6—N2—C5—C4	173.5 (5)
N1—C1—C2—C3	−0.2 (6)	N1—C4—C5—O1	2.9 (8)
Br1—C1—C2—C3	179.7 (4)	C3—C4—C5—O1	178.8 (6)
N1—C1—C2—Br2	−178.9 (4)	N1—C4—C5—N2	−177.2 (5)
Br1—C1—C2—Br2	1.0 (8)	C3—C4—C5—N2	−1.2 (10)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1^i	0.88	1.89	2.751 (6)	166

Symmetry code: (i) −x+2, −y+1, −z+2.