Methyl 2-(4,5-dibromo-1H-pyrrole-2-carboxamido)propionate

The racemic title compound, C₉H₁₀Br₂N₂O₃, crystallizes as an inversion twin with two symmetry-independent mol­ecules in the asymmetric unit; these are linked into pseudo-centrosymmetric dimers by inter­molecular N—H...O hydrogen bonds. Weaker N—H...O hydrogen bonds link these dimers into two-dimensional layers parallel to the ab plane.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.011 Å
• R factor = 0.052
• wR factor = 0.148
• Data-to-parameter ratio = 17.4

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR) is > 1.10
            Tmin and Tmax reported:      0.159     0.272
            Tmin and Tmax expected:      0.071     0.172
            RR =      1.411
            Please check that your absorption correction is appropriate.
STRVA01_ALERT_4_C           Flack test results are ambiguous.
           From the CIF: _refine_ls_abs_structure_Flack    0.592
           From the CIF: _refine_ls_abs_structure_Flack_su    0.016
PLAT060_ALERT_3_C Ratio Tmax/Tmin (Exp-to-Rep) (too) Large .......       1.48
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.63
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.68
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT318_ALERT_2_C Check Hybridisation of  N2     in Main Residue .          ?
PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...         11
PLAT790_ALERT_4_C Centre of Gravity not Within Unit Cell: Resd.  #          1
              C9 H10 Br2 N2 O3

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.633
            Tmax scaled      0.172 Tmin scaled      0.101
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           26.95
           From the CIF: _reflns_number_total               5111
           Count of symmetry unique reflns         2658
           Completeness (_total/calc)            192.29%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      2453
           Fraction of Friedel pairs measured     0.923
           Are heavy atom types Z>Si present        yes
PLAT033_ALERT_2_G Flack Parameter Value Deviates 2 * su from zero.       0.59
PLAT792_ALERT_1_G Check the Absolute Configuration of C6     = ...          R
PLAT792_ALERT_1_G Check the Absolute Configuration of C15    = ...          S
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          1

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

   2 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
   5 ALERT type 3 Indicator that the structure quality may be low
   5 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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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 (S)-Methyl 2-(4,5-dibromo-1H-pyrrole-2-carboxamido)-3-methylbutanoate (Zeng, 2006) and Methyl 3-(3,4,5-tribromo-1H-pyrrol-2-ylcarboxamido)propionate (Zeng et al., 2007).

In the crystal structure, the two independent molecules are disposed over a false center of inversion (Fig. 1); this feature has been noted in compounds beloning to the Pna2₁ group (Marsh et al., 1998). These two molecules being R– and S-enantiomers are linked through N1—H···O4 and N3—H···O1 hydrogen bonds (Table 1) to form pseudo-centrosymmetric dimer (also shown in Fig. 1), which graph-set analysis describes as an R₂²(10) motif (Bernstein et al., 1995). At the same time, the weaker N2—H···O5 and N4—H···O2 hydrogen bonds link the dimers into two-dimensional layers parallel to ab-plane (Fig. 2).

Related literature

For related literature, see: Banwell et al. (2006); Bernstein et al. (1995); Faulkner (2002); Marsh et al. (1998); Sosa et al. (2002); Zeng (2006); Zeng et al. (2007).

S2. Experimental

The hydrochloric acid salt of DL-methyl 2-aminopropionate (0.70 g, 5 mmol) and 4,5-dibromo-2-trichloroacetylpyrrole (1.85 g, 5 mmol) were added to 12 ml of acetonitrile, followed by the dropwise addition of triethylamine (1.4 ml). The mixture was stirred at room temperature for 8 h, and then poured into water. After filtration, the precipitate was collected as a pale yellow solid. The impure product was dissolved in ethanol at room temperature. Colourless crystals suitable for X-ray analysis (m. p. 485 K, in 81.4% yield) grew over a period of several days when the solution was exposed to air. CH&N elemental analysis. Calc. for C₉H₁₀Br₂N₂O₃: C 30.54, H 2.85, N 7.91%; found: C 30.27, H 2.69, N 8.07%.

S3. Refinement

The H atoms were positioned geometrically [C—H = 1.00 Å for CH, 0.98 Å for CH₃, C—H = 0.95 Å for CH(aromatic), and N—H = 0.88 Å] and refined using a riding model, with U_iso = 1.2U_eq (1.5U_eq for the methyl group) of the parent atom. The highest residual peak [2.35 e Å^-3] is situated 0.97 Å at Br4 atom.

Because of racemic twinning, the TWIN and BASF instructions were used in the final refinement.

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. The crystal packing of (I), showing the two-dimensional network formed by hydrogen bonds (dashed lines).

Methyl 2-(4,5-dibromo-1H-pyrrole-2-carboxamido)propionate

Crystal data

C9H10Br2N2O3	Dx = 1.964 Mg m^−3
Mr = 354.01	Melting point: 485 K
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 5810 reflections
a = 15.8880 (16) Å	θ = 2.6–26.8°
b = 6.1274 (6) Å	µ = 6.77 mm^−1
c = 24.593 (3) Å	T = 173 K
V = 2394.2 (4) Å^3	Plate, colourless
Z = 8	0.43 × 0.40 × 0.26 mm
F(000) = 1376

Data collection

Bruker SMART 1K CCD area-detector diffractometer	5111 independent reflections
Radiation source: fine-focus sealed tube	4233 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.053
φ and ω scans	θmax = 27.0°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −20→20
Tmin = 0.159, Tmax = 0.272	k = −7→7
18530 measured reflections	l = −30→31

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.052	H-atom parameters constrained
wR(F^2) = 0.148	w = 1/[σ^2(Fo^2) + (0.0945P)^2 + 0.3872P] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max = 0.001
5111 reflections	Δρmax = 2.35 e Å^−3
294 parameters	Δρmin = −0.88 e Å^−3
1 restraint	Absolute structure: Flack (1983), 2453 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.592 (16)

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
Br4	0.47977 (6)	0.33319 (16)	0.71923 (3)	0.0387 (2)
Br3	0.36898 (6)	−0.12861 (15)	0.66069 (4)	0.0396 (2)
C12	0.4929 (5)	0.3982 (13)	0.6001 (4)	0.0233 (16)
H12	0.5234	0.5315	0.6017	0.028*
O4	0.4423 (3)	0.2217 (9)	0.4619 (2)	0.0237 (12)
C17	0.5665 (5)	0.7947 (12)	0.4204 (4)	0.0285 (18)
H17A	0.6201	0.8080	0.4399	0.043*
H17B	0.5255	0.8965	0.4360	0.043*
H17C	0.5751	0.8293	0.3819	0.043*
C14	0.4777 (4)	0.3376 (12)	0.4973 (3)	0.0180 (15)
N4	0.5247 (4)	0.5104 (10)	0.4832 (3)	0.0191 (13)
H4	0.5496	0.5890	0.5085	0.023*
C10	0.4226 (5)	0.0981 (13)	0.6243 (3)	0.0211 (15)
C15	0.5345 (4)	0.5679 (13)	0.4257 (3)	0.0205 (15)
H15	0.4781	0.5591	0.4077	0.025*
C11	0.4642 (5)	0.2747 (13)	0.6445 (3)	0.0251 (17)
N3	0.4262 (4)	0.1053 (10)	0.5702 (3)	0.0199 (13)
H3A	0.4048	0.0075	0.5480	0.024*
C13	0.4689 (4)	0.2907 (12)	0.5548 (3)	0.0187 (15)
O5	0.6450 (4)	0.2933 (9)	0.4192 (2)	0.0271 (12)
O6	0.5853 (4)	0.4267 (9)	0.3443 (2)	0.0275 (12)
C16	0.5944 (4)	0.4079 (11)	0.3973 (3)	0.0172 (14)
C18	0.6420 (6)	0.2931 (16)	0.3116 (4)	0.036 (2)
H18A	0.6316	0.1385	0.3193	0.054*
H18B	0.7004	0.3292	0.3207	0.054*
H18C	0.6320	0.3219	0.2730	0.054*
Br1	0.40261 (6)	0.14472 (15)	0.32146 (4)	0.0364 (2)
Br2	0.27815 (6)	−0.30292 (15)	0.26376 (3)	0.0382 (2)
C3	0.2788 (5)	−0.3833 (13)	0.3805 (3)	0.0227 (16)
H3	0.2475	−0.5152	0.3789	0.027*
C5	0.3026 (4)	−0.3344 (11)	0.4843 (3)	0.0162 (14)
C2	0.3038 (5)	−0.2547 (14)	0.3366 (3)	0.0251 (17)
N2	0.2550 (4)	−0.5115 (10)	0.4979 (2)	0.0210 (13)
H2	0.2306	−0.5897	0.4723	0.025*
C6	0.2446 (5)	−0.5711 (12)	0.5552 (3)	0.0203 (15)
H6	0.3004	−0.5624	0.5740	0.024*
N1	0.3516 (4)	−0.0987 (10)	0.4115 (2)	0.0184 (12)
H1	0.3768	−0.0064	0.4335	0.022*
C4	0.3084 (5)	−0.2816 (13)	0.4269 (3)	0.0202 (15)
O1	0.3378 (3)	−0.2291 (9)	0.5192 (2)	0.0252 (12)
O2	0.1322 (4)	−0.2991 (9)	0.5614 (2)	0.0269 (12)
C7	0.1833 (5)	−0.4166 (12)	0.5826 (3)	0.0202 (15)
O3	0.1928 (4)	−0.4370 (10)	0.6358 (2)	0.0306 (13)
C9	0.1369 (6)	−0.3109 (15)	0.6690 (3)	0.033 (2)
H9A	0.1523	−0.1564	0.6667	0.049*
H9B	0.1411	−0.3600	0.7068	0.049*
H9C	0.0790	−0.3302	0.6561	0.049*
C1	0.3490 (5)	−0.0837 (13)	0.3566 (3)	0.0223 (15)
C8	0.2118 (6)	−0.8018 (13)	0.5586 (4)	0.0299 (19)
H8A	0.1564	−0.8097	0.5412	0.045*
H8B	0.2068	−0.8449	0.5968	0.045*
H8C	0.2508	−0.9004	0.5400	0.045*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br4	0.0490 (5)	0.0491 (5)	0.0180 (4)	−0.0051 (4)	−0.0040 (4)	−0.0074 (4)
Br3	0.0530 (6)	0.0371 (5)	0.0288 (5)	−0.0080 (4)	0.0053 (4)	0.0061 (4)
C12	0.020 (3)	0.023 (4)	0.027 (4)	−0.001 (3)	0.003 (3)	−0.004 (3)
O4	0.031 (3)	0.022 (3)	0.018 (3)	−0.009 (2)	−0.003 (2)	−0.002 (2)
C17	0.036 (4)	0.021 (4)	0.028 (4)	0.001 (3)	−0.003 (3)	0.000 (3)
C14	0.018 (3)	0.018 (3)	0.018 (4)	0.006 (3)	0.003 (3)	−0.001 (3)
N4	0.018 (3)	0.018 (3)	0.022 (3)	−0.003 (2)	0.004 (2)	−0.005 (2)
C10	0.023 (4)	0.026 (4)	0.014 (4)	0.002 (3)	0.001 (3)	0.003 (3)
C15	0.018 (3)	0.025 (4)	0.019 (4)	0.004 (3)	0.003 (3)	0.000 (3)
C11	0.025 (4)	0.034 (4)	0.016 (4)	0.000 (3)	−0.002 (3)	−0.004 (3)
N3	0.017 (3)	0.024 (3)	0.019 (3)	−0.002 (2)	0.001 (3)	−0.001 (3)
C13	0.013 (3)	0.016 (4)	0.027 (4)	0.006 (3)	0.004 (3)	0.001 (3)
O5	0.033 (3)	0.025 (3)	0.023 (3)	0.010 (2)	0.001 (2)	0.004 (2)
O6	0.037 (3)	0.031 (3)	0.015 (3)	0.016 (3)	0.002 (2)	0.000 (2)
C16	0.021 (3)	0.015 (3)	0.016 (3)	0.001 (3)	0.002 (3)	−0.001 (3)
C18	0.043 (5)	0.047 (5)	0.018 (5)	0.021 (4)	0.011 (4)	−0.001 (4)
Br1	0.0495 (5)	0.0368 (5)	0.0231 (4)	−0.0152 (4)	−0.0014 (4)	0.0042 (4)
Br2	0.0462 (5)	0.0514 (5)	0.0172 (4)	−0.0163 (4)	−0.0014 (4)	−0.0087 (4)
C3	0.025 (4)	0.021 (4)	0.022 (4)	−0.010 (3)	0.001 (3)	−0.007 (3)
C5	0.015 (3)	0.013 (3)	0.021 (4)	−0.001 (3)	0.004 (3)	−0.004 (3)
C2	0.029 (4)	0.030 (4)	0.016 (4)	−0.005 (4)	0.000 (3)	−0.010 (3)
N2	0.028 (3)	0.017 (3)	0.018 (3)	−0.005 (2)	0.004 (3)	−0.005 (2)
C6	0.020 (3)	0.015 (4)	0.025 (4)	−0.001 (3)	−0.001 (3)	−0.002 (3)
N1	0.021 (3)	0.019 (3)	0.015 (3)	−0.005 (2)	−0.004 (2)	−0.002 (2)
C4	0.027 (4)	0.027 (4)	0.007 (3)	−0.007 (3)	0.003 (3)	−0.004 (3)
O1	0.032 (3)	0.022 (3)	0.021 (3)	−0.010 (2)	−0.002 (2)	−0.002 (2)
O2	0.036 (3)	0.026 (3)	0.019 (3)	0.008 (2)	0.000 (2)	0.003 (2)
C7	0.025 (4)	0.016 (3)	0.020 (4)	−0.004 (3)	0.002 (3)	0.002 (3)
O3	0.041 (3)	0.034 (3)	0.016 (3)	0.013 (3)	0.002 (2)	0.010 (2)
C9	0.043 (5)	0.042 (5)	0.013 (4)	0.013 (4)	0.011 (4)	0.001 (3)
C1	0.025 (4)	0.028 (4)	0.014 (4)	−0.006 (3)	0.002 (3)	0.001 (3)
C8	0.037 (5)	0.018 (4)	0.035 (5)	−0.003 (3)	0.001 (4)	0.008 (3)

Geometric parameters (Å, º)

Br4—C11	1.889 (8)	Br1—C1	1.853 (7)
Br3—C10	1.859 (8)	Br2—C2	1.861 (8)
C12—C13	1.350 (12)	C3—C4	1.382 (10)
C12—C11	1.404 (12)	C3—C2	1.394 (12)
C12—H12	0.9500	C3—H3	0.9500
O4—C14	1.256 (9)	C5—O1	1.210 (9)
C17—C15	1.486 (11)	C5—N2	1.364 (9)
C17—H17A	0.9800	C5—C4	1.451 (10)
C17—H17B	0.9800	C2—C1	1.362 (11)
C17—H17C	0.9800	N2—C6	1.467 (10)
C14—N4	1.341 (9)	N2—H2	0.8800
C14—C13	1.450 (11)	C6—C8	1.509 (10)
N4—C15	1.468 (10)	C6—C7	1.516 (10)
N4—H4	0.8800	C6—H6	1.0000
C10—N3	1.332 (10)	N1—C1	1.352 (10)
C10—C11	1.362 (11)	N1—C4	1.368 (10)
C15—C16	1.534 (10)	N1—H1	0.8800
C15—H15	1.0000	O2—C7	1.203 (9)
N3—C13	1.376 (10)	C7—O3	1.322 (9)
N3—H3A	0.8800	O3—C9	1.433 (10)
O5—C16	1.196 (9)	C9—H9A	0.9800
O6—C16	1.317 (9)	C9—H9B	0.9800
O6—C18	1.458 (9)	C9—H9C	0.9800
C18—H18A	0.9800	C8—H8A	0.9800
C18—H18B	0.9800	C8—H8B	0.9800
C18—H18C	0.9800	C8—H8C	0.9800
C13—C12—C11	106.6 (7)	C4—C3—C2	106.7 (7)
C13—C12—H12	126.7	C4—C3—H3	126.6
C11—C12—H12	126.7	C2—C3—H3	126.6
C15—C17—H17A	109.5	O1—C5—N2	120.4 (7)
C15—C17—H17B	109.5	O1—C5—C4	122.8 (7)
H17A—C17—H17B	109.5	N2—C5—C4	116.8 (6)
C15—C17—H17C	109.5	C1—C2—C3	107.8 (7)
H17A—C17—H17C	109.5	C1—C2—Br2	125.8 (6)
H17B—C17—H17C	109.5	C3—C2—Br2	126.4 (6)
O4—C14—N4	121.1 (7)	C5—N2—C6	119.7 (6)
O4—C14—C13	121.4 (7)	C5—N2—H2	120.1
N4—C14—C13	117.5 (7)	C6—N2—H2	120.1
C14—N4—C15	119.9 (6)	N2—C6—C8	109.0 (6)
C14—N4—H4	120.1	N2—C6—C7	110.1 (6)
C15—N4—H4	120.1	C8—C6—C7	109.8 (6)
N3—C10—C11	108.5 (7)	N2—C6—H6	109.3
N3—C10—Br3	121.7 (6)	C8—C6—H6	109.3
C11—C10—Br3	129.9 (6)	C7—C6—H6	109.3
N4—C15—C17	110.2 (7)	C1—N1—C4	108.5 (6)
N4—C15—C16	110.5 (6)	C1—N1—H1	125.8
C17—C15—C16	110.2 (6)	C4—N1—H1	125.8
N4—C15—H15	108.6	N1—C4—C3	108.1 (7)
C17—C15—H15	108.6	N1—C4—C5	119.0 (6)
C16—C15—H15	108.6	C3—C4—C5	132.9 (7)
C10—C11—C12	107.6 (7)	O2—C7—O3	124.1 (7)
C10—C11—Br4	124.7 (6)	O2—C7—C6	128.0 (7)
C12—C11—Br4	127.7 (6)	O3—C7—C6	107.9 (6)
C10—N3—C13	108.8 (7)	C7—O3—C9	116.2 (6)
C10—N3—H3A	125.6	O3—C9—H9A	109.5
C13—N3—H3A	125.6	O3—C9—H9B	109.5
C12—C13—N3	108.4 (7)	H9A—C9—H9B	109.5
C12—C13—C14	132.9 (7)	O3—C9—H9C	109.5
N3—C13—C14	118.6 (7)	H9A—C9—H9C	109.5
C16—O6—C18	115.4 (6)	H9B—C9—H9C	109.5
O5—C16—O6	124.8 (7)	N1—C1—C2	108.9 (7)
O5—C16—C15	126.0 (7)	N1—C1—Br1	120.2 (6)
O6—C16—C15	109.1 (6)	C2—C1—Br1	130.9 (6)
O6—C18—H18A	109.5	C6—C8—H8A	109.5
O6—C18—H18B	109.5	C6—C8—H8B	109.5
H18A—C18—H18B	109.5	H8A—C8—H8B	109.5
O6—C18—H18C	109.5	C6—C8—H8C	109.5
H18A—C18—H18C	109.5	H8A—C8—H8C	109.5
H18B—C18—H18C	109.5	H8B—C8—H8C	109.5
O4—C14—N4—C15	0.8 (10)	C4—C3—C2—C1	1.4 (9)
C13—C14—N4—C15	−178.8 (6)	C4—C3—C2—Br2	−177.2 (6)
C14—N4—C15—C17	163.4 (6)	O1—C5—N2—C6	1.6 (11)
C14—N4—C15—C16	−74.6 (8)	C4—C5—N2—C6	−178.5 (7)
N3—C10—C11—C12	1.4 (9)	C5—N2—C6—C8	−163.9 (7)
Br3—C10—C11—C12	−179.7 (6)	C5—N2—C6—C7	75.7 (8)
N3—C10—C11—Br4	−178.0 (6)	C1—N1—C4—C3	0.4 (9)
Br3—C10—C11—Br4	0.9 (11)	C1—N1—C4—C5	179.6 (7)
C13—C12—C11—C10	−0.9 (9)	C2—C3—C4—N1	−1.1 (9)
C13—C12—C11—Br4	178.5 (6)	C2—C3—C4—C5	179.8 (9)
C11—C10—N3—C13	−1.4 (9)	O1—C5—C4—N1	−3.6 (12)
Br3—C10—N3—C13	179.6 (5)	N2—C5—C4—N1	176.5 (6)
C11—C12—C13—N3	0.1 (8)	O1—C5—C4—C3	175.4 (8)
C11—C12—C13—C14	178.1 (8)	N2—C5—C4—C3	−4.5 (13)
C10—N3—C13—C12	0.8 (8)	N2—C6—C7—O2	18.8 (11)
C10—N3—C13—C14	−177.6 (6)	C8—C6—C7—O2	−101.1 (10)
O4—C14—C13—C12	−172.8 (8)	N2—C6—C7—O3	−163.4 (6)
N4—C14—C13—C12	6.9 (12)	C8—C6—C7—O3	76.6 (8)
O4—C14—C13—N3	5.1 (10)	O2—C7—O3—C9	0.9 (12)
N4—C14—C13—N3	−175.2 (6)	C6—C7—O3—C9	−177.0 (7)
C18—O6—C16—O5	0.7 (12)	C4—N1—C1—C2	0.5 (9)
C18—O6—C16—C15	176.5 (7)	C4—N1—C1—Br1	−179.3 (5)
N4—C15—C16—O5	−20.3 (11)	C3—C2—C1—N1	−1.2 (10)
C17—C15—C16—O5	101.7 (9)	Br2—C2—C1—N1	177.4 (6)
N4—C15—C16—O6	163.9 (6)	C3—C2—C1—Br1	178.5 (6)
C17—C15—C16—O6	−74.1 (8)	Br2—C2—C1—Br1	−2.9 (12)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N4—H4···O2^i	0.88	2.25	3.122 (8)	169
N3—H3A···O1	0.88	1.93	2.784 (8)	162
N2—H2···O5^ii	0.88	2.26	3.127 (8)	168
N1—H1···O4	0.88	1.88	2.734 (8)	164

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