2-(4-Bromo­phen­yl)-N-(pyrazin-2-yl)acetamide

In the title compound, C₁₂H₁₀BrN₃O, the dihedral angle between the mean planes of the 4-bromo­phenyl and pyrazin-2-yl rings is 54.6 (3)°. An intra­molecular C—H...O hydrogen bond generates an S(6) graph-set motif. In the crystal, weak N—H...N hydrogen bonds link the mol­ecules into chains along [100]. The chains are linked via C—H...N and C—H...O hydrogen bonds, forming two-dimensional networks lying parallel to the ab plane.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.035
• wR factor = 0.095
• Data-to-parameter ratio = 14.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT906_ALERT_3_C Large K value in the Analysis of Variance ......      2.393
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          1

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF          ?
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600          7

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   2 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   2 ALERT level G = General information/check it is not something unexpected

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

---

S1. Comment

N-Substituted 2-arylacetamides are very interesting compounds because of their structural similarity to the lateral chain of natural benzylpenicillin (Mijin et al., 2006, 2008). Amides are also used as ligands due to their excellent coordination abilities (Wu et al., 2008, 2010). Crystal structures of some acetamide derivatives viz., N-(3,4-difluoro phenyl)-2,2-diphenylacetamide, 2-(4-bromophenyl)-N-(5-methylpyridin-2-yl)acetamide, N-(4-bromophenyl)-2-(4-chlorophenyl)acetamide, 2-(4-bromophenyl)-N-(3-chloro-4-fluorophenyl)acetamide, (Fun et al., 2012a,b,c,d) have been reported. In view of the importance of amides, we report herein the crystal structure of the title compound, C₁₂H₁₀BrN₃O, (I).

In (I) the dihedral angle between the mean planes of the 4-Bromophenyl and pyrazine rings is 54.6 (3)° (Fig. 1). An intramolecular C—H···O hydrogen bond generates an S(6) graph-set motif. Bond lengths are in normal ranges (Allen et al., 1987). In the crystal, weak N—H···N hydrogen bonds link the molecules into chains along [100]. The chains are linked via weak C—H···N and C—H···O intermolecular interactions, forming two-dimensional networks lying parallel to the ab plane.

Related literature

For the structural similarity of N-substituted 2-arylacetamides to the lateral chain of natural benzylpenicillin, see: Mijin & Marinkovic (2006); Mijin et al. (2008). For the coordination abilities of amides, see: Wu et al. (2008, 2010). For related structures, see: Fun et al. (2012a,b,c,d). For bond-length data, see: Allen et al. (1987).

S2. Experimental

4-Bromophenylacetic acid (0.213 g, 1 mmol), 2-aminopyrazine (0.095 g, 1 mmol) and 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (1.0 g, 0.01 mol) were dissolved in dichloromethane (20 mL) (Fig. 3). The mixture was stirred in presence of triethylamine at 273 K for about 3 h. The contents were poured into 100 ml of ice-cold aqueous hydrochloric acid with stirring, which was extracted thrice with dichloromethane. The organic layer was washed with saturated NaHCO₃ solution and brine solution, dried and concentrated under reduced pressure to give the title compound (I). Single crystals were grown from methylene chloride by the slow evaporation method (M.P.: 433–435 K).

S3. Refinement

All of the H atoms were placed in their calculated positions and then refined using the riding model with Atom—H lengths of 0.93Å (CH) or 0.97Å (CH₂). Isotropic displacement parameters for these atoms were set to 1.2 (CH, CH₂) times U_eq of the parent atom.

Computing details

Data collection: CrysAlis PRO (Agilent, 2012); cell refinement: CrysAlis PRO (Agilent, 2012); data reduction: CrysAlis PRO (Agilent, 2012); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2012 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Figures

	Fig. 1. Molecular structure of the title compound showing the atom labeling scheme and 30% probability displacement ellipsoids. Dashed line indicates an intramolecular C3—H2···O1 hydrogen bond in an S(6) graph-set motif.
	Fig. 2. Packing diagram of the title compound viewed along the c axis. Dashed lines indicate N—H···N hydrogen bonds and weak C—H···N and C—H···O intermolecular interactions linking the molecules into chains along [100] forming 2-D networks lying parallel to the ab plane.
	Fig. 3. Reaction scheme.

2-(4-Bromophenyl)-N-(pyrazin-2-yl)acetamide

Crystal data

C12H10BrN3O	Dx = 1.659 Mg m^−3
Mr = 292.14	Cu Kα radiation, λ = 1.54184 Å
Orthorhombic, Pbca	Cell parameters from 5193 reflections
a = 10.6804 (4) Å	θ = 4.1–72.4°
b = 7.5196 (3) Å	µ = 4.69 mm^−1
c = 29.1355 (10) Å	T = 173 K
V = 2339.94 (14) Å^3	Chunk, colorless
Z = 8	0.16 × 0.08 × 0.06 mm
F(000) = 1168

Data collection

Agilent Xcalibur Eos Gemini diffractometer	2036 reflections with I > 2σ(I)
Detector resolution: 16.1500 pixels mm^-1	Rint = 0.036
ω scans	θmax = 72.6°, θmin = 5.1°
Absorption correction: multi-scan (CrysAlis PRO and CrysAlis RED; Agilent, 2012)	h = −7→13
Tmin = 0.388, Tmax = 1.000	k = −9→9
13941 measured reflections	l = −35→33
2317 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.035	w = 1/[σ^2(Fo^2) + (0.0494P)^2 + 2.0499P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.095	(Δ/σ)max = 0.001
S = 1.03	Δρmax = 0.75 e Å^−3
2317 reflections	Δρmin = −0.81 e Å^−3
158 parameters

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Br1	0.64022 (3)	0.29843 (4)	0.81514 (2)	0.04987 (14)
O1	0.77445 (16)	0.3961 (3)	0.58151 (7)	0.0473 (5)
N1	0.5962 (2)	0.3332 (3)	0.54173 (7)	0.0339 (5)
H1	0.524 (3)	0.340 (4)	0.5413 (10)	0.033 (8)*
N2	0.55700 (18)	0.1871 (3)	0.47422 (8)	0.0357 (5)
N3	0.81075 (18)	0.1345 (3)	0.45762 (7)	0.0351 (5)
C1	0.6614 (2)	0.4063 (4)	0.57735 (9)	0.0346 (5)
C2	0.6436 (2)	0.2438 (4)	0.50359 (9)	0.0315 (5)
C3	0.7716 (2)	0.2175 (3)	0.49533 (9)	0.0332 (5)
H3	0.8300	0.2586	0.5165	0.040*
C4	0.7231 (2)	0.0759 (3)	0.42843 (9)	0.0367 (6)
H4	0.7475	0.0161	0.4019	0.044*
C5	0.5977 (2)	0.1023 (4)	0.43686 (9)	0.0378 (6)
H5	0.5395	0.0597	0.4158	0.045*
C6	0.5806 (2)	0.5067 (4)	0.61136 (9)	0.0374 (6)
H6A	0.5997	0.6326	0.6093	0.045*
H6B	0.4933	0.4910	0.6031	0.045*
C7	0.5995 (2)	0.4464 (3)	0.66018 (9)	0.0315 (5)
C8	0.7040 (2)	0.5003 (3)	0.68536 (8)	0.0326 (5)
H8	0.7653	0.5691	0.6713	0.039*
C9	0.7177 (2)	0.4531 (3)	0.73080 (9)	0.0341 (5)
H9	0.7876	0.4897	0.7473	0.041*
C10	0.6263 (2)	0.3510 (3)	0.75151 (9)	0.0323 (5)
C11	0.5237 (2)	0.2907 (3)	0.72733 (10)	0.0384 (6)
H11	0.4639	0.2191	0.7414	0.046*
C12	0.5116 (2)	0.3387 (4)	0.68182 (10)	0.0389 (6)
H12	0.4430	0.2980	0.6652	0.047*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0638 (2)	0.0486 (2)	0.0372 (2)	−0.00515 (14)	0.00523 (12)	0.00487 (12)
O1	0.0237 (9)	0.0708 (14)	0.0474 (11)	0.0046 (9)	−0.0071 (7)	−0.0090 (10)
N1	0.0180 (10)	0.0469 (13)	0.0367 (11)	0.0001 (9)	0.0016 (8)	0.0025 (9)
N2	0.0227 (10)	0.0453 (12)	0.0390 (12)	0.0003 (9)	−0.0018 (8)	0.0025 (9)
N3	0.0256 (10)	0.0398 (12)	0.0398 (11)	0.0027 (9)	0.0021 (8)	0.0073 (9)
C1	0.0286 (12)	0.0399 (14)	0.0355 (13)	0.0008 (10)	−0.0016 (10)	0.0050 (11)
C2	0.0225 (11)	0.0376 (12)	0.0344 (13)	−0.0009 (9)	−0.0017 (9)	0.0088 (10)
C3	0.0229 (11)	0.0410 (14)	0.0356 (12)	−0.0003 (10)	0.0008 (9)	0.0081 (10)
C4	0.0336 (13)	0.0408 (14)	0.0357 (13)	0.0025 (11)	0.0005 (10)	0.0038 (11)
C5	0.0314 (12)	0.0438 (14)	0.0382 (14)	−0.0006 (11)	−0.0045 (10)	0.0026 (11)
C6	0.0274 (12)	0.0422 (14)	0.0428 (14)	0.0065 (11)	−0.0032 (10)	0.0007 (12)
C7	0.0230 (11)	0.0306 (12)	0.0409 (13)	0.0042 (9)	−0.0002 (9)	−0.0021 (10)
C8	0.0258 (11)	0.0306 (12)	0.0413 (13)	−0.0057 (10)	0.0028 (9)	−0.0013 (10)
C9	0.0319 (12)	0.0290 (12)	0.0414 (13)	−0.0045 (10)	−0.0040 (10)	−0.0023 (10)
C10	0.0362 (13)	0.0278 (11)	0.0330 (12)	0.0035 (9)	0.0044 (10)	0.0000 (10)
C11	0.0261 (12)	0.0335 (13)	0.0556 (16)	−0.0048 (10)	0.0068 (11)	0.0036 (11)
C12	0.0246 (12)	0.0392 (14)	0.0529 (16)	−0.0038 (10)	−0.0053 (10)	−0.0013 (12)

Geometric parameters (Å, º)

Br1—C10	1.901 (3)	C5—H5	0.9300
O1—C1	1.216 (3)	C6—C7	1.507 (4)
N1—C1	1.365 (3)	C6—H6A	0.9700
N1—C2	1.394 (3)	C6—H6B	0.9700
N1—H1	0.78 (3)	C7—C12	1.391 (4)
N2—C2	1.330 (3)	C7—C8	1.396 (3)
N2—C5	1.334 (3)	C8—C9	1.378 (4)
N3—C3	1.331 (3)	C8—H8	0.9300
N3—C4	1.339 (3)	C9—C10	1.381 (3)
C1—C6	1.516 (4)	C9—H9	0.9300
C2—C3	1.402 (3)	C10—C11	1.379 (4)
C3—H3	0.9300	C11—C12	1.380 (4)
C4—C5	1.376 (4)	C11—H11	0.9300
C4—H4	0.9300	C12—H12	0.9300
C1—N1—C2	128.0 (2)	C1—C6—H6A	109.0
C1—N1—H1	120 (2)	C7—C6—H6B	109.0
C2—N1—H1	113 (2)	C1—C6—H6B	109.0
C2—N2—C5	116.8 (2)	H6A—C6—H6B	107.8
C3—N3—C4	117.3 (2)	C12—C7—C8	118.1 (2)
O1—C1—N1	123.8 (3)	C12—C7—C6	120.9 (2)
O1—C1—C6	122.1 (2)	C8—C7—C6	121.1 (2)
N1—C1—C6	114.0 (2)	C9—C8—C7	121.0 (2)
N2—C2—N1	114.5 (2)	C9—C8—H8	119.5
N2—C2—C3	121.5 (2)	C7—C8—H8	119.5
N1—C2—C3	124.0 (2)	C8—C9—C10	119.2 (2)
N3—C3—C2	120.9 (2)	C8—C9—H9	120.4
N3—C3—H3	119.5	C10—C9—H9	120.4
C2—C3—H3	119.5	C11—C10—C9	121.4 (2)
N3—C4—C5	121.3 (2)	C11—C10—Br1	119.5 (2)
N3—C4—H4	119.4	C9—C10—Br1	119.10 (19)
C5—C4—H4	119.4	C10—C11—C12	118.6 (2)
N2—C5—C4	122.1 (2)	C10—C11—H11	120.7
N2—C5—H5	118.9	C12—C11—H11	120.7
C4—C5—H5	118.9	C11—C12—C7	121.6 (2)
C7—C6—C1	113.0 (2)	C11—C12—H12	119.2
C7—C6—H6A	109.0	C7—C12—H12	119.2
C2—N1—C1—O1	−3.2 (4)	N1—C1—C6—C7	127.0 (2)
C2—N1—C1—C6	175.4 (2)	C1—C6—C7—C12	−103.9 (3)
C5—N2—C2—N1	179.3 (2)	C1—C6—C7—C8	77.7 (3)
C5—N2—C2—C3	0.8 (4)	C12—C7—C8—C9	−2.1 (4)
C1—N1—C2—N2	−179.9 (2)	C6—C7—C8—C9	176.4 (2)
C1—N1—C2—C3	−1.4 (4)	C7—C8—C9—C10	0.0 (4)
C4—N3—C3—C2	−0.8 (4)	C8—C9—C10—C11	2.0 (4)
N2—C2—C3—N3	0.0 (4)	C8—C9—C10—Br1	−176.14 (19)
N1—C2—C3—N3	−178.4 (2)	C9—C10—C11—C12	−1.8 (4)
C3—N3—C4—C5	0.8 (4)	Br1—C10—C11—C12	176.3 (2)
C2—N2—C5—C4	−0.8 (4)	C10—C11—C12—C7	−0.4 (4)
N3—C4—C5—N2	0.0 (4)	C8—C7—C12—C11	2.3 (4)
O1—C1—C6—C7	−54.4 (4)	C6—C7—C12—C11	−176.2 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N3^i	0.78 (3)	2.28 (3)	3.059 (3)	178 (3)
C3—H3···O1	0.93	2.24	2.848 (3)	123
C3—H3···N2^ii	0.93	2.47	3.255 (3)	142
C6—H6A···O1^iii	0.97	2.53	3.424 (4)	154

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