N-(2-Bromo­phen­yl)propionamide

The title compound, C₉H₁₀BrNO, posseses normal geom­etrical parameters. The crystal packing is influenced by an N—H⋯O hydrogen bond.

Comment

The title compound, (I) (Fig. 1), was prepared as part of our ongoing studies of acetanilide derivatives (Ronaldson et al., 2005).

The dihedral angle between the mean planes of the benzene ring (atoms C1–C6) and the N1/O1/C7/C8 side chain is 40.92 (10)°. This is very similar to the value [42.75 (14)°] in N-(2-bromo­phen­yl)acetamide, (II) (Ronaldson et al., 2005). The bond angle sum about N1 in (I) is 360.0°, indicating that this atom is sp² hybridized. The C6—N1 distance of 1.416 (3) Å in (I) is almost identical to the equivalent distance [1.418 (4) Å] in (II). All the other geometrical parameters for (I) lie within their expected ranges (Allen et al., 1995).

The crystal packing in (I) is influenced by an N—H⋯O hydrogen bond (Table 1 and Fig. 2) that links the mol­ecules into chains propagating in the [100] direction. There are no π–π inter­actions in (I). The unit-cell packing is shown in Fig. 3; (I) is essentially isostructural (same space group, similar unit-cell parameters) with (II), except that the unit cell for (I) is slightly expanded in the c-axis direction to accommodate the more bulky terminal ethyl moiety.

Figure 1 View of (I), shown with 50% displacement ellipsoids. H atoms are drawn as small spheres of arbitrary radius.

Figure 2 Detail of (I), showing how N—H⋯O hydrogen bonds (dashed lines) link mol­ecules into a chain. The view direction is perpendicular to the mean plane of the benzene ring of the central mol­ecule, showing that no π–π stacking occurs. All H atoms except H1 have been omitted for clarity. [Symmetry codes: (i) x − 1, y, z; (ii) x + 1, y, z.]

Figure 3 The packing in (I), viewed down [010], with all H atoms except H1 omitted for clarity.

Experimental

2-Bromo­aniline (3.44 g, 20.0 mmol) was added to a solution of propionyl chloride (2.22 g, 24.0 mmol) and DIPEA (N,N-diisopropyl­ethyl­amine) (3.12 g, 24.0 mmol) in dry tetra­hydro­furan (20 ml) at 273 K. The reaction was monitored by thin-layer chromatography and, when complete, the mixture was diluted with water (20 ml) and the product was extracted with EtOAc (3 × 20 ml). The organic phase was washed with water (2 × 20 ml) and brine (20 ml) then dried over MgSO₄ and evaporated under reduced pressure to yield the crude product which was recrystallized from CH₂Cl₂ to give 4.31 g (95% yield) of (I) as colourless needles. M.p. 360–362 K; R_F = 0.19 [hexa­ne/EtOAc (10:1)]; ν_max (KBr disc)/cm⁻¹: 3277 (NH), 2971–2932 (C—H), 1655 (C=O), 1573 (Ar C=C); δ_H (250 MHz, CDCl₃) 1.27 (3H, t, J = 7.5 Hz, CH₃), 2.46 (2H, q, J = 7.5 Hz, CH₂), 6.95 (1H, t, J = 7.5 Hz, Ar—H), 7.29 (1H, t, J = 8.0 Hz, Ar—H), 7.51 (1H, d, J = 8.0 Hz, Ar—H), 8.35 (1H, d, J = 7.5 Hz, Ar—H); δ_C (CDCl₃) 9.6 (CH₃), 31.1 (—CO–CH₂—), 113.2, 121.9, 125.0, 128.4, 132.2 and 135.7 (Ar–C), 172.0 (C=O). [M+H]⁺ 226.994, C₉H₁₀⁷⁹BrNO requires 226.995.

Crystal data

• C₉H₁₀BrNO

• M_r = 228.09

• Monoclinic, P 2₁ /n

• a = 4.8701 (1) Å

• b = 11.8048 (4) Å

• c = 15.9296 (5) Å

• β = 93.964 (2)°

• V = 913.61 (5) ų

• Z = 4

• D_x = 1.658 Mg m⁻³

• Mo Kα radiation

• Cell parameters from 2165 reflections

• θ = 2.9–27.5°

• μ = 4.45 mm⁻¹

• T = 120 (2) K

• Needle, colourless

• 0.36 × 0.05 × 0.02 mm

Data collection

• Nonius KappaCCD diffractometer

• ω and φ scans

• Absorption correction: multi-scan(SADABS; Bruker, 2003)T_min = 0.297, T_max = 0.916

• 13742 measured reflections

• 2092 independent reflections

• 1822 reflections with I > 2σ(I)

• R_int = 0.043

• θ_max = 27.5°

• h = −6 → 6

• k = −15 → 15

• l = −20 → 20

Refinement

• Refinement on F²

• R[F² > 2σ(F²)] = 0.027

• wR(F²) = 0.065

• S = 1.07

• 2092 reflections

• 114 parameters

• H atoms treated by a mixture of independent and constrained refinement

• w = 1/[σ²(F_o²) + (0.0226P)² + 0.9463P] where P = (F_o² + 2F_c²)/3

• (Δ/σ)_max = 0.001

• Δρ_max = 0.38 e Å⁻³

• Δρ_min = −0.37 e Å⁻³

• Extinction correction: SHELXL97

• Extinction coefficient: 0.0039 (9)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1^i	0.85 (3)	2.06 (3)	2.889 (2)	164 (2)
Symmetry code: (i) x-1, y, z.

All C-bound H atoms were placed in idealized positions (C—H = 0.95–0.99 Å) and refined as riding on their carriers with the constraint U_iso(H) = 1.2U_eq(C) or U_iso(H) = 1.5U_eq(methyl C) applied. The methyl group was allowed to rotate about the C9—C8 bond as a rigid group. The N-bound H atom was located in a difference map and its position was freely refned with the constraint U_iso(H) = 1.2U_eq(N).

Data collection: COLLECT (Nonius, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997), and SORTAV (Blessing, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Supporting information

S1. Comment

The title compound, (I) (Fig. 1), was prepared as part of our ongoing studies of acetanilide derivatives (Ronaldson et al., 2005).

The dihedral angle between the best planes of the benzene ring (atoms C1–C6) and the N1/O1/C7/C8 side chain is 40.92 (10)°. This is very similar to the value [42.75 (14)°] in N-(2-bromophenyl)acetamide, (II) (Ronaldson et al., 2005). The bond angle sum about N1 in (I) is 360.0°, indicating that this atom is sp² hybridized. The C6—N1 distance of 1.416 (3) Å in (I) is almost identical to the equivalent distance [1.418 (4) Å] in (II). All the other geometrical parameters for (I) lie within their expected ranges (Allen et al., 1995).

The crystal packing in (I) is infludenced by an N—H···O hydrogen bond (Table 1 and Fig. 2) that links the molecules into chains propagating in the [100] direction. There are no π–π interactions in (I). The unit-cell packing is shown in Fig. 3; (I) is essentially isostructural (same space group, similar unit-cell parameters) with (II), except that the unit cell for (I) is slightly expanded in the c axis direction to accommodate the more bulky terminal ethyl moiety.

S2. Experimental

2-Bromoaniline (3.44 g, 20.0 mmol) was added to a solution of propionyl chloride (2.22 g, 24.0 mmol) and DIPEA (N,N-diisopropylethylamine) (3.12 g, 24.0 mmol) in dry tetrahydrofuran (20 ml) at 273 K. The reaction was monitored by thin-layer chromatography and when complete, the mixture was diluted with water (20 ml) and the product was extracted with EtOAc (3 × 20 ml). The organic phase was then washed with water (2 × 20 ml) and brine (20 ml) then dried over MgSO₄ and evaporated under reduced pressure to yield the crude product which was recrystallized from CH₂Cl₂ to give 4.31 g (95% yield) of (I) as colourless needles. M.p. 360–362 K; R_F = 0.19 [hexane/EtOAc (10:1)]; ν_max (KBr disc)/cm⁻¹: 3277 (NH), 2971–2932 (C—H), 1655 (C═O), 1573 (Ar C═C); δ_H (250 MHz, CDCl₃) 1.27 (3H, t, J = 7.5 Hz, CH₃), 2.46 (2H, q, J = 7.5 Hz, CH₂), 6.95 (1H, t, J = 7.5 Hz, Ar—H), 7.29 (1H, t, J = 8.0 Hz, Ar—H), 7.51 (1H, d, J = 8.0 Hz, Ar—H), 8.35 (1H, d, J = 7.5 Hz, Ar—H); δ_C (CDCl₃) 9.6 (CH₃), 31.1 (—CO–CH₂—), 113.2, 121.9, 125.0, 128.4, 132.2 and 135.7 (Ar–C), 172.0 (C═O). [M+H]⁺ 226.994, C₉H₁₀⁷⁹BrNO requires 226.995.

S3. Refinement

All C-bound H atoms were placed in idealized positions (C—H = 0.95–0.99 Å) and refined as riding on their carriers with the constraint U_iso(H) = 1.2U_eq(C) or U_iso(H) = 1.5U_eq(methyl C) applied. The methyl group was allowed to rotate about the C9—C8 bond as a rigid group. The N-bound H atom was located in a difference map and its position was freely refned with the constraint U_iso(H) = 1.2U_eq(N).

Computing details

Data collection: COLLECT (Nonius, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997), and SORTAV (Blessing, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. View of (I), shown with 50% displacement ellipsoids. H atoms are drawn as small spheres of arbitrary radius.
	Fig. 2. Detail of (I), showing how N—H···O hydrogen bonds (dashed lines) link molecules into a chain. The view direction is perpendicular to the best plane of the benzene ring of the central molecule, showing that no π–π stacking occurs. All H atoms except H1 have been omitted for clarity. [Symmetry codes: (i) x − 1, y, z; (ii) x + 1, y, z.]
	Fig. 3. Unit-cell packing in (I), viewed down [010], with all H atoms except H1 omitted for clarity.

N-(2-Bromophenyl)propionamide

Crystal data

C9H10BrNO	F(000) = 456
Mr = 228.09	Dx = 1.658 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 2165 reflections
a = 4.8701 (1) Å	θ = 2.9–27.5°
b = 11.8048 (4) Å	µ = 4.45 mm^−1
c = 15.9296 (5) Å	T = 120 K
β = 93.964 (2)°	Needle, colourless
V = 913.61 (5) Å^3	0.36 × 0.05 × 0.02 mm
Z = 4

Data collection

Nonius KappaCCD diffractometer	2092 independent reflections
Radiation source: fine-focus sealed tube	1822 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.043
ω and ϕ scans	θmax = 27.5°, θmin = 3.1°
Absorption correction: multi-scan (SADABS; Bruker, 2003)	h = −6→6
Tmin = 0.297, Tmax = 0.916	k = −15→15
13742 measured reflections	l = −20→20

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)] = 0.027	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.065	w = 1/[σ^2(Fo^2) + (0.0226P)^2 + 0.9463P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
2092 reflections	Δρmax = 0.38 e Å^−3
114 parameters	Δρmin = −0.37 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0039 (9)

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
C1	0.4616 (5)	0.54914 (19)	0.20494 (14)	0.0194 (5)
C2	0.5180 (5)	0.6609 (2)	0.22655 (15)	0.0237 (5)
H2	0.4342	0.6949	0.2724	0.028*
C3	0.6975 (5)	0.7226 (2)	0.18071 (16)	0.0273 (5)
H3	0.7417	0.7985	0.1960	0.033*
C4	0.8129 (5)	0.6731 (2)	0.11218 (16)	0.0260 (5)
H4	0.9370	0.7153	0.0809	0.031*
C5	0.7481 (5)	0.5631 (2)	0.08939 (15)	0.0236 (5)
H5	0.8228	0.5311	0.0412	0.028*
C6	0.5740 (4)	0.4983 (2)	0.13620 (14)	0.0186 (5)
C7	0.6917 (4)	0.3057 (2)	0.09094 (13)	0.0186 (5)
C8	0.5718 (5)	0.1890 (2)	0.07664 (16)	0.0238 (5)
H8A	0.4053	0.1950	0.0376	0.029*
H8B	0.5139	0.1594	0.1308	0.029*
C9	0.7679 (5)	0.1053 (2)	0.04102 (19)	0.0334 (6)
H9A	0.6908	0.0288	0.0435	0.050*
H9B	0.9451	0.1080	0.0741	0.050*
H9C	0.7949	0.1249	−0.0176	0.050*
N1	0.5104 (4)	0.38443 (17)	0.11491 (12)	0.0199 (4)
H1	0.342 (6)	0.367 (2)	0.1167 (16)	0.024*
O1	0.9361 (3)	0.32624 (14)	0.08417 (11)	0.0241 (4)
Br1	0.23270 (5)	0.46366 (2)	0.273034 (14)	0.02474 (11)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0135 (10)	0.0232 (12)	0.0217 (11)	−0.0002 (9)	0.0026 (8)	0.0011 (9)
C2	0.0237 (12)	0.0234 (12)	0.0243 (12)	0.0024 (9)	0.0030 (9)	−0.0022 (10)
C3	0.0258 (13)	0.0202 (12)	0.0357 (14)	−0.0008 (10)	0.0011 (10)	−0.0007 (11)
C4	0.0195 (12)	0.0277 (13)	0.0311 (13)	−0.0039 (10)	0.0034 (10)	0.0064 (10)
C5	0.0195 (12)	0.0279 (13)	0.0242 (12)	0.0007 (9)	0.0064 (9)	0.0003 (10)
C6	0.0138 (10)	0.0211 (11)	0.0205 (11)	0.0014 (9)	−0.0008 (9)	0.0013 (9)
C7	0.0162 (11)	0.0244 (12)	0.0152 (10)	−0.0014 (9)	0.0017 (8)	−0.0003 (9)
C8	0.0149 (11)	0.0229 (12)	0.0336 (13)	−0.0034 (9)	0.0019 (9)	−0.0025 (10)
C9	0.0265 (13)	0.0269 (13)	0.0472 (16)	−0.0046 (11)	0.0046 (12)	−0.0115 (12)
N1	0.0119 (9)	0.0239 (10)	0.0242 (10)	−0.0033 (8)	0.0038 (7)	−0.0028 (8)
O1	0.0142 (8)	0.0249 (9)	0.0334 (9)	−0.0022 (6)	0.0043 (7)	−0.0052 (7)
Br1	0.02460 (16)	0.02600 (15)	0.02478 (16)	−0.00150 (9)	0.01004 (10)	−0.00078 (10)

Geometric parameters (Å, º)

C1—C2	1.386 (3)	C6—N1	1.416 (3)
C1—C6	1.393 (3)	C7—O1	1.227 (3)
C1—Br1	1.899 (2)	C7—N1	1.355 (3)
C2—C3	1.384 (3)	C7—C8	1.507 (3)
C2—H2	0.9500	C8—C9	1.512 (3)
C3—C4	1.390 (4)	C8—H8A	0.9900
C3—H3	0.9500	C8—H8B	0.9900
C4—C5	1.379 (3)	C9—H9A	0.9800
C4—H4	0.9500	C9—H9B	0.9800
C5—C6	1.395 (3)	C9—H9C	0.9800
C5—H5	0.9500	N1—H1	0.85 (3)
C2—C1—C6	121.5 (2)	O1—C7—N1	122.9 (2)
C2—C1—Br1	118.57 (17)	O1—C7—C8	122.4 (2)
C6—C1—Br1	119.90 (17)	N1—C7—C8	114.60 (19)
C3—C2—C1	119.4 (2)	C7—C8—C9	113.92 (19)
C3—C2—H2	120.3	C7—C8—H8A	108.8
C1—C2—H2	120.3	C9—C8—H8A	108.8
C2—C3—C4	119.9 (2)	C7—C8—H8B	108.8
C2—C3—H3	120.1	C9—C8—H8B	108.8
C4—C3—H3	120.1	H8A—C8—H8B	107.7
C5—C4—C3	120.3 (2)	C8—C9—H9A	109.5
C5—C4—H4	119.9	C8—C9—H9B	109.5
C3—C4—H4	119.9	H9A—C9—H9B	109.5
C4—C5—C6	120.8 (2)	C8—C9—H9C	109.5
C4—C5—H5	119.6	H9A—C9—H9C	109.5
C6—C5—H5	119.6	H9B—C9—H9C	109.5
C1—C6—C5	118.1 (2)	C7—N1—C6	125.68 (19)
C1—C6—N1	120.4 (2)	C7—N1—H1	119.4 (18)
C5—C6—N1	121.6 (2)	C6—N1—H1	114.9 (18)
C6—C1—C2—C3	−2.3 (4)	C4—C5—C6—C1	1.9 (4)
Br1—C1—C2—C3	176.17 (18)	C4—C5—C6—N1	−178.5 (2)
C1—C2—C3—C4	1.9 (4)	O1—C7—C8—C9	−8.7 (3)
C2—C3—C4—C5	0.4 (4)	N1—C7—C8—C9	173.8 (2)
C3—C4—C5—C6	−2.3 (4)	O1—C7—N1—C6	−0.9 (4)
C2—C1—C6—C5	0.4 (4)	C8—C7—N1—C6	176.7 (2)
Br1—C1—C6—C5	−178.01 (17)	C1—C6—N1—C7	−138.0 (2)
C2—C1—C6—N1	−179.3 (2)	C5—C6—N1—C7	42.4 (3)
Br1—C1—C6—N1	2.3 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1^i	0.85 (3)	2.06 (3)	2.889 (2)	164 (2)

Symmetry code: (i) x−1, y, z.