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The non-H atoms of the title compound, C11H15NO2, are approximately coplanar. In the crystal structure, an N—H...O hydrogen bond leads to C(4) chains of mol­ecules propagating along [010].

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807048854/fj2048sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807048854/fj2048Isup2.hkl
Contains datablock I

CCDC reference: 667326

Key indicators

  • Single-crystal X-ray study
  • T = 93 K
  • Mean [sigma](C-C)= 0.002 Å
  • R factor = 0.043
  • wR factor = 0.115
  • Data-to-parameter ratio = 14.5

checkCIF/PLATON results

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Comment top

The title compound, (I), with R = n-Pr, complements the series of molecules with R = H [N-(4-hydroxyphenyl)acetamide or acetaminophen or paracetamol], R = Me [N-(4-methoxyphenyl)acetamide; Haisa et al. (1980)] and R = Et [N-(4-ethoxyphenyl)acetamide or phenacetin; Hansen et al. (2006)]. Crystallographically, paracetamol is notable for its polymorphism, adopting at least four crystalline forms (Nichols & Frampton, 1998), as well as its participation in a variety of distinctive supramolecular networks (Oswald et al., 2002).

The molecule of (I) is approximately planar, with an r.m.s. deviation from the mean plane of 0.084 Å for the non-hydrogen atoms. The short C6—N1 bond length of 1.4145 (17) Å and the bond-angle sum of 360° for N1 suggest some electronic interaction between the π cloud of the benzene ring and the p electrons of N1, C7 and O1. Otherwise, the geometry of (I) may be regarded as normal (Allen et al., 1995).

In the crystal of (I), an N—H···O hydrogen bond (Table 1) links the molecules into C(4) chains propagating in [010] (Fig. 2). The unit-cell packing for (I) results in distinctive zigzag (100) sheets (Fig. 3). There are no aromatic π-π stacking interactions in (I) as the closest benzene ring centroid-centroid separation is greater than 4.51 Å.

Supramolecular C(4) hydrogen bonded chains containing the characteristic ···O=C—N—H··· amide unit are also observed in the crystals of N-(4-methoxyphenyl)acetamide (Haisa et al., 1980) and phenacetin (Hansen et al., 2006). However, paracetamol adopts different hydrogen bonding patterns: either –N—H···OH or –O—H···O—H··· hydrogen bonds are seen, depending on the polymorph (Nichols & Frampton, 1998)

Related literature top

For background, see: Haisa et al. (1980); Nichols & Frampton (1998); Oswald et al. (2002); Hansen et al. (2006). For reference structural data, see: Allen et al. (1995).

Experimental top

Paracetamol was treated with K2CO3 and 1-iodopropane in acetone to yield the crude pruduct. Recrystallization from acetone yielded colourless prisms of (I).

Refinement top

The N-bound hydrogen atom was located in a difference map and its position was freely refined with Uiso(H) = 1.2Ueq(N). The C-bound hydrogen atoms were geometrically placed (C—H = 0.95–0.99 Å) and refined as riding with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C). The methyl groups were allowed to rotate, but not tip, to best fit the electron density.

Structure description top

The title compound, (I), with R = n-Pr, complements the series of molecules with R = H [N-(4-hydroxyphenyl)acetamide or acetaminophen or paracetamol], R = Me [N-(4-methoxyphenyl)acetamide; Haisa et al. (1980)] and R = Et [N-(4-ethoxyphenyl)acetamide or phenacetin; Hansen et al. (2006)]. Crystallographically, paracetamol is notable for its polymorphism, adopting at least four crystalline forms (Nichols & Frampton, 1998), as well as its participation in a variety of distinctive supramolecular networks (Oswald et al., 2002).

The molecule of (I) is approximately planar, with an r.m.s. deviation from the mean plane of 0.084 Å for the non-hydrogen atoms. The short C6—N1 bond length of 1.4145 (17) Å and the bond-angle sum of 360° for N1 suggest some electronic interaction between the π cloud of the benzene ring and the p electrons of N1, C7 and O1. Otherwise, the geometry of (I) may be regarded as normal (Allen et al., 1995).

In the crystal of (I), an N—H···O hydrogen bond (Table 1) links the molecules into C(4) chains propagating in [010] (Fig. 2). The unit-cell packing for (I) results in distinctive zigzag (100) sheets (Fig. 3). There are no aromatic π-π stacking interactions in (I) as the closest benzene ring centroid-centroid separation is greater than 4.51 Å.

Supramolecular C(4) hydrogen bonded chains containing the characteristic ···O=C—N—H··· amide unit are also observed in the crystals of N-(4-methoxyphenyl)acetamide (Haisa et al., 1980) and phenacetin (Hansen et al., 2006). However, paracetamol adopts different hydrogen bonding patterns: either –N—H···OH or –O—H···O—H··· hydrogen bonds are seen, depending on the polymorph (Nichols & Frampton, 1998)

For background, see: Haisa et al. (1980); Nichols & Frampton (1998); Oswald et al. (2002); Hansen et al. (2006). For reference structural data, see: Allen et al. (1995).

Computing details top

Data collection: CrystalClear (Rigaku, 2004); cell refinement: CrystalClear (Rigaku, 2004); data reduction: CrystalClear (Rigaku, 2004); 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 (Sheldrick, 1997).

Figures top
[Figure 1] Fig. 1. View of the molecular structure of (I) showing 50% displacement ellipsoids (arbitrary spheres for the H atoms).
[Figure 2] Fig. 2. Fragement of a [010] hydrogen bonded chain of molecules in the crystal of (I) with all H atoms except Hxx omitted for clarity. Symmetry codes: (i) 3/2 - x,y + 1/2,z; (ii) x, y + 1, z.
[Figure 3] Fig. 3. The unit cell packing for (I), with H atoms omitted for clarity.
N-(4-Propoxyphenyl)acetamide top
Crystal data top
C11H15NO2F(000) = 832
Mr = 193.24Dx = 1.222 Mg m3
Orthorhombic, PbcnMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2abCell parameters from 6098 reflections
a = 11.7776 (11) Åθ = 2.4–28.7°
b = 9.4779 (8) ŵ = 0.08 mm1
c = 18.8180 (18) ÅT = 93 K
V = 2100.6 (3) Å3Prism, colourless
Z = 80.20 × 0.10 × 0.10 mm
Data collection top
Rigaku Mercury CCD
diffractometer
1702 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.027
Graphite monochromatorθmax = 25.3°, θmin = 2.8°
ω and φ scansh = 1414
12750 measured reflectionsk = 1011
1916 independent reflectionsl = 2216
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.043Hydrogen site location: difmap and geom
wR(F2) = 0.115H atoms treated by a mixture of independent and constrained refinement
S = 1.06 w = 1/[σ2(Fo2) + (0.0648P)2 + 0.5326P]
where P = (Fo2 + 2Fc2)/3
1916 reflections(Δ/σ)max < 0.001
132 parametersΔρmax = 0.17 e Å3
0 restraintsΔρmin = 0.17 e Å3
Crystal data top
C11H15NO2V = 2100.6 (3) Å3
Mr = 193.24Z = 8
Orthorhombic, PbcnMo Kα radiation
a = 11.7776 (11) ŵ = 0.08 mm1
b = 9.4779 (8) ÅT = 93 K
c = 18.8180 (18) Å0.20 × 0.10 × 0.10 mm
Data collection top
Rigaku Mercury CCD
diffractometer
1702 reflections with I > 2σ(I)
12750 measured reflectionsRint = 0.027
1916 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0430 restraints
wR(F2) = 0.115H atoms treated by a mixture of independent and constrained refinement
S = 1.06Δρmax = 0.17 e Å3
1916 reflectionsΔρmin = 0.17 e Å3
132 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
xyzUiso*/Ueq
C10.54255 (11)0.29534 (13)0.34000 (7)0.0215 (3)
H1A0.57120.21070.31970.026*
C20.45492 (11)0.29033 (14)0.38907 (7)0.0226 (3)
H20.42420.20150.40230.027*
C30.41105 (11)0.41241 (14)0.41933 (7)0.0207 (3)
C40.45639 (11)0.54225 (14)0.39988 (7)0.0219 (3)
H40.42740.62680.42000.026*
C50.54437 (11)0.54724 (13)0.35089 (7)0.0210 (3)
H50.57520.63610.33780.025*
C60.58849 (10)0.42529 (13)0.32056 (7)0.0182 (3)
C70.74534 (11)0.34160 (14)0.24285 (7)0.0211 (3)
C80.83580 (12)0.39449 (15)0.19276 (8)0.0281 (4)
H8A0.84230.49720.19710.042*
H8B0.81520.37000.14380.042*
H8C0.90870.35060.20480.042*
C90.27433 (12)0.51676 (14)0.49810 (7)0.0245 (3)
H9A0.24520.58130.46100.029*
H9B0.33210.56760.52650.029*
C100.17881 (12)0.46751 (16)0.54514 (8)0.0316 (4)
H10A0.20920.40200.58140.038*
H10B0.12270.41530.51610.038*
C110.12012 (14)0.59032 (16)0.58193 (8)0.0351 (4)
H11A0.05860.55440.61200.053*
H11B0.08870.65450.54610.053*
H11C0.17520.64120.61140.053*
N10.67758 (9)0.44174 (12)0.27083 (6)0.0193 (3)
H10.6928 (14)0.5298 (18)0.2586 (7)0.023*
O10.73594 (9)0.21529 (10)0.25639 (5)0.0298 (3)
O20.32328 (8)0.39351 (10)0.46613 (5)0.0257 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0241 (7)0.0167 (7)0.0237 (7)0.0015 (5)0.0002 (5)0.0011 (5)
C20.0252 (7)0.0182 (7)0.0246 (7)0.0031 (5)0.0005 (5)0.0019 (5)
C30.0199 (7)0.0236 (7)0.0187 (6)0.0002 (5)0.0009 (5)0.0020 (5)
C40.0247 (7)0.0183 (7)0.0228 (7)0.0025 (5)0.0002 (5)0.0023 (5)
C50.0222 (7)0.0173 (7)0.0235 (7)0.0014 (5)0.0007 (5)0.0015 (5)
C60.0183 (6)0.0191 (7)0.0174 (6)0.0009 (5)0.0039 (5)0.0009 (5)
C70.0201 (7)0.0211 (8)0.0220 (7)0.0022 (5)0.0027 (5)0.0005 (5)
C80.0259 (7)0.0272 (8)0.0313 (8)0.0028 (6)0.0045 (6)0.0004 (6)
C90.0247 (7)0.0245 (7)0.0243 (7)0.0029 (6)0.0012 (6)0.0001 (6)
C100.0279 (8)0.0344 (9)0.0326 (8)0.0007 (6)0.0083 (6)0.0021 (6)
C110.0326 (8)0.0397 (9)0.0329 (8)0.0064 (7)0.0087 (7)0.0012 (7)
N10.0209 (6)0.0151 (6)0.0218 (6)0.0007 (4)0.0015 (4)0.0008 (4)
O10.0313 (6)0.0180 (6)0.0401 (6)0.0052 (4)0.0057 (4)0.0021 (4)
O20.0262 (5)0.0238 (5)0.0270 (5)0.0000 (4)0.0080 (4)0.0000 (4)
Geometric parameters (Å, º) top
C1—C21.3856 (19)C8—H8A0.9800
C1—C61.3941 (18)C8—H8B0.9800
C1—H1A0.9500C8—H8C0.9800
C2—C31.3894 (18)C9—O21.4349 (16)
C2—H20.9500C9—C101.506 (2)
C3—O21.3697 (16)C9—H9A0.9900
C3—C41.3905 (18)C9—H9B0.9900
C4—C51.3877 (19)C10—C111.521 (2)
C4—H40.9500C10—H10A0.9900
C5—C61.3899 (17)C10—H10B0.9900
C5—H50.9500C11—H11A0.9800
C6—N11.4145 (17)C11—H11B0.9800
C7—O11.2289 (17)C11—H11C0.9800
C7—N11.3471 (17)N1—H10.884 (17)
C7—C81.5083 (19)
C2—C1—C6119.62 (12)H8A—C8—H8C109.5
C2—C1—H1A120.2H8B—C8—H8C109.5
C6—C1—H1A120.2O2—C9—C10107.12 (11)
C1—C2—C3121.44 (12)O2—C9—H9A110.3
C1—C2—H2119.3C10—C9—H9A110.3
C3—C2—H2119.3O2—C9—H9B110.3
O2—C3—C2115.80 (11)C10—C9—H9B110.3
O2—C3—C4125.09 (12)H9A—C9—H9B108.5
C2—C3—C4119.10 (12)C9—C10—C11111.72 (12)
C5—C4—C3119.46 (11)C9—C10—H10A109.3
C5—C4—H4120.3C11—C10—H10A109.3
C3—C4—H4120.3C9—C10—H10B109.3
C4—C5—C6121.58 (11)C11—C10—H10B109.3
C4—C5—H5119.2H10A—C10—H10B107.9
C6—C5—H5119.2C10—C11—H11A109.5
C5—C6—C1118.80 (12)C10—C11—H11B109.5
C5—C6—N1117.21 (11)H11A—C11—H11B109.5
C1—C6—N1123.98 (11)C10—C11—H11C109.5
O1—C7—N1123.50 (12)H11A—C11—H11C109.5
O1—C7—C8121.12 (12)H11B—C11—H11C109.5
N1—C7—C8115.38 (12)C7—N1—C6128.33 (11)
C7—C8—H8A109.5C7—N1—H1116.3 (10)
C7—C8—H8B109.5C6—N1—H1115.3 (10)
H8A—C8—H8B109.5C3—O2—C9117.79 (10)
C7—C8—H8C109.5
C6—C1—C2—C30.3 (2)C2—C1—C6—N1179.72 (11)
C1—C2—C3—O2178.89 (11)O2—C9—C10—C11179.87 (12)
C1—C2—C3—C40.1 (2)O1—C7—N1—C62.0 (2)
O2—C3—C4—C5178.96 (12)C8—C7—N1—C6177.89 (12)
C2—C3—C4—C50.1 (2)C5—C6—N1—C7168.77 (12)
C3—C4—C5—C60.1 (2)C1—C6—N1—C711.8 (2)
C4—C5—C6—C10.17 (19)C2—C3—O2—C9179.29 (11)
C4—C5—C6—N1179.59 (11)C4—C3—O2—C90.40 (18)
C2—C1—C6—C50.34 (19)C10—C9—O2—C3178.51 (11)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.884 (17)1.949 (17)2.7988 (15)160.8 (14)
Symmetry code: (i) x+3/2, y+1/2, z.

Experimental details

Crystal data
Chemical formulaC11H15NO2
Mr193.24
Crystal system, space groupOrthorhombic, Pbcn
Temperature (K)93
a, b, c (Å)11.7776 (11), 9.4779 (8), 18.8180 (18)
V3)2100.6 (3)
Z8
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.20 × 0.10 × 0.10
Data collection
DiffractometerRigaku Mercury CCD
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
12750, 1916, 1702
Rint0.027
(sin θ/λ)max1)0.602
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.043, 0.115, 1.06
No. of reflections1916
No. of parameters132
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.17, 0.17

Computer programs: CrystalClear (Rigaku, 2004), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O1i0.884 (17)1.949 (17)2.7988 (15)160.8 (14)
Symmetry code: (i) x+3/2, y+1/2, z.
 

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