Redetermination of p-ethoxy­acetanilide (phenacetin)

The crystal structure of the title compound, C₁₀H₁₃NO₂, has been redetermined in order to obtain more precise structure parameters.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.039
• wR factor = 0.111
• Data-to-parameter ratio = 17.2

checkCIF/PLATON results

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Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   2 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
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: CAD-4-PC Software (Enraf–Nonius, 1992); cell refinement: CELDIM in CAD-4-PC Software; data reduction: XCAD4 (McArdle & Higgins, 1995); program(s) used to solve structure: OSCAIL-X for Windows (McArdle, 2005) and SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: OSCAIL-X for Windows and SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEX (McArdle, 1993) and ORTEPIII (Burnett & Johnson, (1996); software used to prepare material for publication: OSCAIL-X for Windows.

p-ethoxyacetanilide

Crystal data

C10H13NO2	F(000) = 384
Mr = 179.21	Dx = 1.238 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71069 Å
a = 13.3236 (14) Å	Cell parameters from 25 reflections
b = 9.6159 (15) Å	θ = 13–20°
c = 7.7331 (15) Å	µ = 0.09 mm^−1
β = 103.992 (14)°	T = 298 K
V = 961.4 (3) Å^3	Block, colourless
Z = 4	0.50 × 0.40 × 0.30 mm

Data collection

Enraf–Nonius CAD-4 diffractometer	1056 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.015
Graphite monochromator	θmax = 27.0°, θmin = 1.6°
ω/2θ scans	h = −16→16
Absorption correction: ψ scan [ABSCALC in OSCAIL (McArdle & Daly, 1999) and North et al. (1968)]	k = 0→12
Tmin = 0.958, Tmax = 0.975	l = 0→9
2299 measured reflections	3 standard reflections every 120 min
2083 independent reflections	intensity decay: 1%

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)] = 0.039	H-atom parameters constrained
wR(F^2) = 0.111	w = 1/[σ^2(Fo^2) + (0.0541P)^2 + 0.0361P] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max = 0.009
2083 reflections	Δρmax = 0.16 e Å^−3
121 parameters	Δρmin = −0.14 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.021 (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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

4.4927 (0.0057) x + 6.6715 (0.0056) y - 5.4054 (0.0041) z = 1.6589 (0.0013)

* -0.0018 (0.0015) C1 * 0.0039 (0.0014) C2 * 0.0124 (0.0015) C3 * 0.0081 (0.0014) C4 * 0.0117 (0.0014) C5 * 0.0078 (0.0014) C6 * -0.0173 (0.0011) O7 * -0.0249 (0.0011) N10 - 0.3652 (0.0029) C9 - 0.1752 (0.0026) C8 1.0528 (0.0023) O13 0.3274 (0.0027) C12 0.4879 (0.0022) C11

Rms deviation of fitted atoms = 0.0130

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
O7	0.46006 (8)	0.10210 (14)	0.20468 (17)	0.0577 (4)
O13	−0.01286 (10)	0.27655 (13)	−0.17104 (19)	0.0605 (4)
N10	0.05111 (9)	0.06024 (14)	−0.18550 (18)	0.0431 (4)
H10	0.0356	−0.0219	−0.2274	0.056*
C1	0.35754 (12)	0.10087 (18)	0.1151 (2)	0.0424 (4)
C2	0.28182 (13)	0.18444 (18)	0.1543 (3)	0.0494 (5)
H2	0.2988	0.2481	0.2473	0.064*
C3	0.18047 (13)	0.17362 (18)	0.0551 (2)	0.0483 (5)
H3	0.1299	0.2306	0.0818	0.063*
C4	0.15391 (12)	0.07959 (16)	−0.0822 (2)	0.0380 (4)
C5	0.23094 (12)	−0.00290 (17)	−0.1207 (2)	0.0464 (5)
H5	0.2142	−0.0664	−0.2140	0.060*
C6	0.33167 (13)	0.00742 (17)	−0.0235 (2)	0.0478 (5)
H6	0.3824	−0.0487	−0.0514	0.062*
C8	0.49046 (13)	0.1847 (2)	0.3612 (3)	0.0550 (5)
H8A	0.4473	0.1641	0.4426	0.072*
H8B	0.4834	0.2827	0.3309	0.072*
C9	0.60192 (15)	0.1503 (2)	0.4464 (3)	0.0678 (6)
H9A	0.6095	0.0514	0.4614	0.095*
H9B	0.6223	0.1949	0.5607	0.095*
H9C	0.6449	0.1827	0.3715	0.095*
C11	−0.02454 (13)	0.15589 (18)	−0.2251 (2)	0.0445 (5)
C12	−0.12500 (14)	0.1060 (2)	−0.3406 (3)	0.0608 (6)
H12A	−0.1774	0.1088	−0.2744	0.085*
H12B	−0.1171	0.0122	−0.3779	0.085*
H12C	−0.1449	0.1649	−0.4434	0.085*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O7	0.0369 (7)	0.0685 (9)	0.0615 (9)	0.0054 (6)	−0.0001 (6)	−0.0186 (7)
O13	0.0568 (8)	0.0394 (7)	0.0778 (10)	0.0108 (6)	0.0016 (7)	−0.0003 (7)
N10	0.0358 (8)	0.0335 (7)	0.0558 (10)	−0.0011 (6)	0.0027 (7)	−0.0003 (7)
C1	0.0323 (9)	0.0431 (9)	0.0493 (11)	0.0000 (7)	0.0051 (8)	−0.0021 (9)
C2	0.0422 (10)	0.0515 (11)	0.0514 (11)	0.0021 (8)	0.0051 (9)	−0.0176 (9)
C3	0.0405 (10)	0.0503 (10)	0.0535 (11)	0.0062 (8)	0.0103 (9)	−0.0103 (9)
C4	0.0351 (9)	0.0326 (9)	0.0445 (10)	−0.0003 (7)	0.0062 (7)	0.0036 (8)
C5	0.0432 (10)	0.0379 (9)	0.0536 (11)	0.0028 (8)	0.0029 (8)	−0.0106 (8)
C6	0.0408 (9)	0.0431 (10)	0.0572 (11)	0.0094 (8)	0.0070 (8)	−0.0100 (9)
C8	0.0457 (11)	0.0581 (12)	0.0556 (12)	−0.0021 (9)	0.0010 (9)	−0.0110 (10)
C9	0.0521 (12)	0.0701 (14)	0.0690 (14)	0.0018 (10)	−0.0089 (10)	−0.0065 (12)
C11	0.0399 (10)	0.0419 (10)	0.0513 (11)	0.0036 (8)	0.0104 (8)	0.0091 (9)
C12	0.0401 (10)	0.0645 (13)	0.0707 (13)	0.0022 (9)	−0.0007 (9)	0.0093 (11)

Geometric parameters (Å, º)

O7—C1	1.3742 (19)	C5—C6	1.374 (2)
O7—C8	1.422 (2)	C5—H5	0.9300
O13—C11	1.230 (2)	C6—H6	0.9300
N10—C11	1.344 (2)	C8—C9	1.509 (2)
N10—C4	1.421 (2)	C8—H8A	0.9700
N10—H10	0.8600	C8—H8B	0.9700
C1—C6	1.377 (2)	C9—H9A	0.9600
C1—C2	1.380 (2)	C9—H9B	0.9600
C2—C3	1.386 (2)	C9—H9C	0.9600
C2—H2	0.9300	C11—C12	1.497 (2)
C3—C4	1.374 (2)	C12—H12A	0.9600
C3—H3	0.9300	C12—H12B	0.9600
C4—C5	1.385 (2)	C12—H12C	0.9600
C1—O7—C8	118.53 (13)	O7—C8—C9	107.27 (15)
C11—N10—C4	127.32 (14)	O7—C8—H8A	110.3
C11—N10—H10	116.3	C9—C8—H8A	110.3
C4—N10—H10	116.3	O7—C8—H8B	110.3
O7—C1—C6	115.42 (15)	C9—C8—H8B	110.3
O7—C1—C2	125.09 (16)	H8A—C8—H8B	108.5
C6—C1—C2	119.49 (15)	C8—C9—H9A	109.5
C1—C2—C3	120.07 (17)	C8—C9—H9B	109.5
C1—C2—H2	120.0	H9A—C9—H9B	109.5
C3—C2—H2	120.0	C8—C9—H9C	109.5
C4—C3—C2	120.75 (16)	H9A—C9—H9C	109.5
C4—C3—H3	119.6	H9B—C9—H9C	109.5
C2—C3—H3	119.6	O13—C11—N10	122.80 (16)
C3—C4—C5	118.49 (15)	O13—C11—C12	121.77 (16)
C3—C4—N10	123.61 (15)	N10—C11—C12	115.44 (16)
C5—C4—N10	117.89 (15)	C11—C12—H12A	109.5
C6—C5—C4	121.17 (16)	C11—C12—H12B	109.5
C6—C5—H5	119.4	H12A—C12—H12B	109.5
C4—C5—H5	119.4	C11—C12—H12C	109.5
C5—C6—C1	120.02 (16)	H12A—C12—H12C	109.5
C5—C6—H6	120.0	H12B—C12—H12C	109.5
C1—C6—H6	120.0
C8—O7—C1—C6	−173.23 (16)	C3—C4—C5—C6	0.6 (3)
C8—O7—C1—C2	6.7 (3)	N10—C4—C5—C6	−178.31 (16)
O7—C1—C2—C3	−179.65 (17)	C4—C5—C6—C1	0.1 (3)
C6—C1—C2—C3	0.3 (3)	O7—C1—C6—C5	179.43 (17)
C1—C2—C3—C4	0.4 (3)	C2—C1—C6—C5	−0.5 (3)
C2—C3—C4—C5	−0.8 (3)	C1—O7—C8—C9	171.64 (16)
C2—C3—C4—N10	178.02 (17)	C4—N10—C11—O13	−1.2 (3)
C11—N10—C4—C3	30.5 (3)	C4—N10—C11—C12	178.71 (17)
C11—N10—C4—C5	−150.72 (17)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O13	0.93	2.42	2.915 (2)	114
N10—H10···O13^i	0.86	2.09	2.9426 (18)	175

Symmetry code: (i) −x, y−1/2, −z−1/2.