4-[(4-Ethoxy­phenyl)­amino­acetyl]-1,2,3,4-tetra­hydro­quinoxalin-2-one

All interatomic distances in the title compound, C₂₀H₂₁N₃O₄, are normal. The heteroatom ring of the quinoxalinone system exists in a conformation intermediate between half-chair and sofa. The (4-ethoxy­phenyl)­amino moiety is nearly planar. The amino­oxoethyl part can also be considered planar. There is one weak intramolecular C—H...O hydrogen bond in the structure. The structure is assembled by intermolecular N—H...O hydrogen bonds, to form a two-dimensional framework. One further C—H...O short intermolecular interaction is present in the structure.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.074
• wR factor = 0.248
• Data-to-parameter ratio = 15.7

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



RADNW_01  Alert C The radiation wavelength lies outside the expected range
          for the supplied radiation type. Expected range 1.54175-1.54180
          Wavelength given =    1.54052

REFLT_03
         From the CIF: _diffrn_reflns_theta_max           80.59
         From the CIF: _reflns_number_total               3916
         TEST2: Reflns within _diffrn_reflns_theta_max
         Count of symmetry unique reflns         4201
         Completeness (_total/calc)             93.22%
          Alert C: < 95% complete

General Notes



RADNW_01  The radiation wavelength given implies that Cu Kalpha1 has
          been used. Please check that this is correct.
          Wavelength given =    1.54052


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 2 Alert Level C = Please check

---

Computing details

Data collection: KM-4 Software (Kuma, 1993); cell refinement: KM-4 Software; data reduction: DATAPROC (Gałdecki et al., 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL/PC (Sheldrick, 1990b) and ORTEP-3 (Farrugia, 1997).

4-(2-Acetyl-2-(4-ethoxyphenyl)amino-1-oxoethyl)-1,2,3,4- tetrahydro-2-quinoxalinone

Crystal data

C20H21N3O4	F(000) = 776
Mr = 367.40	Dx = 1.283 Mg m^−3
Monoclinic, P21/n	Cu Kα radiation, λ = 1.54052 Å
a = 8.289 (1) Å	Cell parameters from 99 reflections
b = 12.117 (2) Å	θ = 5–60°
c = 19.225 (3) Å	µ = 0.75 mm^−1
β = 99.88 (1)°	T = 293 K
V = 1902.3 (5) Å^3	Sphere, colourless
Z = 4	0.51 mm (radius)

Data collection

Kuma KM-4 diffractometer	1952 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.034
Graphite monochromator	θmax = 80.6°, θmin = 4.3°
ω–2θ scans	h = −9→9
Absorption correction: numerical (X-RED; Stoe & Cie, 1999)	k = 0→15
Tmin = 0.692, Tmax = 0.715	l = −24→0
4204 measured reflections	2 standard reflections every 100 reflections
3916 independent reflections	intensity decay: −4.0%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.074	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.248	H atoms treated by a mixture of independent and constrained refinement
S = 0.96	w = 1/[σ^2(Fo^2) + (0.1581P)^2] where P = (Fo^2 + 2Fc^2)/3
3916 reflections	(Δ/σ)max = 0.006
250 parameters	Δρmax = 0.58 e Å^−3
0 restraints	Δρmin = −0.33 e Å^−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.

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
N12	0.6189 (3)	0.7165 (2)	0.13601 (15)	0.0485 (6)
C21	0.5487 (4)	0.7771 (3)	0.1819 (2)	0.0564 (8)
O13	0.4613 (3)	0.7330 (2)	0.21980 (14)	0.0674 (7)
C22	0.5818 (6)	0.8990 (3)	0.1872 (3)	0.0767 (12)
H22A	0.6972	0.9119	0.1907	0.092*
H22B	0.5453	0.9279	0.2283	0.092*
H22C	0.5241	0.9351	0.1458	0.092*
C12	0.5837 (4)	0.5990 (2)	0.13085 (18)	0.0459 (7)
H12A	0.5941	0.5677	0.1779	0.055*
H12B	0.6624	0.5626	0.1066	0.055*
C11	0.4122 (4)	0.5786 (3)	0.09102 (17)	0.0479 (7)
O11	0.3327 (3)	0.6527 (2)	0.05875 (16)	0.0746 (8)
N1	0.3484 (3)	0.4755 (2)	0.09372 (14)	0.0465 (6)
C8	0.1713 (4)	0.4615 (3)	0.06975 (19)	0.0574 (9)
H8A	0.1532	0.4065	0.0325	0.069*
H8B	0.1248	0.5306	0.0504	0.069*
C7	0.0872 (4)	0.4264 (3)	0.1285 (2)	0.0615 (10)
O1	−0.0516 (3)	0.4530 (3)	0.1315 (2)	0.0998 (11)
N2	0.1776 (4)	0.3617 (3)	0.17842 (19)	0.0591 (8)
H3	0.135 (5)	0.325 (4)	0.204 (2)	0.077 (14)*
C6	0.3362 (4)	0.3262 (3)	0.17427 (17)	0.0478 (7)
C1	0.4261 (4)	0.3832 (2)	0.13107 (17)	0.0459 (7)
C2	0.5806 (4)	0.3460 (3)	0.1232 (2)	0.0559 (9)
H2	0.6379	0.3806	0.0918	0.067*
C3	0.6476 (5)	0.2573 (3)	0.1625 (3)	0.0719 (12)
H3A	0.7519	0.2329	0.1583	0.086*
C4	0.5623 (5)	0.2043 (3)	0.2081 (2)	0.0703 (11)
H4	0.6106	0.1458	0.2353	0.084*
C5	0.4061 (5)	0.2371 (3)	0.2136 (2)	0.0612 (9)
H5	0.3478	0.1998	0.2436	0.073*
C13	0.6987 (4)	0.7639 (3)	0.08156 (18)	0.0550 (8)
C18	0.8668 (5)	0.7447 (3)	0.0833 (2)	0.0610 (9)
H18	0.9247	0.7028	0.1198	0.073*
C17	0.9453 (5)	0.7855 (4)	0.0335 (2)	0.0733 (11)
H17	1.0555	0.7695	0.0346	0.088*
C16	0.8651 (5)	0.8491 (4)	−0.0176 (2)	0.0724 (12)
C15	0.7003 (7)	0.8703 (4)	−0.0238 (2)	0.0884 (15)
H15	0.6462	0.9126	−0.0610	0.106*
C14	0.6124 (6)	0.8251 (3)	0.0289 (2)	0.0774 (12)
H14	0.5009	0.8378	0.0265	0.093*
O12	0.9570 (4)	0.8877 (3)	−0.06865 (19)	0.1013 (11)
C19	0.8841 (8)	0.9603 (4)	−0.1158 (3)	0.1053 (18)
H19A	0.8537	1.0256	−0.0918	0.126*
H19B	0.7854	0.9283	−0.1425	0.126*
C20	1.0017 (7)	0.9920 (4)	−0.1656 (3)	0.0962 (16)
H20A	0.9531	1.0489	−0.1972	0.115*
H20B	1.0235	0.9285	−0.1923	0.115*
H20C	1.1024	1.0186	−0.1385	0.115*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N12	0.0395 (15)	0.0437 (13)	0.0646 (16)	−0.0056 (10)	0.0153 (12)	−0.0047 (12)
C21	0.050 (2)	0.0485 (17)	0.073 (2)	−0.0019 (15)	0.0162 (17)	0.0002 (17)
O13	0.0607 (16)	0.0601 (15)	0.0901 (18)	−0.0025 (12)	0.0379 (14)	0.0010 (13)
C22	0.090 (3)	0.0451 (19)	0.102 (3)	−0.0049 (19)	0.039 (3)	−0.008 (2)
C12	0.0352 (16)	0.0406 (15)	0.0628 (19)	−0.0038 (12)	0.0110 (13)	0.0005 (13)
C11	0.0434 (18)	0.0477 (17)	0.0531 (17)	−0.0012 (13)	0.0098 (14)	0.0023 (14)
O11	0.0546 (15)	0.0594 (15)	0.103 (2)	−0.0041 (11)	−0.0069 (14)	0.0292 (14)
N1	0.0294 (13)	0.0459 (13)	0.0627 (15)	−0.0012 (10)	0.0035 (11)	0.0017 (12)
C8	0.0340 (18)	0.062 (2)	0.071 (2)	−0.0068 (14)	−0.0042 (15)	0.0063 (17)
C7	0.0266 (17)	0.066 (2)	0.090 (3)	−0.0063 (15)	0.0063 (16)	0.005 (2)
O1	0.0327 (15)	0.113 (3)	0.155 (3)	0.0056 (15)	0.0225 (17)	0.032 (2)
N2	0.0405 (17)	0.0590 (17)	0.080 (2)	−0.0048 (13)	0.0158 (15)	0.0079 (16)
C6	0.0338 (16)	0.0477 (16)	0.0605 (18)	−0.0039 (13)	0.0039 (13)	−0.0067 (14)
C1	0.0368 (17)	0.0382 (14)	0.0611 (18)	−0.0029 (12)	0.0035 (13)	−0.0066 (13)
C2	0.0377 (18)	0.0460 (16)	0.085 (2)	−0.0005 (13)	0.0132 (16)	−0.0083 (17)
C3	0.0398 (19)	0.0516 (19)	0.121 (3)	0.0065 (15)	0.005 (2)	−0.005 (2)
C4	0.060 (2)	0.0447 (18)	0.098 (3)	0.0034 (16)	−0.011 (2)	0.0023 (19)
C5	0.058 (2)	0.0508 (19)	0.072 (2)	−0.0066 (16)	0.0013 (17)	0.0069 (17)
C13	0.059 (2)	0.0455 (17)	0.062 (2)	−0.0134 (15)	0.0143 (17)	−0.0052 (15)
C18	0.055 (2)	0.062 (2)	0.070 (2)	−0.0146 (16)	0.0243 (18)	−0.0118 (17)
C17	0.066 (3)	0.077 (3)	0.081 (3)	−0.009 (2)	0.025 (2)	−0.009 (2)
C16	0.065 (3)	0.078 (3)	0.081 (3)	−0.032 (2)	0.030 (2)	−0.012 (2)
C15	0.121 (4)	0.068 (3)	0.068 (3)	−0.022 (3)	−0.006 (3)	0.011 (2)
C14	0.081 (3)	0.068 (2)	0.082 (3)	−0.015 (2)	0.010 (2)	0.010 (2)
O12	0.104 (3)	0.101 (3)	0.102 (2)	−0.008 (2)	0.025 (2)	0.017 (2)
C19	0.141 (5)	0.070 (3)	0.090 (3)	−0.023 (3)	−0.020 (3)	−0.008 (3)
C20	0.132 (5)	0.082 (3)	0.085 (3)	−0.022 (3)	0.048 (3)	0.007 (2)

Geometric parameters (Å, º)

N12—C21	1.354 (4)	C2—C3	1.375 (5)
N12—C13	1.449 (4)	C2—H2	0.9300
N12—C12	1.454 (4)	C3—C4	1.375 (6)
C21—O13	1.234 (4)	C3—H3A	0.9300
C21—C22	1.502 (5)	C4—C5	1.376 (5)
C22—H22A	0.9600	C4—H4	0.9300
C22—H22B	0.9600	C5—H5	0.9300
C22—H22C	0.9600	C13—C14	1.356 (5)
C12—C11	1.515 (4)	C13—C18	1.407 (5)
C12—H12A	0.9700	C18—C17	1.342 (5)
C12—H12B	0.9700	C18—H18	0.9300
C11—O11	1.219 (4)	C17—C16	1.332 (6)
C11—N1	1.361 (4)	C17—H17	0.9300
N1—C1	1.422 (4)	C16—C15	1.375 (7)
N1—C8	1.470 (4)	C16—O12	1.421 (5)
C8—C7	1.487 (5)	C15—C14	1.452 (6)
C8—H8A	0.9700	C15—H15	0.9300
C8—H8B	0.9700	C14—H14	0.9300
C7—O1	1.206 (4)	O12—C19	1.331 (6)
C7—N2	1.361 (5)	C19—C20	1.528 (7)
N2—C6	1.398 (4)	C19—H19A	0.9700
N2—H3	0.78 (4)	C19—H19B	0.9700
C6—C5	1.387 (5)	C20—H20A	0.9600
C6—C1	1.391 (4)	C20—H20B	0.9600
C1—C2	1.391 (4)	C20—H20C	0.9600
C21—N12—C13	123.8 (3)	C3—C2—H2	120.4
C21—N12—C12	118.2 (3)	C1—C2—H2	120.4
C13—N12—C12	116.8 (3)	C2—C3—C4	120.8 (3)
O13—C21—N12	120.8 (3)	C2—C3—H3A	119.6
O13—C21—C22	120.4 (3)	C4—C3—H3A	119.6
N12—C21—C22	118.9 (3)	C3—C4—C5	120.5 (3)
C21—C22—H22A	109.5	C3—C4—H4	119.7
C21—C22—H22B	109.5	C5—C4—H4	119.7
H22A—C22—H22B	109.5	C4—C5—C6	119.5 (3)
C21—C22—H22C	109.5	C4—C5—H5	120.2
H22A—C22—H22C	109.5	C6—C5—H5	120.2
H22B—C22—H22C	109.5	C14—C13—C18	120.1 (4)
N12—C12—C11	110.8 (3)	C14—C13—N12	120.6 (3)
N12—C12—H12A	109.5	C18—C13—N12	119.3 (3)
C11—C12—H12A	109.5	C17—C18—C13	121.4 (4)
N12—C12—H12B	109.5	C17—C18—H18	119.3
C11—C12—H12B	109.5	C13—C18—H18	119.3
H12A—C12—H12B	108.1	C16—C17—C18	119.8 (4)
O11—C11—N1	121.1 (3)	C16—C17—H17	120.1
O11—C11—C12	121.0 (3)	C18—C17—H17	120.1
N1—C11—C12	117.9 (3)	C17—C16—C15	122.4 (4)
C11—N1—C1	126.5 (2)	C17—C16—O12	116.1 (4)
C11—N1—C8	117.9 (3)	C15—C16—O12	121.3 (4)
C1—N1—C8	114.1 (3)	C16—C15—C14	118.6 (4)
N1—C8—C7	111.6 (3)	C16—C15—H15	120.7
N1—C8—H8A	109.3	C14—C15—H15	120.7
C7—C8—H8A	109.3	C13—C14—C15	117.6 (4)
N1—C8—H8B	109.3	C13—C14—H14	121.2
C7—C8—H8B	109.3	C15—C14—H14	121.2
H8A—C8—H8B	108.0	C19—O12—C16	117.0 (5)
O1—C7—N2	122.3 (4)	O12—C19—C20	109.2 (5)
O1—C7—C8	122.4 (4)	O12—C19—H19A	109.8
N2—C7—C8	115.3 (3)	C20—C19—H19A	109.8
C7—N2—C6	123.1 (3)	O12—C19—H19B	109.8
C7—N2—H3	121 (3)	C20—C19—H19B	109.8
C6—N2—H3	113 (3)	H19A—C19—H19B	108.3
C5—C6—C1	119.8 (3)	C19—C20—H20A	109.5
C5—C6—N2	121.1 (3)	C19—C20—H20B	109.5
C1—C6—N2	119.1 (3)	H20A—C20—H20B	109.5
C2—C1—C6	120.1 (3)	C19—C20—H20C	109.5
C2—C1—N1	123.1 (3)	H20A—C20—H20C	109.5
C6—C1—N1	116.7 (3)	H20B—C20—H20C	109.5
C3—C2—C1	119.1 (3)
C1—C6—N2—C7	20.2 (5)	C8—N1—C11—C12	166.0 (3)
C6—N2—C7—C8	−2.5 (5)	N1—C11—C12—N12	−167.1 (3)
N2—C7—C8—N1	−32.3 (4)	C11—C12—N12—C21	74.5 (4)
C7—C8—N1—C1	51.6 (4)	C11—C12—N12—C13	−93.1 (3)
C8—N1—C1—C6	−35.7 (4)	C12—N12—C13—C18	−75.5 (4)
N1—C1—C6—N2	0.1 (4)	C12—N12—C13—C14	103.6 (4)
C1—N1—C11—O11	−178.0 (3)	C15—C16—O12—C19	11.1 (6)
C8—N1—C11—O11	−12.6 (5)	C17—C16—O12—C19	−173.2 (4)
C1—N1—C11—C12	0.6 (5)	C16—O12—C19—C20	179.8 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8B···O11	0.97	2.26	2.702 (4)	107
N2—H3···O13^i	0.78 (4)	2.11 (4)	2.891 (4)	174 (4)
C20—H20B···O13^ii	0.96	2.58	3.486 (6)	158

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