2-[2-(5-Nitro-2-thienyl)­ethenyl]-4H-3,1-benzoxazine-4-one, 2-[2-(4-nitro­phenyl)­ethenyl]-4H-3,1-benzoxazine-4-one and 6,7-di­methoxy-2-[2-(4-nitro­phenyl)­ethenyl]-4H-3,1-benzoxazine-4-one

The three title compounds, i.e. C₁₄H₈N₂O₄S, (I), C₁₆H₁₀N₂O₄, (II), and C₁₈H₁₄N₂O₆, (III), respectively, are almost planar. The benzoxazinone and nitro­aryl moieties are in a trans configuration with respect to the ethyl­ene group. The nitro group in all three mol­ecules is almost coplanar with the aryl substituent and shows quite strong conjugation with the rest of the [pi]-system of the mol­ecules. The mol­ecules of (I) form layers along the crystallographic b axis, with a distance between adjacent layers of about 3.5 Å. However, the mol­ecules of (II) and (III) form stacks, with distances between adjacent mol­ecules of about 6.0 and 3.6 Å, respectively.

Computing details

For all compounds, data collection: P3 (Siemens, 1989); cell refinement: P3; data reduction: XDISK (Siemens, 1989); program(s) used to solve structure: SHELXTL (Sheldrick, 1994); program(s) used to refine structure: SHELXTL; software used to prepare material for publication: SHELXTL.

(I)

Crystal data

C14H8N2O4S	Dx = 1.569 Mg m^−3
Mr = 300.28	Melting point = 217–219 K
Orthorhombic, Pca21	Mo Kα radiation, λ = 0.71073 Å
a = 7.0127 (11) Å	Cell parameters from 24 reflections
b = 12.524 (2) Å	θ = 10–13°
c = 14.477 (3) Å	µ = 0.27 mm^−1
V = 1271.5 (4) Å^3	T = 293 K
Z = 4	Parallelepiped, yellow
F(000) = 616	0.40 × 0.20 × 0.20 mm

Data collection

Siemens P3/PC diffractometer	Rint = 0.000
Radiation source: fine-focus sealed tube	θmax = 30.1°, θmin = 1.6°
Graphite monochromator	h = 0→9
θ/2θ scans	k = 0→17
1938 measured reflections	l = 0→20
1938 independent reflections	2 standard reflections every 98 reflections
1073 reflections with I > 2σ(I)	intensity decay: none

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.051	H atoms: see below
wR(F^2) = 0.100	Calculated w = 1/[σ^2(Fo^2) + (0.0589P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.96	(Δ/σ)max < 0.001
1903 reflections	Δρmax = 0.24 e Å^−3
190 parameters	Δρmin = −0.27 e Å^−3
1 restraint	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.25 (14)

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 on F² for ALL reflections except for 35 with very negative F² or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating _R_factor_obs 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
S1	−0.00976 (15)	0.71741 (8)	0.75978 (9)	0.0436 (2)
O1	−0.1099 (4)	0.8751 (2)	0.4286 (2)	0.0397 (6)
O2	−0.2030 (5)	1.0363 (2)	0.3868 (2)	0.0553 (8)
O4	0.1771 (5)	0.5081 (2)	0.9293 (2)	0.0632 (9)
O3	0.0302 (6)	0.6583 (3)	0.9510 (2)	0.0740 (11)
N1	0.0093 (5)	0.7465 (3)	0.3241 (3)	0.0423 (8)
N2	0.0923 (6)	0.5873 (3)	0.9010 (2)	0.0496 (9)
C1	0.0208 (5)	0.7867 (3)	0.1615 (3)	0.0423 (9)
H1	0.0701 (5)	0.7191 (3)	0.1498 (3)	0.051*
C2	−0.0104 (6)	0.8572 (3)	0.0898 (3)	0.0426 (9)
H2	0.0188 (6)	0.8363 (3)	0.0298 (3)	0.051*
C3	−0.0839 (6)	0.9577 (3)	0.1050 (3)	0.0440 (9)
H3	−0.1041 (6)	1.0038 (3)	0.0557 (3)	0.053*
C4	−0.1273 (5)	0.9897 (3)	0.1937 (2)	0.0375 (8)
H4	−0.1766 (5)	1.0576 (3)	0.2043 (2)	0.045*
C5	−0.0969 (5)	0.9198 (3)	0.2678 (3)	0.0334 (7)
C6	−0.0217 (5)	0.8175 (3)	0.2509 (3)	0.0338 (8)
C7	−0.1409 (5)	0.9522 (3)	0.3621 (2)	0.0361 (8)
C8	−0.0334 (5)	0.7779 (3)	0.4047 (3)	0.0366 (9)
C9	−0.0006 (5)	0.7100 (3)	0.4854 (3)	0.0407 (9)
H9	0.0453 (5)	0.6414 (3)	0.4747 (3)	0.049*
C10	−0.0307 (5)	0.7378 (3)	0.5721 (3)	0.0402 (9)
H10	−0.0790 (5)	0.8056 (3)	0.5840 (3)	0.048*
C11	0.0081 (5)	0.6677 (3)	0.6499 (3)	0.0383 (8)
C12	0.0693 (6)	0.5631 (3)	0.6504 (3)	0.0441 (10)
H12	0.0867 (6)	0.5226 (3)	0.5971 (3)	0.053*
C13	0.1025 (6)	0.5244 (3)	0.7394 (3)	0.0448 (9)
H13	0.1435 (6)	0.4554 (3)	0.7524 (3)	0.054*
C14	0.0680 (5)	0.5992 (3)	0.8039 (3)	0.0401 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0509 (5)	0.0373 (4)	0.0424 (4)	0.0070 (5)	0.0018 (5)	0.0022 (5)
O1	0.044 (2)	0.0402 (13)	0.0344 (12)	0.0086 (12)	0.0038 (12)	0.0006 (11)
O2	0.075 (2)	0.0452 (15)	0.0459 (15)	0.024 (2)	−0.0012 (15)	−0.0048 (13)
O4	0.086 (2)	0.0522 (15)	0.051 (2)	−0.0052 (15)	−0.022 (2)	0.0102 (15)
O3	0.107 (3)	0.072 (2)	0.043 (2)	0.003 (2)	0.003 (2)	−0.010 (2)
N1	0.050 (2)	0.035 (2)	0.042 (2)	0.0009 (15)	−0.0001 (14)	0.0012 (14)
N2	0.059 (2)	0.051 (2)	0.039 (2)	−0.012 (2)	−0.004 (2)	0.002 (2)
C1	0.045 (2)	0.040 (2)	0.043 (2)	0.003 (2)	0.002 (2)	−0.012 (2)
C2	0.044 (2)	0.053 (2)	0.031 (2)	−0.004 (2)	0.002 (2)	−0.009 (2)
C3	0.043 (2)	0.050 (2)	0.039 (2)	−0.005 (2)	−0.002 (2)	0.004 (2)
C4	0.038 (2)	0.039 (2)	0.035 (2)	−0.001 (2)	−0.005 (2)	0.000 (2)
C5	0.029 (2)	0.036 (2)	0.035 (2)	−0.0014 (14)	−0.001 (2)	0.0026 (14)
C6	0.035 (2)	0.032 (2)	0.034 (2)	−0.0038 (14)	−0.002 (2)	0.003 (2)
C7	0.036 (2)	0.037 (2)	0.035 (2)	0.005 (2)	0.003 (2)	0.0018 (15)
C8	0.035 (2)	0.033 (2)	0.042 (2)	−0.001 (2)	−0.004 (2)	0.003 (2)
C9	0.048 (2)	0.033 (2)	0.042 (2)	0.001 (2)	0.000 (2)	0.004 (2)
C10	0.037 (2)	0.041 (2)	0.042 (2)	0.006 (2)	0.002 (2)	0.004 (2)
C11	0.041 (2)	0.038 (2)	0.036 (2)	0.000 (2)	−0.002 (2)	0.0031 (15)
C12	0.059 (3)	0.037 (2)	0.037 (2)	0.006 (2)	−0.003 (2)	−0.001 (2)
C13	0.052 (2)	0.035 (2)	0.047 (2)	0.004 (2)	0.001 (2)	0.006 (2)
C14	0.044 (2)	0.037 (2)	0.040 (2)	−0.002 (2)	−0.003 (2)	0.006 (2)

Geometric parameters (Å, º)

S1—C14	1.702 (4)	C2—C3	1.379 (6)
S1—C11	1.712 (4)	C3—C4	1.378 (5)
O1—C8	1.374 (4)	C4—C5	1.401 (5)
O1—C7	1.381 (4)	C5—C6	1.407 (5)
O2—C7	1.195 (4)	C5—C7	1.457 (5)
O4—N2	1.228 (4)	C8—C9	1.464 (5)
O3—N2	1.227 (5)	C9—C10	1.320 (6)
N1—C8	1.267 (5)	C10—C11	1.455 (5)
N1—C6	1.400 (5)	C11—C12	1.379 (5)
N2—C14	1.423 (5)	C12—C13	1.396 (5)
C1—C2	1.380 (6)	C13—C14	1.345 (5)
C1—C6	1.384 (5)
C14—S1—C11	90.5 (2)	O2—C7—O1	117.7 (3)
C8—O1—C7	120.3 (3)	O2—C7—C5	127.1 (3)
C8—N1—C6	117.6 (4)	O1—C7—C5	115.2 (3)
O3—N2—O4	124.1 (4)	N1—C8—O1	126.8 (3)
O3—N2—C14	117.7 (4)	N1—C8—C9	121.1 (4)
O4—N2—C14	118.2 (4)	O1—C8—C9	112.0 (3)
C2—C1—C6	119.4 (3)	C10—C9—C8	125.5 (4)
C3—C2—C1	121.6 (4)	C9—C10—C11	123.2 (4)
C4—C3—C2	119.8 (4)	C12—C11—C10	129.5 (4)
C3—C4—C5	119.8 (3)	C12—C11—S1	111.4 (3)
C4—C5—C6	119.5 (3)	C10—C11—S1	119.1 (3)
C4—C5—C7	120.8 (3)	C11—C12—C13	112.7 (4)
C6—C5—C7	119.7 (3)	C14—C13—C12	111.7 (3)
C1—C6—N1	119.8 (3)	C13—C14—N2	126.3 (3)
C1—C6—C5	119.8 (3)	C13—C14—S1	113.7 (3)
N1—C6—C5	120.3 (4)	N2—C14—S1	120.0 (3)
C6—C1—C2—C3	−0.3 (6)	C7—O1—C8—N1	−2.6 (6)
C1—C2—C3—C4	0.2 (6)	C7—O1—C8—C9	176.4 (3)
C2—C3—C4—C5	−0.1 (6)	N1—C8—C9—C10	176.1 (4)
C3—C4—C5—C6	0.2 (5)	O1—C8—C9—C10	−3.0 (6)
C3—C4—C5—C7	179.7 (4)	C8—C9—C10—C11	−178.7 (3)
C2—C1—C6—N1	179.9 (4)	C9—C10—C11—C12	−3.9 (7)
C2—C1—C6—C5	0.3 (5)	C9—C10—C11—S1	172.4 (3)
C8—N1—C6—C1	−179.3 (3)	C14—S1—C11—C12	0.9 (3)
C8—N1—C6—C5	0.3 (5)	C14—S1—C11—C10	−176.0 (3)
C4—C5—C6—C1	−0.2 (5)	C10—C11—C12—C13	176.1 (4)
C7—C5—C6—C1	−179.8 (3)	S1—C11—C12—C13	−0.4 (5)
C4—C5—C6—N1	−179.9 (3)	C11—C12—C13—C14	−0.5 (6)
C7—C5—C6—N1	0.5 (5)	C12—C13—C14—N2	−178.2 (4)
C8—O1—C7—O2	−178.1 (3)	C12—C13—C14—S1	1.2 (5)
C8—O1—C7—C5	3.2 (5)	O3—N2—C14—C13	−170.4 (4)
C4—C5—C7—O2	−0.4 (6)	O4—N2—C14—C13	11.0 (6)
C6—C5—C7—O2	179.2 (4)	O3—N2—C14—S1	10.2 (5)
C4—C5—C7—O1	178.2 (3)	O4—N2—C14—S1	−168.4 (3)
C6—C5—C7—O1	−2.3 (5)	C11—S1—C14—C13	−1.2 (3)
C6—N1—C8—O1	0.7 (6)	C11—S1—C14—N2	178.2 (3)
C6—N1—C8—C9	−178.3 (3)

(II)

Crystal data

C16H10N2O4	Dx = 1.462 Mg m^−3
Mr = 294.26	Melting point = 237–239 K
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
a = 14.627 (3) Å	Cell parameters from 24 reflections
b = 7.491 (2) Å	θ = 9–10°
c = 12.344 (5) Å	µ = 0.11 mm^−1
β = 98.71 (3)°	T = 213 K
V = 1337.0 (7) Å^3	Parallelepiped, yellow
Z = 4	0.30 × 0.20 × 0.20 mm
F(000) = 608

Data collection

Syntex P21/PC diffractometer	Rint = 0.000
Radiation source: fine-focus sealed tube	θmax = 30.1°, θmin = 2.8°
Graphite monochromator	h = 0→20
θ/2θ scans	k = 0→10
2042 measured reflections	l = −17→17
2042 independent reflections	2 standard reflections every 98 reflections
1011 reflections with I > 2σ(I)	intensity decay: none

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.081	H atoms: see below
wR(F^2) = 0.178	Calculated w = 1/[σ^2(Fo^2) + (0.1P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.17	(Δ/σ)max < 0.001
2004 reflections	Δρmax = 0.51 e Å^−3
199 parameters	Δρmin = −0.26 e Å^−3
2 restraints	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.06 (20)

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 on F² for ALL reflections except for 38 with very negative F² or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating _R_factor_obs 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
O1	−0.7222 (2)	−0.1198 (5)	−0.1953 (3)	0.0428 (9)
O2	−0.7517 (3)	−0.2956 (6)	−0.0621 (3)	0.0556 (11)
O3	−0.1929 (3)	0.1458 (7)	−0.4408 (4)	0.0614 (13)
O4	−0.2773 (3)	0.2381 (8)	−0.5889 (4)	0.076 (2)
N1	−0.8348 (3)	0.0393 (6)	−0.3137 (4)	0.0419 (11)
N2	−0.2673 (3)	0.1752 (6)	−0.4957 (4)	0.0443 (12)
C1	−0.9944 (4)	0.0321 (8)	−0.2795 (5)	0.0458 (13)
H1	−1.0120 (4)	0.1023 (8)	−0.3423 (5)	0.055*
C2	−1.0589 (4)	−0.0192 (9)	−0.2155 (6)	0.056 (2)
H2	−1.1199 (4)	0.0230 (9)	−0.2322 (6)	0.067*
C3	−1.0352 (4)	−0.1335 (10)	−0.1254 (6)	0.057 (2)
H3	−1.0804 (4)	−0.1738 (10)	−0.0847 (6)	0.068*
C4	−0.9443 (4)	−0.1854 (9)	−0.0980 (5)	0.051 (2)
H4	−0.9269 (4)	−0.2580 (9)	−0.0362 (5)	0.061*
C5	−0.8787 (4)	−0.1317 (7)	−0.1603 (5)	0.0410 (13)
C6	−0.9016 (3)	−0.0215 (7)	−0.2503 (4)	0.0351 (12)
C7	−0.7829 (3)	−0.1946 (8)	−0.1319 (5)	0.0418 (13)
C8	−0.7522 (4)	−0.0056 (7)	−0.2827 (4)	0.0357 (11)
C9	−0.6745 (4)	0.0496 (7)	−0.3358 (4)	0.0406 (12)
H9	−0.6878 (4)	0.1270 (7)	−0.3960 (4)	0.049*
C10	−0.5891 (4)	0.0030 (7)	−0.3086 (5)	0.0467 (14)
H10	−0.5772 (4)	−0.0732 (7)	−0.2476 (5)	0.056*
C11	−0.5082 (3)	0.0514 (7)	−0.3587 (5)	0.0396 (13)
C12	−0.5138 (3)	0.1603 (7)	−0.4547 (4)	0.0392 (12)
H12	−0.5710 (3)	0.2069 (7)	−0.4877 (4)	0.047*
C13	−0.4349 (4)	0.1959 (8)	−0.4978 (5)	0.0450 (13)
H13	−0.4382 (4)	0.2657 (8)	−0.5616 (5)	0.054*
C14	−0.3514 (3)	0.1310 (7)	−0.4492 (4)	0.0350 (11)
C15	−0.3431 (4)	0.0251 (7)	−0.3575 (5)	0.0416 (13)
H15	−0.2852 (4)	−0.0198 (7)	−0.3256 (5)	0.050*
C16	−0.4213 (4)	−0.0136 (8)	−0.3135 (5)	0.0440 (14)
H16	−0.4163 (4)	−0.0863 (8)	−0.2509 (5)	0.053*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.029 (2)	0.047 (2)	0.055 (2)	−0.003 (2)	0.015 (2)	0.009 (2)
O2	0.048 (2)	0.064 (3)	0.057 (3)	0.001 (2)	0.013 (2)	0.016 (2)
O3	0.032 (2)	0.089 (4)	0.063 (3)	−0.011 (2)	0.011 (2)	−0.009 (2)
O4	0.056 (3)	0.103 (4)	0.076 (3)	0.022 (3)	0.033 (2)	0.052 (3)
N1	0.028 (2)	0.044 (2)	0.055 (3)	−0.003 (2)	0.012 (2)	0.002 (2)
N2	0.038 (2)	0.042 (3)	0.059 (3)	−0.009 (2)	0.026 (2)	−0.004 (2)
C1	0.038 (3)	0.055 (3)	0.044 (3)	0.008 (3)	0.006 (2)	−0.002 (3)
C2	0.032 (3)	0.068 (4)	0.069 (4)	−0.001 (3)	0.008 (3)	−0.014 (3)
C3	0.036 (3)	0.079 (4)	0.060 (4)	−0.014 (3)	0.017 (3)	−0.013 (3)
C4	0.051 (3)	0.064 (4)	0.042 (3)	−0.013 (3)	0.021 (3)	−0.003 (3)
C5	0.034 (2)	0.046 (3)	0.043 (3)	0.001 (2)	0.004 (2)	−0.007 (3)
C6	0.027 (2)	0.037 (3)	0.041 (3)	−0.001 (2)	0.002 (2)	−0.010 (2)
C7	0.032 (3)	0.045 (3)	0.049 (3)	−0.008 (2)	0.007 (2)	−0.007 (3)
C8	0.035 (3)	0.041 (3)	0.033 (3)	0.007 (2)	0.011 (2)	0.005 (2)
C9	0.036 (3)	0.047 (3)	0.041 (3)	−0.002 (2)	0.013 (2)	−0.005 (2)
C10	0.040 (3)	0.039 (3)	0.063 (4)	−0.004 (3)	0.015 (3)	−0.009 (3)
C11	0.033 (3)	0.038 (3)	0.050 (3)	−0.006 (2)	0.016 (2)	−0.005 (3)
C12	0.034 (3)	0.042 (3)	0.042 (3)	0.003 (2)	0.004 (2)	0.007 (2)
C13	0.049 (3)	0.041 (3)	0.047 (3)	0.000 (3)	0.012 (3)	0.007 (3)
C14	0.033 (2)	0.037 (3)	0.038 (3)	0.000 (2)	0.014 (2)	0.002 (2)
C15	0.029 (3)	0.043 (3)	0.054 (4)	0.002 (2)	0.007 (2)	−0.003 (3)
C16	0.043 (3)	0.056 (3)	0.035 (3)	0.001 (3)	0.014 (2)	0.003 (3)

Geometric parameters (Å, º)

O1—C7	1.388 (6)	C4—C5	1.377 (8)
O1—C8	1.394 (6)	C5—C6	1.384 (7)
O2—C7	1.185 (7)	C5—C7	1.470 (8)
O3—N2	1.211 (6)	C8—C9	1.456 (7)
O4—N2	1.232 (7)	C9—C10	1.291 (8)
N1—C8	1.256 (7)	C10—C11	1.462 (8)
N1—C6	1.417 (7)	C11—C16	1.395 (7)
N2—C14	1.472 (6)	C11—C12	1.431 (8)
C1—C2	1.375 (9)	C12—C13	1.369 (8)
C1—C6	1.409 (7)	C13—C14	1.366 (7)
C2—C3	1.404 (10)	C14—C15	1.372 (8)
C3—C4	1.377 (9)	C15—C16	1.369 (8)
C7—O1—C8	122.0 (4)	O1—C7—C5	113.8 (5)
C8—N1—C6	117.1 (4)	N1—C8—O1	125.2 (5)
O3—N2—O4	124.1 (5)	N1—C8—C9	124.5 (5)
O3—N2—C14	118.3 (5)	O1—C8—C9	110.2 (4)
O4—N2—C14	117.6 (4)	C10—C9—C8	126.7 (6)
C2—C1—C6	119.4 (6)	C9—C10—C11	129.5 (6)
C1—C2—C3	121.1 (6)	C16—C11—C12	117.7 (5)
C4—C3—C2	118.7 (6)	C16—C11—C10	119.5 (5)
C5—C4—C3	120.5 (6)	C12—C11—C10	122.9 (5)
C4—C5—C6	121.2 (5)	C13—C12—C11	119.1 (5)
C4—C5—C7	119.5 (5)	C14—C13—C12	120.7 (5)
C6—C5—C7	119.3 (5)	C13—C14—C15	122.0 (5)
C5—C6—C1	118.8 (5)	C13—C14—N2	119.5 (4)
C5—C6—N1	122.2 (4)	C15—C14—N2	118.5 (4)
C1—C6—N1	119.0 (5)	C16—C15—C14	118.3 (5)
O2—C7—O1	117.3 (4)	C15—C16—C11	122.2 (5)
O2—C7—C5	128.8 (5)
C6—C1—C2—C3	−4.1 (9)	C7—O1—C8—N1	−0.9 (8)
C1—C2—C3—C4	3.9 (10)	C7—O1—C8—C9	−178.8 (4)
C2—C3—C4—C5	−2.5 (10)	N1—C8—C9—C10	−178.0 (5)
C3—C4—C5—C6	1.4 (9)	O1—C8—C9—C10	−0.1 (8)
C3—C4—C5—C7	−177.6 (6)	C8—C9—C10—C11	179.2 (5)
C4—C5—C6—C1	−1.6 (8)	C9—C10—C11—C16	179.0 (6)
C7—C5—C6—C1	177.4 (5)	C9—C10—C11—C12	−2.6 (9)
C4—C5—C6—N1	178.2 (5)	C16—C11—C12—C13	0.0 (8)
C7—C5—C6—N1	−2.8 (7)	C10—C11—C12—C13	−178.5 (5)
C2—C1—C6—C5	2.9 (8)	C11—C12—C13—C14	−1.1 (8)
C2—C1—C6—N1	−176.9 (5)	C12—C13—C14—C15	1.5 (8)
C8—N1—C6—C5	−2.5 (7)	C12—C13—C14—N2	−178.4 (5)
C8—N1—C6—C1	177.3 (5)	O3—N2—C14—C13	166.2 (5)
C8—O1—C7—O2	177.1 (5)	O4—N2—C14—C13	−14.6 (7)
C8—O1—C7—C5	−4.4 (7)	O3—N2—C14—C15	−13.7 (7)
C4—C5—C7—O2	3.3 (9)	O4—N2—C14—C15	165.4 (5)
C6—C5—C7—O2	−175.8 (6)	C13—C14—C15—C16	−0.9 (8)
C4—C5—C7—O1	−175.1 (5)	N2—C14—C15—C16	179.1 (5)
C6—C5—C7—O1	5.9 (7)	C14—C15—C16—C11	−0.2 (8)
C6—N1—C8—O1	4.5 (8)	C12—C11—C16—C15	0.6 (8)
C6—N1—C8—C9	−177.9 (5)	C10—C11—C16—C15	179.2 (5)

(III)

Crystal data

C18H14N2O6	F(000) = 368
Mr = 354.31	Dx = 1.483 Mg m^−3
Triclinic, P1	Melting point = 271–273 K
a = 6.8484 (10) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.2348 (14) Å	Cell parameters from 30 reflections
c = 16.806 (3) Å	θ = 10–13°
α = 93.801 (15)°	µ = 0.11 mm^−1
β = 96.783 (13)°	T = 208 K
γ = 105.321 (13)°	Parallelepiped, yellow
V = 793.3 (2) Å^3	0.30 × 0.20 × 0.20 mm
Z = 2

Data collection

Syntex P21/PC diffractometer	Rint = 0.026
Radiation source: fine-focus sealed tube	θmax = 25.0°, θmin = 1.2°
Graphite monochromator	h = −6→8
θ/2θ scans	k = −8→8
3051 measured reflections	l = −19→19
2792 independent reflections	2 standard reflections every 98 reflections
1723 reflections with I > 2σ(I)	intensity decay: none

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)] = 0.045	Hydrogen site location: difference Fourier map
wR(F^2) = 0.101	H atoms: see below
S = 1.02	Calculated w = 1/[σ^2(Fo^2) + (0.0595P)^2 + 0.0324P] where P = (Fo^2 + 2Fc^2)/3
2727 reflections	(Δ/σ)max < 0.001
237 parameters	Δρmax = 0.17 e Å^−3
0 restraints	Δρmin = −0.23 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 on F² for ALL reflections except for 65 with very negative F² or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating _R_factor_obs 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
O1	0.7447 (2)	0.2485 (2)	−0.08201 (9)	0.0328 (4)
O2	1.0598 (2)	0.3411 (3)	−0.11130 (9)	0.0413 (5)
O3	0.2058 (3)	0.4578 (3)	0.36360 (10)	0.0603 (6)
O4	−0.0891 (3)	0.3593 (3)	0.29043 (11)	0.0557 (6)
O5	0.5763 (3)	−0.1354 (2)	−0.43977 (9)	0.0453 (5)
O6	0.9542 (3)	0.0596 (2)	−0.41253 (9)	0.0437 (5)
N1	0.4612 (3)	0.0670 (3)	−0.17394 (11)	0.0305 (5)
N2	0.0971 (3)	0.3945 (3)	0.29916 (12)	0.0381 (5)
C1	0.5129 (4)	−0.0386 (3)	−0.30661 (13)	0.0338 (6)
H1	0.3733 (4)	−0.1055 (3)	−0.31775 (13)	0.041*
C2	0.6379 (4)	−0.0404 (3)	−0.36500 (13)	0.0344 (6)
C3	0.8467 (4)	0.0640 (3)	−0.34945 (13)	0.0335 (6)
C4	0.9265 (4)	0.1582 (3)	−0.27480 (13)	0.0330 (6)
H4	1.0666 (4)	0.2230 (3)	−0.26351 (13)	0.040*
C5	0.8005 (3)	0.1586 (3)	−0.21507 (12)	0.0276 (5)
C6	0.5930 (3)	0.0627 (3)	−0.23073 (12)	0.0275 (5)
C7	0.8853 (3)	0.2568 (3)	−0.13567 (13)	0.0310 (5)
C8	0.5399 (3)	0.1592 (3)	−0.10479 (13)	0.0282 (5)
C9	0.4198 (4)	0.1803 (3)	−0.04135 (13)	0.0316 (6)
H9	0.2794 (4)	0.1160 (3)	−0.05028 (13)	0.038*
C10	0.4957 (3)	0.2850 (3)	0.02876 (13)	0.0303 (5)
H10	0.6361 (3)	0.3491 (3)	0.03605 (13)	0.036*
C11	0.3845 (3)	0.3117 (3)	0.09609 (12)	0.0278 (5)
C12	0.1732 (3)	0.2416 (3)	0.09265 (13)	0.0331 (6)
H12	0.0943 (3)	0.1761 (3)	0.04442 (13)	0.040*
C13	0.0783 (3)	0.2665 (3)	0.15876 (14)	0.0329 (6)
H13	−0.0640 (3)	0.2173 (3)	0.15631 (14)	0.039*
C14	0.1962 (3)	0.3651 (3)	0.22857 (13)	0.0297 (5)
C15	0.4043 (4)	0.4386 (3)	0.23412 (14)	0.0354 (6)
H15	0.4816 (4)	0.5052 (3)	0.28244 (14)	0.042*
C16	0.4979 (3)	0.4131 (3)	0.16744 (13)	0.0330 (6)
H16	0.6400 (3)	0.4649 (3)	0.17020 (13)	0.040*
C17	0.3690 (4)	−0.2523 (4)	−0.45761 (15)	0.0551 (8)
H17A	0.3468 (9)	−0.319 (2)	−0.5112 (5)	0.083*
H17B	0.2770 (4)	−0.1711 (5)	−0.4552 (11)	0.083*
H17C	0.3426 (9)	−0.3455 (18)	−0.4185 (7)	0.083*
C18	1.1432 (4)	0.2031 (4)	−0.4084 (2)	0.0491 (7)
H18A	1.1928 (14)	0.1998 (18)	−0.4600 (4)	0.074*
H18B	1.2423 (9)	0.1786 (15)	−0.3672 (8)	0.074*
H18C	1.1236 (7)	0.3289 (4)	−0.3951 (11)	0.074*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0263 (9)	0.0445 (10)	0.0257 (8)	0.0067 (7)	0.0067 (7)	−0.0032 (7)
O2	0.0279 (10)	0.0609 (12)	0.0303 (9)	0.0067 (8)	0.0030 (7)	−0.0060 (8)
O3	0.0634 (13)	0.087 (2)	0.0282 (10)	0.0221 (11)	0.0057 (9)	−0.0117 (10)
O4	0.0407 (12)	0.0661 (13)	0.0532 (12)	−0.0012 (9)	0.0242 (9)	−0.0118 (10)
O5	0.0489 (11)	0.0476 (11)	0.0276 (9)	−0.0054 (8)	0.0092 (8)	−0.0091 (8)
O6	0.0435 (11)	0.0498 (11)	0.0316 (9)	−0.0009 (8)	0.0173 (8)	−0.0069 (8)
N1	0.0298 (11)	0.0326 (11)	0.0280 (10)	0.0056 (8)	0.0071 (8)	0.0013 (8)
N2	0.0418 (14)	0.0375 (12)	0.0339 (12)	0.0071 (10)	0.0133 (10)	−0.0019 (9)
C1	0.0348 (14)	0.0322 (14)	0.0303 (13)	0.0012 (10)	0.0068 (11)	0.0038 (10)
C2	0.0429 (15)	0.0302 (13)	0.0261 (13)	0.0028 (11)	0.0068 (11)	0.0001 (10)
C3	0.0412 (15)	0.0347 (14)	0.0254 (13)	0.0083 (11)	0.0136 (11)	0.0019 (10)
C4	0.0306 (13)	0.0350 (13)	0.0317 (13)	0.0056 (10)	0.0075 (10)	−0.0003 (10)
C5	0.0309 (13)	0.0282 (12)	0.0245 (12)	0.0085 (10)	0.0055 (10)	0.0034 (9)
C6	0.0335 (14)	0.0263 (12)	0.0227 (12)	0.0074 (10)	0.0060 (10)	0.0026 (9)
C7	0.0305 (14)	0.0365 (13)	0.0282 (12)	0.0109 (11)	0.0075 (10)	0.0044 (10)
C8	0.0264 (13)	0.0310 (13)	0.0276 (12)	0.0081 (10)	0.0044 (10)	0.0029 (10)
C9	0.0297 (13)	0.0324 (13)	0.0323 (13)	0.0060 (10)	0.0089 (10)	0.0029 (10)
C10	0.0291 (13)	0.0309 (13)	0.0312 (12)	0.0081 (10)	0.0068 (10)	0.0034 (10)
C11	0.0319 (13)	0.0269 (12)	0.0253 (12)	0.0088 (10)	0.0052 (10)	0.0028 (10)
C12	0.0306 (13)	0.0378 (14)	0.0273 (12)	0.0052 (10)	0.0032 (10)	−0.0035 (10)
C13	0.0264 (13)	0.0343 (13)	0.0339 (13)	0.0023 (10)	0.0056 (10)	−0.0037 (10)
C14	0.0357 (14)	0.0279 (12)	0.0275 (12)	0.0091 (10)	0.0125 (10)	0.0012 (9)
C15	0.0338 (14)	0.0381 (14)	0.0295 (13)	0.0052 (11)	0.0002 (10)	−0.0035 (11)
C16	0.0275 (13)	0.0390 (14)	0.0313 (13)	0.0064 (10)	0.0071 (10)	0.0013 (11)
C17	0.055 (2)	0.058 (2)	0.0337 (15)	−0.0121 (14)	0.0043 (13)	−0.0096 (13)
C18	0.039 (2)	0.058 (2)	0.043 (2)	−0.0022 (13)	0.0192 (12)	−0.0081 (13)

Geometric parameters (Å, º)

O1—C8	1.376 (2)	C2—C3	1.413 (3)
O1—C7	1.387 (3)	C3—C4	1.366 (3)
O2—C7	1.198 (3)	C4—C5	1.399 (3)
O3—N2	1.225 (3)	C5—C6	1.392 (3)
O4—N2	1.222 (2)	C5—C7	1.448 (3)
O5—C2	1.355 (3)	C8—C9	1.445 (3)
O5—C17	1.433 (3)	C9—C10	1.327 (3)
O6—C3	1.363 (3)	C10—C11	1.466 (3)
O6—C18	1.420 (3)	C11—C16	1.393 (3)
N1—C8	1.283 (3)	C11—C12	1.394 (3)
N1—C6	1.393 (3)	C12—C13	1.377 (3)
N2—C14	1.465 (3)	C13—C14	1.378 (3)
C1—C2	1.378 (3)	C14—C15	1.373 (3)
C1—C6	1.401 (3)	C15—C16	1.380 (3)
C8—O1—C7	121.6 (2)	N1—C6—C1	118.8 (2)
C2—O5—C17	117.5 (2)	O2—C7—O1	117.2 (2)
C3—O6—C18	117.2 (2)	O2—C7—C5	127.9 (2)
C8—N1—C6	117.2 (2)	O1—C7—C5	114.9 (2)
O4—N2—O3	123.3 (2)	N1—C8—O1	124.9 (2)
O4—N2—C14	118.4 (2)	N1—C8—C9	122.9 (2)
O3—N2—C14	118.2 (2)	O1—C8—C9	112.2 (2)
C2—C1—C6	120.2 (2)	C10—C9—C8	124.0 (2)
O5—C2—C1	124.8 (2)	C9—C10—C11	127.1 (2)
O5—C2—C3	114.9 (2)	C16—C11—C12	118.5 (2)
C1—C2—C3	120.2 (2)	C16—C11—C10	117.7 (2)
O6—C3—C4	125.0 (2)	C12—C11—C10	123.8 (2)
O6—C3—C2	115.4 (2)	C13—C12—C11	121.1 (2)
C4—C3—C2	119.6 (2)	C12—C13—C14	118.7 (2)
C3—C4—C5	120.2 (2)	C15—C14—C13	122.1 (2)
C6—C5—C4	120.6 (2)	C15—C14—N2	118.6 (2)
C6—C5—C7	119.1 (2)	C13—C14—N2	119.3 (2)
C4—C5—C7	120.3 (2)	C14—C15—C16	118.8 (2)
C5—C6—N1	122.2 (2)	C15—C16—C11	120.9 (2)
C5—C6—C1	119.0 (2)
C17—O5—C2—C1	−4.1 (4)	C6—C5—C7—O1	−1.5 (3)
C17—O5—C2—C3	176.7 (2)	C4—C5—C7—O1	179.4 (2)
C6—C1—C2—O5	179.2 (2)	C6—N1—C8—O1	−2.1 (3)
C6—C1—C2—C3	−1.7 (4)	C6—N1—C8—C9	178.0 (2)
C18—O6—C3—C4	−18.5 (4)	C7—O1—C8—N1	4.4 (3)
C18—O6—C3—C2	162.2 (2)	C7—O1—C8—C9	−175.6 (2)
O5—C2—C3—O6	2.1 (3)	N1—C8—C9—C10	−175.6 (2)
C1—C2—C3—O6	−177.1 (2)	O1—C8—C9—C10	4.5 (3)
O5—C2—C3—C4	−177.3 (2)	C8—C9—C10—C11	−179.3 (2)
C1—C2—C3—C4	3.5 (4)	C9—C10—C11—C16	174.0 (2)
O6—C3—C4—C5	177.9 (2)	C9—C10—C11—C12	−6.0 (4)
C2—C3—C4—C5	−2.8 (3)	C16—C11—C12—C13	−1.9 (3)
C3—C4—C5—C6	0.3 (3)	C10—C11—C12—C13	178.1 (2)
C3—C4—C5—C7	179.4 (2)	C11—C12—C13—C14	0.9 (4)
C4—C5—C6—N1	−177.1 (2)	C12—C13—C14—C15	0.0 (4)
C7—C5—C6—N1	3.8 (3)	C12—C13—C14—N2	179.4 (2)
C4—C5—C6—C1	1.6 (3)	O4—N2—C14—C15	167.5 (2)
C7—C5—C6—C1	−177.5 (2)	O3—N2—C14—C15	−10.7 (3)
C8—N1—C6—C5	−2.0 (3)	O4—N2—C14—C13	−12.0 (3)
C8—N1—C6—C1	179.3 (2)	O3—N2—C14—C13	169.9 (2)
C2—C1—C6—C5	−0.9 (3)	C13—C14—C15—C16	0.2 (4)
C2—C1—C6—N1	177.9 (2)	N2—C14—C15—C16	−179.3 (2)
C8—O1—C7—O2	178.3 (2)	C14—C15—C16—C11	−1.2 (4)
C8—O1—C7—C5	−2.3 (3)	C12—C11—C16—C15	2.0 (3)
C6—C5—C7—O2	177.7 (2)	C10—C11—C16—C15	−178.0 (2)
C4—C5—C7—O2	−1.4 (4)