1-Methyl-4H-3,1-benzoxazine-2,4(1H)dione.

In its crystal structure, the title compound, C(9)H(7)NO(3), forms π-stacked dimers, with a centroid-centroid distance of 3.475 (5) Å between the benzenoid and the 2,4 dicarbonyl oxazine rings. These dimers then form staircase-like linear chains through further π-stacking between the benzenoid rings [centroid-centroid distance of 3.761 (2) Å]. The methyl-H atoms are disordered due to rotation about the C-N bond and were modeled with equal occupancy.

Related literature

The title compound is a key inter­mediate for the synthesis of a variety of compounds, see: Coppola (1980 ▶); Kappe & Stadlbauer (1981 ▶); Shvekhgeimer (2001 ▶). Isatoaic anhydrides are important for the synthesis of a variety of commercial compounds. The crystal structures of two other n class="Chemical">isotoic anydrides have been reported: for the brominated 6-bromo-2H-3,1-benzoxazine-2,4(1H)-dione, see: Lubini & Wouters (1996 ▶) and for the unfunctionalized 2H-3,1-benzoxazine-2,4(1H)-dione, see: Kashino et al. (1978 ▶).

Experimental

Crystal data

C9H7NO3

M = 177.16

Monoclinic,

a = 7.632 (2) Å

b = 8.818 (2) Å

c = 11.719 (3) Å

β = 93.599 (4)°

V = 787.1 (4) Å3

Z = 4

Mo Kα radiation

μ = 0.11 mm−1

T = 296 K

0.5 × 0.5 × 0.4 mm

Data collection

Bruker APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T min = 0.902, T max = 0.934

13548 measured reflections

2191 independent reflections

1532 reflections with I > 2σ(I)

R int = 0.029

Refinement

R[F 2 > 2σ(F 2)] = 0.052

wR(F 2) = 0.160

S = 1.07

2191 reflections

118 parameters

H-atom parameters constrained

Δρmax = 0.20 e Å−3

Δρmin = −0.21 e Å−3

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT-Plus (Bruker, 2008 ▶); data reduction: SAINT-Plus (Bruker, 2008 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: CrystalMaker (CrystalMaker, 2009 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810006094/fj2280sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810006094/fj2280Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C9H7NO3	F(000) = 368
Mr = 177.16	Dx = 1.495 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 5577 reflections
a = 7.632 (2) Å	θ = 5.8–59.2°
b = 8.818 (2) Å	µ = 0.11 mm−1
c = 11.719 (3) Å	T = 296 K
β = 93.599 (4)°	Block, colorless
V = 787.1 (4) Å3	0.5 × 0.5 × 0.4 mm
Z = 4

Bruker APEXII CCD diffractometer	2191 independent reflections
Radiation source: fine-focus sealed tube	1532 reflections with I > 2σ(I)
graphite	Rint = 0.029
ω and φ scans	θmax = 30.1°, θmin = 2.9°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −10→10
Tmin = 0.902, Tmax = 0.934	k = −9→12
13548 measured reflections	l = −16→16

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.052	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.160	H-atom parameters constrained
S = 1.07	w = 1/[σ2(Fo2) + (0.0717P)2 + 0.1822P] where P = (Fo2 + 2Fc2)/3
2191 reflections	(Δ/σ)max < 0.001
118 parameters	Δρmax = 0.20 e Å−3
0 restraints	Δρmin = −0.21 e Å−3

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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.

	x	y	z	Uiso*/Ueq	Occ. (<1)
O3	0.9373 (2)	0.59606 (17)	0.17004 (14)	0.0830 (5)
O2	0.9649 (2)	1.0762 (2)	0.27147 (12)	0.0906 (6)
O1	0.93997 (16)	0.83752 (18)	0.21847 (10)	0.0668 (4)
N1	0.80524 (17)	0.76241 (15)	0.04367 (11)	0.0494 (3)
C1	0.8953 (2)	0.7229 (2)	0.14315 (15)	0.0576 (4)
C2	0.9119 (2)	0.9903 (2)	0.19846 (14)	0.0596 (5)
C3	0.7855 (2)	1.1789 (2)	0.06087 (16)	0.0607 (5)
H3	0.8214	1.2561	0.1112	0.073*
C4	0.6984 (3)	1.2139 (2)	−0.04182 (18)	0.0662 (5)
H4	0.6748	1.3144	−0.0613	0.079*
C5	0.6463 (2)	1.0989 (2)	−0.11575 (15)	0.0591 (4)
H5	0.5872	1.1228	−0.1853	0.071*
C6	0.6794 (2)	0.95018 (19)	−0.08922 (13)	0.0488 (4)
H6	0.6430	0.8742	−0.1404	0.059*
C7	0.76789 (17)	0.91246 (16)	0.01464 (11)	0.0402 (3)
C8	0.82028 (18)	1.02777 (18)	0.08998 (12)	0.0462 (4)
C9	0.7552 (3)	0.6393 (2)	−0.0348 (2)	0.0780 (6)
H9A	0.6927	0.6799	−0.1016	0.117*	0.50
H9B	0.6811	0.5691	0.0022	0.117*	0.50
H9C	0.8587	0.5878	−0.0567	0.117*	0.50
H9D	0.7956	0.5446	−0.0025	0.117*	0.50
H9E	0.8072	0.6554	−0.1063	0.117*	0.50
H9F	0.6297	0.6367	−0.0474	0.117*	0.50

	U11	U22	U33	U12	U13	U23
O3	0.0874 (10)	0.0758 (10)	0.0840 (10)	0.0213 (8)	−0.0077 (8)	0.0243 (8)
O2	0.0825 (10)	0.1184 (14)	0.0673 (9)	−0.0039 (9)	−0.0231 (7)	−0.0386 (9)
O1	0.0639 (7)	0.0889 (10)	0.0455 (6)	0.0043 (7)	−0.0147 (5)	0.0028 (6)
N1	0.0527 (7)	0.0442 (7)	0.0499 (7)	0.0013 (5)	−0.0079 (5)	−0.0009 (5)
C1	0.0515 (9)	0.0646 (11)	0.0558 (9)	0.0072 (7)	−0.0025 (7)	0.0104 (8)
C2	0.0470 (8)	0.0819 (13)	0.0489 (8)	−0.0014 (8)	−0.0060 (6)	−0.0148 (8)
C3	0.0554 (9)	0.0509 (10)	0.0758 (11)	−0.0090 (7)	0.0049 (8)	−0.0169 (8)
C4	0.0670 (11)	0.0474 (10)	0.0839 (13)	−0.0007 (8)	0.0030 (9)	0.0084 (8)
C5	0.0597 (10)	0.0622 (11)	0.0549 (9)	0.0018 (8)	−0.0015 (7)	0.0128 (8)
C6	0.0505 (8)	0.0531 (9)	0.0418 (7)	−0.0028 (7)	−0.0048 (6)	−0.0009 (6)
C7	0.0368 (6)	0.0443 (8)	0.0393 (6)	−0.0016 (5)	0.0001 (5)	−0.0022 (5)
C8	0.0390 (7)	0.0530 (9)	0.0463 (7)	−0.0044 (6)	0.0003 (5)	−0.0095 (6)
C9	0.0984 (15)	0.0469 (10)	0.0854 (14)	0.0068 (10)	−0.0219 (11)	−0.0154 (9)

O3—C1	1.201 (2)	C4—H4	0.9300
O2—C2	1.194 (2)	C5—C6	1.368 (2)
O1—C1	1.371 (2)	C5—H5	0.9300
O1—C2	1.382 (3)	C6—C7	1.3944 (19)
N1—C1	1.361 (2)	C6—H6	0.9300
N1—C7	1.3912 (19)	C7—C8	1.3888 (19)
N1—C9	1.459 (2)	C9—H9A	0.9600
C2—C8	1.450 (2)	C9—H9B	0.9600
C3—C4	1.373 (3)	C9—H9C	0.9600
C3—C8	1.397 (3)	C9—H9D	0.9600
C3—H3	0.9300	C9—H9E	0.9600
C4—C5	1.376 (3)	C9—H9F	0.9600
C1—O1—C2	125.43 (13)	C7—C8—C3	120.04 (14)
C1—N1—C7	122.51 (14)	C7—C8—C2	119.62 (15)
C1—N1—C9	116.62 (15)	C3—C8—C2	120.34 (15)
C7—N1—C9	120.81 (13)	N1—C9—H9A	109.5
O3—C1—N1	125.14 (18)	N1—C9—H9B	109.5
O3—C1—O1	117.80 (16)	H9A—C9—H9B	109.5
N1—C1—O1	117.06 (15)	N1—C9—H9C	109.5
O2—C2—O1	117.05 (18)	H9A—C9—H9C	109.5
O2—C2—C8	127.4 (2)	H9B—C9—H9C	109.5
O1—C2—C8	115.59 (14)	N1—C9—H9D	109.5
C4—C3—C8	120.15 (16)	H9A—C9—H9D	141.1
C4—C3—H3	119.9	H9B—C9—H9D	56.3
C8—C3—H3	119.9	H9C—C9—H9D	56.3
C3—C4—C5	119.44 (17)	N1—C9—H9E	109.5
C3—C4—H4	120.3	H9A—C9—H9E	56.3
C5—C4—H4	120.3	H9B—C9—H9E	141.1
C6—C5—C4	121.41 (16)	H9C—C9—H9E	56.3
C6—C5—H5	119.3	H9D—C9—H9E	109.5
C4—C5—H5	119.3	N1—C9—H9F	109.5
C5—C6—C7	119.98 (15)	H9A—C9—H9F	56.3
C5—C6—H6	120.0	H9B—C9—H9F	56.3
C7—C6—H6	120.0	H9C—C9—H9F	141.1
C8—C7—N1	119.63 (13)	H9D—C9—H9F	109.5
C8—C7—C6	118.98 (14)	H9E—C9—H9F	109.5
N1—C7—C6	121.39 (13)