2-(3-Oxo-3,4-dihydro-2H-1,4-benzothia­zin-4-yl)acetamide

In the title compound, C₁₀H₁₀N₂O₂S, the thia­zine ring approximates to an envelope form with the S atom in the flap position. The amide group attached to the acetate group is almost perpendicular to the mean plane of the thia­zine ring [dihedral angle = 88.83 (8)°]. In the crystal, inversion dimers linked by pairs of N—H...O hydrogen bonds occur. Further N—H...O and C—H...O hydrogen bonds link the dimers into a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.039
• wR factor = 0.107
• Data-to-parameter ratio = 17.9

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT919_ALERT_3_B Reflection(s) # Likely Affected by the Beamstop           1

Alert level C
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600         16

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 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
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

S1. Comment

As part of our ongoing studies of 1,4-thiazine compounds (Saeed et al., 2010) we have synthesized 2-(3-oxo-2,3-dihydro benzo[b][1,4]thiazin-4-yl)acetamide for derivaziation and we report here the structure of the title compound.

The bond lengths and bond angles of the structure of the title compound is in comparison with our previously published structure of 2-(3-Oxo-3,4-dihydro-2H-1,4-benzothiazin-4-yl)acetohydrazide (II) (Saeed et al., 2010). These molecules only differ in amide (I) and hydrazide (II) groups attached to carbonyl carbon of acetate. The dihedral angle between the two rings C1–C6 and C1/C6/N1/C7/C8/S1 are almost same in these molecules i.e. 17.47 (0.09)° and 16.77 (0.10)° respectively. The amide group C9/C10/O2/N2 attached to the thiazine ring is oriented at dihedral angle of 72.05 (0.08)° and 88.83 (0.08)° with respect to the aromatic and thiazine ring. The amido hydrogens atoms are involved N–H···O type interactions with the oxygens of two different molecules. The N–H···O and weak C–H···O form dimers which results in 16 members ring motif R₂²(16) (Bernstein et al., 1995) along the b axes.

Related literature

For a related structure and background references, see: Saeed et al. (2010). For graph-set notation, see: Bernstein et al. (1995)

S2. Refinement

The C-H H-atoms were positioned gemetrically with C—H = 0.93 Å for aromatic and C—H = 0.97 Å for the methylene carbon atoms and were refined using a riding model with U_iso(H) = 1.2 U_eq(C). The N-H H atoms were located in difference map with N—H= 0.84 (4)–0.87 (3) Å, U_iso(H) = 1.2 for N atoms.

Computing details

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of (I) with displacement ellipsoids drawn at the 50% probability level.
	Fig. 2. The crystal packing of (I) with intermolecular hydrogen bonds shown by dashed lines. The hydrogen atom not involved in hydrogen bonding have been omitted for clarity.

2-(3-Oxo-3,4-dihydro-2H-1,4-benzothiazin-4-yl)acetamide

Crystal data

C10H10N2O2S	F(000) = 464
Mr = 222.26	Dx = 1.451 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2429 reflections
a = 8.0652 (6) Å	θ = 2.5–24.3°
b = 4.8415 (3) Å	µ = 0.30 mm^−1
c = 26.1517 (19) Å	T = 296 K
β = 94.798 (4)°	Needle, colorless
V = 1017.58 (12) Å^3	0.28 × 0.09 × 0.06 mm
Z = 4

Data collection

Bruker Kappa APEXII CCD diffractometer	2544 independent reflections
Radiation source: fine-focus sealed tube	1693 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
ϕ and ω scans	θmax = 28.4°, θmin = 1.6°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −10→10
Tmin = 0.921, Tmax = 0.982	k = −6→6
11611 measured reflections	l = −34→34

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.107	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0425P)^2 + 0.2819P] where P = (Fo^2 + 2Fc^2)/3
2544 reflections	(Δ/σ)max < 0.001
142 parameters	Δρmax = 0.24 e Å^−3
0 restraints	Δρmin = −0.26 e Å^−3

Special details

Experimental. To a solution of (1.56 g)ethyl 2-(3-oxo-2,3-dihydrobenzo[b][1,4]thiazin-4-yl)- acetate in 10.0 ml ethanol, 5.0 ml of 33% ammonia was added and the mixture was left for a week at room temperature. The crystals of 2-(3-oxo-2,3-dihydrobenzo[1,4]thiazin-4-yl)acetamide appeared were filtered, washed with water and dried.(M.p 475k)

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
C1	0.3288 (2)	0.0539 (4)	0.31875 (7)	0.0388 (4)
C2	0.4502 (3)	−0.1224 (4)	0.30259 (9)	0.0529 (5)
H2	0.4358	−0.2023	0.2702	0.063*
C3	0.5914 (3)	−0.1799 (5)	0.33408 (10)	0.0584 (6)
H3	0.6726	−0.2962	0.3228	0.070*
C4	0.6121 (3)	−0.0650 (5)	0.38215 (9)	0.0530 (6)
H4	0.7083	−0.1011	0.4032	0.064*
C5	0.4909 (2)	0.1035 (4)	0.39939 (8)	0.0437 (5)
H5	0.5047	0.1759	0.4324	0.052*
C6	0.3480 (2)	0.1667 (3)	0.36793 (7)	0.0338 (4)
C7	0.0611 (2)	0.3388 (4)	0.36763 (7)	0.0378 (4)
C8	0.0096 (2)	0.1364 (4)	0.32606 (7)	0.0416 (4)
H8A	−0.1005	0.1838	0.3108	0.050*
H8B	0.0043	−0.0472	0.3407	0.050*
C9	0.2668 (3)	0.5317 (4)	0.42842 (7)	0.0419 (5)
H9A	0.2076	0.7047	0.4225	0.050*
H9B	0.3851	0.5713	0.4306	0.050*
C10	0.2227 (2)	0.4090 (3)	0.47892 (7)	0.0364 (4)
N1	0.22507 (19)	0.3468 (3)	0.38519 (6)	0.0361 (4)
N2	0.2048 (2)	0.5907 (4)	0.51556 (7)	0.0455 (4)
O1	−0.04093 (19)	0.4905 (3)	0.38558 (6)	0.0541 (4)
O2	0.2099 (2)	0.1598 (3)	0.48455 (6)	0.0621 (5)
S1	0.15349 (7)	0.13660 (13)	0.277323 (19)	0.05234 (19)
H1N	0.170 (3)	0.539 (5)	0.5448 (10)	0.063*
H2N	0.200 (3)	0.758 (5)	0.5079 (9)	0.063*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0372 (11)	0.0433 (10)	0.0364 (10)	−0.0020 (8)	0.0064 (8)	0.0017 (8)
C2	0.0504 (14)	0.0582 (13)	0.0518 (13)	0.0043 (11)	0.0148 (11)	−0.0085 (10)
C3	0.0427 (13)	0.0595 (13)	0.0757 (17)	0.0117 (11)	0.0204 (12)	0.0056 (12)
C4	0.0333 (12)	0.0619 (13)	0.0638 (14)	0.0005 (10)	0.0038 (10)	0.0158 (11)
C5	0.0363 (11)	0.0515 (11)	0.0430 (11)	−0.0067 (9)	0.0009 (9)	0.0047 (9)
C6	0.0341 (10)	0.0320 (8)	0.0360 (9)	−0.0051 (7)	0.0064 (8)	0.0037 (7)
C7	0.0421 (11)	0.0369 (9)	0.0354 (9)	0.0030 (8)	0.0097 (8)	0.0096 (8)
C8	0.0337 (10)	0.0518 (11)	0.0389 (10)	0.0008 (9)	0.0000 (8)	0.0045 (9)
C9	0.0567 (13)	0.0299 (9)	0.0395 (10)	−0.0068 (9)	0.0072 (9)	−0.0014 (8)
C10	0.0422 (11)	0.0288 (9)	0.0378 (10)	0.0007 (8)	0.0015 (8)	0.0012 (7)
N1	0.0407 (9)	0.0342 (8)	0.0339 (8)	−0.0020 (7)	0.0052 (7)	−0.0014 (6)
N2	0.0665 (13)	0.0331 (8)	0.0372 (9)	−0.0014 (8)	0.0064 (9)	0.0003 (7)
O1	0.0539 (10)	0.0549 (8)	0.0553 (9)	0.0169 (7)	0.0163 (8)	0.0037 (7)
O2	0.1082 (14)	0.0280 (7)	0.0531 (9)	−0.0020 (7)	0.0254 (9)	0.0033 (6)
S1	0.0471 (3)	0.0784 (4)	0.0311 (3)	0.0047 (3)	0.0010 (2)	−0.0017 (2)

Geometric parameters (Å, º)

C1—C2	1.391 (3)	C7—N1	1.364 (2)
C1—C6	1.394 (3)	C7—C8	1.496 (3)
C1—S1	1.754 (2)	C8—S1	1.794 (2)
C2—C3	1.377 (3)	C8—H8A	0.9700
C2—H2	0.9300	C8—H8B	0.9700
C3—C4	1.372 (3)	C9—N1	1.459 (2)
C3—H3	0.9300	C9—C10	1.517 (3)
C4—C5	1.377 (3)	C9—H9A	0.9700
C4—H4	0.9300	C9—H9B	0.9700
C5—C6	1.393 (3)	C10—O2	1.221 (2)
C5—H5	0.9300	C10—N2	1.318 (2)
C6—N1	1.422 (2)	N2—H1N	0.87 (3)
C7—O1	1.225 (2)	N2—H2N	0.84 (3)
C2—C1—C6	119.62 (19)	C7—C8—H8A	109.4
C2—C1—S1	120.25 (16)	S1—C8—H8A	109.4
C6—C1—S1	120.14 (15)	C7—C8—H8B	109.4
C3—C2—C1	120.7 (2)	S1—C8—H8B	109.4
C3—C2—H2	119.7	H8A—C8—H8B	108.0
C1—C2—H2	119.7	N1—C9—C10	112.25 (14)
C4—C3—C2	119.8 (2)	N1—C9—H9A	109.2
C4—C3—H3	120.1	C10—C9—H9A	109.2
C2—C3—H3	120.1	N1—C9—H9B	109.2
C3—C4—C5	120.3 (2)	C10—C9—H9B	109.2
C3—C4—H4	119.8	H9A—C9—H9B	107.9
C5—C4—H4	119.8	O2—C10—N2	123.82 (18)
C4—C5—C6	120.8 (2)	O2—C10—C9	121.34 (17)
C4—C5—H5	119.6	N2—C10—C9	114.82 (15)
C6—C5—H5	119.6	C7—N1—C6	123.91 (15)
C5—C6—C1	118.77 (17)	C7—N1—C9	115.64 (16)
C5—C6—N1	120.77 (17)	C6—N1—C9	120.03 (16)
C1—C6—N1	120.44 (17)	C10—N2—H1N	120.5 (16)
O1—C7—N1	121.15 (18)	C10—N2—H2N	118.6 (16)
O1—C7—C8	121.10 (19)	H1N—N2—H2N	119 (2)
N1—C7—C8	117.75 (16)	C1—S1—C8	95.57 (9)
C7—C8—S1	111.06 (13)
C6—C1—C2—C3	−2.0 (3)	N1—C9—C10—N2	−158.55 (18)
S1—C1—C2—C3	177.41 (17)	O1—C7—N1—C6	176.58 (16)
C1—C2—C3—C4	0.8 (3)	C8—C7—N1—C6	−2.8 (2)
C2—C3—C4—C5	1.2 (3)	O1—C7—N1—C9	4.0 (2)
C3—C4—C5—C6	−1.9 (3)	C8—C7—N1—C9	−175.37 (15)
C4—C5—C6—C1	0.6 (3)	C5—C6—N1—C7	−153.56 (17)
C4—C5—C6—N1	−178.24 (17)	C1—C6—N1—C7	27.6 (2)
C2—C1—C6—C5	1.3 (3)	C5—C6—N1—C9	18.7 (2)
S1—C1—C6—C5	−178.14 (14)	C1—C6—N1—C9	−160.18 (16)
C2—C1—C6—N1	−179.83 (17)	C10—C9—N1—C7	78.0 (2)
S1—C1—C6—N1	0.7 (2)	C10—C9—N1—C6	−94.8 (2)
O1—C7—C8—S1	136.66 (16)	C2—C1—S1—C8	142.29 (17)
N1—C7—C8—S1	−43.93 (19)	C6—C1—S1—C8	−38.29 (16)
N1—C9—C10—O2	23.3 (3)	C7—C8—S1—C1	57.82 (15)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H1N···O1^i	0.87 (3)	2.18 (3)	3.026 (2)	164 (2)
N2—H2N···O2^ii	0.84 (3)	2.04 (3)	2.873 (2)	174 (2)
C8—H8B···O1^iii	0.97	2.57	3.532 (2)	173

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