Crystal structures and Hirshfeld surfaces of two 1,3-benzoxa­thiol-2-one derivatives

The packing motifs in the title compounds both feature C—H⋯O inter­actions but they show distinctly different Hirshfeld surface fingerprints.

Abstract

The crystal structures of 6-meth­oxy-1,3-benzoxa­thiol-2-one, C₉H₈O₃S, (I), and 2-oxo-1,3-benzoxa­thiol-6-yl acetate, C₉H₆O₄S, (II), are described. Compound (I) is almost planar (r.m.s. deviation for the non-H atoms = 0.011 Å), whereas (II) shows a substantial twist between the fused-ring system and the acetate substituent [dihedral angle = 74.42 (3)°]. For both structures, the bond distances in the heterocyclic ring suggest that little if any conjugation occurs. In the crystal of (I), C—H⋯O hydrogen bonds link the mol­ecules into [1-11] chains incorporating alternating R ₂ ²(8) and R ₂ ²(12) inversion dimers. The extended structure of (II) features C(7) [201] chains linked by C—H⋯O hydrogen bonds, with further C—H⋯O bonds and weak π–π stacking inter­actions connecting the chains into a three-dimensional network. Hirshfeld fingerprint analyses for (I) and (II) are presented and discussed.

Chemical context  

1,3-Benzoxa­thiol-2-one and its derivatives have various biological properties including anti­bacterial, anti­mycotic, anti­oxidant, anti­tumor and anti-inflammatory activities (Vellasco Júnior et al., 2011 ▸; Chazin et al., 2015 ▸). They also act as inhibitors of carbonic anhydrase II (Barrese et al., 2008 ▸) and mono­amine oxidase (Mostert et al., 2016 ▸). The first synthesized 1,3-benzoxa­thiol-2-one, 6-hy­droxy-1,3-benzoxa­thiol-2-one C₇H₄O₃S, also known as tioxolone or thioxolone, has been used for many years in the treatment of acne and other skin diseases (e.g. psoriasis) (Berg & Fiedler, 1959 ▸).

A recent study reported the syntheses and anti­fungal activities of some derivatives of tioxolone (Terra et al., 2018 ▸). In the present article we report the crystal structures and Hirshfeld surface analyses of two compounds with different substituents at the 6-position of the ring system obtained in that study, viz. 6-meth­oxy-1,3-benzoxa­thiol-2-one, C₉H₈O₃S, (I), and 2-oxo-1,3-benzoxa­thiol-6-yl acetate, C₉H₈O₃S, (II)..

Structural commentary  

Compound (I) crystallizes in space group P with one mol­ecule in the asymmetric unit (Fig. 1 ▸), which is almost planar (r.m.s. deviation for the non-hydrogen atoms = 0.011 Å): the eth­oxy side chain adopts an extended conformation [C6—O3—C8—C9 = 179.82 (12)°]. Within the oxa­thiol-2-one ring system, the C1—O1, C1=O2 and C1—S1 bond lengths are 1.3732 (18), 1.1905 (19) and 1.7766 (16)Å, respectively, and the O1—C1—S1 and C1—S1—C3 bond angles are 111.07 (11) and 90.62 (7)°, respectively. These distance data suggest that there is little if any conjugation (i.e. partial double-bond character) involving the C1—O1 and C1—S1 bonds with the C1=O2 group.

Figure 1.

The mol­ecular structure of (I), showing 50% displacement ellipsoids.

A single mol­ecule of compound (II) makes up the asymmetric unit in space group P2₁/c (Fig. 2 ▸). The ring system is almost planar (r.m.s. deviation for C1–C7/O1/S1 = 0.032 Å) but there is a substantial twist about the C6—O3 bond, as indicated by the dihedral angle between the ring system and the acetate group of 74.42 (3)°. Key geometrical data for the heterocyclic ring are C1—O1 = 1.3864 (15), C1=O2 = 1.1936 (15), C1—S1 = 1.7709 (13) Å, O1—C1—S1 = 111.57 (8) and C1—S1—C3 = 90.43 (6)°. These data are similar to the equivalent values for (I) and again indicate a lack of significant electronic delocalization within the oxa­thiol-2-one ring system.

Figure 2.

The mol­ecular structure of (II), showing 50% displacement ellipsoids.

Supra­molecular features  

In the crystal of (I), the mol­ecules are linked by C—H⋯O hydrogen bonds (Table 1 ▸). The C5—H5⋯O3ⁱ [symmetry code: (i) −x, 1 − y, −z] link generates inversion dimers featuring (8) loops. Based on its length, the C7—H7⋯O2ⁱⁱ [symmetry code: (ii) 1 − x, −y, 1 − z] bond is much weaker, but if it is considered significant, it generates a second inversion dimer [with an (12) graph-set symbol], which links the dimers into [11] chains (Fig. 3 ▸). No C—H⋯π inter­actions could be identified in the crystal of (I) and any aromatic π–π stacking must be extremely weak, as the shortest centroid–centroid separation is 3.9149 (10) Å.

Table 1. Hydrogen-bond geometry (Å, °) for (I) .

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯O3i	0.95	2.48	3.432 (2)	175
C7—H7⋯O2ii	0.95	2.66	3.5983 (19)	170

Symmetry codes: (i) ; (ii) .

Figure 3.

Fragment of a [11] hydrogen-bonded chain in (I); all hydrogen atoms except H5 and H7 have been omitted for clarity. Symmetry codes as in Table 1 ▸.

In the crystal of (II), C4—H4⋯O4ⁱ [symmetry code: (i) x − 1,  − y, z − ] hydrogen bonds (Table 2 ▸) link the mol­ecules into C(7) chains propagating in [201], with adjacent mol­ecules in the chain related by c-glide symmetry (plus translation) (Fig. 4 ▸). The C9—H9C⋯O2ⁱⁱ [symmetry code: (ii) 1 − x, −y, 1 − z] bonds arising from the methyl group generate inversion dimers [(16) loops], which connect the chains into a three-dimensional network. There are no C—H⋯π bonds in the crystal of (II) but the packing is consolidated by weak aromatic π–π stacking between inversion-related C2–C7 benzene rings with a centroid–centroid separation of 3.7220 (8) Å.

Table 2. Hydrogen-bond geometry (Å, °) for (II) .

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C4—H4⋯O4i	0.95	2.35	3.2606 (15)	159
C9—H9C⋯O2ii	0.98	2.50	3.4030 (16)	153

Symmetry codes: (i) ; (ii) .

Figure 4.

Fragment of a [201] hydrogen-bonded chain in (II); all hydrogen atoms except H4 omitted for clarity. Symmetry codes as in Table 2 ▸; additionally (iii) x − 2, y, z − 1.

Hirshfeld analyses  

Hirshfeld surface fingerprint plots for (I) (Fig. 5 ▸), (II) (Fig. 6 ▸) and tioxolone (refcode: EVOQEL), which features classical O—H⋯O hydrogen bonds (Byres & Cox, 2004 ▸) (Fig. 7 ▸) were calculated with CrystalExplorer17 (Turner et al., 2017 ▸). The plot for EVOQEL has very pronounced ‘wingtip’ features that correspond to the short, classical O—H⋯O hydrogen bond found in this structure (compare: McKinnon et al., 2007 ▸). In (I) and (II), the wingtips associated with the longer and presumably weaker C—H⋯O bonds are far less pronounced.

Figure 5.

Hirshfeld fingerprint plot for (I)

Figure 6.

Hirshfeld fingerprint plot for (II)

Figure 7.

Hirshfeld fingerprint plot for tioxolone [atomic coordinates from Byres & Cox (2004 ▸)].

When the fingerprint plots are decomposed into the separate types of contacts (McKinnon et al., 2007 ▸), some inter­esting differences arise (Table 3 ▸): as a percentage of surface inter­actions, H⋯H contacts (i.e. van der Waals inter­actions) are far more prominent in (I) than in (II), which is comparable with EVOQEL, whereas C⋯H/H⋯C contacts are similar for the three structures. The O⋯H/H⋯O contacts are the most important contributors in all three structures, and in (II) they actually contribute a higher percentage to the surface than in EVOQEL, despite the fact that EVOQEL features both O—H⋯O and C—H⋯O hydrogen bonds and only one of its hydrogen atoms is not involved in such bonds (Byres & Cox, 2004 ▸). The C⋯C contacts (associated with aromatic π–π stacking) contribute a small percentage in (I) and (II) and about twice the amount in EVOQEL where the shortest centroid–centroid separation is 3.508 (2) Å. Despite the small percentage for (II), the Hirshfeld surface (Fig. 8 ▸) clearly shows red spots associated with these contacts. The S⋯H/H⋯S contacts are similar in the three structures, and not insignificant at ∼10% of the surfaces, but they can hardly represent directional C—H⋯S hydrogen bonds, as the shortest H⋯S separations (3.21, 3.11 and 3.28 Å in (I), (II) and EVOQEL, respectively) are much longer than the van der Waals contact distance (Bondi, 1964 ▸) of 3.00 Å for H and S. Finally, S⋯O/O⋯S contacts have very different contributions in the three structures: negligible in (I), but clearly present in (II) and EVOQEL. This seems to correlate with the shortest S⋯O contact distances of 3.623 (2), 3.2742 (10) and 3.341 (2) Å for (I), (II) and EVOQEL, respectively: the distance in (II) is actually slightly shorter than the van der Waals contact distance of 3.32Å for sulfur and oxygen,

Table 3. Hirshfeld contact inter­actions (%).

Contact type	(I)	(II)	EVOQEL
H⋯H	28.7	14.8	13.5
O⋯H/H⋯O	30.1	39.5	36.0
C⋯H/H⋯C	11.3	13.4	8.6
S⋯H/H⋯S	11.1	10.8	8.8
C⋯C	5.9	4.4	10.4
S⋯O/O⋯S	1.5	7.0	10.1

Figure 8.

Hirshfeld surface plot mapped over d _norm for (II) showing red spots associated with short C⋯C and C⋯O contacts: the slightly smaller spots refer to the former.

Database survey  

A survey of of the Cambridge Structural Database (Groom et al., 2016 ▸: updated to September 2017) for the benzoxa­thiol-2-one fused ring system (any substituents) yielded just three matches, viz. 6-hy­droxy-1,3-benzoxa­thiol-2-one (refcode: EVOQEL; Byres & Cox, 2004 ▸); N-(4,7-dimethyl-2-oxo-benzo[1,3]oxa­thiol-5-yl)-4-benzene­sulfonamide (NAJQOG; Avdeenko et al., 2009 ▸); 7-phenyl-1,3-benzoxa­thiol-2-one (JOSGUV; Zhao et al., 2014 ▸). To this list may be added the structure of 6-meth­oxy-5-nitro­benzo[d][1,3]oxa­thiol-2-one (CCDC deposition number 1404755) as recently reported by Terra et al. (2017 ▸).

Synthesis and crystallization  

Compounds (I) and (II) were prepared as described previously (Terra et al., 2018 ▸) and recrystallized from methanol solution as colourless plates of (I) and colourless blocks of (II).

Refinement  

Crystal data, data collection and structure refinement details are summarized in Table 4 ▸. The hydrogen atoms were geometrically placed (C—H = 0.95–0.99 Å) and refined as riding atoms. The constraint U _iso(H) = 1.2U _eq(carrier) or 1.5U _eq(methyl carrier) was applied in all cases. The methyl groups were allowed to rotate, but not to tip, to best fit the electron density.

Table 4. Experimental details.

	(I)	(II)
Crystal data
Chemical formula	C9H8O3S	C9H6O4S
M r	196.21	210.20
Crystal system, space group	Triclinic, P	Monoclinic, P21/c
Temperature (K)	100	100
a, b, c (Å)	3.9149 (6), 10.3237 (12), 11.7003 (14)	5.6232 (5), 14.5650 (14), 10.8572 (11)
α, β, γ (°)	66.526 (6), 81.110 (9), 84.349 (9)	90, 96.045 (2), 90
V (Å3)	428.18 (10)	884.28 (15)
Z	2	4
Radiation type	Mo Kα	Mo Kα
μ (mm−1)	0.35	0.35
Crystal size (mm)	0.17 × 0.17 × 0.03	0.26 × 0.11 × 0.08
Data collection
Diffractometer	Rigaku Saturn CCD	Rigaku Saturn CCD
Absorption correction	Multi-scan (FS_ABSCOR; Rigaku, 2013 ▸)	Multi-scan (FS_ABSCOR; Rigaku, 2013 ▸)
T min, T max	0.714, 1.000	0.829, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	5189, 1674, 1540	11487, 2028, 1903
R int	0.040	0.036
(sin θ/λ)max (Å−1)	0.617	0.650
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.034, 0.094, 1.04	0.028, 0.081, 1.10
No. of reflections	1674	2028
No. of parameters	119	128
H-atom treatment	H-atom parameters constrained	H-atom parameters constrained
Δρmax, Δρmin (e Å−3)	0.52, −0.20	0.33, −0.21

Computer programs: CrystalClear (Rigaku, 2014 ▸), SHELXS97 (Sheldrick, 2008 ▸), SHELXL2014 (Sheldrick, 2015 ▸), ORTEP-3 for Windows (Farrugia, 2012 ▸) and publCIF (Westrip, 2010 ▸).

Supplementary Material

CCDC references: 1404758, 1404756

Additional supporting information: crystallographic information; 3D view; checkCIF report

supplementary crystallographic information

6-Methoxy-1,3-benzoxathiol-2-one (I). Crystal data

C9H8O3S	Z = 2
Mr = 196.21	F(000) = 204
Triclinic, P1	Dx = 1.522 Mg m−3
a = 3.9149 (6) Å	Mo Kα radiation, λ = 0.71073 Å
b = 10.3237 (12) Å	Cell parameters from 1390 reflections
c = 11.7003 (14) Å	θ = 1.9–27.5°
α = 66.526 (6)°	µ = 0.35 mm−1
β = 81.110 (9)°	T = 100 K
γ = 84.349 (9)°	Plate, colourless
V = 428.18 (10) Å3	0.17 × 0.17 × 0.03 mm

6-Methoxy-1,3-benzoxathiol-2-one (I). Data collection

Rigaku Saturn CCD diffractometer	1540 reflections with I > 2σ(I)
ω scans	Rint = 0.040
Absorption correction: multi-scan (FS_ABSCOR; Rigaku, 2013)	θmax = 26.0°, θmin = 1.9°
Tmin = 0.714, Tmax = 1.000	h = −4→4
5189 measured reflections	k = −12→12
1674 independent reflections	l = −14→14

6-Methoxy-1,3-benzoxathiol-2-one (I). Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.034	H-atom parameters constrained
wR(F2) = 0.094	w = 1/[σ2(Fo2) + (0.0607P)2 + 0.0766P] where P = (Fo2 + 2Fc2)/3
S = 1.04	(Δ/σ)max < 0.001
1674 reflections	Δρmax = 0.52 e Å−3
119 parameters	Δρmin = −0.20 e Å−3
0 restraints

6-Methoxy-1,3-benzoxathiol-2-one (I). Special details

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.

6-Methoxy-1,3-benzoxathiol-2-one (I). Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.0898 (4)	0.15148 (16)	0.62375 (14)	0.0238 (3)
C2	0.1487 (4)	0.21490 (16)	0.40934 (14)	0.0221 (3)
C3	−0.0473 (4)	0.33140 (16)	0.41485 (14)	0.0221 (3)
C4	−0.1375 (4)	0.43830 (16)	0.30435 (15)	0.0238 (3)
H4	−0.2733	0.5190	0.3064	0.029*
C5	−0.0252 (4)	0.42431 (16)	0.19181 (15)	0.0245 (3)
H5	−0.0854	0.4961	0.1157	0.029*
C6	0.1770 (4)	0.30535 (16)	0.18846 (14)	0.0223 (3)
C7	0.2673 (4)	0.19732 (16)	0.29857 (14)	0.0230 (3)
H7	0.4028	0.1161	0.2975	0.028*
C8	0.4817 (4)	0.18554 (16)	0.06172 (15)	0.0240 (3)
H8A	0.3576	0.0970	0.1095	0.029*
H8B	0.7026	0.1773	0.0959	0.029*
C9	0.5494 (4)	0.21106 (18)	−0.07580 (15)	0.0283 (4)
H9A	0.6977	0.1336	−0.0867	0.042*
H9B	0.6651	0.3005	−0.1224	0.042*
H9C	0.3294	0.2157	−0.1077	0.042*
O1	0.2250 (3)	0.11453 (11)	0.52491 (10)	0.0244 (3)
O2	0.1322 (3)	0.07887 (11)	0.72936 (10)	0.0282 (3)
O3	0.2727 (3)	0.30495 (11)	0.07165 (10)	0.0251 (3)
S1	−0.14241 (9)	0.31705 (4)	0.57093 (3)	0.02391 (16)

6-Methoxy-1,3-benzoxathiol-2-one (I). Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.0236 (8)	0.0232 (7)	0.0273 (8)	−0.0042 (6)	−0.0017 (6)	−0.0124 (6)
C2	0.0220 (7)	0.0193 (7)	0.0254 (8)	−0.0039 (6)	−0.0056 (6)	−0.0076 (6)
C3	0.0218 (7)	0.0212 (7)	0.0264 (8)	−0.0034 (6)	−0.0037 (6)	−0.0117 (6)
C4	0.0228 (7)	0.0213 (8)	0.0301 (8)	0.0010 (6)	−0.0056 (6)	−0.0125 (6)
C5	0.0257 (8)	0.0216 (7)	0.0273 (8)	−0.0009 (6)	−0.0069 (6)	−0.0096 (6)
C6	0.0214 (7)	0.0222 (8)	0.0258 (7)	−0.0045 (6)	−0.0026 (6)	−0.0112 (6)
C7	0.0223 (7)	0.0201 (7)	0.0286 (8)	−0.0013 (6)	−0.0042 (6)	−0.0110 (6)
C8	0.0245 (7)	0.0216 (7)	0.0280 (8)	0.0002 (6)	−0.0040 (6)	−0.0120 (6)
C9	0.0289 (8)	0.0302 (8)	0.0288 (8)	−0.0026 (7)	−0.0007 (6)	−0.0153 (7)
O1	0.0290 (6)	0.0210 (5)	0.0239 (6)	0.0013 (4)	−0.0044 (4)	−0.0096 (4)
O2	0.0335 (6)	0.0260 (6)	0.0246 (6)	−0.0001 (5)	−0.0037 (5)	−0.0095 (5)
O3	0.0300 (6)	0.0221 (6)	0.0247 (6)	0.0026 (4)	−0.0044 (4)	−0.0112 (5)
S1	0.0252 (2)	0.0234 (2)	0.0259 (2)	0.00092 (16)	−0.00403 (16)	−0.01255 (17)

6-Methoxy-1,3-benzoxathiol-2-one (I). Geometric parameters (Å, º)

C1—O2	1.1905 (19)	C5—H5	0.9500
C1—O1	1.3732 (18)	C6—O3	1.3617 (18)
C1—S1	1.7766 (16)	C6—C7	1.395 (2)
C2—C3	1.380 (2)	C7—H7	0.9500
C2—C7	1.383 (2)	C8—O3	1.4452 (18)
C2—O1	1.3926 (18)	C8—C9	1.508 (2)
C3—C4	1.394 (2)	C8—H8A	0.9900
C3—S1	1.7552 (16)	C8—H8B	0.9900
C4—C5	1.381 (2)	C9—H9A	0.9800
C4—H4	0.9500	C9—H9B	0.9800
C5—C6	1.405 (2)	C9—H9C	0.9800
O2—C1—O1	122.22 (14)	C2—C7—C6	116.34 (14)
O2—C1—S1	126.71 (12)	C2—C7—H7	121.8
O1—C1—S1	111.07 (11)	C6—C7—H7	121.8
C3—C2—C7	123.62 (14)	O3—C8—C9	107.02 (12)
C3—C2—O1	114.96 (13)	O3—C8—H8A	110.3
C7—C2—O1	121.41 (13)	C9—C8—H8A	110.3
C2—C3—C4	119.56 (14)	O3—C8—H8B	110.3
C2—C3—S1	110.37 (11)	C9—C8—H8B	110.3
C4—C3—S1	130.07 (12)	H8A—C8—H8B	108.6
C5—C4—C3	118.55 (14)	C8—C9—H9A	109.5
C5—C4—H4	120.7	C8—C9—H9B	109.5
C3—C4—H4	120.7	H9A—C9—H9B	109.5
C4—C5—C6	120.85 (14)	C8—C9—H9C	109.5
C4—C5—H5	119.6	H9A—C9—H9C	109.5
C6—C5—H5	119.6	H9B—C9—H9C	109.5
O3—C6—C7	123.91 (13)	C1—O1—C2	112.97 (12)
O3—C6—C5	115.01 (13)	C6—O3—C8	117.75 (12)
C7—C6—C5	121.08 (14)	C3—S1—C1	90.62 (7)
C7—C2—C3—C4	0.7 (2)	C5—C6—C7—C2	−0.4 (2)
O1—C2—C3—C4	179.88 (13)	O2—C1—O1—C2	−179.25 (14)
C7—C2—C3—S1	−179.08 (11)	S1—C1—O1—C2	0.23 (15)
O1—C2—C3—S1	0.14 (16)	C3—C2—O1—C1	−0.24 (18)
C2—C3—C4—C5	−0.3 (2)	C7—C2—O1—C1	178.99 (12)
S1—C3—C4—C5	179.33 (12)	C7—C6—O3—C8	−0.3 (2)
C3—C4—C5—C6	−0.3 (2)	C5—C6—O3—C8	179.90 (13)
C4—C5—C6—O3	−179.56 (13)	C9—C8—O3—C6	179.82 (12)
C4—C5—C6—C7	0.6 (2)	C2—C3—S1—C1	−0.01 (11)
C3—C2—C7—C6	−0.3 (2)	C4—C3—S1—C1	−179.71 (15)
O1—C2—C7—C6	−179.47 (13)	O2—C1—S1—C3	179.32 (15)
O3—C6—C7—C2	179.87 (13)	O1—C1—S1—C3	−0.13 (11)

6-Methoxy-1,3-benzoxathiol-2-one (I). Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···O3i	0.95	2.48	3.432 (2)	175
C7—H7···O2ii	0.95	2.66	3.5983 (19)	170

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

2-Oxo-1,3-benzoxathiol-6-yl acetate (II). Crystal data

C9H6O4S	F(000) = 432
Mr = 210.20	Dx = 1.579 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 5.6232 (5) Å	Cell parameters from 3355 reflections
b = 14.5650 (14) Å	θ = 2.3–27.5°
c = 10.8572 (11) Å	µ = 0.35 mm−1
β = 96.045 (2)°	T = 100 K
V = 884.28 (15) Å3	Block, colourless
Z = 4	0.26 × 0.11 × 0.08 mm

2-Oxo-1,3-benzoxathiol-6-yl acetate (II). Data collection

Rigaku Saturn CCD diffractometer	1903 reflections with I > 2σ(I)
ω scans	Rint = 0.036
Absorption correction: multi-scan (FS_ABSCOR; Rigaku, 2013)	θmax = 27.5°, θmin = 2.4°
Tmin = 0.829, Tmax = 1.000	h = −7→7
11487 measured reflections	k = −18→18
2028 independent reflections	l = −14→14

2-Oxo-1,3-benzoxathiol-6-yl acetate (II). Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.028	H-atom parameters constrained
wR(F2) = 0.081	w = 1/[σ2(Fo2) + (0.0423P)2 + 0.328P] where P = (Fo2 + 2Fc2)/3
S = 1.10	(Δ/σ)max = 0.001
2028 reflections	Δρmax = 0.33 e Å−3
128 parameters	Δρmin = −0.21 e Å−3
0 restraints

2-Oxo-1,3-benzoxathiol-6-yl acetate (II). Special details

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.

2-Oxo-1,3-benzoxathiol-6-yl acetate (II). Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.1830 (2)	0.03032 (8)	0.18546 (11)	0.0210 (2)
C2	0.1514 (2)	0.07946 (8)	0.38446 (11)	0.0167 (2)
C3	−0.0602 (2)	0.11624 (8)	0.32717 (11)	0.0174 (2)
C4	−0.2186 (2)	0.16130 (8)	0.39666 (11)	0.0194 (2)
H4	−0.3625	0.1872	0.3580	0.023*
C5	−0.1609 (2)	0.16746 (8)	0.52441 (11)	0.0191 (2)
H5	−0.2657	0.1979	0.5742	0.023*
C6	0.0505 (2)	0.12894 (8)	0.57848 (10)	0.0175 (2)
C7	0.2139 (2)	0.08489 (8)	0.51080 (11)	0.0175 (2)
H7	0.3595	0.0601	0.5491	0.021*
C8	0.2608 (2)	0.18164 (8)	0.76657 (11)	0.0183 (2)
C9	0.2792 (2)	0.16577 (9)	0.90343 (11)	0.0222 (3)
H9A	0.1197	0.1535	0.9284	0.033*
H9B	0.3465	0.2204	0.9467	0.033*
H9C	0.3833	0.1129	0.9248	0.033*
O1	0.29007 (15)	0.03350 (6)	0.30638 (8)	0.01950 (19)
O2	0.27313 (17)	−0.00958 (7)	0.10631 (8)	0.0282 (2)
O3	0.08651 (15)	0.12684 (6)	0.70829 (7)	0.0207 (2)
O4	0.37694 (17)	0.23332 (7)	0.71088 (8)	0.0275 (2)
S1	−0.09135 (5)	0.09103 (2)	0.16863 (3)	0.02017 (11)

2-Oxo-1,3-benzoxathiol-6-yl acetate (II). Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.0246 (6)	0.0209 (6)	0.0177 (6)	−0.0017 (5)	0.0030 (4)	0.0015 (4)
C2	0.0164 (5)	0.0158 (5)	0.0181 (6)	−0.0015 (4)	0.0026 (4)	−0.0003 (4)
C3	0.0194 (5)	0.0177 (5)	0.0148 (5)	−0.0023 (4)	−0.0004 (4)	0.0001 (4)
C4	0.0180 (5)	0.0194 (6)	0.0202 (6)	0.0019 (4)	−0.0009 (4)	0.0003 (4)
C5	0.0194 (5)	0.0185 (6)	0.0196 (6)	−0.0010 (4)	0.0028 (4)	−0.0020 (4)
C6	0.0208 (5)	0.0178 (5)	0.0137 (5)	−0.0055 (4)	0.0007 (4)	0.0004 (4)
C7	0.0158 (5)	0.0182 (6)	0.0178 (6)	−0.0017 (4)	−0.0008 (4)	0.0019 (4)
C8	0.0201 (5)	0.0182 (5)	0.0163 (5)	0.0003 (4)	0.0005 (4)	−0.0020 (4)
C9	0.0287 (6)	0.0235 (6)	0.0140 (5)	−0.0009 (5)	0.0007 (4)	−0.0007 (4)
O1	0.0190 (4)	0.0230 (4)	0.0167 (4)	0.0017 (3)	0.0025 (3)	−0.0010 (3)
O2	0.0336 (5)	0.0321 (5)	0.0200 (5)	0.0048 (4)	0.0076 (4)	−0.0030 (4)
O3	0.0239 (4)	0.0251 (5)	0.0128 (4)	−0.0076 (3)	0.0006 (3)	0.0003 (3)
O4	0.0317 (5)	0.0327 (5)	0.0176 (4)	−0.0140 (4)	0.0008 (4)	−0.0002 (4)
S1	0.02389 (18)	0.02219 (18)	0.01374 (17)	0.00119 (11)	−0.00123 (12)	0.00007 (10)

2-Oxo-1,3-benzoxathiol-6-yl acetate (II). Geometric parameters (Å, º)

C1—O2	1.1936 (15)	C5—H5	0.9500
C1—O1	1.3864 (15)	C6—C7	1.3923 (16)
C1—S1	1.7709 (13)	C6—O3	1.4030 (13)
C2—C7	1.3820 (17)	C7—H7	0.9500
C2—O1	1.3835 (14)	C8—O4	1.2008 (15)
C2—C3	1.3905 (16)	C8—O3	1.3665 (14)
C3—C4	1.3908 (16)	C8—C9	1.4965 (16)
C3—S1	1.7506 (12)	C9—H9A	0.9800
C4—C5	1.3936 (16)	C9—H9B	0.9800
C4—H4	0.9500	C9—H9C	0.9800
C5—C6	1.3875 (16)
O2—C1—O1	121.54 (12)	C7—C6—O3	119.12 (10)
O2—C1—S1	126.88 (10)	C2—C7—C6	115.92 (11)
O1—C1—S1	111.57 (8)	C2—C7—H7	122.0
C7—C2—O1	122.33 (10)	C6—C7—H7	122.0
C7—C2—C3	122.57 (11)	O4—C8—O3	122.31 (11)
O1—C2—C3	115.05 (10)	O4—C8—C9	127.77 (11)
C2—C3—C4	120.37 (11)	O3—C8—C9	109.92 (10)
C2—C3—S1	110.57 (9)	C8—C9—H9A	109.5
C4—C3—S1	128.97 (9)	C8—C9—H9B	109.5
C3—C4—C5	118.37 (11)	H9A—C9—H9B	109.5
C3—C4—H4	120.8	C8—C9—H9C	109.5
C5—C4—H4	120.8	H9A—C9—H9C	109.5
C6—C5—C4	119.62 (11)	H9B—C9—H9C	109.5
C6—C5—H5	120.2	C2—O1—C1	112.32 (9)
C4—C5—H5	120.2	C8—O3—C6	118.24 (9)
C5—C6—C7	123.14 (11)	C3—S1—C1	90.43 (6)
C5—C6—O3	117.42 (10)
C7—C2—C3—C4	0.48 (18)	C7—C2—O1—C1	174.88 (10)
O1—C2—C3—C4	177.81 (10)	C3—C2—O1—C1	−2.46 (14)
C7—C2—C3—S1	−176.35 (9)	O2—C1—O1—C2	−177.20 (11)
O1—C2—C3—S1	0.98 (13)	S1—C1—O1—C2	2.77 (12)
C2—C3—C4—C5	−0.77 (18)	O4—C8—O3—C6	2.67 (17)
S1—C3—C4—C5	175.41 (9)	C9—C8—O3—C6	−177.05 (10)
C3—C4—C5—C6	−0.02 (17)	C5—C6—O3—C8	−111.17 (12)
C4—C5—C6—C7	1.17 (18)	C7—C6—O3—C8	75.10 (14)
C4—C5—C6—O3	−172.28 (10)	C2—C3—S1—C1	0.52 (9)
O1—C2—C7—C6	−176.54 (10)	C4—C3—S1—C1	−175.96 (12)
C3—C2—C7—C6	0.60 (17)	O2—C1—S1—C3	178.09 (12)
C5—C6—C7—C2	−1.43 (17)	O1—C1—S1—C3	−1.88 (9)
O3—C6—C7—C2	171.91 (10)

2-Oxo-1,3-benzoxathiol-6-yl acetate (II). Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···O4i	0.95	2.35	3.2606 (15)	159
C9—H9C···O2ii	0.98	2.50	3.4030 (16)	153

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