Ethyl cis-3-(2-methoxy­phenyl)-1-4-thia­zine-2-carboxyl­ate 1,1-dioxide at 150 K

The thia­zine ring in the title compound, C₁₄H₁₉NO₅S, adopts a slightly distorted chair conformation. The substituents, viz. the ethoxy­carbonyl and methoxy­phenyl groups, are located cis to one another. In the crystal structure, the inversion-related mol­ecules exist as C—H...O hydrogen-bonded dimers, and these are linked by N—H...O and C—H...O interactions to form layers parallel to the ac plane.

Key indicators

• Single-crystal X-ray study
• T = 150 K
• R factor = 0.032
• wR factor = 0.100
• Data-to-parameter ratio = 15.9

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S1. Comment

Thiazines are heterocylces having a sulfur, a nitrogen and two double bonds. Because of their various biological applications [for example, as antitumour, antiviral (Shehata et al., 1996), bactericidal, parasiticidal (Boulton & Mckillop, 1984) and antituberculotic agents (Bukowski, 2001), as antipileptics, tranquilizers, sedatives, cardiovascular agents (Yamamoto et al., 2000), herbicide antidotes (Foery et al., 1986), antihypertensives (Faull, 1996) and anaesthetics (Bojar et al., 1987), and in gastric ulceration studies (Tozkoparan et al., 2002)] thiazine derivatives have attracted considerable interest. Studies of heterocycles report potent cerebral protectant and calcium antagonist activities (Erker, 1998) of the substituted 1,4-thiazine derivatives. They also show inhibitory activity on the central nervous system (Grandolini et al., 1997; Malinka et al., 2002). Since the structural data on thiazines are limited, X-ray crystallographic studies on a series of thiazine derivatives have been undertaken. We report here the crystal and molecular structure of the title thiazine derivative, (I).

The torsion angles (Table 1) indicate that the thiazine ring in (I) adopts a slightly distorted chair conformation. The ethoxycarbonyl and 2-methoxyphenyl groups are located cis to one another. This relative configuration of the groups is probably fixed during the formation of the six-membered ring of (I) from the acyclic starting material during the cyclization step, in order to minimize the steric and/or electronic interactions. The methoxyphenyl substituent adopts an equatorial position and the ethoxycarbonyl substituent adopts an axial position. The other chair conformation, which could arise from ring flipping, with equatorial ethoxycarbonyl and axial o-methoxyphenyl groups, is not preferred by the molecules, presumably because of the larger steric requirements of the methoxyphenyl ring than the ethoxycarbonyl group.

The C—S bond lengths of 1.7874 (14) and 1.7676 (15) Å in the present structure are comparable to the corresponding distances of 1.793 (3) and 1.798 (3) Å in methyl 6-benzoyl-3,5-diphenyl-1,4-thiazine-2-carboxylate- 1,1-dioxide (Krishnaiah & Jagadeesh Kumar, 1995) and 1.795 (3) and 1.795 (2) Å in thiazine-3-one (Ramasubbu et al., 1988). The C—C and C—N distances agree with the standard expected values, except for a slight deviation in the C1—C2 bond, which can be attributed to the effect of the bulky substituents at these C atoms of the thiazine ring. The C9—C8—C13 bond angle [118.6 (1)°] deviates slightly from the usual value of 120°, which may be due to the fact that atom C8 is attached directly to the thiazine ring and may experience some steric effect.

In the crystal, the inversion-related molecules are linked by C7—H7A···O3ⁱ hydrogen bonds to form centrosymmetric dimers, and the dimers are linked by N1—H1N···O1ⁱⁱ and C9—H9···O1ⁱⁱ interactions to form molecular chains along the c axis. Adjacent chains are linked along the a axis via C14—H14A···O2ⁱⁱⁱ hydrogen bonds to form layers parallel to the ac plane (Fig. 2).

S2. Experimental

A mixture of diethyl ethane-1,2-disulfonylacetate (6.6 g), o-methoxybenzaldehyde (5.6 ml) and ammonium acetate (1.6 g) in ethanol (100 ml) was heated under reflux for 20 h. The excess of solvent was removed by distillation and the mixture was kept overnight. The separated solid was filtered off, washed with water and dried. The product upon crystallization from ethanol afforded (I) as colourless single crystals in the form of transparent plates (yield 15%; m.p. 416–418 K).

S3. Refinement

Atom H1N was found in a difference Fourier map and its positional parameters and U_iso value were refined. All other H atoms were placed in calculated positions and allowed to ride on their parent C atoms, with C—H distances in the range 0.94–0.98 Å; the U_iso(H) values were set equal to 1.5U_eq(parent atom) for the methyl H atoms and 1.2U_eq(parent atom) for the other atoms. A rotating group model was used for the methyl groups.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SMART; data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The structure of the molecule of (I), showing the atom-numbering scheme. Displacement ellipsoids are shown at the 50% probability level.
	Fig. 2. The molecular packing in (I), viewed along the c axis.

Ethyl cis-3-(2-methoxyphenyl)-1–4-thiazine-2-carboxylate 1,1-dioxide

Crystal data

C14H19NO5S	F(000) = 1328
Mr = 313.37	Dx = 1.363 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 1024 reflections
a = 25.706 (5) Å	θ = 1.6–26.4°
b = 9.7180 (19) Å	µ = 0.23 mm^−1
c = 12.245 (2) Å	T = 150 K
β = 93.44 (3)°	Plate, colourless
V = 3053.4 (10) Å^3	0.48 × 0.40 × 0.14 mm
Z = 8

Data collection

Bruker SMART CCD diffractometer	3132 independent reflections
Radiation source: fine-focus sealed tube	2870 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
Detector resolution: 8 pixels mm^-1	θmax = 26.4°, θmin = 1.6°
ω scans	h = −32→32
Absorption correction: multi-scan (SADABS; Bruker, 1998)	k = −12→12
Tmin = 0.90, Tmax = 0.97	l = −15→15
15899 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.032	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.100	w = 1/[σ^2(Fo^2) + (0.0555P)^2 + 2.1671P] where P = (Fo^2 + 2Fc^2)/3
S = 1.15	(Δ/σ)max < 0.001
3132 reflections	Δρmax = 0.42 e Å^−3
197 parameters	Δρmin = −0.27 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0092 (6)

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
S	0.322714 (12)	0.14726 (3)	0.23218 (3)	0.01968 (13)
O1	0.35941 (4)	0.11629 (11)	0.15045 (8)	0.0267 (2)
O2	0.27908 (4)	0.23532 (11)	0.20095 (9)	0.0288 (3)
O3	0.41381 (4)	0.04073 (12)	0.39844 (11)	0.0357 (3)
O4	0.44836 (4)	0.24755 (12)	0.36081 (9)	0.0286 (3)
O5	0.33309 (4)	0.50833 (10)	0.44500 (8)	0.0243 (2)
N1	0.30418 (5)	0.09722 (13)	0.48119 (10)	0.0236 (3)
H1N	0.3298 (8)	0.043 (2)	0.5029 (15)	0.029 (5)*
C1	0.35721 (5)	0.22912 (13)	0.34544 (10)	0.0175 (3)
H1	0.3640	0.3247	0.3249	0.021*
C2	0.32297 (5)	0.23077 (14)	0.44831 (11)	0.0191 (3)
H2	0.2923	0.2877	0.4293	0.023*
C3	0.27169 (6)	0.02871 (15)	0.39572 (12)	0.0267 (3)
H3A	0.2419	0.0870	0.3764	0.032*
H3B	0.2586	−0.0562	0.4253	0.032*
C4	0.29924 (6)	−0.00532 (15)	0.29055 (12)	0.0252 (3)
H4A	0.2750	−0.0506	0.2385	0.030*
H4B	0.3281	−0.0676	0.3077	0.030*
C5	0.40920 (5)	0.15926 (15)	0.37093 (11)	0.0218 (3)
C6	0.50085 (6)	0.1969 (2)	0.39315 (15)	0.0386 (4)
H6A	0.5261	0.2414	0.3491	0.046*
H6B	0.5025	0.0986	0.3802	0.046*
C7	0.51395 (7)	0.2258 (2)	0.51068 (16)	0.0466 (5)
H7A	0.5483	0.1921	0.5306	0.070*
H7B	0.4892	0.1807	0.5543	0.070*
H7C	0.5128	0.3232	0.5232	0.070*
C8	0.35455 (5)	0.30447 (14)	0.53943 (11)	0.0201 (3)
C9	0.38086 (6)	0.23571 (16)	0.62550 (11)	0.0258 (3)
H9	0.37817	0.136	0.63040	0.031*
C10	0.41106 (6)	0.30728 (18)	0.70496 (12)	0.0312 (3)
H10	0.4293	0.2584	0.7636	0.037*
C11	0.41468 (6)	0.44924 (17)	0.69896 (12)	0.0311 (3)
H11	0.4349	0.4977	0.7531	0.037*
C12	0.38872 (6)	0.52107 (16)	0.61361 (12)	0.0263 (3)
H12	0.39115	0.618	0.61002	0.032*
C13	0.35913 (5)	0.44876 (15)	0.53350 (11)	0.0208 (3)
C14	0.33272 (6)	0.65548 (15)	0.43815 (13)	0.0281 (3)
H14A	0.3132	0.6835	0.3726	0.042*
H14B	0.3678	0.6886	0.4367	0.042*
H14C	0.3168	0.6929	0.5006	0.042*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S	0.0228 (2)	0.0165 (2)	0.0195 (2)	−0.00136 (12)	−0.00074 (13)	−0.00127 (11)
O1	0.0362 (6)	0.0230 (5)	0.0213 (5)	−0.0020 (4)	0.0058 (4)	−0.0030 (4)
O2	0.0282 (5)	0.0260 (5)	0.0310 (6)	0.0016 (4)	−0.0085 (4)	−0.0006 (4)
O3	0.0278 (6)	0.0274 (6)	0.0520 (7)	0.0069 (4)	0.0021 (5)	0.0073 (5)
O4	0.0177 (5)	0.0374 (6)	0.0304 (6)	−0.0038 (4)	−0.0001 (4)	0.0033 (4)
O5	0.0303 (5)	0.0176 (5)	0.0242 (5)	0.0000 (4)	−0.0036 (4)	−0.0005 (4)
N1	0.0250 (6)	0.0203 (6)	0.0260 (6)	−0.0034 (5)	0.0053 (5)	0.0020 (5)
C1	0.0189 (6)	0.0162 (6)	0.0174 (6)	−0.0015 (5)	0.0013 (5)	0.0006 (5)
C2	0.0196 (6)	0.0176 (6)	0.0203 (6)	0.0002 (5)	0.0036 (5)	0.0004 (5)
C3	0.0245 (7)	0.0230 (7)	0.0332 (8)	−0.0075 (5)	0.0072 (6)	−0.0022 (6)
C4	0.0285 (7)	0.0176 (7)	0.0297 (7)	−0.0054 (5)	0.0036 (6)	−0.0022 (5)
C5	0.0203 (7)	0.0271 (7)	0.0182 (6)	0.0011 (5)	0.0025 (5)	0.0000 (5)
C6	0.0167 (7)	0.0545 (11)	0.0446 (10)	0.0000 (7)	0.0007 (6)	−0.0005 (8)
C7	0.0304 (9)	0.0681 (13)	0.0401 (10)	0.0037 (8)	−0.0071 (7)	0.0084 (9)
C8	0.0212 (6)	0.0213 (7)	0.0183 (6)	−0.0005 (5)	0.0060 (5)	−0.0018 (5)
C9	0.0329 (8)	0.0254 (7)	0.0194 (7)	0.0019 (6)	0.0041 (6)	0.0018 (5)
C10	0.0381 (8)	0.0367 (9)	0.0185 (7)	0.0048 (7)	−0.0015 (6)	0.0015 (6)
C11	0.0341 (8)	0.0362 (9)	0.0225 (7)	0.0002 (7)	−0.0033 (6)	−0.0087 (6)
C12	0.0295 (7)	0.0241 (7)	0.0254 (7)	−0.0007 (6)	0.0024 (6)	−0.0056 (6)
C13	0.0211 (6)	0.0228 (7)	0.0189 (6)	0.0008 (5)	0.0034 (5)	−0.0007 (5)
C14	0.0322 (8)	0.0182 (7)	0.0332 (8)	−0.0004 (5)	−0.0033 (6)	0.0020 (6)

Geometric parameters (Å, º)

S—O2	1.4440 (11)	C4—H4B	0.97
S—O1	1.4476 (11)	C6—C7	1.485 (3)
S—C4	1.7678 (15)	C6—H6A	0.97
S—C1	1.7874 (14)	C6—H6B	0.97
O3—C5	1.2039 (19)	C7—H7A	0.96
O4—C5	1.3341 (18)	C7—H7B	0.96
O4—C6	1.4682 (18)	C7—H7C	0.96
O5—C13	1.3677 (17)	C8—C9	1.389 (2)
O5—C14	1.4325 (17)	C8—C13	1.409 (2)
N1—C2	1.4501 (17)	C9—C10	1.394 (2)
N1—C3	1.4599 (19)	C9—H9	0.97
N1—H1N	0.87 (2)	C10—C11	1.385 (2)
C1—C5	1.5146 (18)	C10—H10	0.96
C1—C2	1.5796 (18)	C11—C12	1.393 (2)
C1—H1	0.98	C11—H11	0.94
C2—C8	1.5194 (19)	C12—C13	1.395 (2)
C2—H2	0.98	C12—H12	0.95
C3—C4	1.542 (2)	C14—H14A	0.96
C3—H3A	0.97	C14—H14B	0.96
C3—H3B	0.97	C14—H14C	0.96
C4—H4A	0.97
O2—S—O1	117.92 (7)	O4—C5—C1	110.73 (12)
O2—S—C4	109.00 (7)	O4—C6—C7	110.43 (14)
O1—S—C4	110.95 (7)	O4—C6—H6A	109.6
O2—S—C1	106.44 (6)	C7—C6—H6A	109.6
O1—S—C1	108.38 (6)	O4—C6—H6B	109.6
C4—S—C1	103.01 (7)	C7—C6—H6B	109.6
C5—O4—C6	116.47 (13)	H6A—C6—H6B	108.1
C13—O5—C14	118.04 (11)	C6—C7—H7A	109.5
C2—N1—C3	113.26 (11)	C6—C7—H7B	109.5
C2—N1—H1N	111.3 (13)	H7A—C7—H7B	109.5
C3—N1—H1N	109.6 (13)	C6—C7—H7C	109.5
C5—C1—C2	111.56 (11)	H7A—C7—H7C	109.5
C5—C1—S	110.54 (9)	H7B—C7—H7C	109.5
C2—C1—S	110.42 (9)	C9—C8—C13	118.65 (13)
C5—C1—H1	108.1	C9—C8—C2	123.01 (13)
C2—C1—H1	108.1	C13—C8—C2	118.28 (12)
S—C1—H1	108.1	C8—C9—C10	121.00 (14)
N1—C2—C8	112.97 (11)	C8—C9—H9	119.5
N1—C2—C1	115.03 (11)	C10—C9—H9	119.5
C8—C2—C1	106.95 (10)	C11—C10—C9	119.77 (14)
N1—C2—H2	107.2	C11—C10—H10	120.1
C8—C2—H2	107.2	C9—C10—H10	120.1
C1—C2—H2	107.2	C10—C11—C12	120.54 (14)
N1—C3—C4	115.13 (12)	C10—C11—H11	119.7
N1—C3—H3A	108.5	C12—C11—H11	119.7
C4—C3—H3A	108.5	C11—C12—C13	119.45 (14)
N1—C3—H3B	108.5	C11—C12—H12	120.3
C4—C3—H3B	108.5	C13—C12—H12	120.3
H3A—C3—H3B	107.5	O5—C13—C12	124.36 (13)
C3—C4—S	110.04 (10)	O5—C13—C8	115.06 (12)
C3—C4—H4A	109.7	C12—C13—C8	120.58 (13)
S—C4—H4A	109.7	O5—C14—H14A	109.5
C3—C4—H4B	109.7	O5—C14—H14B	109.5
S—C4—H4B	109.7	H14A—C14—H14B	109.5
H4A—C4—H4B	108.2	O5—C14—H14C	109.5
O3—C5—O4	125.39 (13)	H14A—C14—H14C	109.5
O3—C5—C1	123.87 (13)	H14B—C14—H14C	109.5
O2—S—C1—C5	−169.33 (9)	C2—C1—C5—O4	−117.18 (12)
O1—S—C1—C5	−41.56 (11)	S—C1—C5—O4	119.55 (11)
C4—S—C1—C5	76.06 (10)	C5—O4—C6—C7	−90.30 (19)
O2—S—C1—C2	66.75 (10)	N1—C2—C8—C9	25.17 (18)
O1—S—C1—C2	−165.48 (9)	C1—C2—C8—C9	−102.39 (14)
C4—S—C1—C2	−47.87 (10)	N1—C2—C8—C13	−157.68 (12)
C3—N1—C2—C8	177.20 (11)	C1—C2—C8—C13	74.76 (14)
C3—N1—C2—C1	−59.62 (15)	C13—C8—C9—C10	0.3 (2)
C5—C1—C2—N1	−68.46 (15)	C2—C8—C9—C10	177.43 (13)
S—C1—C2—N1	54.88 (13)	C8—C9—C10—C11	0.6 (2)
C5—C1—C2—C8	57.88 (14)	C9—C10—C11—C12	−0.5 (2)
S—C1—C2—C8	−178.78 (9)	C10—C11—C12—C13	−0.3 (2)
C2—N1—C3—C4	62.44 (16)	C14—O5—C13—C12	−5.0 (2)
N1—C3—C4—S	−59.42 (15)	C14—O5—C13—C8	175.29 (12)
O2—S—C4—C3	−62.81 (12)	C11—C12—C13—O5	−178.44 (13)
O1—S—C4—C3	165.73 (10)	C11—C12—C13—C8	1.2 (2)
C1—S—C4—C3	49.94 (12)	C9—C8—C13—O5	178.50 (12)
C6—O4—C5—O3	−4.2 (2)	C2—C8—C13—O5	1.23 (17)
C6—O4—C5—C1	174.45 (12)	C9—C8—C13—C12	−1.2 (2)
C2—C1—C5—O3	61.54 (18)	C2—C8—C13—C12	−178.45 (12)
S—C1—C5—O3	−61.73 (16)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7A···O3^i	0.96	2.59	3.339 (2)	135
N1—H1N···O1^ii	0.87 (2)	2.47 (2)	3.204 (2)	142 (2)
C9—H9···O1^ii	0.97	2.51	3.481 (2)	173
C14—H14A···O2^iii	0.96	2.54	3.343 (2)	142
C1—H1···O5	0.98	2.47	3.054 (2)	118

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