organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
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ISSN: 2056-9890
Volume 65| Part 10| October 2009| Pages o2358-o2359

2-(3-Oxo-3,4-di­hydro-2H-1,4-benzo­thia­zin-4-yl)acetic acid monohydrate

aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and bDepartment of Studies in Chemistry, Mangalore University, Mangalagangothri, Mangalore 574 199, India
*Correspondence e-mail: hkfun@usm.my

(Received 29 August 2009; accepted 31 August 2009; online 5 September 2009)

In the title compound, C10H9NO3S·H2O, the thio­morpholine ring exists in a conformation inter­mediate between twist-boat and half-chair. An inter­molecular O—H⋯O hydrogen bond links the acid and water mol­ecules together. In the crystal packing, inter­molecular O—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network.

Related literature

For the biological activity of 4H-benzo(1,4)thia­zine, see: Armenise et al. (1991[Armenise, D., Trapani, G., Arrivo, V. & Morlacchi, F. (1991). Farmaco. 46, 1023-1032.]); Gupta et al. (1993[Gupta, R. R., Dev, P. K., Sharma, M. L., Rajoria, C. M., Gupta, A. & Nyati, M. (1993). Anti-Ca. Drugs. 4, 589-592.]); Fringuelli et al. (2005[Fringuelli, R., Milanese, L. & Schiaffella, F. (2005). Mini-Rev. Med. Chem. 5, 1061-1073(13).]). For medical applications of sulfone derivatives of 4H-benzo(1,4)thia­zine, see: Shinji & Koshiro (1995[Shinji, S. & Koshiro, A. (1995). Biol. Pharm. Bull. 18, 586-594.]); Szule et al. (1988[Szule, Z., Mlochow, J. & Palus, J. (1988). J. Prakt. Chem. 330, 1023-1028.]); Culbertson (1991[Culbertson, T. P. (1991). J. Heterocycl. Chem. 28, 1701-1708.]). For a related structure, see: Zhang et al. (2008[Zhang, P., Du, N., Wang, L.-Z. & Li, Y. (2008). Acta Cryst. E64, o746.]). For bond-length data, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]). For ring puckering parameters, see: Cremer & Pople (1975[Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.]). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986[Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105-107.]).

[Scheme 1]

Experimental

Crystal data
  • C10H9NO3S·H2O

  • Mr = 241.26

  • Monoclinic, P 21 /c

  • a = 7.5897 (1) Å

  • b = 9.2208 (2) Å

  • c = 15.6701 (3) Å

  • β = 94.336 (1)°

  • V = 1093.50 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.29 mm−1

  • T = 100 K

  • 0.49 × 0.34 × 0.11 mm

Data collection
  • Bruker SMART APEXII CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.870, Tmax = 0.969

  • 25955 measured reflections

  • 4859 independent reflections

  • 3833 reflections with I > 2σ(I)

  • Rint = 0.036

Refinement
  • R[F2 > 2σ(F2)] = 0.040

  • wR(F2) = 0.128

  • S = 0.83

  • 4859 reflections

  • 157 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.54 e Å−3

  • Δρmin = −0.26 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O2—H1O2⋯O1Wi 0.93 (2) 1.62 (2) 2.5384 (13) 168 (3)
O1W—H2W1⋯O3ii 0.85 (2) 1.96 (2) 2.7893 (13) 168 (2)
O1W—H1W1⋯O1 0.90 (2) 1.85 (2) 2.7221 (13) 163.4 (19)
C2—H2A⋯O1Wiii 0.93 2.51 3.3666 (15) 153
C9—H9A⋯O2iv 0.97 2.58 3.4429 (14) 149
Symmetry codes: (i) x+1, y, z; (ii) [-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (iii) x, y-1, z; (iv) -x+2, -y+1, -z+1.

Data collection: APEX2 (Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

A number of molecules containing the 4H-benzo(1,4)thiazine nucleus in their structures exhibit a broad spectrum of biological activity, including antibacterial (Armenise et al., 1991), anticancer (Gupta et al., 1993), anti-rheumatic, anti-allergic, vasorelaxant, anti-arrhythmic and anti-hypertensive (Fringuelli et al., 2005) properties. The sulfone derivatives of 4H-benzo(1,4)thiazine have been reported to find a number of applications in medicine (Shinji & Koshiro, 1995; Szule et al., 1988; Culbertson, 1991). On the basis of these considerations, our particular attention was paid to the preparation of derivatives of (3-oxo-3,4-dihydro-2H-1,4-benzothiazin-4-yl)acetic acid and we report here the structure of the title 4-benzothiazine derivative.

The asymmetric unit of the title compound (Fig. 1), contains one (3-oxo-3,4-dihydro-2H-1,4-benzothiazin-4-yl)acetic acid and one water molecule. The bond lengths (Allen et al., 1987) and angles in the molecule are within normal ranges. The thiomorpholine ring (C1/C6–C8/N1/S1) exists in a conformation intermediate between twist-boat and half-chair and it is comparable to a closely related structure (Zhang et al., 2008). The puckering parameters (Cremer & Pople, 1975) are Q = 0.6852 (9) Å; Θ = 112.69 (8)° and ϕ = 152.79 (10)°. An intermolecular O1W1—H1W1···O1 hydrogen bond links the acid and water molecules together. In the crystal packing (Fig. 2), intermolecular O2—H1O2···O1W, O1W—H2W1···O3, C2—H2A···O1W and C9—H10A···O2 hydrogen bonds (Table 1) link the molecules into three-dimensional network.

Related literature top

For the biological activity of 4H-benzo(1,4)thiazine, see: Armenise et al. (1991); Gupta et al. (1993); Fringuelli et al. (2005). For medical applications of sulfone derivatives of 4H-benzo(1,4)thiazine, see: Shinji & Koshiro (1995); Szule et al. (1988); Culbertson (1991). For a related structure, see: Zhang et al. (2008). For bond-length data, see: Allen et al. (1987). For ring puckering parameters, see: Cremer & Pople (1975). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986).

Experimental top

A solution of potassium hydroxide (5.85 mmol) in water (10 ml) was added to the solution of ethyl (3-oxo-3,4-dihydro-2H-1,4-benzothiazin-4-yl)acetate (3.9 mmol) in ethanol (10 ml). The resulting reaction mixture was stirred at room temperature for 24 h and the reaction completion was checked by TLC. The reaction mixture was poured into water and acidified with 4 M HCl to form (3-oxo-3,4-dihydro-2H-1,4-benzothiazin-4-yl)acetic acid as colourless solid. Single crystals suitable for X-ray analysis were obtained by crystallization from dichloromethane under slow evaporation (M.p. 338 K).

Refinement top

Atom H1O2, H1W1 and H2W1 were located in a difference map and were refined freely. Other H atoms were positioned geometrically [C—H = 0.93 or 0.97 Å] and were refined using a riding model, with Uiso(H) = 1.2 Ueq(C).

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom numbering scheme. The hydrogen bond is drawn as a dashed line.
[Figure 2] Fig. 2. The crystal packing of the title compound, viewed along b axis. Intermolecular hydrogen bonds are shown by dashed lines.
2-(3-Oxo-3,4-dihydro-2H-1,4-benzothiazin-4-yl)acetic acid monohydrate top
Crystal data top
C10H9NO3S·H2OF(000) = 504
Mr = 241.26Dx = 1.465 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 7672 reflections
a = 7.5897 (1) Åθ = 3.4–33.1°
b = 9.2208 (2) ŵ = 0.29 mm1
c = 15.6701 (3) ÅT = 100 K
β = 94.336 (1)°Block, colourless
V = 1093.50 (3) Å30.49 × 0.34 × 0.11 mm
Z = 4
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
4859 independent reflections
Radiation source: fine-focus sealed tube3833 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.036
ϕ and ω scansθmax = 35.1°, θmin = 2.6°
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
h = 1212
Tmin = 0.870, Tmax = 0.969k = 1413
25955 measured reflectionsl = 2325
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.128H atoms treated by a mixture of independent and constrained refinement
S = 0.83 w = 1/[σ2(Fo2) + (0.0915P)2 + 0.3956P]
where P = (Fo2 + 2Fc2)/3
4859 reflections(Δ/σ)max = 0.001?
157 parametersΔρmax = 0.54 e Å3
0 restraintsΔρmin = 0.26 e Å3
Crystal data top
C10H9NO3S·H2OV = 1093.50 (3) Å3
Mr = 241.26Z = 4
Monoclinic, P21/cMo Kα radiation
a = 7.5897 (1) ŵ = 0.29 mm1
b = 9.2208 (2) ÅT = 100 K
c = 15.6701 (3) Å0.49 × 0.34 × 0.11 mm
β = 94.336 (1)°
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
4859 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
3833 reflections with I > 2σ(I)
Tmin = 0.870, Tmax = 0.969Rint = 0.036
25955 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0400 restraints
wR(F2) = 0.128H atoms treated by a mixture of independent and constrained refinement
S = 0.83Δρmax = 0.54 e Å3
4859 reflectionsΔρmin = 0.26 e Å3
157 parameters
Special details top

Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

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 (Å2) top
xyzUiso*/Ueq
S10.25290 (3)0.20298 (3)0.368735 (18)0.02391 (8)
O1W0.17478 (12)0.72939 (10)0.31220 (6)0.02515 (17)
O10.47141 (12)0.56427 (9)0.33767 (6)0.02699 (18)
O20.94362 (11)0.62615 (9)0.40417 (6)0.02360 (16)
O30.90204 (12)0.44113 (9)0.31220 (6)0.02548 (17)
C10.46033 (14)0.11958 (11)0.38793 (6)0.01900 (18)
C20.47444 (16)0.03074 (12)0.39590 (7)0.0233 (2)
H2A0.37330.08790.39000.028*
C30.63845 (17)0.09543 (12)0.41263 (7)0.0247 (2)
H3A0.64690.19550.41930.030*
C40.78984 (16)0.01067 (12)0.41946 (7)0.0246 (2)
H4A0.89990.05440.42960.030*
C50.77815 (14)0.13934 (12)0.41127 (7)0.02197 (19)
H5A0.88010.19560.41560.026*
C60.61270 (13)0.20523 (11)0.39649 (6)0.01770 (17)
N10.59863 (11)0.35987 (9)0.39215 (6)0.01904 (16)
C70.46962 (14)0.43038 (12)0.34290 (7)0.02067 (19)
C80.32911 (14)0.33868 (13)0.29697 (7)0.0234 (2)
H8A0.37640.29180.24820.028*
H8B0.23090.39950.27600.028*
C90.73286 (14)0.45083 (11)0.43631 (7)0.02047 (18)
H9A0.79340.39590.48250.025*
H9B0.67640.53330.46130.025*
C100.86713 (13)0.50482 (11)0.37642 (7)0.01941 (18)
H1O21.028 (3)0.652 (3)0.3672 (15)0.064 (7)*
H2W10.155 (3)0.784 (2)0.2691 (15)0.056 (6)*
H1W10.270 (3)0.672 (2)0.3095 (13)0.043 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.01398 (12)0.03081 (15)0.02713 (14)0.00430 (9)0.00291 (9)0.00246 (9)
O1W0.0185 (4)0.0229 (4)0.0340 (4)0.0004 (3)0.0017 (3)0.0072 (3)
O10.0224 (4)0.0214 (4)0.0371 (5)0.0033 (3)0.0020 (3)0.0071 (3)
O20.0222 (4)0.0184 (3)0.0304 (4)0.0051 (3)0.0030 (3)0.0026 (3)
O30.0231 (4)0.0232 (4)0.0306 (4)0.0046 (3)0.0049 (3)0.0046 (3)
C10.0179 (4)0.0209 (4)0.0184 (4)0.0039 (3)0.0028 (3)0.0002 (3)
C20.0279 (5)0.0217 (5)0.0208 (4)0.0064 (4)0.0046 (4)0.0016 (3)
C30.0358 (6)0.0175 (4)0.0211 (4)0.0004 (4)0.0050 (4)0.0006 (3)
C40.0264 (5)0.0226 (5)0.0251 (5)0.0052 (4)0.0030 (4)0.0020 (4)
C50.0169 (4)0.0206 (4)0.0284 (5)0.0016 (3)0.0019 (3)0.0028 (4)
C60.0162 (4)0.0169 (4)0.0201 (4)0.0009 (3)0.0022 (3)0.0013 (3)
N10.0136 (3)0.0176 (4)0.0256 (4)0.0004 (3)0.0006 (3)0.0029 (3)
C70.0150 (4)0.0233 (5)0.0239 (4)0.0020 (3)0.0027 (3)0.0048 (3)
C80.0169 (4)0.0296 (5)0.0233 (5)0.0003 (4)0.0008 (3)0.0047 (4)
C90.0172 (4)0.0196 (4)0.0243 (4)0.0020 (3)0.0001 (3)0.0002 (3)
C100.0147 (4)0.0169 (4)0.0262 (5)0.0000 (3)0.0009 (3)0.0000 (3)
Geometric parameters (Å, º) top
S1—C11.7575 (11)C4—C51.3914 (16)
S1—C81.8064 (12)C4—H4A0.9300
O1W—H2W10.85 (2)C5—C61.3984 (15)
O1W—H1W10.90 (2)C5—H5A0.9300
O1—C71.2374 (13)C6—N11.4311 (13)
O2—C101.3189 (13)N1—C71.3648 (13)
O2—H1O20.93 (3)N1—C91.4539 (13)
O3—C101.2116 (14)C7—C81.5014 (16)
C1—C21.3951 (15)C8—H8A0.9700
C1—C61.3985 (14)C8—H8B0.9700
C2—C31.3873 (17)C9—C101.5205 (16)
C2—H2A0.9300C9—H9A0.9700
C3—C41.3871 (17)C9—H9B0.9700
C3—H3A0.9300
C1—S1—C894.86 (5)C7—N1—C6123.32 (9)
H2W1—O1W—H1W1114 (2)C7—N1—C9116.19 (8)
C10—O2—H1O2108.8 (14)C6—N1—C9120.33 (8)
C2—C1—C6119.68 (10)O1—C7—N1120.11 (10)
C2—C1—S1120.78 (8)O1—C7—C8122.76 (10)
C6—C1—S1119.53 (8)N1—C7—C8117.12 (9)
C3—C2—C1120.38 (10)C7—C8—S1109.94 (7)
C3—C2—H2A119.8C7—C8—H8A109.7
C1—C2—H2A119.8S1—C8—H8A109.7
C4—C3—C2119.90 (10)C7—C8—H8B109.7
C4—C3—H3A120.0S1—C8—H8B109.7
C2—C3—H3A120.0H8A—C8—H8B108.2
C3—C4—C5120.42 (11)N1—C9—C10111.92 (9)
C3—C4—H4A119.8N1—C9—H9A109.2
C5—C4—H4A119.8C10—C9—H9A109.2
C4—C5—C6119.83 (10)N1—C9—H9B109.2
C4—C5—H5A120.1C10—C9—H9B109.2
C6—C5—H5A120.1H9A—C9—H9B107.9
C1—C6—C5119.75 (9)O3—C10—O2124.51 (10)
C1—C6—N1119.99 (9)O3—C10—C9123.56 (9)
C5—C6—N1120.24 (9)O2—C10—C9111.90 (9)
C8—S1—C1—C2142.00 (9)C5—C6—N1—C7149.31 (11)
C8—S1—C1—C638.91 (9)C1—C6—N1—C9152.60 (10)
C6—C1—C2—C30.30 (16)C5—C6—N1—C925.91 (14)
S1—C1—C2—C3178.80 (8)C6—N1—C7—O1175.33 (10)
C1—C2—C3—C41.55 (16)C9—N1—C7—O10.07 (15)
C2—C3—C4—C51.24 (17)C6—N1—C7—C84.85 (15)
C3—C4—C5—C60.33 (17)C9—N1—C7—C8179.75 (9)
C2—C1—C6—C51.27 (15)O1—C7—C8—S1134.43 (10)
S1—C1—C6—C5179.63 (8)N1—C7—C8—S145.39 (12)
C2—C1—C6—N1177.25 (9)C1—S1—C8—C760.65 (8)
S1—C1—C6—N11.86 (13)C7—N1—C9—C1077.23 (12)
C4—C5—C6—C11.58 (16)C6—N1—C9—C1098.32 (11)
C4—C5—C6—N1176.93 (10)N1—C9—C10—O326.48 (14)
C1—C6—N1—C732.18 (15)N1—C9—C10—O2155.33 (9)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H1O2···O1Wi0.93 (2)1.62 (2)2.5384 (13)168 (3)
O1W—H2W1···O3ii0.85 (2)1.96 (2)2.7893 (13)168 (2)
O1W—H1W1···O10.90 (2)1.85 (2)2.7221 (13)163.4 (19)
C2—H2A···O1Wiii0.932.513.3666 (15)153
C9—H9A···O2iv0.972.583.4429 (14)149
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1/2, z+1/2; (iii) x, y1, z; (iv) x+2, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC10H9NO3S·H2O
Mr241.26
Crystal system, space groupMonoclinic, P21/c
Temperature (K)100
a, b, c (Å)7.5897 (1), 9.2208 (2), 15.6701 (3)
β (°) 94.336 (1)
V3)1093.50 (3)
Z4
Radiation typeMo Kα
µ (mm1)0.29
Crystal size (mm)0.49 × 0.34 × 0.11
Data collection
DiffractometerBruker SMART APEXII CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2005)
Tmin, Tmax0.870, 0.969
No. of measured, independent and
observed [I > 2σ(I)] reflections
25955, 4859, 3833
Rint0.036
(sin θ/λ)max1)0.809
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.040, 0.128, 0.83
No. of reflections4859
No. of parameters157
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.54, 0.26

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H1O2···O1Wi0.93 (2)1.62 (2)2.5384 (13)168 (3)
O1W—H2W1···O3ii0.85 (2)1.96 (2)2.7893 (13)168 (2)
O1W—H1W1···O10.90 (2)1.85 (2)2.7221 (13)163.4 (19)
C2—H2A···O1Wiii0.93002.51003.3666 (15)153.00
C9—H9A···O2iv0.97002.58003.4429 (14)149.00
Symmetry codes: (i) x+1, y, z; (ii) x+1, y+1/2, z+1/2; (iii) x, y1, z; (iv) x+2, y+1, z+1.
 

Footnotes

Thomson Reuters ResearcherID: A-3561-2009.

Acknowledgements

HKF thanks Universiti Sains Malaysia (USM) for the Research University Golden Goose Grant (No. 1001/PFIZIK/811012). WSL thanks the Malaysian government and USM for the award of the post of Assistant Research Officer under the Research University Golden Goose Grant (No. 1001/PFIZIK/811012).

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CrossRef Web of Science
First citationArmenise, D., Trapani, G., Arrivo, V. & Morlacchi, F. (1991). Farmaco. 46, 1023–1032.  PubMed CAS Web of Science
First citationBruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationCosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105–107.  CrossRef CAS Web of Science IUCr Journals
First citationCremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358.  CrossRef CAS Web of Science
First citationCulbertson, T. P. (1991). J. Heterocycl. Chem. 28, 1701–1708.  CrossRef CAS
First citationFringuelli, R., Milanese, L. & Schiaffella, F. (2005). Mini-Rev. Med. Chem. 5, 1061–1073(13).  Web of Science CrossRef CAS
First citationGupta, R. R., Dev, P. K., Sharma, M. L., Rajoria, C. M., Gupta, A. & Nyati, M. (1993). Anti-Ca. Drugs. 4, 589–592.  CrossRef CAS
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationShinji, S. & Koshiro, A. (1995). Biol. Pharm. Bull. 18, 586–594.  PubMed Web of Science
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals
First citationSzule, Z., Mlochow, J. & Palus, J. (1988). J. Prakt. Chem. 330, 1023–1028.
First citationZhang, P., Du, N., Wang, L.-Z. & Li, Y. (2008). Acta Cryst. E64, o746.  Web of Science CSD CrossRef IUCr Journals

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Volume 65| Part 10| October 2009| Pages o2358-o2359
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