Issue contents
Download PDF of article
Download CIF
3D view
Navigation
Highlighting
Dictionary of Crystallography reference
IUPAC Gold Book reference
more ...
Download citation
FormatBIBTeX
EndNote
RefMan
Refer
Medline
CIF
SGML
Plain Text
share
Previous article
Next article
Previous article
Issue contents
Download PDF of article
Download CIF
3D view
Navigation
Highlighting
Dictionary of Crystallography reference
IUPAC Gold Book reference
more ...
Download citation
FormatBIBTeX
EndNote
RefMan
Refer
Medline
CIF
SGML
Plain Text
share
Next article

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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 64| Part 3| March 2008| Page o557
doi:10.1107/S1600536808003498

1-Methyl-1H-2,1-benzo­thia­zin-4(3H)-one 2,2-dioxide

M. Nawaz Tahir,a* Muhammad Shafiq,b Islam Ullah Khan,b Waseeq Ahmad Siddiquic and Muhammad Nadeem Arshadb

aUniversity of Sargodha, Department of Physics, Sargodha, Pakistan, bGovernment College University, Department of Chemistry, Lahore, Pakistan, and cUniversity of Sargodha, Department of Chemistry, Sargodha, Pakistan
*Correspondence e-mail: dmntahir_uos@yahoo.com

(Received 13 January 2008; accepted 31 January 2008; online 6 February 2008)

In the crystal structure of the title compound, C9H9NO3S, there is distorted tetra­hedral geometry around the S atom. The sulfonyl group is almost normal to the benzene ring, while the carbonyl O atom and methyl C atom are on opposite sides of this ring. The heterocyclic ring adopts a half-boat conformation with the S atom out of the plane. The mol­ecules are dimerized by hydrogen bonding involving the benzene ring and the sulfonyl group. These dimers are linked to each other in the same way. There is an intra­molecular hydrogen bond between a methyl C—H group and a sulfonyl O atom, and a π–π inter­action between the aromatic rings of two dimers at a centroid-to-centroid distance of 3.6373 (13) Å.

Related literature

For related literature, see: Cremer & Pople (1975[Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.]); Harmata et al. (2004[Harmata, M., Hong, X. & Barnes, C. L. (2004). Org. Lett. 6, 2201-2203.]); Lombardino (1972[Lombardino, J. G. (1972). J. Heterocycl. Chem. 9, 315-317.]); Misu & Togo (2003[Misu, Y. & Togo, H. (2003). Org. Biomol. Chem. 1, 1342-1346.]); Shafiq et al. (2008[Shafiq, M., Tahir, M. N., Khan, I. U., Siddiqui, W. A. & Arshad, M. N. (2008). Acta Cryst. E64, o389.]); Siddiqui et al. (2007[Siddiqui, W. A., Ahmad, S., Siddiqui, H. L., Tariq, M. I. & Parvez, M. (2007). Acta Cryst. E63, o4585.]).

[Scheme 1]

Experimental

Crystal data

  • C9H9NO3S

  • Mr = 211.23

  • Triclinic, [P \overline 1]

  • a = 7.4553 (4) Å

  • b = 8.5437 (4) Å

  • c = 8.7097 (4) Å

  • α = 67.691 (2)°

  • β = 70.467 (2)°

  • γ = 66.327 (2)°

  • V = 459.09 (4) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.33 mm−1

  • T = 296 (2) K

  • 0.20 × 0.15 × 0.10 mm
Data collection

  • Bruker Kappa APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2007[Bruker (2007). APEX2 (Version 1.27), SAINT (Version 7.12a) and SADABS (Version 2004/I). Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.952, Tmax = 0.971

  • 7205 measured reflections

  • 1787 independent reflections

  • 1678 reflections with I > 2σ(I)

  • Rint = 0.019
Refinement

  • R[F2 > 2σ(F2)] = 0.032

  • wR(F2) = 0.095

  • S = 1.09

  • 1678 reflections

  • 127 parameters

  • H-atom parameters constrained

  • Δρmax = 0.22 e Å−3

  • Δρmin = −0.42 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
C2—H2⋯O1i 0.93 2.58 3.432 (2) 152
C4—H4⋯O2ii 0.93 2.46 3.238 (3) 142
C9—H9A⋯O2 0.96 2.31 2.830 (3) 113
Symmetry codes: (i) -x, -y+2, -z+1; (ii) x, y-1, z+1.

Data collection: APEX2 (Bruker, 2007[Bruker (2007). APEX2 (Version 1.27), SAINT (Version 7.12a) and SADABS (Version 2004/I). Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: APEX2; data reduction: SAINT (Bruker, 2007[Bruker (2007). APEX2 (Version 1.27), SAINT (Version 7.12a) and SADABS (Version 2004/I). Bruker AXS Inc., Madison, Wisconsin, USA.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]) and PLATON.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808003498/bq2063sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808003498/bq2063Isup2.hkl

checkCIF report


Comment top

Benzothiazines belong to an important heterocyclic class of compounds which find a number of applications in medicinal chemistry. Derivatives of 2,1-benzothiazines were reported to possess potent biological activities such as lipoxygenase inhibition and are used as drugs for heart diseases (Misu, & Togo, 2003). These are used as intermediate precursors for the preparation of drugs used for curing Tuberculosis (Harmata et al., 2004). The importance of 2,1-benzothiazine derivatives in medicinal chemistry has brought enormous attention to their synthesis. Herein, we report the crystal structure of the title compound.

The structure determination of the title compound (I) is in continuation to our research on derivatives of 2,1 benzothiazine (Shafiq et al., 2008). The structural isomer (II), 2-methyl-2H-1,2-benzothiazin-4(3H)one 1,1-dioxide of (I) has been reported (Siddiqui et al., 2007).

In the title compound the bond distances S1—N1 [1.6429 (13) Å] and S1—C8 [1.7514 (17) Å], have been significantly changed in comparison to 1.629 (3) Å and 1.760 (4) Å respectively as reported in (II). The change in bond angles around S is large enough which is evident from the range [99.47 (8)°-118.32 (8)°] in (I), as compared to (II) [103.05 (16)°- 118.66 (16)°]. All the atoms in heterocyclic thiazine as well as C-atoms of phenyl ring are nearly planer except that of S1. The S1 is displaced by 0.7834 (15) Å from the plane (a) defined by (C1 to C8, N1) and C-atom of methyl group is at a distance of 0.340 (3) Å from it. Thus the atoms of the two rings form a long half boat confirmation. The plane (b) defined by the atoms (O1,S1,O2) makes a dihedral angle of 89.81 (6)° to the plane (a) and hence these two planes are almost normal to each other. The O1-atom is at longest distance of -2.1912 (16) Å from plane (a). In the asymmetric unit there is an intramolecular H-bond as given in Table 2. The confirmation of the hetrocyclic ring in terms of the puckering parameters (Cremer & Pople, 1975) is described by; Q = 0.5767 (14) Å, θ = 54.98 (16)° and ϕ = 359.7 (2)°. The title compound is basically dimerized by H-bonding through C2—H2···O1i (i = -x, -y + 2, -z + 1) as shown in Fig 2. It is interesting that the ring formed in dimer is of twelve bonds to which the methyl groups adopt cis, trans position. The dimers are linked to each other by symmetry code ii = x, y - 1, z + 1. The closest interaction [3.283 (2) Å] occurs between O1···O1iii (symmetry code: iii = -x, -y + 2, -z), other than atoms involved in intermolecular H-bond. There is no X—H···Cg bond, however there exist a π-π interaction between the aromatic rings of two dimers at a distance of 3.6373 (13) Å by the symmetry operation 1 - x, 1 - y, 1 - z.

Related literature top

For related literature, see: Cremer & Pople (1975); Harmata et al. (2004); Lombardino (1972); Misu & Togo (2003); Shafiq et al. (2008); Siddiqui et al. (2007).

Experimental top

The title compound (I) was synthesized using the reported procedure (Lombardino, 1972) and crystals were grown by slow evaporation from a solution of CH3OH at 298 K.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: APEX2 (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: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. ORTEP drawing of the title compound, C10H11NO3S, with the atom numbering scheme. The thermal ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. The packing figure (PLATON: Spek, 2003) which shows the dimeric nature of the compound owing to inter molecular hydrogen bondings and also showing a link between dimers.
1-Methyl-1H-2,1-benzothiazin-4(3H)-one 2,2-dioxide top
Crystal data top
C9H9NO3SZ = 2
Mr = 211.23F(000) = 220
Triclinic, P1Dx = 1.528 Mg m−3
Hall symbol: -P 1Mo Kα radiation radiation, λ = 0.71073 Å
a = 7.4553 (4) ÅCell parameters from 1678 reflections
b = 8.5437 (4) Åθ = 2.6–25.9°
c = 8.7097 (4) ŵ = 0.33 mm−1
α = 67.691 (2)°T = 296 K
β = 70.467 (2)°Prismatic, colourless
γ = 66.327 (2)°0.20 × 0.15 × 0.10 mm
V = 459.09 (4) Å3
Data collection top
Bruker Kappa-APEXII CCD
diffractometer		1787 independent reflections
Radiation source: fine-focus sealed tube1678 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.020
Detector resolution: 7.50 pixels mm-1θmax = 25.9°, θmin = 2.6°
ω scansh = −9→9
Absorption correction: multi-scan
(SADABS; Bruker, 2007)		k = −10→10
Tmin = 0.952, Tmax = 0.971l = −10→10
7205 measured reflections
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)] = 0.032Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.095H-atom parameters constrained
S = 1.09 w = 1/[σ2(Fo2) + (0.0531P)2 + 0.1411P]
where P = (Fo2 + 2Fc2)/3
1678 reflections(Δ/σ)max < 0.001
127 parametersΔρmax = 0.22 e Å−3
0 restraintsΔρmin = −0.42 e Å−3
Crystal data top
C9H9NO3Sγ = 66.327 (2)°
Mr = 211.23V = 459.09 (4) Å3
Triclinic, P1Z = 2
a = 7.4553 (4) ÅMo Kα radiation
b = 8.5437 (4) ŵ = 0.33 mm−1
c = 8.7097 (4) ÅT = 296 K
α = 67.691 (2)°0.20 × 0.15 × 0.10 mm
β = 70.467 (2)°
Data collection top
Bruker Kappa-APEXII CCD
diffractometer		1787 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2007)		1678 reflections with I > 2σ(I)
Tmin = 0.952, Tmax = 0.971Rint = 0.020
7205 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0320 restraints
wR(F2) = 0.095H-atom parameters constrained
S = 1.09Δρmax = 0.22 e Å−3
1678 reflectionsΔρmin = −0.42 e Å−3
127 parameters
Special details top

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
S10.18773 (6)0.94371 (5)0.15987 (5)0.03811 (16)
O1−0.02000 (18)0.95817 (16)0.20416 (15)0.0472 (3)
O20.2454 (2)1.09673 (18)0.05037 (17)0.0618 (4)
O30.3153 (2)0.46358 (19)0.16958 (19)0.0641 (4)
N10.2759 (2)0.87608 (18)0.33158 (17)0.0410 (3)
C10.2522 (2)0.71412 (19)0.45108 (18)0.0327 (3)
C20.2208 (3)0.6907 (2)0.6241 (2)0.0447 (4)
H20.21510.78140.66160.054*
C30.1982 (3)0.5318 (3)0.7405 (2)0.0540 (5)
H30.17820.51660.85590.065*
C40.2048 (3)0.3964 (3)0.6881 (2)0.0548 (5)
H40.18830.29080.76720.066*
C50.2359 (2)0.4185 (2)0.5186 (2)0.0462 (4)
H50.23980.32700.48330.055*
C60.2618 (2)0.57543 (19)0.39688 (19)0.0341 (3)
C70.2997 (2)0.5863 (2)0.2155 (2)0.0399 (4)
C80.3241 (3)0.7571 (2)0.0823 (2)0.0434 (4)
H8A0.27850.7728−0.01620.052*
H8B0.46500.74810.04650.052*
C90.3194 (3)1.0018 (3)0.3773 (3)0.0555 (5)
H9A0.33011.10260.28010.083*
H9B0.44360.94500.41490.083*
H9C0.21331.04090.46710.083*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S10.0511 (3)0.0305 (2)0.0313 (2)−0.01201 (17)−0.01384 (17)−0.00395 (16)
O10.0486 (7)0.0447 (7)0.0460 (7)−0.0040 (5)−0.0179 (5)−0.0152 (5)
O20.0921 (11)0.0419 (7)0.0480 (7)−0.0301 (7)−0.0247 (7)0.0087 (6)
O30.0813 (10)0.0563 (8)0.0664 (9)−0.0287 (7)0.0007 (7)−0.0364 (7)
N10.0614 (9)0.0327 (7)0.0371 (7)−0.0211 (6)−0.0205 (6)−0.0033 (6)
C10.0317 (7)0.0311 (7)0.0322 (7)−0.0082 (6)−0.0092 (6)−0.0055 (6)
C20.0462 (9)0.0493 (10)0.0356 (8)−0.0100 (7)−0.0121 (7)−0.0113 (7)
C30.0454 (10)0.0683 (13)0.0313 (8)−0.0154 (9)−0.0091 (7)0.0017 (8)
C40.0474 (10)0.0477 (10)0.0511 (11)−0.0196 (8)−0.0126 (8)0.0116 (8)
C50.0414 (9)0.0330 (8)0.0580 (11)−0.0132 (7)−0.0129 (8)−0.0029 (7)
C60.0304 (7)0.0293 (7)0.0386 (8)−0.0084 (6)−0.0068 (6)−0.0072 (6)
C70.0364 (8)0.0391 (8)0.0458 (9)−0.0101 (6)−0.0046 (6)−0.0193 (7)
C80.0500 (9)0.0451 (9)0.0317 (8)−0.0113 (7)−0.0055 (7)−0.0141 (7)
C90.0770 (13)0.0443 (10)0.0624 (11)−0.0274 (9)−0.0267 (10)−0.0143 (8)
Geometric parameters (Å, º) top
S1—O21.4262 (13)C3—H30.9300
S1—O11.4302 (13)C4—C51.365 (3)
S1—N11.6429 (13)C4—H40.9300
S1—C81.7574 (17)C5—C61.397 (2)
O3—C71.209 (2)C5—H50.9300
N1—C11.4175 (18)C6—C71.482 (2)
N1—C91.452 (2)C7—C81.515 (2)
C1—C21.393 (2)C8—H8A0.9700
C1—C61.402 (2)C8—H8B0.9700
C2—C31.387 (2)C9—H9A0.9600
C2—H20.9300C9—H9B0.9600
C3—C41.375 (3)C9—H9C0.9600
O2—S1—O1118.32 (8)C4—C5—C6121.56 (17)
O2—S1—N1107.31 (8)C4—C5—H5119.2
O1—S1—N1110.55 (7)C6—C5—H5119.2
O2—S1—C8111.61 (9)C5—C6—C1118.92 (15)
O1—S1—C8107.95 (8)C5—C6—C7117.93 (14)
N1—S1—C899.47 (8)C1—C6—C7123.14 (14)
C1—N1—C9121.70 (14)O3—C7—C6122.71 (16)
C1—N1—S1116.58 (10)O3—C7—C8118.80 (15)
C9—N1—S1119.32 (12)C6—C7—C8118.48 (13)
C2—C1—C6119.27 (14)C7—C8—S1111.72 (11)
C2—C1—N1120.09 (14)C7—C8—H8A109.3
C6—C1—N1120.63 (13)S1—C8—H8A109.3
C3—C2—C1119.87 (17)C7—C8—H8B109.3
C3—C2—H2120.1S1—C8—H8B109.3
C1—C2—H2120.1H8A—C8—H8B107.9
C4—C3—C2121.05 (17)N1—C9—H9A109.5
C4—C3—H3119.5N1—C9—H9B109.5
C2—C3—H3119.5H9A—C9—H9B109.5
C5—C4—C3119.31 (16)N1—C9—H9C109.5
C5—C4—H4120.3H9A—C9—H9C109.5
C3—C4—H4120.3H9B—C9—H9C109.5
O2—S1—N1—C1−174.04 (12)C4—C5—C6—C1−1.1 (2)
O1—S1—N1—C155.60 (13)C4—C5—C6—C7178.55 (15)
C8—S1—N1—C1−57.74 (13)C2—C1—C6—C51.2 (2)
O2—S1—N1—C923.23 (18)N1—C1—C6—C5−179.41 (14)
O1—S1—N1—C9−107.13 (15)C2—C1—C6—C7−178.43 (14)
C8—S1—N1—C9139.53 (15)N1—C1—C6—C70.9 (2)
C9—N1—C1—C215.9 (2)C5—C6—C7—O3−2.5 (2)
S1—N1—C1—C2−146.39 (13)C1—C6—C7—O3177.15 (16)
C9—N1—C1—C6−163.48 (16)C5—C6—C7—C8178.83 (14)
S1—N1—C1—C634.24 (18)C1—C6—C7—C8−1.5 (2)
C6—C1—C2—C3−0.5 (2)O3—C7—C8—S1151.98 (15)
N1—C1—C2—C3−179.84 (14)C6—C7—C8—S1−29.30 (18)
C1—C2—C3—C4−0.4 (3)O2—S1—C8—C7166.75 (12)
C2—C3—C4—C50.6 (3)O1—S1—C8—C7−61.58 (13)
C3—C4—C5—C60.2 (3)N1—S1—C8—C753.77 (13)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2···O1i0.932.583.432 (2)152
C4—H4···O2ii0.932.463.238 (3)142
C9—H9A···O20.962.312.830 (3)113
Symmetry codes: (i) −x, −y+2, −z+1; (ii) x, y−1, z+1.

Experimental details

Crystal data
Chemical formulaC9H9NO3S
Mr211.23
Crystal system, space groupTriclinic, P1
Temperature (K)296
a, b, c (Å)7.4553 (4), 8.5437 (4), 8.7097 (4)
α, β, γ (°)67.691 (2), 70.467 (2), 66.327 (2)
V (Å3)459.09 (4)
Z2
Radiation typeMo Kα
µ (mm−1)0.33
Crystal size (mm)0.20 × 0.15 × 0.10
Data collection
DiffractometerBruker Kappa-APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2007)
Tmin, Tmax0.952, 0.971
No. of measured, independent and
observed [I > 2σ(I)] reflections		7205, 1787, 1678
Rint0.020
(sin θ/λ)max (Å−1)0.615
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.032, 0.095, 1.09
No. of reflections1678
No. of parameters127
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.22, −0.42

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2003), WinGX (Farrugia, 1999) and PLATON (Spek, 2003).

Selected geometric parameters (Å, º) top
S1—O21.4262 (13)S1—N11.6429 (13)
S1—O11.4302 (13)S1—C81.7574 (17)
O2—S1—O1118.32 (8)O1—S1—C8107.95 (8)
O2—S1—N1107.31 (8)N1—S1—C899.47 (8)
O1—S1—N1110.55 (7)O3—C7—C6122.71 (16)
O2—S1—C8111.61 (9)O3—C7—C8118.80 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2···O1i0.932.583.432 (2)152
C4—H4···O2ii0.932.463.238 (3)142
C9—H9A···O20.962.312.830 (3)113
Symmetry codes: (i) −x, −y+2, −z+1; (ii) x, y−1, z+1.
 

Acknowledgements

The authors acknowledge the Higher Education Commission, Islamabad, Pakistan, and Bana International, Karachi, Pakistan, for funding the purchase of the diffractometer and for technical support, respectively.

References

First citationBruker (2007). APEX2 (Version 1.27), SAINT (Version 7.12a) and SADABS (Version 2004/I). Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
 First citationCremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354–1358.  CrossRef CAS Web of Science Google Scholar
 First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
 First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals Google Scholar
 First citationHarmata, M., Hong, X. & Barnes, C. L. (2004). Org. Lett. 6, 2201–2203.  Web of Science CSD CrossRef PubMed CAS Google Scholar
 First citationLombardino, J. G. (1972). J. Heterocycl. Chem. 9, 315–317.  CrossRef CAS Google Scholar
 First citationMisu, Y. & Togo, H. (2003). Org. Biomol. Chem. 1, 1342–1346.  Web of Science CrossRef PubMed CAS Google Scholar
 First citationShafiq, M., Tahir, M. N., Khan, I. U., Siddiqui, W. A. & Arshad, M. N. (2008). Acta Cryst. E64, o389.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationSiddiqui, W. A., Ahmad, S., Siddiqui, H. L., Tariq, M. I. & Parvez, M. (2007). Acta Cryst. E63, o4585.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationSpek, A. L. (2003). J. Appl. Cryst. 36, 7–13.  Web of Science CrossRef CAS IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 64| Part 3| March 2008| Page o557
doi:10.1107/S1600536808003498
Follow Acta Cryst. E
Sign up for e-alerts
E-alerts
Follow Acta Cryst. on Twitter
Twitter
Follow us on facebook
Facebook
Sign up for RSS feeds
RSS