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

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ISSN: 2056-9890

4-Nitro-2-phen­oxy­aniline

aDepartment of Studies in Physics, Manasagangotri, University of Mysore, Mysore 570 006, India, bDepartment of P. G. Studies and Research in Industrial Chemistry, Kuvempu University, Jnana Sahyadri, Shankaraghatta, Karnataka, India, and cChemistry Department, Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Bangalore 560 035, India
*Correspondence e-mail: mas@physics.uni-mysore.ac.in

(Received 11 March 2010; accepted 31 March 2010; online 8 May 2010)

In the title compound, C12H10N2O3, the oxygen atom bridging the two aromatic rings is in a synperiplanar (+sp) conformation. The dihedral angle between the aromatic rings is 71.40 (12)°. In the crystal, mol­ecules are linked by inter­molecular N—H⋯O hydrogen bonds.

Related literature

For the pharmacological properties of nitro-2-phenoxy­aniline, see: Moore & Harrington (1974[Moore, G. G. L. & Harrington, J. K. (1974). US Patent No. 3840597.]); Prasad et al. (2005[Prasad, A., Sharma, M. L., Kanwar, S., Rathee, R. & Sharma, S. D. (2005). J. Sci. Ind. Res. 64, 756-760.]). For the herbicidal applications of biphenyl ether derivatives, see: Yu et al., (2008[Yu, H.-B., Wu, H.-F., Cui, D.-L. & Li, B. (2008). Ark. Kemi, 2, 94-104.]). For the applications of Schiff bases derived from aromatic amines, see: Singh et al. (1975[Singh, P., Goel, R. L. & Singh, B. P. (1975). J. Indian Chem. Soc. 52, 958-959.]); Cimerman et al. (2000[Cimerman, Z., Miljanić, S. & Galić, N. (2000). Croat. Chem. Acta, 73, 81-95.]). For their biological and pharmacological acitvity, see: Singh et al. (1975[Singh, P., Goel, R. L. & Singh, B. P. (1975). J. Indian Chem. Soc. 52, 958-959.]); Cimerman et al. (2000[Cimerman, Z., Miljanić, S. & Galić, N. (2000). Croat. Chem. Acta, 73, 81-95.]); Shah et al. (1992[Shah, S., Vyas, R. & Mehta, R. H. (1992). J. Indian Chem. Soc. 69, 590-596.]); Pandeya et al. (1999[Pandeya, S. N., Sriram, D., Nath, G. & De Clercq, E. (1999). Eur. J. Pharm. Soc. 9, 25-31.]); More et al. (2001[More, P. G., Bhalvankar, R. B. & Patter, S. C. (2001). J. Indian Chem. Soc. 78, 474-475.]). For the preparation of 4-nitro-2-phenoxy­aniline, see: Shreenivasa et al. (2009[Shreenivasa, M. T., Chetan, B. P. & Bhat, A. R. (2009). J. Pharm. Sci. Technol. 1, 88-94.]). For a related structure, see: Naveen et al. (2006[Naveen, S., Anil Kumar, K., Channe Gowda, D., Sridhar, M. A. & Shashidhara Prasad, J. (2006). Acta Cryst. E62, o3790-o3791.]).

[Scheme 1]

Experimental

Crystal data
  • C12H10N2O3

  • Mr = 230.22

  • Monoclinic, P 21 /c

  • a = 10.4100 (12) Å

  • b = 15.6570 (18) Å

  • c = 6.9600 (17) Å

  • β = 103.406 (4)°

  • V = 1103.5 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 293 K

  • 0.32 × 0.3 × 0.25 mm

Data collection
  • MacScience DIPLabo 32001 diffractometer

  • 3336 measured reflections

  • 1889 independent reflections

  • 1498 reflections with I > 2σ(I)

  • Rint = 0.033

Refinement
  • R[F2 > 2σ(F2)] = 0.053

  • wR(F2) = 0.167

  • S = 1.09

  • 1889 reflections

  • 154 parameters

  • H-atom parameters constrained

  • Δρmax = 0.13 e Å−3

  • Δρmin = −0.15 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N10—H10A⋯O9i 0.86 2.17 3.023 (3) 170
Symmetry code: (i) [-x+1, y-{\script{1\over 2}}, -z+{\script{1\over 2}}].

Data collection: XPRESS (MacScience, 2002[MacScience (2002). XPRESS. MacScience Co. Ltd, Yokohama, Japan.]); cell refinement: SCALEPACK (Ot­win­owski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: DENZO (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]) and SCALEPACK; program(s) used to solve structure: SHELXS7 (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: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]) and ORTEPII (Johnson, 1976[Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

The phenoxy anilines are versatile intermediates for synthesizing several pharmaceutical drugs i.e. Nimesulide, Ampxipine and Loxapine. The Nitro-2-phenoxyaniline is an intermediate for the synthesis of Nimesulide and it was probably the first COX-2 selective non-steroidal anti inflammatory drug (NSAID) identified with this key pharmacological properties (Moore & Harrington, 1974; Prasad et al. 2005). It is a unique molecule with twin aromatic ring structure. The nitro-2-phenoxyaniline is a derivative of biphenyl ether. More generally, biphenyl ether derivatives have many biological, herbicidal (Yu et al., 2008) and organic chemistry applications. Schiff bases derived from aromatic amines have a wide variety of applications in many fields, viz., biological, inorganic and anlytical chemistry (Singh et al., 1975; Cimerman et al., 2000). They are known to exhibit potent antibacterial, anticonvulsant, anti-inflammatory (Shah et al. 1992), anticancer (Pandeya et al., 1999), anti-hypertensive and hypnotic (More et al., 2001) activities. With this background, the title compound (I), was synthesized and we report its crystal structure here.

A perspective view of (I) is shown in Fig. 1. The two aromatic rings are not coplanar. This is confirmed by the dihedral angle value of 71.38 (12)° between two six-membered rings. The oxygen atom connecting the two aromatic rings is in syn-periplanar (sp) conformation as indicated by the torsion angle value of 13.0 (3)°. The nitro group lies in the plane of the aniline ring as indicated by the C2—C1—N7—O8 and C6—C1—N7—O9 torsion angles of -176.1 (2)° and -174.4 (2)°, respectively. These values are different from the values reported earlier (Naveen S. et al. 2006). The structure exhibits both inter and intramolecular N—H···O interaction. The intermolecular N10—H10A···O9 interaction has a length of 2.17Å and angle of 170° with symmetry codes 3/2-x,-1/2+y,1-z. The molecules exhibit layered stackings when viewd down the 'b' axis as shown in Fig. 2.

Related literature top

For the pharmacological properties of nitro-2-phenoxyaniline, see: Moore & Harrington (1974); Prasad et al. (2005). For the herbicidal applications of biphenyl ether derivatives, see: Yu et al., (2008). For the applications of Schiff bases derived from aromatic amines, see: Singh et al. (1975); Cimerman et al. (2000). For their biological and pharmacological acitvity, see: Singh et al. (1975); Cimerman et al. (2000); Shah et al. (1992); Pandeya et al. (1999); More et al. (2001). For the preparation of 4-nitro-2-phenoxyaniline, see: Shreenivasa et al. (2009). For a related structure, see: Naveen et al. (2006).

Experimental top

The 4-nitro-2-phenoxyaniline was prepared by condensation of o-chloronitrobenzene with phenol followed by acetylation and nitration (Shreenivasa et al., 2009). The final product obtained was recrystallized using ethanol as a solvent. Colorless crystals were appeared after 4 days by slow evaporation.

Refinement top

H atoms were placed at idealized positions and allowed to ride on their parent atoms with C–H distances in the range 0.93–0.98 Å; Uiso(H) = 1.2Ueq(carrier atom) for all H atoms.

Structure description top

The phenoxy anilines are versatile intermediates for synthesizing several pharmaceutical drugs i.e. Nimesulide, Ampxipine and Loxapine. The Nitro-2-phenoxyaniline is an intermediate for the synthesis of Nimesulide and it was probably the first COX-2 selective non-steroidal anti inflammatory drug (NSAID) identified with this key pharmacological properties (Moore & Harrington, 1974; Prasad et al. 2005). It is a unique molecule with twin aromatic ring structure. The nitro-2-phenoxyaniline is a derivative of biphenyl ether. More generally, biphenyl ether derivatives have many biological, herbicidal (Yu et al., 2008) and organic chemistry applications. Schiff bases derived from aromatic amines have a wide variety of applications in many fields, viz., biological, inorganic and anlytical chemistry (Singh et al., 1975; Cimerman et al., 2000). They are known to exhibit potent antibacterial, anticonvulsant, anti-inflammatory (Shah et al. 1992), anticancer (Pandeya et al., 1999), anti-hypertensive and hypnotic (More et al., 2001) activities. With this background, the title compound (I), was synthesized and we report its crystal structure here.

A perspective view of (I) is shown in Fig. 1. The two aromatic rings are not coplanar. This is confirmed by the dihedral angle value of 71.38 (12)° between two six-membered rings. The oxygen atom connecting the two aromatic rings is in syn-periplanar (sp) conformation as indicated by the torsion angle value of 13.0 (3)°. The nitro group lies in the plane of the aniline ring as indicated by the C2—C1—N7—O8 and C6—C1—N7—O9 torsion angles of -176.1 (2)° and -174.4 (2)°, respectively. These values are different from the values reported earlier (Naveen S. et al. 2006). The structure exhibits both inter and intramolecular N—H···O interaction. The intermolecular N10—H10A···O9 interaction has a length of 2.17Å and angle of 170° with symmetry codes 3/2-x,-1/2+y,1-z. The molecules exhibit layered stackings when viewd down the 'b' axis as shown in Fig. 2.

For the pharmacological properties of nitro-2-phenoxyaniline, see: Moore & Harrington (1974); Prasad et al. (2005). For the herbicidal applications of biphenyl ether derivatives, see: Yu et al., (2008). For the applications of Schiff bases derived from aromatic amines, see: Singh et al. (1975); Cimerman et al. (2000). For their biological and pharmacological acitvity, see: Singh et al. (1975); Cimerman et al. (2000); Shah et al. (1992); Pandeya et al. (1999); More et al. (2001). For the preparation of 4-nitro-2-phenoxyaniline, see: Shreenivasa et al. (2009). For a related structure, see: Naveen et al. (2006).

Computing details top

Data collection: XPRESS (MacScience, 2002); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO (Otwinowski & Minor, 1997) and SCALEPACK; program(s) used to solve structure: SHELXS7 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009) and ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. A view of (I), with 50% probability displacement ellipsoids.
[Figure 2] Fig. 2. Packing diagram of the molecule viewed down the 'b' axis. The dotted lines represents the hydrogen bonds.
4-Nitro-2-phenoxyaniline top
Crystal data top
C12H10N2O3F(000) = 480
Mr = 230.22Dx = 1.386 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 14613 reflections
a = 10.4100 (12) Åθ = 2.4–32.5°
b = 15.6570 (18) ŵ = 0.10 mm1
c = 6.9600 (17) ÅT = 293 K
β = 103.406 (4)°Block, colorless
V = 1103.5 (3) Å30.32 × 0.3 × 0.25 mm
Z = 4
Data collection top
MacScience DIPLabo 32001
diffractometer
1498 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.033
Graphite monochromatorθmax = 25.0°, θmin = 2.4°
Detector resolution: 10.0 pixels mm-1h = 1212
ω scank = 1818
3336 measured reflectionsl = 88
1889 independent 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)] = 0.053Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.167H-atom parameters constrained
S = 1.09 w = 1/[σ2(Fo2) + (0.0811P)2 + 0.2121P]
where P = (Fo2 + 2Fc2)/3
1889 reflections(Δ/σ)max < 0.001
154 parametersΔρmax = 0.13 e Å3
0 restraintsΔρmin = 0.15 e Å3
Crystal data top
C12H10N2O3V = 1103.5 (3) Å3
Mr = 230.22Z = 4
Monoclinic, P21/cMo Kα radiation
a = 10.4100 (12) ŵ = 0.10 mm1
b = 15.6570 (18) ÅT = 293 K
c = 6.9600 (17) Å0.32 × 0.3 × 0.25 mm
β = 103.406 (4)°
Data collection top
MacScience DIPLabo 32001
diffractometer
1498 reflections with I > 2σ(I)
3336 measured reflectionsRint = 0.033
1889 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0530 restraints
wR(F2) = 0.167H-atom parameters constrained
S = 1.09Δρmax = 0.13 e Å3
1889 reflectionsΔρmin = 0.15 e Å3
154 parameters
Special details top

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.

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
C10.4153 (2)0.11783 (12)0.1849 (3)0.0575 (5)
C20.4872 (2)0.04830 (14)0.2715 (3)0.0624 (5)
H20.56410.05610.36920.075*
C30.4446 (2)0.03248 (13)0.2129 (3)0.0618 (5)
H30.49200.07940.27370.074*
C40.3320 (2)0.04544 (12)0.0647 (3)0.0578 (5)
C50.2615 (2)0.02705 (13)0.0233 (3)0.0637 (6)
C60.3010 (2)0.10777 (13)0.0368 (3)0.0643 (6)
H60.25270.15500.02000.077*
N70.46086 (19)0.20258 (12)0.2446 (3)0.0696 (5)
O80.39280 (19)0.26405 (10)0.1748 (3)0.0929 (6)
O90.56703 (18)0.21113 (11)0.3643 (3)0.0956 (6)
N100.28775 (19)0.12433 (11)0.0016 (3)0.0742 (6)
H10A0.33000.16890.05420.089*
H10B0.21740.12980.09090.089*
O110.15146 (19)0.00647 (10)0.1675 (3)0.0991 (7)
C120.0845 (2)0.06917 (13)0.2929 (3)0.0710 (6)
C130.0425 (2)0.08508 (17)0.2880 (4)0.0802 (7)
H130.08040.05680.19740.096*
C140.1149 (3)0.1424 (2)0.4153 (5)0.0973 (9)
H140.20220.15280.41100.117*
C150.0624 (4)0.18388 (18)0.5465 (5)0.1026 (10)
H150.11270.22340.63180.123*
C160.0659 (4)0.16812 (19)0.5551 (4)0.1079 (11)
H160.10240.19670.64690.129*
C170.1418 (3)0.10918 (18)0.4262 (5)0.0934 (8)
H170.22870.09760.43090.112*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0635 (11)0.0525 (10)0.0538 (11)0.0002 (9)0.0079 (9)0.0054 (8)
C20.0669 (12)0.0677 (13)0.0474 (10)0.0017 (10)0.0026 (9)0.0018 (9)
C30.0713 (13)0.0586 (11)0.0523 (11)0.0093 (9)0.0079 (9)0.0073 (9)
C40.0647 (12)0.0528 (11)0.0553 (11)0.0008 (9)0.0125 (9)0.0022 (8)
C50.0613 (12)0.0559 (11)0.0657 (12)0.0024 (9)0.0018 (10)0.0025 (9)
C60.0619 (12)0.0545 (11)0.0690 (13)0.0044 (9)0.0003 (10)0.0015 (9)
N70.0731 (11)0.0609 (11)0.0687 (11)0.0001 (9)0.0042 (9)0.0105 (9)
O80.0977 (12)0.0569 (9)0.1100 (14)0.0061 (9)0.0044 (10)0.0108 (9)
O90.0884 (12)0.0789 (11)0.0993 (13)0.0071 (9)0.0195 (10)0.0197 (10)
N100.0811 (12)0.0523 (10)0.0814 (13)0.0015 (8)0.0031 (10)0.0031 (9)
O110.0898 (12)0.0568 (9)0.1187 (15)0.0097 (8)0.0408 (11)0.0116 (9)
C120.0720 (14)0.0539 (11)0.0716 (14)0.0052 (10)0.0151 (11)0.0015 (10)
C130.0787 (15)0.0843 (16)0.0693 (14)0.0030 (13)0.0001 (11)0.0023 (12)
C140.0888 (18)0.0959 (19)0.0906 (19)0.0195 (15)0.0131 (15)0.0042 (16)
C150.119 (2)0.0790 (17)0.0801 (18)0.0069 (17)0.0377 (17)0.0022 (15)
C160.148 (3)0.088 (2)0.0770 (18)0.031 (2)0.0041 (19)0.0114 (15)
C170.0778 (16)0.0823 (17)0.113 (2)0.0124 (13)0.0075 (15)0.0026 (16)
Geometric parameters (Å, º) top
C1—C21.378 (3)N10—H10A0.8600
C1—C61.390 (3)N10—H10B0.8600
C1—N71.438 (3)O11—C121.389 (3)
C2—C31.371 (3)C12—C131.353 (4)
C2—H20.9300C12—C171.367 (4)
C3—C41.385 (3)C13—C141.359 (4)
C3—H30.9300C13—H130.9300
C4—N101.355 (3)C14—C151.337 (5)
C4—C51.412 (3)C14—H140.9300
C5—C61.365 (3)C15—C161.374 (5)
C5—O111.375 (3)C15—H150.9300
C6—H60.9300C16—C171.397 (4)
N7—O81.227 (2)C16—H160.9300
N7—O91.227 (2)C17—H170.9300
C2—C1—C6121.29 (18)C4—N10—H10B120.0
C2—C1—N7119.55 (18)H10A—N10—H10B120.0
C6—C1—N7119.14 (18)C5—O11—C12120.32 (16)
C3—C2—C1119.54 (19)C13—C12—C17121.1 (2)
C3—C2—H2120.2C13—C12—O11117.8 (2)
C1—C2—H2120.2C17—C12—O11121.0 (2)
C2—C3—C4121.10 (18)C12—C13—C14120.2 (3)
C2—C3—H3119.4C12—C13—H13119.9
C4—C3—H3119.4C14—C13—H13119.9
N10—C4—C3122.70 (19)C15—C14—C13120.9 (3)
N10—C4—C5119.24 (19)C15—C14—H14119.6
C3—C4—C5118.06 (18)C13—C14—H14119.6
C6—C5—O11125.60 (19)C14—C15—C16119.9 (3)
C6—C5—C4121.45 (19)C14—C15—H15120.1
O11—C5—C4112.93 (18)C16—C15—H15120.1
C5—C6—C1118.53 (19)C15—C16—C17120.1 (3)
C5—C6—H6120.7C15—C16—H16119.9
C1—C6—H6120.7C17—C16—H16119.9
O8—N7—O9121.99 (19)C12—C17—C16117.9 (3)
O8—N7—C1119.21 (17)C12—C17—H17121.1
O9—N7—C1118.80 (18)C16—C17—H17121.1
C4—N10—H10A120.0
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N10—H10A···O9i0.862.173.023 (3)170
Symmetry code: (i) x+1, y1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC12H10N2O3
Mr230.22
Crystal system, space groupMonoclinic, P21/c
Temperature (K)293
a, b, c (Å)10.4100 (12), 15.6570 (18), 6.9600 (17)
β (°) 103.406 (4)
V3)1103.5 (3)
Z4
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.32 × 0.3 × 0.25
Data collection
DiffractometerMacScience DIPLabo 32001
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
3336, 1889, 1498
Rint0.033
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.053, 0.167, 1.09
No. of reflections1889
No. of parameters154
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.13, 0.15

Computer programs: XPRESS (MacScience, 2002), SCALEPACK (Otwinowski & Minor, 1997), DENZO (Otwinowski & Minor, 1997) and SCALEPACK, SHELXS7 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009) and ORTEPII (Johnson, 1976).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N10—H10A···O9i0.86002.17003.023 (3)170.00
Symmetry code: (i) x+1, y1/2, z+1/2.
 

Acknowledgements

The authors are grateful to the DST and Government of India project SP/I2/FOO/93 and the University of Mysore for financial assistance. MM would like to thank the University of Mysore for awarding a project under the head DV3/136/2007–2008/24.09.09.

References

First citationCimerman, Z., Miljanić, S. & Galić, N. (2000). Croat. Chem. Acta, 73, 81–95.  CAS Google Scholar
First citationJohnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA.  Google Scholar
First citationMacScience (2002). XPRESS. MacScience Co. Ltd, Yokohama, Japan.  Google Scholar
First citationMoore, G. G. L. & Harrington, J. K. (1974). US Patent No. 3840597.  Google Scholar
First citationMore, P. G., Bhalvankar, R. B. & Patter, S. C. (2001). J. Indian Chem. Soc. 78, 474–475.  CAS Google Scholar
First citationNaveen, S., Anil Kumar, K., Channe Gowda, D., Sridhar, M. A. & Shashidhara Prasad, J. (2006). Acta Cryst. E62, o3790–o3791.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.  Google Scholar
First citationPandeya, S. N., Sriram, D., Nath, G. & De Clercq, E. (1999). Eur. J. Pharm. Soc. 9, 25–31.  Web of Science CrossRef CAS Google Scholar
First citationPrasad, A., Sharma, M. L., Kanwar, S., Rathee, R. & Sharma, S. D. (2005). J. Sci. Ind. Res. 64, 756–760.  CAS Google Scholar
First citationShah, S., Vyas, R. & Mehta, R. H. (1992). J. Indian Chem. Soc. 69, 590–596.  CAS Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationShreenivasa, M. T., Chetan, B. P. & Bhat, A. R. (2009). J. Pharm. Sci. Technol. 1, 88–94.  Google Scholar
First citationSingh, P., Goel, R. L. & Singh, B. P. (1975). J. Indian Chem. Soc. 52, 958–959.  CAS Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationYu, H.-B., Wu, H.-F., Cui, D.-L. & Li, B. (2008). Ark. Kemi, 2, 94–104.  CrossRef Google Scholar

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