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Acta Cryst. (2010). E66, o746    [ doi:10.1107/S1600536810007506 ]

Diethyl 2-[(N-benzyl-N-methylamino)(phenyl)methyl]propanedioate

I. Meskini, M. Daoudi, J.-C. Daran, H. Zouihri and T. Ben Hadda

Abstract top

In the title compound, C22H27NO4, the mean planes of the two benzene rings form a dihedral angle of 73.54 (13)°. One of the methyl groups is disordered over two sites, with site occupation factors of 0.47 (15) and 0.53 (15). The crystal packing is controlled by van der Waals forces and a possible C-H...O interaction, forming a chain running parallel to the a axis.

Comment top

The rational design of new HIV-1 Integrase (H—I) inhibitors, one validated target for chemotherapeutic intervention (Dayam et al., 2007), is fundamentally based on intermolecular coordination between H—I / chemical inhibitor / metals (Mg+2 and Mn+2, co-factors of the enzyme), leading in the formation of bimetallic complexes (Zeng et al., 2008a; Sechi et al., 2009a). Thereby, several bimetallic metal complexes, in many cases exploring the known-well polydentate ligands, appear in this scenario as the most promising concept to employ in either enzyme / drug interaction or electron transfer process, in the later case involving the biological oxygen transfer (Sechi et al., 2009b; Ramkumar et al., 2008). Another exciting example of application of such polydentate ligand involves the synergic water activation, that occurs via the so-called, remote metallic atoms. Such organometallic compounds are structurally deemed to promote or block the H—I activity (Zeng et al., 2008b). The explanations given above clearly demonstrate that polydentate ligands are of special interest in the bioorganometallic chemistry (Patil et al., 2007). Looking for the design of new bimetallic coordinating ligands to further explore in the building of intermolecular system involving H—I/ inhibitor/ metal complexation, we have targeted to study the crystallographic structure of a polydendate malonate N,O,O-ligand, the title compound (I).

In the molecule of (I) (Fig. 1), the benzene rings (C11—C16) and (C21—C26) are planar, with r.m.s deviation of 0.003 (3) Å and 0.009 (2) Å, respectively. The dihedral angle between the planes of these rings is 73.54 (13)°. The planes of the two carbonyl groups (O1,O2,C6) and (O3,O4,C5) are twisted by dihedral angles of 66.0 (3)° and 67.2 (3)°, respectively, with respect to (C4,C2,C21,N1) plane.

The Bond lengths and angles in the title compound have normal values (Allen et al., 1987). The only significant intermolecular interaction in (I), as identified by PLATON (Spek, 2003) is a C32—H32A···O3 H-bond (Table 1).

Related literature top

For related compounds displaying biological activity, see: Dayam et al. (2007); Patil et al. (2007); Ramkumar et al. (2008); Sechi et al. (2009a,b); Zeng et al. (2008a,b). For the synthetic procedure, see: Pommier & Neamati (2006). For bond-length data, see: Allen et al. (1987).

Experimental top

The title compound, (I), was synthesized from 2-(benzylidene)-malonic acid diethyl esters in the presence of benzyl methylamine, in an aqueous medium at room temperature following the procedures reported earlier (Pommier & Neamati, 2006). To a solution of 2-(benzylidene)-malonic acid diethyl ester (1.24 g, 5 mmol) in water (20 ml) was added the benzyl methylamine (0.60 g, 6 mmol) and the stirring was continued at room temperature until the complete consumption of the starting material. After removing solvent, the crude products were dissolved in diethyl ether (2x40 ml) and washed with water until the pH became neutral. The organic solvent layer was dried with sodium sulphate and then evaporated. The residue was purified by recrystallization from a mixture of diethylether/hexane (2:1) to give the pure compound (I) as colorless crystals in 78% yield.

Refinement top

All H atoms were fixed geometrically and treated as riding with C—H = 0.98 Å (methyne), 0.97 Å (methylene), 0.96Å (methyl) and 0.93Å (aromatic) with Uiso(H) = 1.2Ueq(C) or Uiso(H) = 1.5Ueq(C-methyl).

One of the methyl group is disordered over two positions with roughly identical occupation factors (0.47 and 0.53). These occupation factors were initially refined restraining their sum to be equal to 1 and applying an overall isotropic thermal parameter for the C atom. Moreover, C—C distances were restraint to have reasonable values. Once the occupation factors have been determined, they were fixed and not refined and the temperature factors were refined freely.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. : Molecular structure of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii.
[Figure 2] Fig. 2. : Partial packing view showing the chain generated by C—H···O hydrogen bonds shown as dashed lines. [Symmetry code: (i) x-1,y,z].
Diethyl 2-[(N-benzyl-N-methylamino)(phenyl)methyl]propanedioate top
Crystal data top
C22H27NO4F(000) = 792
Mr = 369.45Dx = 1.205 Mg m−3
Monoclinic, P21/cMelting point = 380–382 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 9.3074 (2) ÅCell parameters from 3214 reflections
b = 5.9077 (1) Åθ = 1.9–25.3°
c = 37.0971 (7) ŵ = 0.08 mm−1
β = 92.999 (1)°T = 296 K
V = 2037.00 (7) Å3Block, colourless
Z = 40.24 × 0.20 × 0.13 mm
Data collection top
Bruker X8 APEXII CCD area-detector
diffractometer		3411 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.038
graphiteθmax = 26.4°, θmin = 1.1°
φ and ω scansh = −11→11
25575 measured reflectionsk = −7→7
4138 independent reflectionsl = −46→46
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)] = 0.070Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.159H-atom parameters constrained
S = 1.25 w = 1/[σ2(Fo2) + (0.0364P)2 + 1.9835P]
where P = (Fo2 + 2Fc2)/3
4138 reflections(Δ/σ)max < 0.001
257 parametersΔρmax = 0.27 e Å−3
1 restraintΔρmin = −0.26 e Å−3
Crystal data top
C22H27NO4V = 2037.00 (7) Å3
Mr = 369.45Z = 4
Monoclinic, P21/cMo Kα radiation
a = 9.3074 (2) ŵ = 0.08 mm−1
b = 5.9077 (1) ÅT = 296 K
c = 37.0971 (7) Å0.24 × 0.20 × 0.13 mm
β = 92.999 (1)°
Data collection top
Bruker X8 APEXII CCD area-detector
diffractometer		3411 reflections with I > 2σ(I)
25575 measured reflectionsRint = 0.038
4138 independent reflectionsθmax = 26.4°
Refinement top
R[F2 > 2σ(F2)] = 0.070H-atom parameters constrained
wR(F2) = 0.159Δρmax = 0.27 e Å−3
S = 1.25Δρmin = −0.26 e Å−3
4138 reflectionsAbsolute structure: ?
257 parametersFlack parameter: ?
1 restraintRogers parameter: ?
Special details top

Experimental. Yield = 78% (1.24 g). Rf = 0.45 (ether/hexane:1/1). Mp = 380-382 K.

IR Spectroscopic (KBr, ν cm-1) analysis: 2860/2984 (C—H);1745 (CO); 1216/1301 (C—O); 1584/1601 (C=C), 1138, 1021.

NMR analysis: 1H-NMR (250 MHz, CDCl3) δ (ppm): 7.2-7.4(m, 10H, aromat), 4.65 (d, H, Ph—C3H, 3J = 12.15 Hz), 4.01 (dq, 2HAB, OCH2CH3, 2JAB = 14.34 Hz, 3J =7.06 Hz), 4.35 (dq, 2HAB, OCH2CH3, 2JAB = 14.34 Hz,3J = 7.06 Hz), 4.32 (d, H, C2H(CO2Et)2 , 3J = 12.20 Hz), 3.5 (d, 1H, CH2Ph, 3J = 13.2 Hz), 3.25 (d, 1H, CH2Ph, 3J = 13.5 Hz), 2.05 (s, 3H, CH3), 1.33 (t, 3H, OCH2CH3, 3J = 7.2 Hz), 1.01 (t, 3H, OCH2CH3, 3J = 7.2 Hz). 13C-NMR (250 MHz, CDCl3) δ (ppm): 167.97 (C=O), 167.93 (C=O), 133.4 (Cquat, C-(Ph), 132.6 (Cquat, CPhCH2), 126.91/128.03 (Ctert, 10CH aromt), 67.47 (Ctert, C3HPh), 61.24 -61.3 (2 C, 2CH2CH3, ester), 55.39 (Ctert, C2H-(CO2Et), 58.70 (Cses, CľH2N), 36.94 (Cter, CH3N), 14.15/13.73 ( 2 C, 2CH3, esters).. MS (IE) Calcd for [M]+ C22H27NO4: 369.45. [M+H]+. (m/z) = 370, [M—CH(CO2Et)2]+ (m/z) = 159 (100%).

Elemental analysis for C22H27NO4 : Calc (Found): C 71.52 (71.48), H 7.37 (7.35), N 3.79 (3.81).

The purity of the compound was checked by determining its melting point (380-382 K). Suitable single crystal of malonate derivative (I) was obtained by recrystallization from ethanol. A colorless crystal of (I) having approximate dimensions of 0.24 x 0.20 x 0.09 mm was mounted on a glass fibre. All measurements were made in the φ and ω scans technique on a CCD X8 Bruker diffractometer with graphite monochromatized MoKα radiation at room temperature (296 (2) K).

The data collection nominally covered a sphere of reciprocal space, by a combination of five sets of exposures; each set had a different φ angle for the crystal and each exposure covered 0.5° in ω and 30 seconds in time. The crystal-to-detector distance was 37.5 mm.

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*/UeqOcc. (<1)
C10.4969 (3)0.3979 (4)0.18855 (6)0.0302 (5)
H1A0.54420.54080.18410.036*
H1B0.56460.30160.20210.036*
C20.5612 (3)0.3238 (4)0.12647 (6)0.0290 (5)
H20.59000.48320.12790.035*
C30.4123 (3)0.0546 (4)0.15968 (7)0.0391 (6)
H3A0.3777−0.00940.13710.059*
H3B0.33740.04940.17650.059*
H3C0.4938−0.03050.16910.059*
C40.4827 (3)0.2917 (4)0.08947 (6)0.0318 (6)
H40.44930.13490.08700.038*
C50.5794 (3)0.3490 (5)0.05896 (6)0.0354 (6)
C60.3536 (3)0.4517 (5)0.08739 (6)0.0402 (7)
C110.3667 (3)0.4396 (4)0.21050 (6)0.0277 (5)
C120.3634 (3)0.3693 (5)0.24598 (7)0.0379 (6)
H120.44110.29030.25650.045*
C130.2448 (3)0.4158 (5)0.26603 (7)0.0453 (7)
H130.24340.36730.28990.054*
C140.1298 (3)0.5327 (5)0.25081 (7)0.0404 (7)
H140.05090.56490.26430.048*
C150.1318 (3)0.6024 (5)0.21538 (7)0.0388 (6)
H150.05360.68050.20490.047*
C160.2495 (3)0.5565 (4)0.19540 (6)0.0328 (6)
H160.25000.60460.17150.039*
C210.6990 (3)0.1854 (4)0.13072 (6)0.0274 (5)
C220.7136 (3)−0.0263 (4)0.11485 (6)0.0306 (5)
H220.6362−0.08970.10150.037*
C230.8421 (3)−0.1431 (5)0.11870 (7)0.0380 (6)
H230.8507−0.28390.10780.046*
C240.9581 (3)−0.0524 (5)0.13858 (7)0.0396 (6)
H241.0448−0.13080.14080.048*
C250.9443 (3)0.1542 (5)0.15501 (7)0.0403 (7)
H251.02130.21510.16880.048*
C260.8162 (3)0.2716 (5)0.15109 (6)0.0352 (6)
H260.80820.41150.16230.042*
C310.0998 (4)0.4617 (8)0.07836 (10)0.0745 (12)
H31A0.06440.47590.10240.089*0.53
H31B0.11560.61240.06900.089*0.53
H31C0.02770.37310.09000.089*0.47
H31D0.11450.59990.09220.089*0.47
C320.0021 (6)0.3502 (13)0.05651 (16)0.0556 (17)0.53
H32A−0.08530.43640.05420.083*0.53
H32B−0.01730.20470.06670.083*0.53
H32C0.03980.33050.03310.083*0.53
C32B0.0454 (7)0.5197 (15)0.04332 (18)0.059 (2)0.47
H32D0.05140.39080.02770.088*0.47
H32E0.10100.64180.03420.088*0.47
H32F−0.05330.56590.04430.088*0.47
C410.6429 (4)0.2245 (6)0.00078 (8)0.0617 (10)
H41A0.69150.36980.00090.074*
H41B0.58370.2120−0.02140.074*
C420.7512 (5)0.0371 (8)0.00302 (11)0.0870 (13)
H42A0.81780.06230.02330.131*
H42B0.80250.0334−0.01880.131*
H42C0.7029−0.10470.00600.131*
N10.4551 (2)0.2901 (3)0.15416 (5)0.0284 (5)
O10.3600 (3)0.6519 (4)0.09128 (6)0.0592 (6)
O20.2341 (2)0.3345 (4)0.07988 (5)0.0529 (6)
O30.6643 (3)0.5002 (4)0.05932 (5)0.0576 (6)
O40.5537 (2)0.2080 (4)0.03170 (5)0.0509 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0356 (13)0.0276 (13)0.0275 (12)−0.0006 (11)0.0029 (10)−0.0026 (10)
C20.0402 (14)0.0208 (12)0.0263 (11)0.0010 (11)0.0052 (10)−0.0036 (10)
C30.0504 (16)0.0299 (14)0.0380 (14)−0.0036 (13)0.0112 (12)−0.0053 (12)
C40.0401 (14)0.0275 (13)0.0277 (12)0.0078 (11)0.0007 (10)−0.0033 (10)
C50.0488 (16)0.0314 (15)0.0260 (12)0.0143 (13)0.0012 (11)−0.0011 (11)
C60.0539 (18)0.0454 (18)0.0209 (12)0.0153 (15)−0.0006 (11)−0.0032 (12)
C110.0350 (13)0.0221 (12)0.0260 (11)−0.0042 (10)0.0035 (9)−0.0055 (10)
C120.0437 (15)0.0389 (15)0.0311 (13)0.0070 (13)0.0022 (11)0.0039 (11)
C130.0549 (17)0.0533 (19)0.0288 (13)0.0034 (15)0.0119 (12)0.0065 (13)
C140.0393 (15)0.0461 (17)0.0370 (14)0.0000 (13)0.0124 (11)−0.0046 (13)
C150.0362 (14)0.0424 (16)0.0379 (14)0.0048 (13)0.0024 (11)−0.0014 (12)
C160.0414 (14)0.0329 (14)0.0244 (11)0.0009 (12)0.0037 (10)0.0009 (10)
C210.0357 (13)0.0242 (12)0.0229 (11)0.0001 (11)0.0060 (9)0.0038 (9)
C220.0324 (13)0.0269 (13)0.0320 (12)0.0010 (11)−0.0028 (10)−0.0006 (10)
C230.0425 (15)0.0295 (14)0.0417 (14)0.0065 (12)−0.0018 (12)0.0001 (12)
C240.0337 (14)0.0449 (17)0.0400 (14)0.0060 (13)−0.0009 (11)0.0090 (13)
C250.0338 (14)0.0526 (18)0.0343 (13)−0.0098 (13)−0.0006 (11)−0.0007 (13)
C260.0465 (15)0.0309 (14)0.0287 (12)−0.0108 (12)0.0078 (11)−0.0039 (11)
C310.059 (2)0.104 (3)0.060 (2)0.048 (2)−0.0056 (17)−0.011 (2)
C320.030 (3)0.085 (5)0.051 (3)0.008 (3)−0.005 (3)−0.014 (3)
C32B0.035 (3)0.081 (6)0.061 (4)0.010 (4)0.004 (3)0.024 (4)
C410.102 (3)0.053 (2)0.0321 (15)0.002 (2)0.0242 (16)−0.0109 (14)
C420.115 (3)0.082 (3)0.068 (2)0.019 (3)0.041 (2)−0.011 (2)
N10.0364 (11)0.0226 (10)0.0265 (10)0.0002 (9)0.0063 (8)−0.0030 (8)
O10.0856 (17)0.0391 (13)0.0525 (13)0.0256 (12)0.0007 (11)−0.0037 (10)
O20.0466 (12)0.0626 (15)0.0481 (12)0.0262 (11)−0.0087 (9)−0.0141 (11)
O30.0867 (16)0.0475 (13)0.0407 (11)−0.0182 (13)0.0234 (11)−0.0123 (10)
O40.0759 (15)0.0480 (13)0.0296 (9)−0.0057 (11)0.0112 (9)−0.0109 (9)
Geometric parameters (Å, °) top
C1—N11.460 (3)C21—C221.392 (3)
C1—C111.515 (3)C22—C231.382 (3)
C1—H1A0.9700C22—H220.9300
C1—H1B0.9700C23—C241.383 (4)
C2—N11.475 (3)C23—H230.9300
C2—C211.522 (3)C24—C251.373 (4)
C2—C41.533 (3)C24—H240.9300
C2—H20.9800C25—C261.380 (4)
C3—N11.464 (3)C25—H250.9300
C3—H3A0.9600C26—H260.9300
C3—H3B0.9600C31—C321.357 (6)
C3—H3C0.9600C31—C32B1.412 (7)
C4—C51.521 (4)C31—O21.457 (4)
C4—C61.528 (4)C31—H31A0.9700
C4—H40.9800C31—H31B0.9700
C5—O31.192 (3)C31—H31C0.9700
C5—O41.323 (3)C31—H31D0.9700
C6—O11.192 (3)C32—H31C1.2600
C6—O21.327 (4)C32—H32A0.9600
C11—C121.382 (3)C32—H32B0.9600
C11—C161.385 (3)C32—H32C0.9600
C12—C131.390 (4)C32B—H32D0.9600
C12—H120.9300C32B—H32E0.9600
C13—C141.370 (4)C32B—H32F0.9600
C13—H130.9300C41—O41.454 (3)
C14—C151.378 (4)C41—C421.497 (5)
C14—H140.9300C41—H41A0.9700
C15—C161.381 (4)C41—H41B0.9700
C15—H150.9300C42—H42A0.9600
C16—H160.9300C42—H42B0.9600
C21—C261.392 (3)C42—H42C0.9600
N1—C1—C11110.89 (19)C23—C24—H24120.2
N1—C1—H1A109.5C24—C25—C26120.0 (2)
C11—C1—H1A109.5C24—C25—H25120.0
N1—C1—H1B109.5C26—C25—H25120.0
C11—C1—H1B109.5C25—C26—C21121.5 (2)
H1A—C1—H1B108.0C25—C26—H26119.3
N1—C2—C21116.50 (19)C21—C26—H26119.3
N1—C2—C4107.57 (19)C32—C31—C32B51.0 (4)
C21—C2—C4112.69 (19)C32—C31—O2108.7 (4)
N1—C2—H2106.5C32B—C31—O2115.3 (4)
C21—C2—H2106.5C32—C31—H31A110.0
C4—C2—H2106.5C32B—C31—H31A134.6
N1—C3—H3A109.5O2—C31—H31A110.0
N1—C3—H3B109.5C32—C31—H31B110.0
H3A—C3—H3B109.5C32B—C31—H31B60.1
N1—C3—H3C109.5O2—C31—H31B110.0
H3A—C3—H3C109.5H31A—C31—H31B108.3
H3B—C3—H3C109.5C32—C31—H31C63.0
C5—C4—C6108.6 (2)C32B—C31—H31C108.5
C5—C4—C2111.5 (2)O2—C31—H31C108.5
C6—C4—C2107.79 (19)H31A—C31—H31C50.3
C5—C4—H4109.6H31B—C31—H31C140.9
C6—C4—H4109.6C32—C31—H31D142.7
C2—C4—H4109.6C32B—C31—H31D108.4
O3—C5—O4125.0 (2)O2—C31—H31D108.5
O3—C5—C4125.2 (2)H31A—C31—H31D59.1
O4—C5—C4109.8 (2)H31B—C31—H31D52.9
O1—C6—O2125.4 (3)H31C—C31—H31D107.5
O1—C6—C4125.0 (3)C31—C32—H31C43.3
O2—C6—C4109.6 (2)C31—C32—H32A109.5
C12—C11—C16118.6 (2)H31C—C32—H32A98.3
C12—C11—C1121.4 (2)C31—C32—H32B109.5
C16—C11—C1119.9 (2)H31C—C32—H32B74.8
C11—C12—C13120.6 (2)C31—C32—H32C109.5
C11—C12—H12119.7H31C—C32—H32C147.7
C13—C12—H12119.7C31—C32B—H32D109.5
C14—C13—C12120.2 (2)C31—C32B—H32E109.5
C14—C13—H13119.9H32D—C32B—H32E109.5
C12—C13—H13119.9C31—C32B—H32F109.5
C13—C14—C15119.6 (2)H32D—C32B—H32F109.5
C13—C14—H14120.2H32E—C32B—H32F109.5
C15—C14—H14120.2O4—C41—C42108.5 (3)
C14—C15—C16120.3 (3)O4—C41—H41A110.0
C14—C15—H15119.9C42—C41—H41A110.0
C16—C15—H15119.9O4—C41—H41B110.0
C15—C16—C11120.7 (2)C42—C41—H41B110.0
C15—C16—H16119.6H41A—C41—H41B108.4
C11—C16—H16119.6C41—C42—H42A109.5
C26—C21—C22117.9 (2)C41—C42—H42B109.5
C26—C21—C2119.5 (2)H42A—C42—H42B109.5
C22—C21—C2122.6 (2)C41—C42—H42C109.5
C23—C22—C21120.5 (2)H42A—C42—H42C109.5
C23—C22—H22119.7H42B—C42—H42C109.5
C21—C22—H22119.7C1—N1—C3110.74 (19)
C22—C23—C24120.6 (3)C1—N1—C2113.09 (19)
C22—C23—H23119.7C3—N1—C2114.98 (19)
C24—C23—H23119.7C6—O2—C31116.5 (3)
C25—C24—C23119.5 (3)C5—O4—C41118.2 (2)
C25—C24—H24120.2
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C32—H32A···O3i0.962.383.273 (3)155
Symmetry codes: (i) x−1, y, z.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C32—H32A···O3i0.962.383.273 (3)155
Symmetry codes: (i) x−1, y, z.
Acknowledgements top

This work was supported by grants from Project PGR-UMP-BH-2005, the Centre National de Recherche Scientifique, CNRS (France) and the Centre National pour la Recherche Scientifique et Technique, CNRST (Morocco).

references
References top

Allen, F. H., Kennard, O., Watson, D. G., Brammmer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2. pp. S1–19.

Bruker (2005). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.

Dayam, R., Al-Mawsawi, L. Q. & Neamati, N. (2007). Bioorg. Med. Chem. Lett. 17, 6155–6159.

Patil, S., Kamath, S., Sanchez, T., Neamati, N., Schinazi, R. F. & Buolamwini, J. K. (2007). Bioorg. Med. Chem. 15, 1212–1228.

Pommier, Y. & Neamati, N. (2006). Bioorg. Med. Chem. 14, 3785–3792.

Ramkumar, K., Tambov, K. V., Gundla, R., Manaev, A. V., Yarovenko, V., Traven, V. F. & Neamati, N. (2008). Bioorg. Med. Chem. 16, 8988–8998.

Sechi, M., Carta, F., Sannia, L., Dallocchio, R., Dessì, A., Al-Safi, R. I. & Neamati, N. (2009a). Antivir. Res. 81, 267–276.

Sechi, M., Rizzi, G., Bacchi, A., Carcelli, M., Rogolino, D., Pala, N., Sanchez, T. W., Taheri, L., Dayam, R. & Neamati, N. (2009b). Bioorg. Med. Chem. 17, 2925–2935.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Spek, A. L. (2009). Acta Cryst. D65, 148–155.

Westrip, S. P. (2010). publCIF. In preparation.

Zeng, L. F., Jiang, X. H., Sanchez, T., Zhang, H. S., Dayam, R., Neamati, N. & Long, Y. Q. (2008b). Bioorg. Med. Chem. 16, 7777–7787.

Zeng, L. F., Zhang, H.-S., Wang, Y. H., Sanchez, T., Zheng, Y. T., Neamati, N. & Long, Y. Q. (2008a). Bioorg. Med. Chem. Lett. 18, 4521–4524.