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Journal logoCRYSTALLOGRAPHIC
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ISSN: 2056-9890
Volume 68| Part 5| May 2012| Page o1572

(1S,2E,6R,7aR)-2-Benzyl­­idene-1,6-dihy­dr­oxy-2,3,5,6,7,7a-hexa­hydro-1H-pyrrolizin-3-one

aLaboratory of Structural Biology and Crystallography, Institute of Chemistry, University of Campinas, CP6154, CEP13083-970, Campinas, SP, Brazil, and bLaboratory of Synthesis of Natural Products and Drugs, Institute of Chemistry, University of Campinas, CP6154, CEP13083-970, Campinas, SP, Brazil
*Correspondence e-mail: aparicio@iqm.unicamp.br

(Received 17 March 2012; accepted 23 April 2012; online 28 April 2012)

In the title compound, C14H15NO3, the conformation of the double bond was determined to be E, confirming the result obtained from two-dimensional NMR data. The five-membered rings of the pyrrolizine unit exhibit C-envelope conformations, with C atoms displaced from the mean planes formed by the remaining rings atoms by 0.1468 (15) and 0.5405 (17) Å. The mean planes of these rings (through all ring atoms) have a dihedral angle of 49.03 (10)°. In the crystal, mol­ecules are linked by O—H⋯O hydrogen bonds. The absolute configuration of the mol­ecule was established, as judged by the, as judged by the obtained values for the Hooft and Flack parameters.

Related literature

For the preparation of the title compound, see: Freire et al. (2011[Freire, K. R. L., Tormena, C. F. & Coelho, F. (2011). Synlett, 14, 2059-2063.]). For the use of this type of compound as LFA-1 (Lymphocyte Function-Associated Anti­gen-1) inhibitors, see: Baumann (2007[Baumann, K. O. (2007). WO Patent 2007039286; Chem. Abstr. 146, 421836.]). For related structures, see: Oliveira et al. (2012a[Oliveira, F. L., Freire, K. R. L., Aparicio, R. & Coelho, F. (2012a). Acta Cryst. E68, o586.],b[Oliveira, F. L., Freire, K. R. L., Aparicio, R. & Coelho, F. (2012b). Acta Cryst. E68, o587.]).

[Scheme 1]

Experimental

Crystal data
  • C14H15NO3

  • Mr = 245.27

  • Orthorhombic, P 21 21 21

  • a = 6.5007 (3) Å

  • b = 13.6783 (7) Å

  • c = 13.8382 (7) Å

  • V = 1230.47 (11) Å3

  • Z = 4

  • Cu Kα radiation

  • μ = 0.77 mm−1

  • T = 100 K

  • 0.31 × 0.13 × 0.13 mm

Data collection
  • Bruker Kappa APEXII DUO diffractometer

  • Absorption correction: numerical (SADABS; Bruker, 2010[Bruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.924, Tmax = 1.000

  • 32528 measured reflections

  • 2219 independent reflections

  • 2203 reflections with I > 2σ(I)

  • Rint = 0.034

Refinement
  • R[F2 > 2σ(F2)] = 0.037

  • wR(F2) = 0.098

  • S = 1.06

  • 2219 reflections

  • 165 parameters

  • H-atom parameters constrained

  • Δρmax = 0.27 e Å−3

  • Δρmin = −0.23 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]) and Hooft et al. (2008[Hooft, R. W. W., Straver, L. H. & Spek, A. L. (2008). J. Appl. Cryst. 41, 96-103.]); Hooft parameter = 0.01(2), 905 Bijvoet pairs

  • Flack parameter: 0.1 (3)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1—H1⋯O3i 0.84 2.04 2.776 (2) 147
O3—H3⋯O2ii 0.84 1.85 2.6810 (17) 168
Symmetry codes: (i) [-x, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (ii) x-1, y, z.

Data collection: APEX2 (Bruker, 2010)[Bruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]; cell refinement: SAINT (Bruker, 2010[Bruker (2010). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; 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: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

Supporting information


Comment top

The title compound (Fig. 1) is a new asymmetric benzyl-pyrrolizidinone which has been synthesized from a chiral Morita-Baylis-Hillman adduct. It belongs to a class of compounds with potential pharmacological properties as mediators of the LFA-1 (lymphocyte function-associated antigen 1) function, particularly as anti-inflammatory agents and for the treatment of autoimmune diseases (Baumann, 2007). It has three defined stereocenters and a double bond with E configuration. The five membered rings N1/C3/C2/C1/C7A and N1/C5/C6/C7/C7A of the pyrrolizine moiety exhibit C2- and C5-envelope conformations, respectively, with C2 and C5 atoms displaced from the mean-planes formed by the remaining rings atoms by 0.1468 (15) and 0.5405 (17) Å, respectively. The mean planes of these rings have a dihedral angle of 49.03 (10)°. The configuration of the double bond determined by X-ray crystallography confirms the two-dimensional-NOESY NMR analysis. The crystal structure is stabilized by intermolecular hydrogen bonds (Tab. 1 and Fig. 2).

Related literature top

For the preparation of the title compound, see: Freire et al. (2011). For the use of this type of compound as LFA-1 (Lymphocyte Function-Associated Antigen-1) inhibitors, see: Baumann (2007). For related structures, see: Oliveira et al. (2012a,b).

Experimental top

The title compound was prepared using a synthetic sequence previously described (Freire et al., 2011) and purified by flash silica gel column chromatography (CH2Cl2:MeOH – solvent gradient: 100:0 to 95:05) to afford 0.14 g (as a white solid) in 76% yield, followed by recrystallization using the liquid-vapor saturation method. Subsequently, it was dissolved in ethanol and crystallized under the vapor pressure of ethyl ether (a less polar liquid), in a closed camera, thus allowing for the slow formation of good diffracting crystals.

Refinement top

The calculated Flack parameter was F = 0.1 (3) (Flack, 1983). Further analysis OF the absolute structure was performed with PLATON (Spek, 2009), using likelihood methods (Hooft et al., 2008). The calculated value for the Hooft parameter was y = 0.01 (2), with a corresponding probability of 1x10-100 for an inverted structure. These results unequivocally indicate that the absolute structure has been correctly assigned. All H atoms were placed in calculated positions with O—H = 0.84 Å and C—H = 0.95, 0.99 and 1.00 Å for aryl, methylene and methyne H-atoms, respectively, and refined in the riding model approximation with Uiso(H) = 1.5 Ueq(O) or 1.2 Ueq(C).

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); 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. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as small spheres of arbitrary radius.
[Figure 2] Fig. 2. A view of the hydrogen bonding interactions (dotted lines) in the crystal structure of the title compound. H atoms non-participating in hydrogen-bonding were omitted for clarity.
(1S,2E,6R,7aR)-2-Benzylidene-1,6-dihydroxy- 2,3,5,6,7,7a-hexahydro-1H-pyrrolizin-3-one top
Crystal data top
C14H15NO3Dx = 1.324 Mg m3
Mr = 245.27Cu Kα radiation, λ = 1.54178 Å
Orthorhombic, P212121Cell parameters from 2219 reflections
a = 6.5007 (3) Åθ = 4.6–68.1°
b = 13.6783 (7) ŵ = 0.77 mm1
c = 13.8382 (7) ÅT = 100 K
V = 1230.47 (11) Å3Rectangular, colourless
Z = 40.31 × 0.13 × 0.13 mm
F(000) = 520
Data collection top
Bruker Kappa APEXII DUO
diffractometer
2219 independent reflections
Radiation source: fine-focus sealed tube2203 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.034
Bruker APEX CCD area–detector scansθmax = 68.1°, θmin = 4.6°
Absorption correction: numerical
(SADABS; Bruker, 2010)
h = 75
Tmin = 0.924, Tmax = 1.000k = 1616
32528 measured reflectionsl = 1616
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.037H-atom parameters constrained
wR(F2) = 0.098 w = 1/[σ2(Fo2) + (0.0574P)2 + 0.2433P]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max < 0.001
2219 reflectionsΔρmax = 0.27 e Å3
165 parametersΔρmin = 0.23 e Å3
0 restraintsAbsolute structure: Flack (1983) and Hooft et al. (2008); Hooft parameter = 0.01(2), 905 Bijvoet pairs
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.1 (3)
Crystal data top
C14H15NO3V = 1230.47 (11) Å3
Mr = 245.27Z = 4
Orthorhombic, P212121Cu Kα radiation
a = 6.5007 (3) ŵ = 0.77 mm1
b = 13.6783 (7) ÅT = 100 K
c = 13.8382 (7) Å0.31 × 0.13 × 0.13 mm
Data collection top
Bruker Kappa APEXII DUO
diffractometer
2219 independent reflections
Absorption correction: numerical
(SADABS; Bruker, 2010)
2203 reflections with I > 2σ(I)
Tmin = 0.924, Tmax = 1.000Rint = 0.034
32528 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.037H-atom parameters constrained
wR(F2) = 0.098Δρmax = 0.27 e Å3
S = 1.06Δρmin = 0.23 e Å3
2219 reflectionsAbsolute structure: Flack (1983) and Hooft et al. (2008); Hooft parameter = 0.01(2), 905 Bijvoet pairs
165 parametersAbsolute structure parameter: 0.1 (3)
0 restraints
Special details top

Experimental. [α]D20 + 40 (c 1, MeOH); IR (Film, νmax): 3427, 3195, 2940, 2855, 1668, 1634, 1493, 1424, 1268, 1156, 1067 cm-1; 1H NMR (400 MHz, CD3CN) δ 1.30 (m, J = 13.8, 9.1, 5.4 Hz, 1H, H-14 A), 2.38 (m, J = 13.8, 6.8 Hz, 1H, H-14B), 3.27 (dd, J = 12.3, 6.1 Hz, 1H, H-2 A), 3.56 (dd, J = 12.3, 3.3 Hz, 1H, H-2B), 3.69 (ddd, J = 9.1, 7.4, 1.8 Hz, 1H, H-10), 4.47 (qd, J = 6.1, 3.3 Hz, 1H, H-1 A), 4.91 (dd, J = 1.8 Hz, 1H, H-11), 7.35 (d, J = 2.1 Hz, 1H, H-5), 7.41 (m, 3H, Ph), 7.79 (m, 2H, Ph); 13C NMR (62.5 MHz, (CD3)2CO) δ 38.1, 52.1, 68.2, 70.1, 72.0, 129.2, 130.3, 131.3, 134.1, 134.2, 137.1, 172.1; HRMS (ESI-TOF) Calcd. for C14H16NO3 [M + H]+ 246.1130. Found 246.1168.

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
O10.2407 (3)0.95636 (13)0.17238 (19)0.1020 (7)
H10.17251.00260.19620.153*
O20.52812 (19)0.71064 (10)0.18954 (10)0.0546 (3)
O30.14247 (18)0.65007 (11)0.28956 (12)0.0615 (4)
H30.25550.66530.26430.092*
N10.2098 (2)0.75095 (9)0.13314 (9)0.0364 (3)
C60.1266 (3)0.91174 (13)0.09912 (14)0.0478 (4)
H1A0.09300.95870.04600.057*
C50.2537 (3)0.82646 (13)0.06255 (12)0.0465 (4)
H2A0.20990.80630.00300.056*
H2B0.40210.84280.06140.056*
C30.3405 (2)0.71615 (11)0.20026 (12)0.0364 (3)
C20.2186 (2)0.68831 (11)0.28681 (11)0.0336 (3)
C40.3095 (2)0.64180 (11)0.36077 (11)0.0381 (3)
H50.44830.62370.34900.046*
C80.2326 (3)0.61406 (11)0.45626 (11)0.0389 (4)
C130.3573 (3)0.55253 (13)0.51150 (13)0.0498 (4)
H70.48640.53210.48640.060*
C120.2964 (4)0.52072 (15)0.60216 (14)0.0635 (6)
H80.38220.47790.63820.076*
C110.1114 (4)0.55125 (15)0.63990 (13)0.0631 (6)
H90.06870.52940.70190.076*
C7A0.0026 (2)0.75856 (12)0.16618 (11)0.0378 (3)
H100.08810.71140.12830.045*
C10.0020 (2)0.72470 (11)0.27237 (11)0.0364 (3)
H110.02530.78140.31620.044*
C100.0113 (4)0.61354 (15)0.58734 (13)0.0603 (5)
H120.13800.63530.61400.072*
C90.0468 (3)0.64509 (14)0.49607 (13)0.0498 (4)
H130.04010.68790.46070.060*
C70.0656 (3)0.86200 (15)0.13809 (16)0.0584 (5)
H14A0.17440.86030.08800.070*
H14B0.11890.89770.19510.070*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0789 (13)0.0675 (10)0.159 (2)0.0143 (9)0.0431 (13)0.0432 (12)
O20.0280 (6)0.0762 (9)0.0597 (7)0.0084 (6)0.0039 (5)0.0184 (7)
O30.0281 (6)0.0713 (9)0.0852 (10)0.0097 (6)0.0096 (6)0.0430 (8)
N10.0322 (6)0.0392 (6)0.0379 (6)0.0041 (5)0.0002 (5)0.0048 (5)
C60.0442 (9)0.0423 (8)0.0570 (10)0.0035 (7)0.0013 (8)0.0138 (8)
C50.0410 (10)0.0574 (10)0.0411 (8)0.0042 (7)0.0057 (7)0.0141 (7)
C30.0278 (8)0.0392 (8)0.0421 (8)0.0037 (6)0.0011 (6)0.0029 (6)
C20.0292 (7)0.0355 (7)0.0361 (7)0.0007 (6)0.0034 (6)0.0018 (6)
C40.0309 (7)0.0418 (8)0.0418 (8)0.0003 (6)0.0042 (6)0.0033 (7)
C80.0451 (9)0.0348 (7)0.0367 (8)0.0039 (7)0.0068 (7)0.0012 (6)
C130.0540 (11)0.0485 (10)0.0469 (9)0.0012 (8)0.0085 (8)0.0047 (8)
C120.0888 (16)0.0570 (11)0.0448 (10)0.0003 (11)0.0128 (11)0.0131 (9)
C110.0951 (16)0.0564 (11)0.0377 (9)0.0114 (11)0.0023 (10)0.0015 (8)
C7A0.0255 (7)0.0454 (8)0.0425 (8)0.0020 (6)0.0051 (6)0.0094 (6)
C10.0283 (7)0.0387 (7)0.0420 (8)0.0030 (6)0.0001 (6)0.0077 (6)
C100.0782 (14)0.0562 (10)0.0464 (9)0.0000 (11)0.0177 (10)0.0107 (8)
C90.0599 (11)0.0458 (9)0.0437 (9)0.0058 (8)0.0036 (8)0.0026 (7)
C70.0440 (10)0.0594 (11)0.0717 (12)0.0174 (8)0.0097 (9)0.0263 (10)
Geometric parameters (Å, º) top
O1—C61.397 (3)C8—C91.393 (3)
O1—H10.8400C8—C131.397 (2)
O2—C31.231 (2)C13—C121.386 (3)
O3—C11.4074 (19)C13—H70.9500
O3—H30.8400C12—C111.376 (4)
N1—C31.346 (2)C12—H80.9500
N1—C51.450 (2)C11—C101.375 (3)
N1—C7A1.458 (2)C11—H90.9500
C6—C51.517 (2)C7A—C71.524 (2)
C6—C71.521 (3)C7A—C11.541 (2)
C6—H1A1.0000C7A—H101.0000
C5—H2A0.9900C1—H111.0000
C5—H2B0.9900C10—C91.387 (3)
C3—C21.486 (2)C10—H120.9500
C2—C41.342 (2)C9—H130.9500
C2—C11.507 (2)C7—H14A0.9900
C4—C81.463 (2)C7—H14B0.9900
C4—H50.9500
C6—O1—H1109.5C8—C13—H7119.4
C1—O3—H3109.5C11—C12—C13119.9 (2)
C3—N1—C5126.33 (14)C11—C12—H8120.1
C3—N1—C7A113.99 (12)C13—C12—H8120.1
C5—N1—C7A110.30 (12)C10—C11—C12119.62 (18)
O1—C6—C5106.77 (16)C10—C11—H9120.2
O1—C6—C7111.99 (19)C12—C11—H9120.2
C5—C6—C7102.82 (14)N1—C7A—C7103.95 (13)
O1—C6—H1A111.6N1—C7A—C1105.03 (12)
C5—C6—H1A111.6C7—C7A—C1121.85 (16)
C7—C6—H1A111.6N1—C7A—H10108.4
N1—C5—C6102.46 (13)C7—C7A—H10108.4
N1—C5—H2A111.3C1—C7A—H10108.4
C6—C5—H2A111.3O3—C1—C2111.20 (12)
N1—C5—H2B111.3O3—C1—C7A111.48 (13)
C6—C5—H2B111.3C2—C1—C7A104.12 (12)
H2A—C5—H2B109.2O3—C1—H11110.0
O2—C3—N1124.34 (16)C2—C1—H11110.0
O2—C3—C2127.58 (15)C7A—C1—H11110.0
N1—C3—C2108.08 (12)C11—C10—C9121.1 (2)
C4—C2—C3120.10 (14)C11—C10—H12119.5
C4—C2—C1132.00 (14)C9—C10—H12119.5
C3—C2—C1107.86 (12)C10—C9—C8120.10 (19)
C2—C4—C8131.40 (15)C10—C9—H13120.0
C2—C4—H5114.3C8—C9—H13120.0
C8—C4—H5114.3C6—C7—C7A106.55 (14)
C9—C8—C13118.05 (16)C6—C7—H14A110.4
C9—C8—C4125.05 (15)C7A—C7—H14A110.4
C13—C8—C4116.90 (16)C6—C7—H14B110.4
C12—C13—C8121.3 (2)C7A—C7—H14B110.4
C12—C13—H7119.4H14A—C7—H14B108.6
C3—N1—C5—C6109.15 (17)C3—N1—C7A—C7130.55 (16)
C7A—N1—C5—C634.96 (17)C5—N1—C7A—C718.33 (18)
O1—C6—C5—N181.68 (19)C3—N1—C7A—C11.52 (18)
C7—C6—C5—N136.33 (18)C5—N1—C7A—C1147.35 (13)
C5—N1—C3—O231.5 (3)C4—C2—C1—O352.6 (2)
C7A—N1—C3—O2174.55 (16)C3—C2—C1—O3129.73 (14)
C5—N1—C3—C2147.63 (14)C4—C2—C1—C7A172.77 (17)
C7A—N1—C3—C24.63 (18)C3—C2—C1—C7A9.56 (16)
O2—C3—C2—C47.9 (3)N1—C7A—C1—O3126.78 (14)
N1—C3—C2—C4172.96 (14)C7—C7A—C1—O3115.79 (17)
O2—C3—C2—C1170.10 (17)N1—C7A—C1—C26.80 (16)
N1—C3—C2—C19.04 (17)C7—C7A—C1—C2124.23 (16)
C3—C2—C4—C8173.90 (15)C12—C11—C10—C91.0 (3)
C1—C2—C4—C83.5 (3)C11—C10—C9—C80.3 (3)
C2—C4—C8—C910.3 (3)C13—C8—C9—C101.1 (3)
C2—C4—C8—C13170.38 (17)C4—C8—C9—C10179.60 (17)
C9—C8—C13—C121.8 (3)O1—C6—C7—C7A88.1 (2)
C4—C8—C13—C12178.83 (17)C5—C6—C7—C7A26.1 (2)
C8—C13—C12—C111.1 (3)N1—C7A—C7—C65.9 (2)
C13—C12—C11—C100.3 (3)C1—C7A—C7—C6112.09 (18)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O3i0.842.042.776 (2)147
O3—H3···O2ii0.841.852.6810 (17)168
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x1, y, z.

Experimental details

Crystal data
Chemical formulaC14H15NO3
Mr245.27
Crystal system, space groupOrthorhombic, P212121
Temperature (K)100
a, b, c (Å)6.5007 (3), 13.6783 (7), 13.8382 (7)
V3)1230.47 (11)
Z4
Radiation typeCu Kα
µ (mm1)0.77
Crystal size (mm)0.31 × 0.13 × 0.13
Data collection
DiffractometerBruker Kappa APEXII DUO
diffractometer
Absorption correctionNumerical
(SADABS; Bruker, 2010)
Tmin, Tmax0.924, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
32528, 2219, 2203
Rint0.034
(sin θ/λ)max1)0.602
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.098, 1.06
No. of reflections2219
No. of parameters165
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.27, 0.23
Absolute structureFlack (1983) and Hooft et al. (2008); Hooft parameter = 0.01(2), 905 Bijvoet pairs
Absolute structure parameter0.1 (3)

Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2010), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O3i0.842.042.776 (2)146.6
O3—H3···O2ii0.841.852.6810 (17)168.4
Symmetry codes: (i) x, y+1/2, z+1/2; (ii) x1, y, z.
 

Acknowledgements

The authors acknowledge the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for financial support. FLO and KRLF were supported by bursaries from CAPES and CNPq, respectively. KRLF is currently a FAPESP post-doctoral fellow. RA and FC are recipients of research grants from CNPq.

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Volume 68| Part 5| May 2012| Page o1572
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