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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 69| Part 4| April 2013| Pages o567-o568

N-But­­oxy­carbonyl-5-oxo-L-proline ethyl ester

aDepartment of Physics, Thiagarajar College, Madurai 625 009, India, and bX-ray Crystallography Unit, school of Physics, Universiti Sains Malaysia, 11800-USM, Penang, Malaysia
*Correspondence e-mail: vasan692000@yahoo.co.in

(Received 4 March 2013; accepted 17 March 2013; online 23 March 2013)

The mol­ecular structure of the title compound, C12H19NO5, may be visualized as made up of two nearly perpendicular planes [dihedral angle = 87.39 (12)°] and its crystal structure is a good example of C—H⋯O inter­actions assuming significance in optimizing supra­molecular aggregation in crystals in a mol­ecule which is severely imbalanced in terms of donors to acceptor atoms. The pyrrolidine ring adopts a (3T2) twist conformation with puckering parameters Q = 0.2630 (4) Å and φ = 59 (9)°. The crystal structure features R24(10) and R34(26) ring motifs formed by four weak C—H⋯O inter­actions, leading to supra­molecular sheets lying parallel to the bc plane.

Related literature

For general background, see: Holladay et al. (1991[Holladay, M. W., Lin, N., May, C. S., Garvey, D. S., Witte, D. G., Miller, T. G., Wolfram, A. W. & Nadzan, A. M. (1991). J. Med. Chem. 34, 455-457.]); Kayushina & Vainshtein (1966[Kayushina, R. L. & Vainshtein, B. K. (1966). Soviet Phys. Crystallogr. 10, 698-706.]); Wu (2009[Wu, G. (2009). Amino Acids, 37, 1-17.]). For the biological activity of proline derivatives, see: Hayashi et al. (2003[Hayashi, S., Tajkhorshid, E. & Schulten, K. (2003). Biophys. J. 85, 1440-1449.]); Nishikawa & Murakami (2005[Nishikawa, T. & Murakami, M. (2005). J. Mol. Biol. 352, 319-328.]). For hydrogen bonding, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N. L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]). For puckering parameters, see: Cremer & Pople (1975[Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.]). For a description of the Cambridge Structural Database, see: Allen (2002[Allen, F. H. (2002). Acta Cryst. B58, 380-388.]).

[Scheme 1]

Experimental

Crystal data
  • C12H19NO5

  • Mr = 257.28

  • Orthorhombic, P 21 21 21

  • a = 26.6884 (13) Å

  • b = 5.7650 (3) Å

  • c = 8.7054 (4) Å

  • V = 1339.40 (11) Å3

  • Z = 4

  • Cu Kα radiation

  • μ = 0.83 mm−1

  • T = 100 K

  • 0.44 × 0.21 × 0.11 mm

Data collection
  • Bruker SMART APEXII CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.711, Tmax = 0.914

  • 9641 measured reflections

  • 2184 independent reflections

  • 2144 reflections with I > 2σ(I)

  • Rint = 0.049

Refinement
  • R[F2 > 2σ(F2)] = 0.060

  • wR(F2) = 0.166

  • S = 1.09

  • 2184 reflections

  • 167 parameters

  • H-atom parameters constrained

  • Δρmax = 0.37 e Å−3

  • Δρmin = −0.22 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C2—H2A⋯O3i 1.00 2.51 3.436 (5) 154
C3—H3B⋯O3ii 0.99 2.46 3.095 (5) 121
C6—H6B⋯O5iii 0.99 2.50 3.344 (5) 143
C12—H12A⋯O5i 0.98 2.55 3.327 (5) 136
Symmetry codes: (i) x, y-1, z; (ii) [-x+2, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]; (iii) x, y, z+1.

Data collection: APEX2 (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2009[Bruker (2009). 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

Proline (Kayushina & Vainshtein, 1966) is a functional amino acid that participates in the regulation of key metabolic pathways essential for maintenance, growth, reproduction and immunity (Wu, 2009). Many substituted proline derivatives are known for their active role in biological functions. For instance, 5-oxo-proline or pyroglutamic acid, found in many proteins including bacteriorhodopsin, acts as a proton pump, captures light energy and uses it to move protons across the membrane out of the cell (Hayashi, et al., 2003; Nishikawa, et al., 2005). Also, N-boc-4-oxo-L-proline ethyl ester is a part of the starting material on stereoselective synthesis of peptide hormone cholecystokinin (Holladay, et al., 1991). The present paper describes the accurate description of the crystal structures of N-boc-5-oxo-L-proline ethyl ester (Fig.1).

The molecular mainframe of the title compound may be visualized as made up of two nearly perpendicular planes (N1/C8/O4/O5) and (O1/C1/O2/C2) with 87.39 (12) °. The orientation of the carbonyl O3 (substituted to the pyrrolidine ring), O4 (ethyl ester carbonyl) and O5 (tert-butyloxycarbonyl) may be described by the torsion angles about the C2—N1 bond which are -171.05 (4) °, -54.37 (6) ° and -170.82 (4) °, respectively. The pyrrolidine adopts the twisted conformation (3T2) with C2 and C3 atoms deviating from the plane defined by the rest of the atoms by about -0.3872 (6) Å and 0.4068 (6) Å, respectively with the associated puckering parameters (Cremer & Pople, 1975) of Q=0.2630 (4) Å, ϕ= 59 (9) °.

The crystal structure of the title compound is a simple example which demonstrates the importance of weak C–H···O interactions assuming significance in optimizing supramolecular aggregation in crystals. The molecule may be thought of as highly imbalanced in terms of donors to acceptor atoms which has at least three carbonyl O atoms O3, O4 and O5, out of the total five O atoms (O1O5), available for participation in intermolecular interactions. O1 and O2 of the respective ethyl ester and the tert-butyloxy groups do not participate in the hydrogen-bonding environment owing to unfavourable steric reasons. The intermolecular interaction patterns may be vizualized as molecular chains interconnected to each other to form a sheet. The ethyl C2 and ethyl C3 atoms act as donors to the carbonyl O3 which is a bifurcated acceptor at (x, y - 1, z) and (-x + 2, y - 1/2, -z + 1/2), respectively. The associated graph-set motif (Bernstein et al., 1995) is a R42(10) ring through C2—H2A···O3 and C3—H3A···O3 hydrogen bond leading to chains parallel to the b-axis (Fig.2). The ethyl C6 and ethyl C12 atoms act as donors to the bifurcated acceptor (carbonyl) O5 at (x, y, z + 1) and (x, y - 1, z), respectively, forming a R43 (26) ring motif through a C6—H6B···O5 and C12—H12A···O5 hydrogen bonds forming sheets parallel to the bc-plane (Fig.3).

Related literature top

For general background, see: Holladay et al. (1991); Kayushina & Vainshtein (1966); Wu (2009). For the biological activity of proline derivatives, see: Hayashi et al. (2003); Nishikawa & Murakami (2005). For hydrogen bonding, see: Bernstein et al. (1995). For puckering parameters, see: Cremer & Pople (1975). For a description of the Cambridge Structural Database, see: Allen (2002).

Experimental top

To a solution of oxo proline ethylester (0.5 g,3.26 mmol) in dichloromethane (10 ml), was added triethylamine (0.5 ml, 3.26 mmol), di-tert-butyl-dicarbonate (1.4 g, 6.52 mmol) and 4-(dimethylamino)-pyridine (0.4 g, 3.26 mmol) under N2. The resulting yellow solution was stirred at room temperature for 2 h. The reaction mixture was concentrated. The residue was purified by column chromatography to afford boc-oxo-L-proline ethylester (0.8 g, 95%). Crystals of the title compound were grown from its solution in ethanol by slow evaporation at room temperature.

Refinement top

All the hydrogen atoms were placed at geometrically calculated positions. They were allowed to ride on respective parent atoms with Uiso values constrained to 1.2 times Ueq (1.5 times for ethyl H atoms) and the target C—H distance fixed at 0.96 Å for ethyl hydrogen atoms and 0.93 Å for all others.

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); 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 molecule of title compound, showing the atom-labeling scheme. Displacement ellipsoids are drawn at the 50% probability.
[Figure 2] Fig. 2. Part of the crystal structure of title compound, showing the formation of a R42(10) chain running parallel to the b-axis. Dashed lines indicate hydrogen bonds. For the sake of clarity, H atoms are omitted.
[Figure 3] Fig. 3. Part of the crystal structure of title compound, showing the formation of supramolecular sheets of R43(26) ring parallel to the bc-plane. Dashed lines indicate hydrogen bonds. For the sake of clarity, H atoms bonded to C atoms have been omitted
N-Butoxycarbonyl-5-oxo-L-proline ethyl ester top
Crystal data top
C12H19NO5F(000) = 552
Mr = 257.28Dx = 1.276 Mg m3
Orthorhombic, P212121Cu Kα radiation, λ = 1.54178 Å
Hall symbol: P 2ac 2abCell parameters from 2145 reflections
a = 26.6884 (13) Åθ = 5.2–67.7°
b = 5.7650 (3) ŵ = 0.83 mm1
c = 8.7054 (4) ÅT = 100 K
V = 1339.40 (11) Å3Block, colourless
Z = 40.44 × 0.21 × 0.11 mm
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
2184 independent reflections
Radiation source: fine-focus sealed tube2144 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.049
ϕ and ω scansθmax = 65.0°, θmin = 7.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
h = 3131
Tmin = 0.711, Tmax = 0.914k = 56
9641 measured reflectionsl = 1010
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)] = 0.060Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.166H-atom parameters constrained
S = 1.09 w = 1/[σ2(Fo2) + (0.0688P)2 + 1.9721P]
where P = (Fo2 + 2Fc2)/3
2184 reflections(Δ/σ)max < 0.001
167 parametersΔρmax = 0.37 e Å3
0 restraintsΔρmin = 0.22 e Å3
Crystal data top
C12H19NO5V = 1339.40 (11) Å3
Mr = 257.28Z = 4
Orthorhombic, P212121Cu Kα radiation
a = 26.6884 (13) ŵ = 0.83 mm1
b = 5.7650 (3) ÅT = 100 K
c = 8.7054 (4) Å0.44 × 0.21 × 0.11 mm
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
2184 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
2144 reflections with I > 2σ(I)
Tmin = 0.711, Tmax = 0.914Rint = 0.049
9641 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0600 restraints
wR(F2) = 0.166H-atom parameters constrained
S = 1.09Δρmax = 0.37 e Å3
2184 reflectionsΔρmin = 0.22 e Å3
167 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
O10.90408 (10)0.9206 (5)0.6629 (3)0.0370 (7)
O40.87203 (9)0.6029 (5)0.3651 (3)0.0363 (6)
O30.95830 (10)1.1864 (5)0.2879 (3)0.0385 (6)
O20.91287 (10)0.5496 (5)0.7415 (3)0.0418 (7)
O50.88646 (10)0.8660 (5)0.1762 (3)0.0390 (7)
N10.93969 (11)0.8201 (6)0.3819 (3)0.0322 (7)
C50.96730 (14)1.0270 (7)0.3731 (4)0.0336 (8)
C41.00831 (15)1.0151 (7)0.4918 (4)0.0386 (9)
H4A1.00151.12350.57740.046*
H4B1.04111.05490.44560.046*
C31.00806 (15)0.7635 (7)0.5485 (4)0.0378 (9)
H3A1.01480.75610.66030.045*
H3B1.03350.67000.49380.045*
C20.95504 (14)0.6769 (7)0.5120 (4)0.0346 (8)
H2A0.95630.51030.48030.042*
C10.92075 (14)0.7041 (7)0.6499 (4)0.0362 (9)
C60.87505 (15)0.9735 (8)0.8004 (4)0.0412 (9)
H6A0.87601.14270.81950.049*
H6B0.89040.89480.88980.049*
C70.82162 (16)0.8971 (8)0.7847 (5)0.0473 (10)
H7A0.80250.94920.87440.071*
H7B0.82030.72760.77810.071*
H7C0.80720.96470.69150.071*
C80.89734 (14)0.7707 (7)0.2939 (4)0.0351 (9)
C90.82710 (14)0.4960 (7)0.2939 (5)0.0414 (9)
C100.81499 (16)0.3074 (8)0.4085 (6)0.0484 (11)
H10A0.84270.19630.41260.073*
H10B0.78430.22710.37690.073*
H10C0.81010.37640.51020.073*
C110.78525 (15)0.6769 (8)0.2898 (6)0.0510 (11)
H11A0.78140.74630.39200.077*
H11B0.75380.60230.25970.077*
H11C0.79370.79810.21530.077*
C120.83972 (17)0.3976 (8)0.1365 (5)0.0483 (11)
H12A0.86950.29860.14440.072*
H12B0.84640.52510.06500.072*
H12C0.81140.30560.09870.072*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0497 (15)0.0307 (15)0.0307 (14)0.0008 (11)0.0045 (11)0.0004 (11)
O40.0413 (14)0.0347 (15)0.0327 (14)0.0024 (11)0.0049 (11)0.0012 (11)
O30.0514 (15)0.0343 (15)0.0299 (13)0.0023 (12)0.0013 (11)0.0055 (13)
O20.0514 (16)0.0403 (17)0.0337 (14)0.0004 (12)0.0029 (12)0.0086 (13)
O50.0558 (16)0.0319 (15)0.0292 (14)0.0016 (12)0.0065 (11)0.0035 (11)
N10.0416 (16)0.0317 (17)0.0233 (14)0.0021 (13)0.0015 (13)0.0043 (14)
C50.043 (2)0.033 (2)0.0250 (17)0.0001 (16)0.0050 (15)0.0017 (17)
C40.044 (2)0.042 (2)0.0294 (19)0.0046 (18)0.0010 (16)0.0040 (18)
C30.042 (2)0.043 (2)0.0288 (19)0.0037 (17)0.0004 (15)0.0043 (17)
C20.044 (2)0.029 (2)0.0311 (18)0.0025 (16)0.0027 (15)0.0054 (16)
C10.0379 (19)0.041 (2)0.0293 (19)0.0021 (16)0.0072 (15)0.0011 (18)
C60.051 (2)0.045 (2)0.0272 (18)0.0005 (18)0.0077 (17)0.0008 (18)
C70.052 (2)0.046 (3)0.044 (2)0.0044 (19)0.0069 (19)0.002 (2)
C80.041 (2)0.030 (2)0.034 (2)0.0048 (15)0.0007 (16)0.0002 (16)
C90.041 (2)0.034 (2)0.048 (2)0.0004 (17)0.0083 (17)0.005 (2)
C100.048 (2)0.037 (3)0.061 (3)0.0058 (18)0.001 (2)0.004 (2)
C110.044 (2)0.040 (3)0.069 (3)0.0004 (18)0.011 (2)0.003 (3)
C120.064 (3)0.037 (2)0.044 (2)0.002 (2)0.015 (2)0.003 (2)
Geometric parameters (Å, º) top
O1—C11.330 (5)C6—C71.499 (6)
O1—C61.458 (4)C6—H6A0.9900
O4—C81.332 (5)C6—H6B0.9900
O4—C91.484 (5)C7—H7A0.9800
O3—C51.205 (5)C7—H7B0.9800
O2—C11.214 (5)C7—H7C0.9800
O5—C81.198 (5)C9—C101.510 (6)
N1—C81.395 (5)C9—C121.521 (6)
N1—C51.404 (5)C9—C111.529 (6)
N1—C21.461 (5)C10—H10A0.9800
C5—C41.506 (5)C10—H10B0.9800
C4—C31.533 (6)C10—H10C0.9800
C4—H4A0.9900C11—H11A0.9800
C4—H4B0.9900C11—H11B0.9800
C3—C21.534 (5)C11—H11C0.9800
C3—H3A0.9900C12—H12A0.9800
C3—H3B0.9900C12—H12B0.9800
C2—C11.517 (5)C12—H12C0.9800
C2—H2A1.0000
C1—O1—C6116.4 (3)H6A—C6—H6B107.9
C8—O4—C9121.1 (3)C6—C7—H7A109.5
C8—N1—C5124.7 (3)C6—C7—H7B109.5
C8—N1—C2122.5 (3)H7A—C7—H7B109.5
C5—N1—C2112.0 (3)C6—C7—H7C109.5
O3—C5—N1125.2 (3)H7A—C7—H7C109.5
O3—C5—C4127.0 (4)H7B—C7—H7C109.5
N1—C5—C4107.8 (3)O5—C8—O4127.4 (4)
C5—C4—C3105.1 (3)O5—C8—N1124.9 (4)
C5—C4—H4A110.7O4—C8—N1107.7 (3)
C3—C4—H4A110.7O4—C9—C10101.3 (3)
C5—C4—H4B110.7O4—C9—C12110.6 (3)
C3—C4—H4B110.7C10—C9—C12111.9 (4)
H4A—C4—H4B108.8O4—C9—C11108.5 (3)
C4—C3—C2104.2 (3)C10—C9—C11110.5 (4)
C4—C3—H3A110.9C12—C9—C11113.3 (4)
C2—C3—H3A110.9C9—C10—H10A109.5
C4—C3—H3B110.9C9—C10—H10B109.5
C2—C3—H3B110.9H10A—C10—H10B109.5
H3A—C3—H3B108.9C9—C10—H10C109.5
N1—C2—C1112.7 (3)H10A—C10—H10C109.5
N1—C2—C3103.6 (3)H10B—C10—H10C109.5
C1—C2—C3111.0 (3)C9—C11—H11A109.5
N1—C2—H2A109.8C9—C11—H11B109.5
C1—C2—H2A109.8H11A—C11—H11B109.5
C3—C2—H2A109.8C9—C11—H11C109.5
O2—C1—O1125.1 (4)H11A—C11—H11C109.5
O2—C1—C2123.3 (4)H11B—C11—H11C109.5
O1—C1—C2111.5 (3)C9—C12—H12A109.5
O1—C6—C7111.7 (3)C9—C12—H12B109.5
O1—C6—H6A109.3H12A—C12—H12B109.5
C7—C6—H6A109.3C9—C12—H12C109.5
O1—C6—H6B109.3H12A—C12—H12C109.5
C7—C6—H6B109.3H12B—C12—H12C109.5
C8—N1—C5—O30.8 (6)N1—C2—C1—O2149.4 (4)
C2—N1—C5—O3171.0 (4)C3—C2—C1—O294.8 (4)
C8—N1—C5—C4177.3 (3)N1—C2—C1—O135.4 (4)
C2—N1—C5—C47.1 (4)C3—C2—C1—O180.3 (4)
O3—C5—C4—C3171.4 (4)C1—O1—C6—C781.1 (4)
N1—C5—C4—C310.6 (4)C9—O4—C8—O55.8 (6)
C5—C4—C3—C223.0 (4)C9—O4—C8—N1174.7 (3)
C8—N1—C2—C172.0 (4)C5—N1—C8—O519.8 (6)
C5—N1—C2—C198.5 (4)C2—N1—C8—O5170.9 (4)
C8—N1—C2—C3167.9 (3)C5—N1—C8—O4159.7 (3)
C5—N1—C2—C321.6 (4)C2—N1—C8—O49.5 (5)
C4—C3—C2—N126.7 (4)C8—O4—C9—C10175.3 (3)
C4—C3—C2—C194.6 (4)C8—O4—C9—C1256.5 (5)
C6—O1—C1—O21.3 (5)C8—O4—C9—C1168.4 (4)
C6—O1—C1—C2173.7 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2A···O3i1.002.513.436 (5)154
C3—H3B···O3ii0.992.463.095 (5)121
C6—H6B···O5iii0.992.503.344 (5)143
C12—H12A···O5i0.982.553.327 (5)136
Symmetry codes: (i) x, y1, z; (ii) x+2, y1/2, z+1/2; (iii) x, y, z+1.

Experimental details

Crystal data
Chemical formulaC12H19NO5
Mr257.28
Crystal system, space groupOrthorhombic, P212121
Temperature (K)100
a, b, c (Å)26.6884 (13), 5.7650 (3), 8.7054 (4)
V3)1339.40 (11)
Z4
Radiation typeCu Kα
µ (mm1)0.83
Crystal size (mm)0.44 × 0.21 × 0.11
Data collection
DiffractometerBruker SMART APEXII CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2009)
Tmin, Tmax0.711, 0.914
No. of measured, independent and
observed [I > 2σ(I)] reflections
9641, 2184, 2144
Rint0.049
(sin θ/λ)max1)0.588
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.060, 0.166, 1.09
No. of reflections2184
No. of parameters167
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.37, 0.22

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

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2A···O3i1.002.513.436 (5)154
C3—H3B···O3ii0.992.463.095 (5)121
C6—H6B···O5iii0.992.503.344 (5)143
C12—H12A···O5i0.982.553.327 (5)136
Symmetry codes: (i) x, y1, z; (ii) x+2, y1/2, z+1/2; (iii) x, y, z+1.
 

Acknowledgements

The authors thank Dr MutharasuDevarajan, Associate Professor, and the staff of the X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, for their help with the data collection.

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Volume 69| Part 4| April 2013| Pages o567-o568
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