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

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ISSN: 2056-9890

rac-Ethyl 6-hy­dr­oxy-6-methyl-3-oxo-4-phenyl-1,3,4,5,6,7-hexa­hydro­benzo[c][1,2]oxazole-5-carboxyl­ate

aBaku State University, Z. Khalilov St. 23, Baku AZ-1148, Azerbaijan
*Correspondence e-mail: mammadova.87@mail.ru

(Received 1 June 2011; accepted 13 October 2011; online 22 October 2011)

In the title compound, C17H19NO5, the cyclo­hexene ring is in a half-chair conformation and the isoxazole ring in an envelope conformation with the N atom as the flap. The C atoms in the 4- and 6-positions are of the same absolute configuration, whereas the C atom in the 5-position is of the opposite configuration, i.e. (4S*,5R*,6S*). The methyl fragment of the eth­oxy­carbonyl group at position 5 is disordered over two sets of sites in a 0.60:0.40 ratio. The crystal packing displays inter­molecular N—H⋯O and O—H⋯O hydrogen bonds.

Related literature

For general background to the synthesis of isoxazoles, see: Kashima et al. (1981[Kashima, C., Yoshihara, N. & Shirai, S. I. (1981). Heterocycles, 16, 145.]); Goda et al. (2003[Goda, F. E., Maroul, A. R. & El-Bendory, E. R. (2003). Saudi Pharm. J. 3, 111-117.]).

[Scheme 1]

Experimental

Crystal data
  • C17H19NO5

  • Mr = 317.33

  • Monoclinic, P 21

  • a = 6.0712 (6) Å

  • b = 13.4343 (13) Å

  • c = 10.0821 (10) Å

  • β = 96.882 (2)°

  • V = 816.39 (14) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 296 K

  • 0.30 × 0.20 × 0.20 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1998[Sheldrick, G. M. (1998). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.972, Tmax = 0.981

  • 9534 measured reflections

  • 4059 independent reflections

  • 2458 reflections with I > 2σ(I)

  • Rint = 0.049

Refinement
  • R[F2 > 2σ(F2)] = 0.059

  • wR(F2) = 0.115

  • S = 1.00

  • 4059 reflections

  • 218 parameters

  • 3 restraints

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.17 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
N1—H1A⋯O6 0.90 1.991 2.846 (3) 159
O6—H6A⋯O3 0.82 1.95 2.767 (3) 171

Data collection: APEX2 (Bruker, 2005[Bruker (2005). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT-Plus (Bruker, 2001[Bruker (2001). SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT-Plus; 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.

Supporting information


Comment top

The wide range of biological activities of isoxazoles has made them popular synthetic targets. Numerous methods for the synthesis of these heterocycles involve approaches based on either intermolecular cycloaddition of 1,3-dipoles to alkynes or condensations of hydroxylamine with β-diketone equivalent with three carbon 1,3-difunctionalized units bearing sp or sp2 carbons, such as propargylic ketones (Kashima et al.1981). Synthesis of isoxazole derivatives has been a subject of consistent interest because of the wide applications of such heterocycles in pharmaceutical and agrochemical industry (Goda et al. 2003). The structure of ethyl-6-hydroxy-6-methyl-3-oxo-4-phenyl-1,3,4,5,6,7- hexahydrobenzo[c]\ isoxazole-5-carboxylate is (I) reported here (Fig. 1). The cyclohexene ring has a half-chair conformation. The phenyl ring is in a pseudo-equatorial position. The torsion angle between the ethoxycarbonyl group and the phenyl substituent C8—C4—C5—C14 is 60.6 (3) which indicates the pseudo-axial location of hydrogen atoms at C4 and C5. The izoxazole ring has an envelope conformation [the torsion angles C7a—N1—O2—C3 is -6.9 (3)° and N1—O2—C3—C3A is 5.2 (3)°]. The title compound (I) is chiral with three stereogenic centres-(4S*,5R*,6S*). The crystal structure involves intermolecular N—H···O and O—H···O hydrogen bonds (Table 1, Fig. 2).

Related literature top

For general background to the synthesis of isoxazoles, see: Kashima et al. (1981); Goda et al. (2003).

Experimental top

(rac)-Diethyl-4-hydroxy-4-methyl-6-oxo-2-phenyl-1,3-dicarboxylate (20 mmol), hydroxylamine hydrochloride (20 mmol) were dissolved in 20 ml e thanol. Then, 2 drops of H2SO4 were added and mixture was stirred at 345–350 K for 10 h. After cooling to a room temperature white crystals were obtained. The crystals were filtered off and washed with ethanol. Then, they were dissolved in ethanol (50 ml)and recrystallized to yield colourless block-shaped crystals of the title compound.

Refinement top

The hydrogen atoms of the NH and OH-groups (I) molecule were localized in the difference-Fourier map and included in the refinement with fixed positional and isotropic displacement parameters [Uiso(H) = 1.5Ueq(C) for CH3-group and Uiso(H) = 1.2Ueq(N) for amino groups]. The other hydrogen atoms were placed in calculated positions with and refined in the riding model with fixed isotropic displacement parameters [Uiso(H) = 1.2Ueq(C)].

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus (Bruker, 2001); 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).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
[Figure 2] Fig. 2. The hydrogen-bonding (dashed lines) in crystal packing of the title compound. H atoms not involved in hydrogen bonding have been omitted for clarity.
rac-Ethyl 6-hydroxy-6-methyl-3-oxo-4-phenyl-1,3,4,5,6,7- hexahydrobenzo[c][1,2]oxazole-5-carboxylate top
Crystal data top
C17H19NO5F(000) = 336
Mr = 317.33Dx = 1.291 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ybCell parameters from 1319 reflections
a = 6.0712 (6) Åθ = 2.5–21.8°
b = 13.4343 (13) ŵ = 0.10 mm1
c = 10.0821 (10) ÅT = 296 K
β = 96.882 (2)°Prism, colourless
V = 816.39 (14) Å30.30 × 0.20 × 0.20 mm
Z = 2
Data collection top
Bruker APEXII CCD
diffractometer
4059 independent reflections
Radiation source: fine-focus sealed tube2458 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.049
phi and ω scansθmax = 28.4°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1998)
h = 88
Tmin = 0.972, Tmax = 0.981k = 1717
9534 measured reflectionsl = 1313
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)] = 0.059Hydrogen site location: difference Fourier map
wR(F2) = 0.115H atoms treated by a mixture of independent and constrained refinement
S = 1.00 w = 1/[σ2(Fo2) + (0.0469P)2]
where P = (Fo2 + 2Fc2)/3
4059 reflections(Δ/σ)max < 0.001
218 parametersΔρmax = 0.17 e Å3
3 restraintsΔρmin = 0.15 e Å3
Crystal data top
C17H19NO5V = 816.39 (14) Å3
Mr = 317.33Z = 2
Monoclinic, P21Mo Kα radiation
a = 6.0712 (6) ŵ = 0.10 mm1
b = 13.4343 (13) ÅT = 296 K
c = 10.0821 (10) Å0.30 × 0.20 × 0.20 mm
β = 96.882 (2)°
Data collection top
Bruker APEXII CCD
diffractometer
4059 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1998)
2458 reflections with I > 2σ(I)
Tmin = 0.972, Tmax = 0.981Rint = 0.049
9534 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0593 restraints
wR(F2) = 0.115H atoms treated by a mixture of independent and constrained refinement
S = 1.00Δρmax = 0.17 e Å3
4059 reflectionsΔρmin = 0.15 e Å3
218 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*/UeqOcc. (<1)
N11.0157 (4)0.39444 (17)1.0327 (2)0.0438 (6)
H1A1.144 (6)0.412 (3)1.008 (4)0.080 (12)*
O21.0458 (3)0.29676 (15)1.08762 (19)0.0483 (5)
O30.8411 (3)0.15884 (16)1.0854 (2)0.0596 (6)
O40.0789 (3)0.33341 (17)0.7160 (2)0.0632 (6)
O50.2738 (4)0.33256 (18)0.5417 (2)0.0645 (6)
O60.3701 (3)0.47677 (14)0.90741 (18)0.0455 (5)
H6A0.31540.53270.90280.068*
C30.8575 (4)0.2429 (2)1.0425 (3)0.0407 (7)
C3A0.7212 (4)0.30374 (18)0.9509 (2)0.0328 (6)
C40.5086 (4)0.27814 (19)0.8668 (3)0.0351 (6)
H4A0.38670.28490.92170.042*
C50.4751 (4)0.35572 (19)0.7527 (3)0.0354 (6)
H5A0.58900.34290.69370.042*
C60.5070 (4)0.46411 (19)0.8025 (3)0.0398 (7)
C70.7502 (4)0.4776 (2)0.8598 (3)0.0419 (6)
H7A0.84120.48330.78740.050*
H7B0.76650.53840.91190.050*
C7A0.8259 (4)0.39149 (19)0.9458 (3)0.0374 (7)
C80.5037 (4)0.17410 (18)0.8103 (3)0.0339 (6)
C90.6769 (5)0.1395 (2)0.7449 (3)0.0464 (7)
H9A0.80010.17990.73980.056*
C100.6695 (6)0.0463 (2)0.6873 (4)0.0627 (9)
H10A0.78570.02480.64210.075*
C110.4910 (6)0.0146 (2)0.6965 (3)0.0619 (9)
H11A0.48650.07770.65840.074*
C120.3196 (5)0.0175 (2)0.7619 (3)0.0548 (8)
H12A0.19880.02400.76870.066*
C130.3256 (5)0.1115 (2)0.8177 (3)0.0425 (7)
H13A0.20740.13290.86110.051*
C140.2531 (5)0.3393 (2)0.6713 (3)0.0438 (7)
C150.0727 (7)0.3158 (3)0.4504 (4)0.0902 (13)
H15A0.08260.34500.36330.108*
H15B0.05780.34120.48600.108*
C160.074 (2)0.2027 (3)0.445 (2)0.110 (4)0.60
H16A0.03660.17660.52840.165*0.60
H16B0.21920.17990.43100.165*0.60
H16C0.03240.18020.37360.165*0.60
C16'0.009 (4)0.2095 (5)0.427 (4)0.110 (4)0.40
H16D0.08200.17570.37020.165*0.40
H16E0.16010.21020.38620.165*0.40
H16F0.00110.17530.51150.165*0.40
C170.4449 (5)0.5384 (2)0.6916 (3)0.0588 (9)
H17A0.28850.53430.66300.088*
H17B0.52560.52370.61760.088*
H17C0.48120.60440.72370.088*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0367 (14)0.0418 (15)0.0536 (16)0.0085 (12)0.0080 (12)0.0056 (12)
O20.0403 (10)0.0500 (13)0.0525 (12)0.0055 (10)0.0030 (9)0.0039 (10)
O30.0580 (13)0.0482 (14)0.0691 (14)0.0091 (10)0.0063 (11)0.0181 (11)
O40.0393 (11)0.0811 (17)0.0704 (15)0.0006 (11)0.0108 (10)0.0120 (13)
O50.0652 (13)0.0827 (17)0.0436 (12)0.0143 (12)0.0020 (10)0.0021 (12)
O60.0438 (10)0.0340 (10)0.0620 (13)0.0023 (9)0.0194 (10)0.0033 (10)
C30.0399 (15)0.0399 (18)0.0424 (16)0.0038 (13)0.0056 (13)0.0003 (14)
C3A0.0347 (13)0.0279 (13)0.0367 (14)0.0029 (12)0.0082 (11)0.0040 (12)
C40.0309 (13)0.0346 (15)0.0413 (16)0.0029 (11)0.0100 (12)0.0042 (12)
C50.0355 (14)0.0330 (14)0.0389 (15)0.0001 (11)0.0098 (12)0.0003 (11)
C60.0436 (15)0.0329 (15)0.0450 (17)0.0020 (13)0.0133 (13)0.0037 (13)
C70.0443 (15)0.0287 (14)0.0551 (18)0.0060 (13)0.0158 (13)0.0020 (13)
C7A0.0347 (14)0.0378 (16)0.0409 (17)0.0025 (13)0.0095 (12)0.0096 (13)
C80.0325 (14)0.0347 (15)0.0340 (15)0.0046 (12)0.0025 (12)0.0011 (12)
C90.0431 (16)0.0407 (17)0.0568 (19)0.0052 (13)0.0119 (15)0.0109 (14)
C100.061 (2)0.053 (2)0.076 (3)0.0028 (18)0.0198 (18)0.0212 (18)
C110.079 (2)0.0389 (17)0.066 (2)0.0043 (18)0.0037 (19)0.0137 (17)
C120.062 (2)0.0423 (18)0.060 (2)0.0212 (15)0.0069 (17)0.0048 (16)
C130.0433 (16)0.0412 (17)0.0438 (17)0.0043 (13)0.0083 (13)0.0033 (13)
C140.0468 (16)0.0352 (15)0.0493 (18)0.0044 (13)0.0048 (14)0.0009 (14)
C150.095 (3)0.108 (4)0.063 (2)0.032 (3)0.014 (2)0.002 (2)
C160.105 (12)0.125 (5)0.087 (7)0.055 (4)0.043 (9)0.008 (4)
C16'0.105 (12)0.125 (5)0.087 (7)0.055 (4)0.043 (9)0.008 (4)
C170.067 (2)0.0434 (18)0.067 (2)0.0003 (15)0.0113 (17)0.0132 (16)
Geometric parameters (Å, º) top
N1—C7A1.361 (3)C8—C131.379 (3)
N1—O21.428 (3)C8—C91.387 (4)
N1—H1A0.88 (3)C9—C101.378 (4)
O2—C31.383 (3)C9—H9A0.9300
O3—C31.218 (3)C10—C111.370 (4)
O4—C141.201 (3)C10—H10A0.9300
O5—C141.330 (3)C11—C121.367 (4)
O5—C151.456 (4)C11—H11A0.9300
O6—C61.432 (3)C12—C131.381 (4)
O6—H6A0.8200C12—H12A0.9300
C3—C3A1.422 (4)C13—H13A0.9300
C3A—C7A1.343 (3)C15—C161.521 (3)
C3A—C41.497 (3)C15—C16'1.522 (3)
C4—C81.508 (3)C15—H15A0.9700
C4—C51.548 (3)C15—H15B0.9700
C4—H4A0.9800C16—H16A0.9600
C5—C141.508 (4)C16—H16B0.9600
C5—C61.545 (4)C16—H16C0.9600
C5—H5A0.9800C16'—H16D0.9600
C6—C171.512 (4)C16'—H16E0.9600
C6—C71.531 (4)C16'—H16F0.9600
C7—C7A1.486 (4)C17—H17A0.9600
C7—H7A0.9700C17—H17B0.9600
C7—H7B0.9700C17—H17C0.9600
C7A—N1—O2106.4 (2)C10—C9—H9A119.5
C7A—N1—H1A123 (2)C8—C9—H9A119.5
O2—N1—H1A107 (2)C11—C10—C9120.0 (3)
C3—O2—N1106.91 (19)C11—C10—H10A120.0
C14—O5—C15117.4 (3)C9—C10—H10A120.0
C6—O6—H6A109.5C12—C11—C10119.9 (3)
O3—C3—O2117.9 (2)C12—C11—H11A120.0
O3—C3—C3A134.3 (3)C10—C11—H11A120.0
O2—C3—C3A107.8 (2)C11—C12—C13120.0 (3)
C7A—C3A—C3106.7 (2)C11—C12—H12A120.0
C7A—C3A—C4124.1 (2)C13—C12—H12A120.0
C3—C3A—C4129.1 (2)C8—C13—C12121.2 (3)
C3A—C4—C8113.8 (2)C8—C13—H13A119.4
C3A—C4—C5107.1 (2)C12—C13—H13A119.4
C8—C4—C5110.4 (2)O4—C14—O5123.7 (3)
C3A—C4—H4A108.5O4—C14—C5125.1 (3)
C8—C4—H4A108.5O5—C14—C5111.2 (2)
C5—C4—H4A108.5O5—C15—C1699.6 (4)
C14—C5—C6112.5 (2)O5—C15—C16'118.4 (8)
C14—C5—C4109.6 (2)C16—C15—C16'19.9 (11)
C6—C5—C4113.2 (2)O5—C15—H15A111.8
C14—C5—H5A107.1C16—C15—H15A111.8
C6—C5—H5A107.1C16'—C15—H15A107.2
C4—C5—H5A107.1O5—C15—H15B111.8
O6—C6—C17110.7 (2)C16—C15—H15B111.8
O6—C6—C7109.0 (2)C16'—C15—H15B96.9
C17—C6—C7110.2 (2)H15A—C15—H15B109.6
O6—C6—C5106.90 (19)C15—C16—H16A109.5
C17—C6—C5111.8 (2)C15—C16—H16B109.5
C7—C6—C5108.2 (2)C15—C16—H16C109.5
C7A—C7—C6110.2 (2)C15—C16'—H16D109.5
C7A—C7—H7A109.6C15—C16'—H16E109.5
C6—C7—H7A109.6H16D—C16'—H16E109.5
C7A—C7—H7B109.6C15—C16'—H16F109.5
C6—C7—H7B109.6H16D—C16'—H16F109.5
H7A—C7—H7B108.1H16E—C16'—H16F109.5
C3A—C7A—N1111.7 (2)C6—C17—H17A109.5
C3A—C7A—C7126.2 (2)C6—C17—H17B109.5
N1—C7A—C7122.1 (2)H17A—C17—H17B109.5
C13—C8—C9117.7 (2)C6—C17—H17C109.5
C13—C8—C4121.6 (2)H17A—C17—H17C109.5
C9—C8—C4120.6 (2)H17B—C17—H17C109.5
C10—C9—C8121.1 (3)
C7A—N1—O2—C36.9 (3)C3—C3A—C7A—C7177.7 (2)
N1—O2—C3—O3174.8 (2)C4—C3A—C7A—C71.1 (4)
N1—O2—C3—C3A5.2 (3)O2—N1—C7A—C3A6.3 (3)
O3—C3—C3A—C7A178.5 (3)O2—N1—C7A—C7174.5 (2)
O2—C3—C3A—C7A1.4 (3)C6—C7—C7A—C3A14.4 (4)
O3—C3—C3A—C45.0 (5)C6—C7—C7A—N1164.6 (2)
O2—C3—C3A—C4175.0 (2)C3A—C4—C8—C13132.5 (3)
C7A—C3A—C4—C8137.7 (2)C5—C4—C8—C13107.1 (3)
C3—C3A—C4—C838.2 (3)C3A—C4—C8—C949.6 (3)
C7A—C3A—C4—C515.5 (3)C5—C4—C8—C970.8 (3)
C3—C3A—C4—C5160.4 (2)C13—C8—C9—C101.1 (4)
C3A—C4—C5—C14175.1 (2)C4—C8—C9—C10176.9 (3)
C8—C4—C5—C1460.6 (3)C8—C9—C10—C111.4 (5)
C3A—C4—C5—C648.6 (3)C9—C10—C11—C120.6 (5)
C8—C4—C5—C6172.89 (19)C10—C11—C12—C130.4 (5)
C14—C5—C6—O673.4 (3)C9—C8—C13—C120.0 (4)
C4—C5—C6—O651.5 (3)C4—C8—C13—C12177.9 (3)
C14—C5—C6—C1747.8 (3)C11—C12—C13—C80.7 (5)
C4—C5—C6—C17172.7 (2)C15—O5—C14—O40.8 (4)
C14—C5—C6—C7169.3 (2)C15—O5—C14—C5179.5 (3)
C4—C5—C6—C765.8 (3)C6—C5—C14—O474.8 (3)
O6—C6—C7—C7A71.3 (3)C4—C5—C14—O452.1 (3)
C17—C6—C7—C7A167.1 (2)C6—C5—C14—O5104.9 (3)
C5—C6—C7—C7A44.6 (3)C4—C5—C14—O5128.2 (2)
C3—C3A—C7A—N13.1 (3)C14—O5—C15—C1691.7 (10)
C4—C3A—C7A—N1179.8 (2)C14—O5—C15—C16'84.6 (19)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O60.8971.9912.846 (3)158.84
O6—H6A···O30.821.952.767 (3)171

Experimental details

Crystal data
Chemical formulaC17H19NO5
Mr317.33
Crystal system, space groupMonoclinic, P21
Temperature (K)296
a, b, c (Å)6.0712 (6), 13.4343 (13), 10.0821 (10)
β (°) 96.882 (2)
V3)816.39 (14)
Z2
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.30 × 0.20 × 0.20
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1998)
Tmin, Tmax0.972, 0.981
No. of measured, independent and
observed [I > 2σ(I)] reflections
9534, 4059, 2458
Rint0.049
(sin θ/λ)max1)0.668
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.059, 0.115, 1.00
No. of reflections4059
No. of parameters218
No. of restraints3
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.17, 0.15

Computer programs: APEX2 (Bruker, 2005), SAINT-Plus (Bruker, 2001), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1A···O60.8971.9912.846 (3)158.84
O6—H6A···O30.8201.9542.767 (3)170.97
 

Acknowledgements

We thank Professor Victor N. Khrustalev for fruitful discussions and help in this work.

References

First citationBruker (2001). SAINT-Plus. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationBruker (2005). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationGoda, F. E., Maroul, A. R. & El-Bendory, E. R. (2003). Saudi Pharm. J. 3, 111–117.  Google Scholar
First citationKashima, C., Yoshihara, N. & Shirai, S. I. (1981). Heterocycles, 16, 145.  CrossRef Google Scholar
First citationSheldrick, G. M. (1998). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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