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

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ISSN: 2056-9890

6,7-Dimeth­­oxy-3-meth­­oxy­carbonyl-1-(2-meth­­oxy­phen­yl)-3,4-di­hydro­iso­quinoline 2-oxide

aSchool of Pharmacy and Pharmacology, University of KwaZulu Natal, Durban 4000, South Africa, and bSchool of Chemistry, University of KwaZulu Natal, Durban 4000, South Africa
*Correspondence e-mail: maguireg@ukzn.ac.za

(Received 26 April 2011; accepted 2 May 2011; online 7 May 2011)

In the title compound, C20H21NO6, an N-oxide-based organocatalyst, the N-containing six-membered ring adopts a twisted half-chair conformation. No hydrogen bonding or ππ stacking was found within the crystal structure.

Related literature

For related structures, see: Naicker et al. (2010[Naicker, T., Petzold, K., Singh, T., Arvidsson, P. I., Kruger, H. G., Maguire, G. E. M. & Govender, T. (2010). Tetrahedron Asymmetry, 21, 2859-2867.], 2011[Naicker, T., Govender, T., Kruger, H. G. & Maguire, G. E. M. (2011). Acta Cryst. E67, o883.]).

[Scheme 1]

Experimental

Crystal data
  • C20H21NO6

  • Mr = 371.38

  • Monoclinic, P 21 /n

  • a = 5.4765 (1) Å

  • b = 21.9984 (6) Å

  • c = 15.0007 (4) Å

  • β = 92.774 (2)°

  • V = 1805.08 (8) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 173 K

  • 0.25 × 0.18 × 0.15 mm

Data collection
  • Bruker APEXII diffractometer

  • 7815 measured reflections

  • 3959 independent reflections

  • 3092 reflections with I > 2σ(I)

  • Rint = 0.016

Refinement
  • R[F2 > 2σ(F2)] = 0.053

  • wR(F2) = 0.157

  • S = 1.06

  • 3959 reflections

  • 245 parameters

  • H-atom parameters constrained

  • Δρmax = 0.92 e Å−3

  • Δρmin = −0.33 e Å−3

Data collection: APEX2 (Bruker, 2006[Bruker (2006). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2006[Bruker (2006). APEX2 and SAINT. 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: OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

The title compound is a novel N-oxide based catalyst containing a tetrahydroisoquinoline (TIQ) backbone. This is the first X-ray crystal structure report of this type of organocatalyst within this TIQ class of molecules. This compound and its derivatives are currently being tested in our laboratory as novel organocatalysts for asymmetric allylation reactions (Naicker et al. 2010).

From the crystal structure it is evident that the N-containing six membered ring assumes a twisted half chair conformation (Fig. 1). This differs from a similar structure that we recently reported which displays a twisted half boat conformation (Naicker et al. 2011). A possible reason for the change is the introduction of the oxygen atom O2 onto the sp2 hybridized nitrogen atom. All our previous examples have either a hydrogen or methyl group at that position.

Interestingly there is no classic hydrogen bonding within the crystal packing however, there are various intermolecular and intramolecular short contact interactions that link the molecules together within the crystal lattice. The N-oxide oxygen O2 displays two potential hydrogen bond interactions to C16—H16 and C20A—H20A which are 3.36 Å and 3.34 Å respectively. These interactions result in a layered packing within the crystal stucture as shown along the (100) axis in Fig. 2. A centroid distance of 7.156 Å indicated that there is no π-π stacking within the crystal matrix.

Related literature top

For related structures, see: Naicker et al. (2010, 2011).

Experimental top

(S)-methyl 6,7-dimethoxy-1-(2-methoxyphenyl)-3,4-dihydroisoquinoline-3-carboxylate (1.30 g, 3.7 mmol) was dissolved in dry methylene chloride (50 ml). Potassium carbonate (1.0 g, 7.5 mmol) was added and the reaction cooled to -78 °C. Meta-chloroperbenzoic acid (0.86 g of 75% pure, net 0.65 g, 3.7 mmol) was then added, and the reaction was allowed to stir at -78 °C for 3 h. At this time, the reaction was allowed to warm to room temperature. After stirring for a further 2 h at room temperature, methylene chloride (50 ml) was added to dilute the reaction and celite (500 mg) was added to aid filtration. The reaction was filtered, and the methylene chloride concentrated to dryness affording the crude product which was purified by column chromatography (methylene chloride:methanol, 99:1, Rf = 1/5) (1.20 g, 87% yield).

Melting point 423 K. [α]20D 5.128 (c 0.13 in CHCl3).

IR (neat): 2923, 1742, 1508, 1285, 729 cm-1.

1H NMR (400 MHz, CDCl3) δ 7.55 (dd, J = 7.5, 1.7 Hz, 1H), 7.51 – 7.42 (m, 1H), 7.20 – 6.97 (m, 3H), 6.74 (d, J = 6.5 Hz, 1H), 6.27 (d, J = 13.6 Hz, 1H), 4.94 (dt, J = 5.8, 2.9 Hz, 1H), 3.90 (d, J = 1.8 Hz, 4H), 3.77 (d, J = 4.3 Hz, 3H), 3.73 – 3.54 (m, 6H), 3.49 – 3.33 (m, 1H).

13C NMR (101 MHz, CDCl3) δ 168.74, 157.23, 149.52, 148.17, 131.24, 131.12, 130.43, 122.89, 121.93, 121.49, 121.01, 120.80, 119.71, 112.05, 111.50, 110.64, 110.60, 110.08, 109.50, 77.34, 77.03, 76.71, 70.84, 70.72, 56.17, 56.11, 56.05, 55.93, 55.62, 53.24, 53.10, 30.80, 30.73.

Recrystallization from ethyl acetate at room temperature afforded colourless crystals suitable for X-ray analysis.

Refinement top

All non-hydrogen atoms were refined anisotropically. The hydrogen atoms were placed in idealized positions in a riding model with Uiso set at 1.2 or 1.5 times those of their parent atoms (1.2 for tertiary C—H, secondary C—H2 and aromatic C—H or N—H groups and 1.5 for methyl C—H3) and fixed C—H bond lengths(e.g. 0.88 Å for N—H and others ranging from 0.95 Å to 1.00 Å).

Computing details top

Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 40% probability level. Hydrogen atoms have been omitted for clarity.
[Figure 2] Fig. 2. A partial projection of the title compound, viewed along [100] plane.
6,7-dimethoxy-3-(methoxycarbonyl)-1-(2-methoxyphenyl)- 3,4-dihydroisoquinolin-2-ium-2-olate top
Crystal data top
C20H21NO6F(000) = 784
Mr = 371.38Dx = 1.367 Mg m3
Monoclinic, P21/nMelting point: 423 K
Hall symbol: -P 2ynMo Kα radiation, λ = 0.71073 Å
a = 5.4765 (1) ÅCell parameters from 7815 reflections
b = 21.9984 (6) Åθ = 2.3–27.1°
c = 15.0007 (4) ŵ = 0.10 mm1
β = 92.774 (2)°T = 173 K
V = 1805.08 (8) Å3Block, colourless
Z = 40.25 × 0.18 × 0.15 mm
Data collection top
Bruker APEXII
diffractometer
3092 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.016
Graphite monochromatorθmax = 27.1°, θmin = 2.3°
1.2° ϕ and ω scansh = 77
7815 measured reflectionsk = 2828
3959 independent reflectionsl = 1919
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)] = 0.053H-atom parameters constrained
wR(F2) = 0.157 w = 1/[σ2(Fo2) + (0.080P)2 + 1.0977P]
where P = (Fo2 + 2Fc2)/3
S = 1.06(Δ/σ)max < 0.001
3959 reflectionsΔρmax = 0.92 e Å3
245 parametersΔρmin = 0.33 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0055 (19)
Crystal data top
C20H21NO6V = 1805.08 (8) Å3
Mr = 371.38Z = 4
Monoclinic, P21/nMo Kα radiation
a = 5.4765 (1) ŵ = 0.10 mm1
b = 21.9984 (6) ÅT = 173 K
c = 15.0007 (4) Å0.25 × 0.18 × 0.15 mm
β = 92.774 (2)°
Data collection top
Bruker APEXII
diffractometer
3092 reflections with I > 2σ(I)
7815 measured reflectionsRint = 0.016
3959 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0530 restraints
wR(F2) = 0.157H-atom parameters constrained
S = 1.06Δρmax = 0.92 e Å3
3959 reflectionsΔρmin = 0.33 e Å3
245 parameters
Special details top

Experimental. Half sphere of data collected using COLLECT strategy (Nonius, 2000). Crystal to detector distance = 30 mm; combination of ϕ and ω scans of 1.0°, 40 s per °, 2 iterations.

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
O10.2176 (3)0.22907 (6)0.35593 (9)0.0354 (3)
O20.6006 (2)0.03624 (6)0.11617 (9)0.0322 (3)
O30.2824 (3)0.10179 (6)0.19301 (9)0.0344 (3)
O40.5317 (3)0.12825 (8)0.45676 (10)0.0441 (4)
O50.2474 (3)0.07631 (8)0.52628 (10)0.0485 (4)
O60.2093 (3)0.16305 (7)0.07924 (9)0.0391 (4)
N10.2146 (3)0.17212 (7)0.33291 (10)0.0251 (3)
C10.3125 (3)0.14938 (8)0.26149 (11)0.0246 (4)
C20.3023 (3)0.08366 (8)0.24573 (11)0.0228 (4)
C30.4608 (3)0.05630 (8)0.18643 (11)0.0247 (4)
H30.57490.08060.15670.030*
C40.4517 (3)0.00558 (8)0.17115 (11)0.0246 (4)
C50.2793 (3)0.04178 (8)0.21365 (12)0.0260 (4)
C60.1259 (3)0.01473 (8)0.27287 (12)0.0262 (4)
H60.01150.03900.30250.031*
C70.1370 (3)0.04758 (8)0.28959 (11)0.0238 (4)
C80.0255 (3)0.07830 (8)0.35355 (12)0.0283 (4)
H8A0.07480.04880.39910.034*
H8B0.17520.09320.32100.034*
C90.1083 (3)0.13129 (8)0.39883 (12)0.0259 (4)
H90.01070.15500.43350.031*
C100.3260 (4)0.11235 (9)0.46255 (13)0.0344 (5)
C110.4434 (5)0.06056 (13)0.59251 (17)0.0572 (7)
H11A0.37800.03410.63820.086*
H11B0.50860.09780.62060.086*
H11C0.57440.03930.56290.086*
C120.4564 (3)0.19020 (8)0.20530 (12)0.0278 (4)
C130.6553 (3)0.22127 (8)0.24385 (14)0.0314 (4)
H130.68810.21880.30650.038*
C140.8070 (4)0.25591 (9)0.19251 (17)0.0410 (5)
H140.94270.27700.21950.049*
C150.7571 (4)0.25908 (10)0.10160 (17)0.0455 (6)
H150.86160.28230.06600.055*
C160.5593 (4)0.22943 (10)0.06094 (15)0.0418 (5)
H160.52700.23280.00170.050*
C170.4075 (4)0.19452 (8)0.11258 (13)0.0323 (4)
C180.1512 (5)0.16733 (12)0.01499 (14)0.0520 (6)
H18A0.00590.14280.03030.078*
H18B0.28920.15230.04790.078*
H18C0.11870.20980.03110.078*
C190.7699 (4)0.00092 (10)0.06834 (13)0.0351 (5)
H19A0.86500.02780.03110.053*
H19B0.88060.02070.11080.053*
H19C0.68030.02860.03030.053*
C200.0983 (4)0.13944 (9)0.22980 (15)0.0364 (5)
H20A0.11910.18150.21000.055*
H20B0.06400.12480.20940.055*
H20C0.11400.13780.29510.055*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0496 (8)0.0207 (7)0.0370 (7)0.0003 (6)0.0121 (6)0.0065 (6)
O20.0374 (7)0.0271 (7)0.0335 (7)0.0029 (6)0.0143 (6)0.0035 (5)
O30.0425 (8)0.0194 (6)0.0422 (8)0.0021 (6)0.0122 (6)0.0042 (6)
O40.0335 (8)0.0543 (10)0.0441 (9)0.0016 (7)0.0020 (6)0.0001 (7)
O50.0505 (10)0.0559 (10)0.0386 (8)0.0023 (8)0.0030 (7)0.0157 (7)
O60.0542 (9)0.0366 (8)0.0261 (7)0.0019 (7)0.0020 (6)0.0010 (6)
N10.0295 (8)0.0213 (7)0.0247 (7)0.0006 (6)0.0040 (6)0.0014 (6)
C10.0292 (9)0.0223 (8)0.0223 (8)0.0019 (7)0.0024 (7)0.0001 (7)
C20.0256 (9)0.0225 (8)0.0202 (8)0.0007 (7)0.0006 (6)0.0006 (6)
C30.0279 (9)0.0240 (9)0.0225 (8)0.0005 (7)0.0038 (7)0.0002 (7)
C40.0275 (9)0.0256 (9)0.0211 (8)0.0031 (7)0.0034 (7)0.0019 (7)
C50.0315 (9)0.0203 (8)0.0261 (9)0.0002 (7)0.0003 (7)0.0012 (7)
C60.0277 (9)0.0250 (9)0.0260 (9)0.0032 (7)0.0033 (7)0.0002 (7)
C70.0251 (8)0.0240 (9)0.0225 (8)0.0010 (7)0.0016 (6)0.0010 (7)
C80.0286 (9)0.0269 (9)0.0299 (9)0.0014 (7)0.0071 (7)0.0023 (7)
C90.0304 (9)0.0247 (9)0.0230 (9)0.0025 (7)0.0074 (7)0.0003 (7)
C100.0522 (13)0.0269 (10)0.0245 (9)0.0061 (9)0.0068 (8)0.0033 (7)
C110.0544 (15)0.0673 (17)0.0485 (14)0.0081 (13)0.0119 (11)0.0216 (13)
C120.0350 (10)0.0195 (8)0.0294 (9)0.0038 (7)0.0081 (7)0.0010 (7)
C130.0341 (10)0.0227 (9)0.0379 (10)0.0024 (7)0.0063 (8)0.0016 (8)
C140.0370 (11)0.0267 (10)0.0603 (14)0.0005 (8)0.0124 (10)0.0053 (9)
C150.0492 (13)0.0313 (11)0.0583 (14)0.0040 (9)0.0258 (11)0.0149 (10)
C160.0611 (14)0.0319 (11)0.0339 (11)0.0092 (10)0.0179 (10)0.0106 (9)
C170.0436 (11)0.0242 (9)0.0296 (10)0.0070 (8)0.0071 (8)0.0017 (7)
C180.0755 (17)0.0523 (14)0.0275 (11)0.0137 (13)0.0059 (11)0.0040 (10)
C190.0360 (11)0.0378 (11)0.0325 (10)0.0011 (8)0.0132 (8)0.0016 (8)
C200.0423 (11)0.0236 (9)0.0438 (12)0.0061 (8)0.0059 (9)0.0007 (8)
Geometric parameters (Å, º) top
O1—N11.2995 (19)C8—H8B0.9900
O2—C41.366 (2)C9—C101.549 (3)
O2—C191.429 (2)C9—H91.0000
O3—C51.356 (2)C11—H11A0.9800
O3—C201.436 (2)C11—H11B0.9800
O4—C101.187 (3)C11—H11C0.9800
O5—C101.329 (3)C12—C131.388 (3)
O5—C111.468 (3)C12—C171.407 (3)
O6—C171.362 (3)C13—C141.388 (3)
O6—C181.437 (2)C13—H130.9500
N1—C11.320 (2)C14—C151.380 (3)
N1—C91.476 (2)C14—H140.9500
C1—C21.466 (2)C15—C161.381 (4)
C1—C121.484 (2)C15—H150.9500
C2—C71.393 (2)C16—C171.394 (3)
C2—C31.408 (2)C16—H160.9500
C3—C41.381 (2)C18—H18A0.9800
C3—H30.9500C18—H18B0.9800
C4—C51.411 (3)C18—H18C0.9800
C5—C61.386 (3)C19—H19A0.9800
C6—C71.394 (2)C19—H19B0.9800
C6—H60.9500C19—H19C0.9800
C7—C81.501 (2)C20—H20A0.9800
C8—C91.520 (2)C20—H20B0.9800
C8—H8A0.9900C20—H20C0.9800
C4—O2—C19117.10 (15)O5—C11—H11A109.5
C5—O3—C20117.19 (15)O5—C11—H11B109.5
C10—O5—C11112.08 (18)H11A—C11—H11B109.5
C17—O6—C18117.57 (18)O5—C11—H11C109.5
O1—N1—C1125.52 (15)H11A—C11—H11C109.5
O1—N1—C9114.13 (14)H11B—C11—H11C109.5
C1—N1—C9120.15 (15)C13—C12—C17119.13 (18)
N1—C1—C2119.40 (16)C13—C12—C1119.27 (16)
N1—C1—C12118.66 (15)C17—C12—C1121.42 (17)
C2—C1—C12121.51 (15)C12—C13—C14121.2 (2)
C7—C2—C3119.32 (16)C12—C13—H13119.4
C7—C2—C1120.45 (16)C14—C13—H13119.4
C3—C2—C1120.23 (16)C15—C14—C13118.7 (2)
C4—C3—C2120.54 (16)C15—C14—H14120.6
C4—C3—H3119.7C13—C14—H14120.6
C2—C3—H3119.7C14—C15—C16121.8 (2)
O2—C4—C3124.72 (16)C14—C15—H15119.1
O2—C4—C5115.23 (15)C16—C15—H15119.1
C3—C4—C5120.05 (16)C15—C16—C17119.4 (2)
O3—C5—C6125.37 (16)C15—C16—H16120.3
O3—C5—C4115.48 (16)C17—C16—H16120.3
C6—C5—C4119.13 (16)O6—C17—C16124.20 (18)
C5—C6—C7121.00 (16)O6—C17—C12116.05 (17)
C5—C6—H6119.5C16—C17—C12119.8 (2)
C7—C6—H6119.5O6—C18—H18A109.5
C2—C7—C6119.92 (16)O6—C18—H18B109.5
C2—C7—C8117.68 (15)H18A—C18—H18B109.5
C6—C7—C8122.40 (16)O6—C18—H18C109.5
C7—C8—C9110.07 (15)H18A—C18—H18C109.5
C7—C8—H8A109.6H18B—C18—H18C109.5
C9—C8—H8A109.6O2—C19—H19A109.5
C7—C8—H8B109.6O2—C19—H19B109.5
C9—C8—H8B109.6H19A—C19—H19B109.5
H8A—C8—H8B108.2O2—C19—H19C109.5
N1—C9—C8111.39 (14)H19A—C19—H19C109.5
N1—C9—C10105.07 (14)H19B—C19—H19C109.5
C8—C9—C10114.19 (15)O3—C20—H20A109.5
N1—C9—H9108.7O3—C20—H20B109.5
C8—C9—H9108.7H20A—C20—H20B109.5
C10—C9—H9108.7O3—C20—H20C109.5
O4—C10—O5124.7 (2)H20A—C20—H20C109.5
O4—C10—C9125.50 (18)H20B—C20—H20C109.5
O5—C10—C9109.75 (18)
O1—N1—C1—C2177.89 (16)O1—N1—C9—C8146.52 (15)
C9—N1—C1—C23.4 (2)C1—N1—C9—C838.4 (2)
O1—N1—C1—C125.3 (3)O1—N1—C9—C1089.34 (17)
C9—N1—C1—C12169.18 (15)C1—N1—C9—C1085.72 (18)
N1—C1—C2—C717.8 (2)C7—C8—C9—N151.46 (19)
C12—C1—C2—C7169.84 (16)C7—C8—C9—C1067.4 (2)
N1—C1—C2—C3161.82 (16)C11—O5—C10—O43.0 (3)
C12—C1—C2—C310.6 (3)C11—O5—C10—C9175.79 (18)
C7—C2—C3—C40.5 (3)N1—C9—C10—O40.3 (3)
C1—C2—C3—C4179.88 (16)C8—C9—C10—O4122.1 (2)
C19—O2—C4—C32.9 (3)N1—C9—C10—O5178.51 (15)
C19—O2—C4—C5176.99 (16)C8—C9—C10—O559.1 (2)
C2—C3—C4—O2178.80 (16)N1—C1—C12—C1356.9 (2)
C2—C3—C4—C51.3 (3)C2—C1—C12—C13115.55 (19)
C20—O3—C5—C65.5 (3)N1—C1—C12—C17128.06 (19)
C20—O3—C5—C4175.62 (16)C2—C1—C12—C1759.5 (2)
O2—C4—C5—O31.0 (2)C17—C12—C13—C140.6 (3)
C3—C4—C5—O3178.87 (16)C1—C12—C13—C14174.57 (17)
O2—C4—C5—C6177.95 (15)C12—C13—C14—C150.0 (3)
C3—C4—C5—C62.2 (3)C13—C14—C15—C160.8 (3)
O3—C5—C6—C7179.98 (17)C14—C15—C16—C171.0 (3)
C4—C5—C6—C71.2 (3)C18—O6—C17—C161.3 (3)
C3—C2—C7—C61.5 (2)C18—O6—C17—C12178.88 (18)
C1—C2—C7—C6178.87 (16)C15—C16—C17—O6179.39 (19)
C3—C2—C7—C8178.87 (15)C15—C16—C17—C120.4 (3)
C1—C2—C7—C80.7 (2)C13—C12—C17—O6179.81 (16)
C5—C6—C7—C20.7 (3)C1—C12—C17—O65.1 (3)
C5—C6—C7—C8179.74 (16)C13—C12—C17—C160.4 (3)
C2—C7—C8—C933.2 (2)C1—C12—C17—C16174.66 (17)
C6—C7—C8—C9147.19 (17)

Experimental details

Crystal data
Chemical formulaC20H21NO6
Mr371.38
Crystal system, space groupMonoclinic, P21/n
Temperature (K)173
a, b, c (Å)5.4765 (1), 21.9984 (6), 15.0007 (4)
β (°) 92.774 (2)
V3)1805.08 (8)
Z4
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.25 × 0.18 × 0.15
Data collection
DiffractometerBruker APEXII
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
7815, 3959, 3092
Rint0.016
(sin θ/λ)max1)0.641
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.053, 0.157, 1.06
No. of reflections3959
No. of parameters245
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.92, 0.33

Computer programs: APEX2 (Bruker, 2006), SAINT (Bruker, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), OLEX2 (Dolomanov et al., 2009).

 

Acknowledgements

The authors wish to thank Dr Hong Su of the Chemistry Department, University of Cape Town, for her assistance with the crystallographic data collection.

References

First citationBruker (2006). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationDolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationNaicker, T., Govender, T., Kruger, H. G. & Maguire, G. E. M. (2011). Acta Cryst. E67, o883.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationNaicker, T., Petzold, K., Singh, T., Arvidsson, P. I., Kruger, H. G., Maguire, G. E. M. & Govender, T. (2010). Tetrahedron Asymmetry, 21, 2859–2867.  Web of Science CrossRef CAS 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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