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The furan­oid sugar ring and the 1,2-O-iso­propyl­idene ring of the title compound, C16H24O7, have envelope conformations, while the 5,6-O-iso­propyl­idene ring has a half-chair conformation.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801009710/wn6022sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801009710/wn6022Isup2.hkl
Contains datablock I

CCDC reference: 170764

Key indicators

  • Single-crystal X-ray study
  • T = 273 K
  • Mean [sigma](C-C) = 0.012 Å
  • R factor = 0.064
  • wR factor = 0.200
  • Data-to-parameter ratio = 7.5

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Amber Alert Alert Level B:
PLAT_360 Alert B Short C(sp3)-C(sp3) Bond C(15) - C(16) = 1.32 Ang.
Author response: As discussed in the Comment and exptl_refinement sections, the ethyl ester group is probably disordered, but the data quality does not permit a rational modelling of the disorder.
General Notes

REFLT_03 From the CIF: _diffrn_reflns_theta_max 25.00 From the CIF: _reflns_number_total 1588 Count of symmetry unique reflns 1590 Completeness (_total/calc) 99.87% TEST3: Check Friedels for noncentro structure Estimate of Friedel pairs measured 0 Fraction of Friedel pairs measured 0.000 Are heavy atom types Z>Si present no Please check that the estimate of the number of Friedel pairs is correct. If it is not, please give the correct count in the _publ_section_exptl_refinement section of the submitted CIF.
0 Alert Level A = Potentially serious problem
1 Alert Level B = Potential problem
0 Alert Level C = Please check

Comment top

Branched-chain sugars (Yoshimura, 1984) have been found as components of many antibiotics and other natural products which possess interesting biological activities. Many of these compounds have furopyran structures. Examples of these are azadiractin (Broughton et al., 1986; Ley et al. 1987) and miharamycin A and B (Seto et al., 1983; Koul, 1984a). The former is an insect anti-feedant (Koul, 1984a,b; Rembold, 1984) isolated from the neem tree and the latter are active against rice blast disease caused by Pyricularia oryzae (Ley et al., 1987). Our interest is to find convenient and efficient approaches to the synthesis of furopyran and related fused-ring systems from readily available sugars and their derivatives. As part of this programme, the title compound, (I), was synthesized and its structure determined.

Fig. 1 depicts the correct absolute configuration of (I), which was assigned to agree with the known chirality of D-glucose, from which (I) was synthesized. The molecule contains three five-membered rings which exhibit various conformations. The furanoid sugar ring has an envelope conformation puckered at C1, as indicated by the puckering parameter, ϕ2 = 222 (2)° (Cremer & Pople, 1975). Atom C1 lies 0.295 (8) Å from the plane defined by C2, C3 C4 and O4. The 1,2-O-isopropylidene ring also has an envelope conformation [ϕ2 = 208 (2)°] with C1 lying 0.346 (8) Å from the plane through C10, O1, O2 and C2. The 5,6-O-isopropylidene ring has a half-chair conformation [ϕ2 = 93.0 (17)°] with C6 and O6 lying 0.173 (8) and -0.260 (7) Å, respectively, from the plane defined by O5, C5 and C7.

The atomic displacement parameters for O6 and the adjacent methyl groups of the 5,6-O-isopropylidene ring are slightly enlarged, which suggests that the part of the ring containing O6 is quite flexible. However, there are no significant peaks of residual electron density in the vicinity of O6, so that the possibility of the ring having two different envelope conformations can be excluded. This effect has also been observed in the corresponding 3-C-ethoxycarbonylmethyl derivative (Linden et al., 1996). The elongated atomic displacement ellipsoids for the ethyl group of the ester substituent also suggest that this group is disordered. However, the data quality did not enable a sensible model for the disorder to be developed. As an artefact of the untreated disorder, the bond lengths in this region of the molecule appear to be unduly short.

Experimental top

Compound (I) was prepared according to the procedure of Rosenthal & Nguyen (1967). Suitable crystals were obtained by recrystallization from ether/petroleum ether at room temperature (m.p. 310–311 K).

Refinement top

Crystals of the title compound suffered thermal-shock damage when cooled to low temperatures and it was therefore necessary to record the data at 273 K. The crystals also diffracted quite weakly at this temperature, which lead to a paucity of reflections with significant intensities and a consequent decrease in the precision of the geometric parameters. The methyl H atoms were constrained to an ideal geometry with Uiso(H) = 1.5Ueq(C), but were allowed to rotate freely about the C—C bonds. All other H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with Uiso(H) = 1.2Ueq(C). The absolute configuration could not be determined because of the absence of significant anomalous scatterers in the compound. The enantiomer used in the model was based on the known chirality of D-glucose, from which (I) was synthesized. Friedel pairs were merged before the final refinement.

Computing details top

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1991); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 1999); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.
[3E]-3-deoxy-3-C-ethoxycarbonylmethylene-1,2:5,6-di-O-isopropylidene- α-D-ribohexofuranose top
Crystal data top
C16H24O7Dx = 1.257 Mg m3
Mr = 328.36Melting point = 310–311 K
Monoclinic, P21Mo Kα radiation, λ = 0.71069 Å
a = 5.929 (2) ÅCell parameters from 23 reflections
b = 14.133 (2) Åθ = 13.0–18.5°
c = 10.3892 (12) ŵ = 0.10 mm1
β = 95.065 (16)°T = 273 K
V = 867.2 (3) Å3Prism, colourless
Z = 20.38 × 0.24 × 0.15 mm
F(000) = 352
Data collection top
Rigaku AFC-5R
diffractometer
Rint = 0.018
Radiation source: Rigaku rotating anode generatorθmax = 25.0°, θmin = 2.9°
Graphite monochromatorh = 07
ω–2θ scansk = 016
1752 measured reflectionsl = 1212
1588 independent reflections3 standard reflections every 150 reflections
891 reflections with I > 2σ(I) intensity decay: none
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)] = 0.064Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.200H-atom parameters constrained
S = 1.01 w = 1/[σ2(Fo2) + (0.1053P)2 + 0.2323P]
where P = (Fo2 + 2Fc2)/3
1588 reflections(Δ/σ)max = 0.001
213 parametersΔρmax = 0.47 e Å3
1 restraintΔρmin = 0.20 e Å3
Crystal data top
C16H24O7V = 867.2 (3) Å3
Mr = 328.36Z = 2
Monoclinic, P21Mo Kα radiation
a = 5.929 (2) ŵ = 0.10 mm1
b = 14.133 (2) ÅT = 273 K
c = 10.3892 (12) Å0.38 × 0.24 × 0.15 mm
β = 95.065 (16)°
Data collection top
Rigaku AFC-5R
diffractometer
Rint = 0.018
1752 measured reflections3 standard reflections every 150 reflections
1588 independent reflections intensity decay: none
891 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0641 restraint
wR(F2) = 0.200H-atom parameters constrained
S = 1.01Δρmax = 0.47 e Å3
1588 reflectionsΔρmin = 0.20 e Å3
213 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
O10.2090 (8)0.8413 (5)0.6644 (5)0.0785 (16)
O20.5241 (8)0.8790 (4)0.7964 (5)0.0799 (17)
O40.1001 (9)0.7688 (4)0.8464 (5)0.0764 (15)
O50.0940 (11)0.7568 (4)1.1958 (5)0.0915 (19)
O60.1832 (13)0.6510 (5)1.1705 (7)0.122 (3)
O140.6330 (13)1.0228 (5)1.0402 (6)0.109 (2)
O150.7218 (11)0.9627 (4)1.2341 (6)0.094 (2)
C10.1371 (13)0.8554 (6)0.7860 (7)0.067 (2)
H10.00140.89520.78190.080*
C20.3361 (12)0.9031 (6)0.8642 (7)0.0632 (19)
H20.31600.97170.87140.076*
C30.3455 (10)0.8543 (5)0.9921 (6)0.0520 (16)
C40.1960 (10)0.7672 (5)0.9768 (6)0.0543 (17)
H40.28990.71050.99100.065*
C50.0075 (12)0.7646 (6)1.0654 (8)0.067 (2)
H50.08690.82131.05310.081*
C60.1381 (14)0.6756 (6)1.0443 (8)0.083 (3)
H610.27690.68900.99070.099*
H620.05630.62571.00440.099*
C70.0049 (15)0.6799 (6)1.2552 (8)0.076 (2)
C80.1146 (19)0.7170 (9)1.3757 (10)0.120 (4)
H810.18590.77681.35600.181*
H820.00020.72461.44610.181*
H830.22580.67241.39960.181*
C90.168 (2)0.6039 (9)1.2926 (14)0.146 (5)
H910.10160.55671.34380.219*
H920.29620.63161.34160.219*
H930.21640.57511.21590.219*
C100.4523 (13)0.8375 (6)0.6747 (7)0.070 (2)
C110.5324 (16)0.7385 (8)0.6738 (10)0.101 (3)
H1110.69490.73740.68490.152*
H1120.48150.70950.59280.152*
H1130.47290.70420.74300.152*
C120.5336 (18)0.8934 (8)0.5685 (8)0.102 (3)
H1210.47790.95700.57240.153*
H1220.47990.86550.48730.153*
H1230.69620.89410.57650.153*
C130.4609 (11)0.8801 (5)1.1028 (7)0.0610 (19)
H130.44490.84251.17490.073*
C140.6109 (13)0.9627 (6)1.1208 (7)0.0627 (19)
C150.896 (2)1.0330 (8)1.2629 (13)0.147 (6)
H1510.95371.05321.18290.176*
H1520.82941.08781.30120.176*
C161.066 (2)1.0023 (8)1.3420 (15)0.153 (6)
H1611.02020.99971.42830.230*
H1621.19191.04461.33950.230*
H1631.10900.94031.31580.230*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.068 (3)0.104 (4)0.062 (3)0.007 (3)0.006 (2)0.005 (3)
O20.054 (3)0.123 (5)0.063 (3)0.025 (3)0.006 (2)0.020 (3)
O40.073 (3)0.079 (4)0.074 (3)0.018 (3)0.007 (3)0.002 (3)
O50.118 (5)0.089 (4)0.071 (4)0.049 (4)0.027 (3)0.012 (3)
O60.137 (6)0.123 (6)0.104 (5)0.070 (5)0.005 (5)0.007 (4)
O140.145 (6)0.084 (4)0.093 (5)0.053 (4)0.024 (4)0.010 (4)
O150.106 (5)0.065 (3)0.101 (4)0.035 (4)0.041 (4)0.010 (3)
C10.059 (4)0.075 (5)0.065 (5)0.004 (4)0.003 (3)0.008 (4)
C20.055 (4)0.062 (5)0.073 (5)0.006 (4)0.008 (3)0.005 (4)
C30.044 (3)0.053 (4)0.060 (4)0.004 (3)0.008 (3)0.003 (3)
C40.044 (3)0.055 (4)0.064 (4)0.006 (3)0.007 (3)0.004 (3)
C50.052 (4)0.055 (4)0.098 (6)0.002 (4)0.018 (4)0.002 (4)
C60.070 (5)0.092 (7)0.089 (6)0.033 (5)0.025 (4)0.022 (5)
C70.092 (6)0.055 (4)0.080 (5)0.019 (5)0.010 (5)0.004 (4)
C80.119 (8)0.142 (10)0.107 (7)0.009 (8)0.047 (6)0.022 (8)
C90.151 (12)0.107 (9)0.182 (13)0.032 (9)0.030 (9)0.007 (9)
C100.072 (5)0.086 (6)0.052 (4)0.008 (5)0.001 (3)0.009 (4)
C110.092 (7)0.122 (9)0.090 (6)0.009 (6)0.007 (5)0.020 (6)
C120.111 (7)0.130 (9)0.064 (5)0.025 (7)0.001 (5)0.016 (5)
C130.055 (4)0.064 (5)0.064 (4)0.003 (4)0.006 (3)0.003 (4)
C140.069 (5)0.055 (5)0.063 (5)0.006 (4)0.003 (4)0.004 (4)
C150.163 (12)0.070 (7)0.186 (12)0.040 (8)0.103 (10)0.037 (8)
C160.124 (9)0.094 (9)0.226 (15)0.027 (8)0.065 (10)0.016 (9)
Geometric parameters (Å, º) top
O1—C11.383 (9)C7—C91.512 (14)
O1—C101.438 (9)C7—C81.552 (13)
O2—C21.412 (9)C8—H810.9600
O2—C101.424 (8)C8—H820.9600
O4—C11.402 (10)C8—H830.9600
O4—C41.422 (8)C9—H910.9600
O5—C71.403 (9)C9—H920.9600
O5—C51.410 (9)C9—H930.9600
O6—C71.377 (10)C10—C121.472 (12)
O6—C61.406 (10)C10—C111.479 (14)
O14—C141.208 (9)C11—H1110.9600
O15—C141.296 (9)C11—H1120.9600
O15—C151.445 (12)C11—H1130.9600
C1—C21.529 (11)C12—H1210.9600
C1—H10.9800C12—H1220.9600
C2—C31.494 (10)C12—H1230.9600
C2—H20.9800C13—C141.469 (10)
C3—C131.336 (9)C13—H130.9300
C3—C41.517 (10)C15—C161.315 (14)
C4—C51.510 (9)C15—H1510.9700
C4—H40.9800C15—H1520.9700
C5—C61.530 (11)C16—H1610.9600
C5—H50.9800C16—H1620.9600
C6—H610.9700C16—H1630.9600
C6—H620.9700
C1—O1—C10109.0 (5)H81—C8—H82109.5
C2—O2—C10110.8 (5)C7—C8—H83109.5
C1—O4—C4112.0 (6)H81—C8—H83109.5
C7—O5—C5110.6 (6)H82—C8—H83109.5
C7—O6—C6108.9 (7)C7—C9—H91109.5
C14—O15—C15119.0 (7)C7—C9—H92109.5
O1—C1—O4110.9 (7)H91—C9—H92109.5
O1—C1—C2105.2 (6)C7—C9—H93109.5
O4—C1—C2106.9 (6)H91—C9—H93109.5
O1—C1—H1111.2H92—C9—H93109.5
O4—C1—H1111.2O2—C10—O1105.7 (6)
C2—C1—H1111.2O2—C10—C12110.7 (7)
O2—C2—C3111.3 (6)O1—C10—C12108.5 (7)
O2—C2—C1103.6 (6)O2—C10—C11108.9 (7)
C3—C2—C1103.6 (6)O1—C10—C11110.8 (8)
O2—C2—H2112.6C12—C10—C11112.1 (8)
C3—C2—H2112.6C10—C11—H111109.5
C1—C2—H2112.6C10—C11—H112109.5
C13—C3—C2128.0 (7)H111—C11—H112109.5
C13—C3—C4124.2 (6)C10—C11—H113109.5
C2—C3—C4107.8 (6)H111—C11—H113109.5
O4—C4—C5109.0 (6)H112—C11—H113109.5
O4—C4—C3105.5 (5)C10—C12—H121109.5
C5—C4—C3114.4 (6)C10—C12—H122109.5
O4—C4—H4109.2H121—C12—H122109.5
C5—C4—H4109.2C10—C12—H123109.5
C3—C4—H4109.2H121—C12—H123109.5
O5—C5—C4111.2 (6)H122—C12—H123109.5
O5—C5—C6103.1 (6)C3—C13—C14125.8 (7)
C4—C5—C6111.8 (6)C3—C13—H13117.1
O5—C5—H5110.2C14—C13—H13117.1
C4—C5—H5110.2O14—C14—O15123.5 (7)
C6—C5—H5110.2O14—C14—C13124.9 (7)
O6—C6—C5102.8 (7)O15—C14—C13111.6 (7)
O6—C6—H61111.2C16—C15—O15113.3 (9)
C5—C6—H61111.2C16—C15—H151108.9
O6—C6—H62111.2O15—C15—H151108.9
C5—C6—H62111.2C16—C15—H152108.9
H61—C6—H62109.1O15—C15—H152108.9
O6—C7—O5106.0 (7)H151—C15—H152107.7
O6—C7—C9114.7 (9)C15—C16—H161109.5
O5—C7—C9111.2 (9)C15—C16—H162109.5
O6—C7—C8105.3 (8)H161—C16—H162109.5
O5—C7—C8108.3 (8)C15—C16—H163109.5
C9—C7—C8110.9 (9)H161—C16—H163109.5
C7—C8—H81109.5H162—C16—H163109.5
C7—C8—H82109.5
C10—O1—C1—O490.9 (8)O4—C4—C5—C661.5 (8)
C10—O1—C1—C224.4 (8)C3—C4—C5—C6179.4 (6)
C4—O4—C1—O1134.3 (6)C7—O6—C6—C529.9 (10)
C4—O4—C1—C220.0 (8)O5—C5—C6—O621.6 (8)
C10—O2—C2—C3121.6 (7)C4—C5—C6—O6141.1 (7)
C10—O2—C2—C110.8 (8)C6—O6—C7—O526.6 (10)
O1—C1—C2—O221.5 (8)C6—O6—C7—C996.6 (10)
O4—C1—C2—O296.5 (7)C6—O6—C7—C8141.2 (9)
O1—C1—C2—C3137.7 (6)C5—O5—C7—O611.3 (9)
O4—C1—C2—C319.8 (8)C5—O5—C7—C9114.0 (9)
O2—C2—C3—C1382.5 (9)C5—O5—C7—C8123.9 (8)
C1—C2—C3—C13166.7 (7)C2—O2—C10—O13.3 (9)
O2—C2—C3—C497.8 (7)C2—O2—C10—C12120.5 (8)
C1—C2—C3—C412.9 (7)C2—O2—C10—C11115.8 (7)
C1—O4—C4—C5111.8 (7)C1—O1—C10—O218.0 (9)
C1—O4—C4—C311.5 (7)C1—O1—C10—C12136.7 (8)
C13—C3—C4—O4177.8 (6)C1—O1—C10—C1199.9 (8)
C2—C3—C4—O41.9 (7)C2—C3—C13—C141.8 (11)
C13—C3—C4—C558.0 (9)C4—C3—C13—C14178.6 (7)
C2—C3—C4—C5121.7 (6)C15—O15—C14—O145.7 (14)
C7—O5—C5—C4126.6 (7)C15—O15—C14—C13173.1 (9)
C7—O5—C5—C66.7 (8)C3—C13—C14—O147.1 (13)
O4—C4—C5—O5176.2 (6)C3—C13—C14—O15171.7 (7)
C3—C4—C5—O565.9 (8)C14—O15—C15—C16147.0 (13)

Experimental details

Crystal data
Chemical formulaC16H24O7
Mr328.36
Crystal system, space groupMonoclinic, P21
Temperature (K)273
a, b, c (Å)5.929 (2), 14.133 (2), 10.3892 (12)
β (°) 95.065 (16)
V3)867.2 (3)
Z2
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.38 × 0.24 × 0.15
Data collection
DiffractometerRigaku AFC-5R
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
1752, 1588, 891
Rint0.018
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.064, 0.200, 1.01
No. of reflections1588
No. of parameters213
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.47, 0.20

Computer programs: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1991), MSC/AFC Diffractometer Control Software, TEXSAN (Molecular Structure Corporation, 1999), SHELXS86 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ORTEPII (Johnson, 1976), SHELXL97.

 

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