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The title compound, C7H11NO2, is an intermediate in a synthetic approach to the pyrrolizidine alkaloid loline. It has a brendane skeleton with a 91.8(2)° bond angle for the bridging carbon bearing the OH group.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803016970/cv6216sup1.cif
Contains datablocks 2, ns01

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536803016970/cv62162sup2.hkl
Contains datablock 2

CCDC reference: 222851

Key indicators

  • Single-crystal X-ray study
  • T = 200 K
  • Mean [sigma](C-C) = 0.003 Å
  • R factor = 0.032
  • wR factor = 0.081
  • Data-to-parameter ratio = 9.4

checkCIF/PLATON results

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Alert level G REFLT03_ALERT_4_G 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. From the CIF: _diffrn_reflns_theta_max 28.33 From the CIF: _reflns_number_total 880 Count of symmetry unique reflns 880 Completeness (_total/calc) 100.00% 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
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 0 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion

Comment top

Loline alkaloids (Powell & Petroski, 1992) are a group of pyrrolizidine alkaloids that feature a novel bridging ether as illustrated in loline, (1). These alkaloids occur in Lolium cuneatum (Dannhardt & Steindl, 1985), Festuca arundinacea (Yates & Tookey, 1965), Adenocarpus decorticans (Ribas-Barceló & Ribas-Marqués, 1968), and Argyreia mollis (Tofern et al. 1999) and have interesting biological properties. A number of synthetic approaches to these alkaloids have been reported (Wilson & Sawicki, 1978, Glass et al., 1978; Wilson et al., 1981), as well as a successful synthesis of (±)-loline (Tufariello et al., 1986) and (+)-loline (Blakemore et al., 2001). In our synthetic approach, the title compound, (2), was synthesized and characterized structurally. This paper reports its complete X-ray structural elucidation. This X-ray study shows that the molecule is an analogue of brendane and, in particular, the small bond angle of the one carbon bridge bearing the OH group of 91.8° renders alcohol derivatives unreactive in nucleophilic displacement reactions. In addition, neighboring group participation by ß-nitrogen is precluded by the geometry of the tricyclic ring system. Molecules of (2) form infinite linear chains through hydrogen bonding of the alcohol moiety of one molecule with the amine moiety of the next molecule.

Experimental top

The synthesis of (2) was carried out as reported (Glass et al., 1978). Crystals of (2) were grown by evaporation from benzene.

Refinement top

Due to the very weak anomalous scattering in this experiment [Flack (1983) parameter x = 0.0(1.8)], all Friedel pairs were merged in the final cycles of refinement. The absolute structure of the crystal of this racemic mixture is unknown. All H atoms were positioned geometrically at idealized positions, constrained to ride on the atom to which they are attached and given thermal parameters equal to 1.2 or 1.5 times Uiso of that bonded atom. In the final cycles of refinement, the hydroxyl H atom was freed from the riding constraint.

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SMART; data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. View of (2). Ellipsoids are drawn at the 50% probability level.
(1α,6α,7α,7aβ)-2,3,5,6,7,7a-Hexahydro-1,6-epoxy-1H-pyrrolizin-7-ol top
Crystal data top
C7H11NO2F(000) = 304
Mr = 141.17Dx = 1.413 Mg m3
Orthorhombic, Pna21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2nCell parameters from 2854 reflections
a = 9.9294 (16) Åθ = 3.5–28.2°
b = 7.2910 (12) ŵ = 0.10 mm1
c = 9.1653 (15) ÅT = 200 K
V = 663.52 (19) Å3Irregular block, colorless
Z = 40.09 × 0.09 × 0.08 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer
880 independent reflections
Radiation source: fine-focus sealed tube795 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.029
ϕ and ω scansθmax = 28.3°, θmin = 3.5°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2000)
h = 1213
Tmin = 0.893, Tmax = 0.992k = 99
6311 measured reflectionsl = 1212
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)] = 0.032Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.081H atoms treated by a mixture of independent and constrained refinement
S = 1.07 w = 1/[σ2(Fo2) + (0.0382P)2 + 0.1884P]
where P = (Fo2 + 2Fc2)/3
880 reflections(Δ/σ)max = 0.006
94 parametersΔρmax = 0.29 e Å3
1 restraintΔρmin = 0.17 e Å3
Crystal data top
C7H11NO2V = 663.52 (19) Å3
Mr = 141.17Z = 4
Orthorhombic, Pna21Mo Kα radiation
a = 9.9294 (16) ŵ = 0.10 mm1
b = 7.2910 (12) ÅT = 200 K
c = 9.1653 (15) Å0.09 × 0.09 × 0.08 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer
880 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2000)
795 reflections with I > 2σ(I)
Tmin = 0.893, Tmax = 0.992Rint = 0.029
6311 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0321 restraint
wR(F2) = 0.081H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.29 e Å3
880 reflectionsΔρmin = 0.17 e Å3
94 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
O10.01469 (17)0.1313 (2)0.26377 (19)0.0351 (4)
H1A0.049 (3)0.128 (4)0.309 (4)0.053*
C10.12400 (19)0.1983 (3)0.3451 (2)0.0266 (4)
H1B0.20280.11330.33840.032*
O20.00274 (14)0.40236 (19)0.48968 (17)0.0278 (3)
C20.09750 (19)0.2541 (3)0.5037 (2)0.0267 (4)
H2A0.06670.15160.56800.032*
C30.2343 (2)0.3352 (3)0.5451 (2)0.0289 (4)
H3A0.22600.42000.62890.035*
H3B0.29970.23750.56970.035*
N40.27594 (16)0.4365 (2)0.40824 (19)0.0249 (3)
C50.2674 (2)0.6374 (3)0.4267 (3)0.0307 (5)
H5A0.31900.70050.34920.037*
H5B0.30450.67410.52260.037*
C60.1160 (2)0.6882 (3)0.4167 (3)0.0332 (5)
H6A0.08050.72610.51310.040*
H6B0.10120.78870.34590.040*
C70.0495 (2)0.5109 (3)0.3650 (2)0.0267 (4)
H7A0.02320.53320.29160.032*
C80.16481 (19)0.3943 (3)0.3040 (2)0.0239 (4)
H8A0.18630.41440.19860.029*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0353 (8)0.0405 (8)0.0295 (8)0.0126 (7)0.0049 (6)0.0091 (8)
C10.0276 (9)0.0246 (9)0.0275 (10)0.0004 (7)0.0039 (8)0.0022 (8)
O20.0236 (6)0.0310 (6)0.0287 (7)0.0001 (6)0.0054 (6)0.0015 (6)
C20.0278 (9)0.0273 (9)0.0250 (9)0.0010 (8)0.0048 (8)0.0021 (8)
C30.0270 (10)0.0357 (11)0.0239 (10)0.0001 (8)0.0001 (8)0.0038 (9)
N40.0217 (7)0.0285 (8)0.0244 (8)0.0003 (7)0.0005 (7)0.0015 (7)
C50.0312 (10)0.0286 (10)0.0323 (11)0.0071 (8)0.0004 (9)0.0025 (9)
C60.0354 (11)0.0237 (9)0.0405 (12)0.0015 (8)0.0044 (10)0.0014 (9)
C70.0238 (9)0.0268 (9)0.0295 (10)0.0032 (8)0.0009 (8)0.0012 (8)
C80.0249 (8)0.0249 (9)0.0219 (9)0.0002 (7)0.0005 (8)0.0007 (7)
Geometric parameters (Å, º) top
O1—C11.404 (2)N4—C51.477 (3)
O1—H1A0.76 (3)N4—C81.492 (2)
C1—C81.532 (3)C5—C61.551 (3)
C1—C21.532 (3)C5—H5A0.9900
C1—H1B1.0000C5—H5B0.9900
O2—C21.439 (2)C6—C71.527 (3)
O2—C71.465 (3)C6—H6A0.9900
C2—C31.529 (3)C6—H6B0.9900
C2—H2A1.0000C7—C81.532 (3)
C3—N41.513 (3)C7—H7A1.0000
C3—H3A0.9900C8—H8A1.0000
C3—H3B0.9900
C1—O1—H1A112 (3)N4—C5—H5A110.4
O1—C1—C8113.47 (18)C6—C5—H5A110.4
O1—C1—C2117.58 (17)N4—C5—H5B110.4
C8—C1—C291.80 (15)C6—C5—H5B110.4
O1—C1—H1B110.9H5A—C5—H5B108.6
C8—C1—H1B110.9C7—C6—C5103.61 (16)
C2—C1—H1B110.9C7—C6—H6A111.0
C2—O2—C7105.57 (15)C5—C6—H6A111.0
O2—C2—C3108.19 (16)C7—C6—H6B111.0
O2—C2—C1103.13 (16)C5—C6—H6B111.0
C3—C2—C1100.69 (16)H6A—C6—H6B109.0
O2—C2—H2A114.5O2—C7—C6110.63 (18)
C3—C2—H2A114.5O2—C7—C8102.79 (16)
C1—C2—H2A114.5C6—C7—C8105.06 (16)
N4—C3—C2103.06 (16)O2—C7—H7A112.6
N4—C3—H3A111.2C6—C7—H7A112.6
C2—C3—H3A111.2C8—C7—H7A112.6
N4—C3—H3B111.2N4—C8—C1103.34 (15)
C2—C3—H3B111.2N4—C8—C7101.79 (15)
H3A—C3—H3B109.1C1—C8—C7103.31 (16)
C5—N4—C8103.63 (15)N4—C8—H8A115.5
C5—N4—C3111.93 (17)C1—C8—H8A115.5
C8—N4—C3103.17 (14)C7—C8—H8A115.5
N4—C5—C6106.62 (16)
C7—O2—C2—C365.4 (2)C5—C6—C7—O293.1 (2)
C7—O2—C2—C140.65 (19)C5—C6—C7—C817.2 (2)
O1—C1—C2—O262.7 (2)C5—N4—C8—C1151.00 (16)
C8—C1—C2—O255.11 (17)C3—N4—C8—C134.16 (19)
O1—C1—C2—C3174.39 (18)C5—N4—C8—C744.06 (19)
C8—C1—C2—C356.62 (16)C3—N4—C8—C772.77 (17)
O2—C2—C3—N468.9 (2)O1—C1—C8—N4177.33 (16)
C1—C2—C3—N438.83 (18)C2—C1—C8—N456.09 (16)
C2—C3—N4—C5107.82 (18)O1—C1—C8—C771.5 (2)
C2—C3—N4—C82.98 (19)C2—C1—C8—C749.69 (17)
C8—N4—C5—C633.9 (2)O2—C7—C8—N477.98 (16)
C3—N4—C5—C676.6 (2)C6—C7—C8—N437.8 (2)
N4—C5—C6—C79.9 (2)O2—C7—C8—C128.98 (19)
C2—O2—C7—C6104.85 (18)C6—C7—C8—C1144.78 (18)
C2—O2—C7—C86.88 (19)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···N4i0.76 (3)2.01 (3)2.760 (2)167 (3)
Symmetry code: (i) x1/2, y+1/2, z.

Experimental details

Crystal data
Chemical formulaC7H11NO2
Mr141.17
Crystal system, space groupOrthorhombic, Pna21
Temperature (K)200
a, b, c (Å)9.9294 (16), 7.2910 (12), 9.1653 (15)
V3)663.52 (19)
Z4
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.09 × 0.09 × 0.08
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2000)
Tmin, Tmax0.893, 0.992
No. of measured, independent and
observed [I > 2σ(I)] reflections
6311, 880, 795
Rint0.029
(sin θ/λ)max1)0.668
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.032, 0.081, 1.07
No. of reflections880
No. of parameters94
No. of restraints1
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.29, 0.17

Computer programs: SMART (Bruker, 1997), SMART, SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1997), SHELXTL.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1A···N4i0.76 (3)2.01 (3)2.760 (2)167 (3)
Symmetry code: (i) x1/2, y+1/2, z.
 

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