supplementary materials


bh2468 scheme

Acta Cryst. (2013). E69, o51    [ doi:10.1107/S1600536812049501 ]

3-Hydroxy-1-(4-methoxybenzyl)piperidin-2-one

D. P. Pienaar, S. Khorasani, C. B. de Koning and J. P. Michael

Abstract top

The title compound, C13H17NO3, adopts a conformation in which the aromatic ring and the mean plane of the piperidine ring are almost perpendicular to each other [dihedral angle = 79.25 (6)°]. The presence of the carbonyl group alters the conformation of the piperidine ring from a chair to a twisted half-chair conformation. In the crystal, pairs of strong O-H...O hydrogen bonds link the molecules into inversion dimers. Weak C-H...O interactions extend the hydrogen-bonding network into three dimensions.

Comment top

The title piperidinone was prepared as an early intermediate for the total synthesis of febrifugine, a quinazoline alkaloid with potent antimalarial activity (Murata et al., 1998). Ongoing investigations in our laboratories have made use of similar lactams for the synthesis of febrifugine analogues (Michael et al., 2006). It should be noted that, although the 3-hydroxy substituent was introduced by attempted asymmetric hydroxylation of the enolate of 1-(4-methoxybenzyl)piperidin-2-one with (+)-camphorsulfonyloxaziridine (Davis et al., 1990), partial racemization occurred; the crystals selected for analysis proved to be racemic.

The title organic compound (Fig. 1) adopts a conformation in which the aromatic ring and the piperidine ring are almost perpendicular to each other. Ring puckering analysis, as implemented in PLATON (Spek, 2009), indicates that the piperidine ring adopts a twisted half-chair conformation owing to the presence of the carbonyl group (Boeyens, 1978). Several hydrogen bonds exist in the structure (Table 1), with the most significant being an O—H···O hydrogen bond. These result in the formation of hydrogen bonded pairs of molecules which are related to each other by a center of inversion (Fig. 1). These molecules interact further through C—H···O interactions (Fig. 2) resulting in an extensive hydrogen bonding network of molecules.

Related literature top

For the use of related lactams in the synthesis of febrifugine analogues, see: Michael et al. (2006). For information on the biological activity of febrifugine, a quinazoline alkaloid with potent antimalarial activity, see: Murata et al. (1998). For the use of chiral oxaziridines in asymmetric hydroxylation, see: Davis et al. (1990). For the conformation of six-membered rings, see: Boeyens (1978).

Experimental top

To a solution of lithium hexamethyldisilazide, prepared from n-butyllithium (1.6 M in hexane, 1.83 ml, 2.93 mmol) and hexamethyldisilazane (0.63 ml) in THF (10 ml) at -70 °C was added a solution of 1-(4-methoxybenzyl)piperidin-2-one (322 mg, 1.47 mmol) in THF (20 ml). The solution was stirred at this temperature for 1 h, after which a solution of (+)-camphorsulfonyloxaziridine (0.67 g, 2.9 mmol) in THF (20 ml) was added dropwise. Stirring was maintained for a further 16 h at temperatures kept between -70 and -60 °C. The reaction was quenched by addition of saturated aqueous ammonium chloride solution (10 ml) and allowed to warm to ambient temperature. The organic components were extracted with dichloromethane (4 × 15 ml), the combined organic layers were washed with brine (20 ml), dried over MgSO4, and concentrated in vacuo. Purification by column chromatography on silica gel with hexane-ethyl acetate mixtures (9:1 to 1:1 v/v) yielded the title compound, which was recrystallized from hexane-ethyl acetate to yield the product as irregularly shaped colourless crystals (261 mg, 75%), m.p. 347–349 K.

Refinement top

All H atoms attached to C atoms were positioned geometrically, and allowed to ride on their parent atoms, with C—H bond lengths of 0.95 Å (Ar—H), 1.0 (CH), 0.99 Å (CH2) or 0.98 Å (CH3), and isotropic displacement parameters set to 1.2 (CH and CH2) or 1.5 times (CH3) the Ueq of the parent atom. The alcohol H atom (H2) was located from the difference map and refined freely with isotropic displacement parameter set to 1.5 times the Ueq of the parent atom O2.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT-NT (Bruker, 2005); data reduction: SAINT-NT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and SCHAKAL99 (Keller, 1999); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing the hydrogen bonding to another molecule related by a center of inversion. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. O—H···O and C—H···O interactions in the crystal structure of the title compound, which result in an extensive hydrogen bonding network in three dimensions.
3-Hydroxy-1-(4-methoxybenzyl)piperidin-2-one top
Crystal data top
C13H17NO3F(000) = 504
Mr = 235.28Dx = 1.297 Mg m3
Monoclinic, P21/cMelting point: 347 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 12.980 (3) ÅCell parameters from 958 reflections
b = 7.6143 (17) Åθ = 3.5–28.3°
c = 12.189 (3) ŵ = 0.09 mm1
β = 90.497 (5)°T = 173 K
V = 1204.6 (5) Å3Irregular, colourless
Z = 40.32 × 0.26 × 0.18 mm
Data collection top
Bruker APEXII CCD
diffractometer
2271 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.027
Graphite monochromatorθmax = 28.0°, θmin = 3.1°
φ and ω scansh = 1417
8378 measured reflectionsk = 1010
2895 independent reflectionsl = 169
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)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.124H atoms treated by a mixture of independent and constrained refinement
S = 1.08 w = 1/[σ2(Fo2) + (0.066P)2 + 0.1896P]
where P = (Fo2 + 2Fc2)/3
2895 reflections(Δ/σ)max < 0.001
158 parametersΔρmax = 0.52 e Å3
0 restraintsΔρmin = 0.22 e Å3
0 constraints
Crystal data top
C13H17NO3V = 1204.6 (5) Å3
Mr = 235.28Z = 4
Monoclinic, P21/cMo Kα radiation
a = 12.980 (3) ŵ = 0.09 mm1
b = 7.6143 (17) ÅT = 173 K
c = 12.189 (3) Å0.32 × 0.26 × 0.18 mm
β = 90.497 (5)°
Data collection top
Bruker APEXII CCD
diffractometer
2271 reflections with I > 2σ(I)
8378 measured reflectionsRint = 0.027
2895 independent reflectionsθmax = 28.0°
Refinement top
R[F2 > 2σ(F2)] = 0.042H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.124Δρmax = 0.52 e Å3
S = 1.08Δρmin = 0.22 e Å3
2895 reflectionsAbsolute structure: ?
158 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C20.11028 (9)0.10275 (17)0.35921 (10)0.0283 (3)
C30.06871 (9)0.07971 (17)0.32619 (11)0.0304 (3)
H30.00600.06620.30720.037*
C40.12221 (11)0.15543 (17)0.22690 (12)0.0353 (3)
H4A0.08560.26210.20130.042*
H4B0.19390.18830.24630.042*
C50.12221 (11)0.01793 (18)0.13695 (11)0.0374 (3)
H5A0.15070.06880.06890.045*
H5B0.05080.02090.12140.045*
C60.18684 (10)0.13727 (17)0.17295 (10)0.0323 (3)
H6A0.26050.10380.17160.039*
H6B0.17660.23490.12040.039*
C70.20555 (10)0.36915 (17)0.31491 (12)0.0334 (3)
H7A0.16930.41530.38000.040*
H7B0.19510.45350.25400.040*
C80.31965 (10)0.35530 (15)0.34078 (11)0.0296 (3)
C90.35322 (10)0.27078 (17)0.43529 (11)0.0343 (3)
H90.30370.22270.48380.041*
C100.45748 (11)0.25429 (18)0.46121 (11)0.0349 (3)
H100.47860.19670.52680.042*
C110.53038 (10)0.32307 (16)0.39013 (11)0.0321 (3)
C120.49838 (10)0.4107 (2)0.29565 (12)0.0389 (3)
H120.54790.46000.24770.047*
C130.39415 (10)0.42600 (19)0.27143 (11)0.0365 (3)
H130.37300.48560.20660.044*
C140.66904 (13)0.2242 (2)0.50439 (15)0.0495 (4)
H14A0.64500.28940.56860.074*
H14B0.74450.21920.50550.074*
H14C0.64110.10470.50610.074*
N10.16062 (8)0.19805 (13)0.28388 (8)0.0270 (2)
O10.09468 (8)0.15790 (15)0.45317 (8)0.0444 (3)
O20.07623 (8)0.19755 (14)0.41449 (10)0.0457 (3)
H20.0256 (18)0.165 (3)0.4675 (17)0.069*
O30.63479 (7)0.31060 (14)0.40678 (9)0.0431 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C20.0217 (5)0.0342 (6)0.0289 (6)0.0031 (5)0.0005 (4)0.0000 (5)
C30.0229 (6)0.0295 (6)0.0389 (7)0.0030 (5)0.0027 (5)0.0049 (5)
C40.0332 (7)0.0276 (6)0.0451 (8)0.0003 (5)0.0046 (6)0.0036 (5)
C50.0420 (8)0.0393 (7)0.0309 (7)0.0059 (6)0.0042 (5)0.0062 (5)
C60.0340 (7)0.0356 (7)0.0272 (6)0.0037 (5)0.0051 (5)0.0026 (5)
C70.0288 (6)0.0249 (6)0.0465 (8)0.0013 (5)0.0043 (5)0.0014 (5)
C80.0284 (6)0.0234 (6)0.0371 (7)0.0034 (5)0.0042 (5)0.0038 (5)
C90.0309 (7)0.0336 (7)0.0385 (7)0.0038 (5)0.0097 (5)0.0021 (5)
C100.0352 (7)0.0348 (7)0.0349 (7)0.0028 (5)0.0019 (5)0.0031 (5)
C110.0268 (6)0.0293 (6)0.0404 (7)0.0052 (5)0.0016 (5)0.0049 (5)
C120.0318 (7)0.0448 (8)0.0402 (7)0.0106 (6)0.0075 (5)0.0056 (6)
C130.0343 (7)0.0377 (7)0.0377 (7)0.0067 (6)0.0023 (5)0.0067 (6)
C140.0375 (8)0.0456 (9)0.0652 (11)0.0059 (7)0.0124 (7)0.0064 (7)
N10.0249 (5)0.0262 (5)0.0300 (5)0.0014 (4)0.0030 (4)0.0001 (4)
O10.0430 (6)0.0598 (7)0.0307 (5)0.0174 (5)0.0094 (4)0.0094 (5)
O20.0365 (6)0.0453 (6)0.0553 (7)0.0001 (4)0.0051 (5)0.0202 (5)
O30.0268 (5)0.0473 (6)0.0553 (7)0.0067 (4)0.0021 (4)0.0046 (5)
Geometric parameters (Å, º) top
C2—O11.2381 (15)C7—H7B0.9900
C2—N11.3443 (16)C8—C91.3865 (19)
C2—C31.5426 (18)C8—C131.3977 (18)
C3—O21.4039 (16)C9—C101.393 (2)
C3—C41.5145 (19)C9—H90.9500
C3—H31.0000C10—C111.3909 (19)
C4—C51.5160 (19)C10—H100.9500
C4—H4A0.9900C11—O31.3719 (16)
C4—H4B0.9900C11—C121.391 (2)
C5—C61.5121 (19)C12—C131.3871 (19)
C5—H5A0.9900C12—H120.9500
C5—H5B0.9900C13—H130.9500
C6—N11.4717 (16)C14—O31.4272 (19)
C6—H6A0.9900C14—H14A0.9800
C6—H6B0.9900C14—H14B0.9800
C7—N11.4753 (16)C14—H14C0.9800
C7—C81.5154 (18)O2—H20.96 (2)
C7—H7A0.9900
O1—C2—N1122.21 (12)C8—C7—H7B109.2
O1—C2—C3119.16 (11)H7A—C7—H7B107.9
N1—C2—C3118.62 (11)C9—C8—C13117.85 (12)
O2—C3—C4109.87 (11)C9—C8—C7120.32 (11)
O2—C3—C2110.71 (11)C13—C8—C7121.84 (12)
C4—C3—C2112.93 (10)C8—C9—C10121.88 (12)
O2—C3—H3107.7C8—C9—H9119.1
C4—C3—H3107.7C10—C9—H9119.1
C2—C3—H3107.7C11—C10—C9119.33 (13)
C3—C4—C5108.54 (11)C11—C10—H10120.3
C3—C4—H4A110.0C9—C10—H10120.3
C5—C4—H4A110.0O3—C11—C10123.94 (12)
C3—C4—H4B110.0O3—C11—C12116.31 (12)
C5—C4—H4B110.0C10—C11—C12119.75 (13)
H4A—C4—H4B108.4C13—C12—C11120.02 (12)
C6—C5—C4109.47 (10)C13—C12—H12120.0
C6—C5—H5A109.8C11—C12—H12120.0
C4—C5—H5A109.8C12—C13—C8121.16 (13)
C6—C5—H5B109.8C12—C13—H13119.4
C4—C5—H5B109.8C8—C13—H13119.4
H5A—C5—H5B108.2O3—C14—H14A109.5
N1—C6—C5112.35 (11)O3—C14—H14B109.5
N1—C6—H6A109.1H14A—C14—H14B109.5
C5—C6—H6A109.1O3—C14—H14C109.5
N1—C6—H6B109.1H14A—C14—H14C109.5
C5—C6—H6B109.1H14B—C14—H14C109.5
H6A—C6—H6B107.9C2—N1—C6125.13 (11)
N1—C7—C8112.04 (10)C2—N1—C7119.67 (11)
N1—C7—H7A109.2C6—N1—C7114.78 (10)
C8—C7—H7A109.2C3—O2—H2107.9 (12)
N1—C7—H7B109.2C11—O3—C14117.08 (12)
O1—C2—C3—O236.84 (16)O3—C11—C12—C13178.67 (13)
N1—C2—C3—O2144.47 (12)C10—C11—C12—C131.3 (2)
O1—C2—C3—C4160.52 (12)C11—C12—C13—C80.3 (2)
N1—C2—C3—C420.79 (15)C9—C8—C13—C120.7 (2)
O2—C3—C4—C5174.31 (10)C7—C8—C13—C12179.32 (12)
C2—C3—C4—C550.17 (14)O1—C2—N1—C6176.47 (12)
C3—C4—C5—C664.96 (14)C3—C2—N1—C64.89 (17)
C4—C5—C6—N148.71 (15)O1—C2—N1—C74.33 (18)
N1—C7—C8—C970.61 (15)C3—C2—N1—C7177.02 (10)
N1—C7—C8—C13109.37 (14)C5—C6—N1—C219.25 (17)
C13—C8—C9—C100.5 (2)C5—C6—N1—C7168.28 (10)
C7—C8—C9—C10179.46 (12)C8—C7—N1—C298.18 (13)
C8—C9—C10—C110.5 (2)C8—C7—N1—C674.74 (14)
C9—C10—C11—O3178.55 (12)C10—C11—O3—C141.19 (19)
C9—C10—C11—C121.5 (2)C12—C11—O3—C14178.80 (13)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O1i0.96 (2)1.84 (2)2.7708 (16)161.6 (19)
C6—H6B···O1ii0.992.433.3142 (17)148
C14—H14B···O2iii0.982.523.449 (2)158
Symmetry codes: (i) x, y, z+1; (ii) x, y+1/2, z1/2; (iii) x+1, y, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O1i0.96 (2)1.84 (2)2.7708 (16)161.6 (19)
C6—H6B···O1ii0.992.433.3142 (17)148
C14—H14B···O2iii0.982.523.449 (2)158
Symmetry codes: (i) x, y, z+1; (ii) x, y+1/2, z1/2; (iii) x+1, y, z+1.
Acknowledgements top

This work was supported by the University of the Witwatersrand and the National Research Foundation, Pretoria (grant No. 78837).

references
References top

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Murata, K., Takano, F., Fushiya, S. & Oshima, Y. (1998). J. Nat. Prod. 61, 729–733.

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