tert-Butyl 1-hy­droxy­piperidine-2-carboxyl­ate

Oliver Brücher; Uwe Bergsträsser; Harald Kelm; Jens Hartung

doi:10.1107/S1600536811026894

. 2011 Jul 16;67(Pt 8):o2061. doi: 10.1107/S1600536811026894

tert-Butyl 1-hydroxypiperidine-2-carboxylate

Oliver Brücher ^a, Uwe Bergsträsser ^a, Harald Kelm ^b, Jens Hartung ^a,^*

PMCID: PMC3213507 PMID: 22091086

Abstract

The title compound, C₁₀H₁₉NO₃, is a disubstituted piperidine bearing substituents in two equatorial positions. One of the substituents is a hydroxy group bound to nitrogen and the second a tert-butyl ester group bound to the carbon next to the endocyclic nitrogen. Enantiomers of the title compound form hydrogen-bridged dimers across a center of inversion.

Related literature

For bond lengths, see: Allen et al. (1987 ▶). For structural features associated with hydroxylamine, see: Chung-Phillips & Jebber (1995 ▶). For details of vanadium(V)- and molybdenum(VI)-catalysed oxidations, see: Hartung & Greb (2002 ▶); Reinhardt (2006 ▶). For a related structure, see: Kliegel et al. (2002 ▶). For the synthesis of 1-hydroxy piperidine-2-carboxylic acid, see: Murahashi & Shiota (1987 ▶).

Experimental

Crystal data

C₁₀H₁₉NO₃
M _r = 201.26
Monoclinic,
a = 10.1685 (3) Å
b = 12.1271 (2) Å
c = 10.2083 (3) Å
β = 110.377 (3)°
V = 1180.06 (5) Å³
Z = 4
Cu Kα radiation
μ = 0.68 mm⁻¹
T = 150 K
0.24 × 0.21 × 0.19 mm

Data collection

Oxford Diffraction Gemini S Ultra diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2008 ▶) T _min = 0.854, T _max = 0.882
5815 measured reflections
1851 independent reflections
1440 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.146
S = 1.09
1851 reflections
131 parameters
H-atom parameters constrained
Δρ_max = 0.39 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction, 2008 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2008 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997) ▶; software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811026894/nc2235sup1.cif

e-67-o2061-sup1.cif^{(16.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811026894/nc2235Isup2.hkl

e-67-o2061-Isup2.hkl^{(89.3KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811026894/nc2235Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3⋯N1ⁱ	0.84	2.12	2.8136 (19)	139

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Symmetry code: (i) Inline graphic .

Acknowledgments

This work was supported by the Deutsche Bundesstiftung Umwelt (grant No. 20007/885; scholarship for OB).

supplementary crystallographic information

Comment

1-Hydroxypiperidine-2-carboxylate (Murahashi & Shiota, 1987) attracted our attention, because the compound was expected to bind as dianion to early transition metal ions, such as vanadium(V) or molybdenum(VI). Complexes formed from vanadium(V) or molybdenum(VI) ions are formaly d⁰-metal centers. Complexes having such an electron configuration are able to activate peroxides at low temperatures, which is of importance for modern sustainable oxidation catalysis, for example in natural product synthesis (Hartung & Greb, 2002) or bleaching (Reinhardt, 2006). Since impurities from the synthesis of 1-hydroxypiperidine-2-carboxylate were difficult to separate from standard liquid/liquid and liquid/solid partitioning processes, we chose to convert this acid into a derived O-tert-butyl ester for subsequent sublimination. Colorless crystals of the title compound that deposited from the sublimation process were investigated via X-ray diffraction, in order to obtain a deeper structural insight into the product class of N-hydroxy α-aminocarboxylic acid esters.

The central structural element of the title compound, is a disubstituted piperidine ring. The N-heterocycle bears a hydroxy substituent at nitrogen and a tert-butyl O-ester substituent at the carbon next to the endocyclic nitrogen. Both substituents are bond to equatorial sites in piperidine (Figure 1). A distorted gauche arrangement of subunits C6–N1–O3–H3 = -90.30 ° and C2–N1–O3–H3 151.18 °, in combination with a N1–O3 distance of 1.4477 (18) Å, reflect typical structural characteristics of with compounds having a nitrogen oxygen single bond, such as hydroxylamine (Chung-Phillips & Jebber, 1995) or N-hydroxypiperidinium chloride (Kliegel et al., 2002). The geometrical parameters for the tert-butyl O-ester group in terms of bond distances and angles agree with reference data reported previously (Allen et al., 1987).

In the crystal, association of the title compound, occurs predominantly via H-bonding. Enantiomers of the title compound thus form H-bridged dimers (Figure 2 and Table 1) across a center of inversion [N1ⁱ···H3–O3 = 2.12 Å, N1ⁱ···O3 = 2.8136 (19)].

Experimental

To a suspension of crude N-hydroxypiperidine-2-carboxylic acid (1.15 g, 8 mmol) (Murahashi & Shiota, 1987) in tert-butyl acetate (20 ml) was added at 298 K HClO₄ [0.2 ml, 70% (w/w)]. The mixture was stirred for 10 min at 298 K and treated with a second batch of HClO₄ [2 ml, 70% (w/w)]. Stirring was continued for 20 h at 298 K. pH of the reaction mixture was adjusted to 8–9 by addition of satd. aq. NaHCO₃ [150 ml, 10% (w/w)] and NaOH pellets (0.8 g, 20 mmol). The resulting mixture was extracted with EtOAc (4 x 40 ml). Combined organic washings were dried (MgSO₄) and concentrated under reduced pressure to furnish a brown oily residue that was purified by chromatography [SiO₂, pentane/EtOAc = 2:1 (v/v)]. Yield: 412 mg (25%); mp 356 K; ¹H NMR (600 MHz, CDCl₃, δ_H p.p.m.): 1.20–1.30 (m, 1H), 1.47 (s, 9H), 1.52–1.78 (m, 4H), 1.97 (d, J = 11.1 Hz, 1H), 2.52 (t, J = 9.1 Hz, 1H), 3.02 (d, J = 10.6 Hz, 1H), 3.37 (d, J = 10.2 Hz, 1H), 6.56 (br s, 1H, OH). ¹³C NMR (151 MHz, CDCl₃, δ_C p.p.m.): 23.1, 25.1, 28.0, 29.3, 57.4, 71.2, 81.2, 171.9. Anal. calcd. for C₁₅H₂₃NO₂: C, 59.68; H, 9.52; N, 6.96%; Found C, 59.96; H, 9.49; N 6.94%. Crystalls suitable for X-ray diffraction were obtained by slow sublimation of (I) at 340 K and 0.1 mbar.