(1S,3S,4S)-tert-Butyl N-[1-benzyl-3-hydr­oxy-5-phenyl-4-(picolinamido)pent­yl]carbamate

Jian-Feng Zheng; Su-Yu Huang; Jian-Nan Guo; Yu Zhang; Li-Ren Jin

doi:10.1107/S1600536808018965

. 2008 Jun 28;64(Pt 7):o1362. doi: 10.1107/S1600536808018965

(1S,3S,4S)-tert-Butyl N-[1-benzyl-3-hydroxy-5-phenyl-4-(picolinamido)pentyl]carbamate

Jian-Feng Zheng ^a,^*, Su-Yu Huang ^a, Jian-Nan Guo ^a, Yu Zhang ^a, Li-Ren Jin ^a

PMCID: PMC2961835 PMID: 21202980

Abstract

The title compound, C₂₉H₃₅N₃O₄, was obtained by the reaction of (2S,4S,5S)-tert-butyl N-(4-amino-1-benzyl-3-hydroxy-5-phenylpentyl)carbamate and picolinic acid using oxalyl chloride as a chlorinating reagent to activate the carboxyl group. In the crystal structure there are two molecules in the asymmetric unit, which are aligned edge-to-face. In one molecule, the pyridyl ring forms a dihedral angle of 22.0 (1)° with the phenyl ring of the terminal benzyl group and 14.3 (1)° with the other phenyl ring; in the other molecule, the corresponding angles are 12.1 (1) and 10.6 (1)°, respectively. The packing is stabilized by intermolecular hydrogen bonds and C—H⋯π interactions.

Related literature

For related literature, see: Nishiyama et al. (1989 ▶); Allen et al. (1987 ▶); Pavel et al. (1993 ▶).

Experimental

Crystal data

C₂₉H₃₅N₃O₄
M _r = 489.60
Monoclinic,
a = 11.7573 (12) Å
b = 15.9783 (18) Å
c = 15.0881 (15) Å
β = 103.787 (9)°
V = 2752.8 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 173 (2) K
0.70 × 0.32 × 0.12 mm

Data collection

Bruker APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.947, T _max = 0.991
14395 measured reflections
4903 independent reflections
3396 reflections with I > 2σ(I)
R _int = 0.070

Refinement

R[F ² > 2σ(F ²)] = 0.068
wR(F ²) = 0.180
S = 1.19
4903 reflections
649 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.29 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; 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 datablocks I, global. DOI: 10.1107/S1600536808018965/cf2204sup1.cif

e-64-o1362-sup1.cif^{(40.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808018965/cf2204Isup2.hkl

e-64-o1362-Isup2.hkl^{(365.4KB, hkl)}

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
N2A—H2AA⋯O2B	0.88	2.04	2.888 (5)	162
O1A—H1AB⋯O3B	0.84	1.89	2.707 (5)	164
N2B—H2BA⋯O2Aⁱ	0.88	2.01	2.843 (5)	159
O1B—H1BB⋯O3Aⁱ	0.84	1.88	2.711 (5)	171
C23B—H23B⋯CgAⁱⁱ	0.95	2.97	3.776 (4)	144

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Symmetry codes: (i) Inline graphic ; (ii) . CgA is the centroid of the C6–C11 phenyl ring.

Acknowledgments

The authors thank the Natural Science Foundation of Fujian Province of China (No. U0650024), Xiamen Science Foundation (No.3502Z20055019) and NFFTBS (No. J0630429) for financial support. We also thank Mr Z.-B. Wei, Mr T.-B. Wen and Mr Y.-X. Gao for technical assistance.

supplementary crystallographic information

Comment

The title compound, (1), is a key intermediate for the preparation of recycling chiral ligands, such as oxazoline ligands for asymmetric catalysts. The majority of the syntheses of these ligands have followed a general synthetic route in which acids were first condensed with the corresponding optically active β-aminoalcohols to form the hydroxyamide derivatives. The hydoxy groups in the hydroxyamides were then activated and the resulting intermediates were cyclized to provide the oxazoline ligands (Nishiyama et al., 1989).

The title compound was obtained by the reaction of (2S,4S,5S)-tert-butyl N-(4-amino-1-benzyl-3-hydroxy-5-phenylpentyl)carbamate and picolinic acid using oxalyl chloride as a chlorinating reagent to activate the carboxyl group. An X-ray crystal structure determination was carried out to determine its conformation. Bond lengths are in agreement with values reported in the literature (Allen et al., 1987).

In the crystal structure of (1), there are two molecules in the asymmetric unit (Fig. 1). In molecule A, the dihedral angle of the pyridyl and the C6A/C11A phenyl rings is 22.0 (1)° and for the pyridyl and C13A/C18A rings it is 14.3 (1)°. In molecule B the angles are 12.1 (1)° and 10.6 (1)° respectively. The packing is shown in Fig. 2. Molecules are linked by O—H···O and N—H···O hydrogen bonds involving all the potential donors, generating linear chains parallel to the a axis. The packing is further stablized by C—H···π interactions, with typical geometry (Pavel et al., 1993).

Experimental

Picolinic acid (0.38 g, 3.12 mmol) was suspended in dichloromethane (40 ml) at 273 K. N,N-Dimethylformamide (0.1 ml) and oxalyl chloride (0.27 ml, 3.12 mmol) in dichloromethane (10 ml) were added and stirred for 3 h. The reaction mixture was then cooled to 263 K, (2S,4S,5S)-tert-butyl N-(4-amino-1-benzyl-3-hydroxy-5-phenylpentyl)carbamate (1.00 g, 2.60 mmol) and triethylamine (2.2 ml, 15.60 mmol) in dichloromethane (10 ml) were added dropwise and the mixture was stirred at 273 K. After 0.5 h, the reaction mixture was quenched with water (15 ml). The inorganic layer was separated followed by extraction with dichloromethane. The organic phases were combined and dried over anhydrous MgSO₄ and concentrated in vacuo, and the residue was purified by silica gel column chromatography (ethyl acetate/petroleum ether 1:2), giving the product (1.89 g, 98.2%) as a white solid. Single crystals were obtained by slow evaporation of a solution in ethyl acetate/dichloromethane.