(S)-5-Hexyl-1-[(S)-2-hydr­oxy-1-phenyl­ethyl]-4-meth­oxy-1H-pyrrol-2(5H)-one

Jian-Feng Zheng; Li-Jiao Jiang; Jian-Nan Guo

doi:10.1107/S1600536809014160

. 2009 Apr 22;65(Pt 5):o1094. doi: 10.1107/S1600536809014160

(S)-5-Hexyl-1-[(S)-2-hydroxy-1-phenylethyl]-4-methoxy-1H-pyrrol-2(5H)-one

Jian-Feng Zheng ^a,^*, Li-Jiao Jiang ^a, Jian-Nan Guo ^a

PMCID: PMC2977772 PMID: 21583908

Abstract

The title compound, C₁₉H₂₇NO₃, was obtained by the reaction of (3S,7aR)-7a-hexyl-7-methoxy-3-phenyl-2,3-dihydropyrrolo[2,1-b]oxazol-5(7aH)-one and triethylsilane using titanium(IV) chloride as catalyst. In the molecule, the phenyl and dihydropyrrolone rings form a dihedral angle of 83.8 (1)°. O—H⋯O hydrogen-bonding interactions lead to the formation of a chain parallel to the a axis.

Related literature

For the bioactivity of methyl tetramates, see: Royles (1995 ▶). For the synthesis, see: Jiang et al. (2009 ▶).

Experimental

Crystal data

C₁₉H₂₇NO₃
M _r = 317.42
Orthorhombic,
a = 9.6739 (17) Å
b = 10.0995 (18) Å
c = 17.929 (3) Å
V = 1751.7 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 173 K
0.56 × 0.32 × 0.23 mm

Data collection

Bruker APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.956, T _max = 0.982
12545 measured reflections
1773 independent reflections
1732 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.029
wR(F ²) = 0.079
S = 1.13
1773 reflections
208 parameters
H-atom parameters constrained
Δρ_max = 0.13 e Å⁻³
Δρ_min = −0.13 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SMART; data reduction: SAINT (Bruker, 2001 ▶); 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/S1600536809014160/bt2921sup1.cif

e-65-o1094-sup1.cif^{(20.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809014160/bt2921Isup2.hkl

e-65-o1094-Isup2.hkl^{(87.3KB, 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
O7—H7C⋯O2ⁱ	0.84	1.93	2.7475 (18)	163

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors thank the Xiamen University Science Foundation (grant No. XDKJCX20053013) and the Xiamen Science Foundation (grant No. 3502Z20055019) for financial support. The authors also thank Mr Zan-Bin Wei for technical assistance.

supplementary crystallographic information

Comment

Methyl tetramates bearing C-5 methyl substituents are key frameworks found in a number of bioactive natural products, such as dysideapyrrolidone and dolastatin (Royles, 1995). The title compound, (1), is one of the methyl tetramates which were synthesized when we researched the flexible method for the preparation of methyl (S)-5-alkyltetramate derivatives.

The title compound, (1), was obtained by the reaction of (3S,7aR)-7a-hexyl-7-methoxy-3-phenyl-2,3- dihydropyrrolo[2,1-b]oxazol-5(7aH)-one and triethylsilane using titanium (IV) chloride as catalyst. The absolute configuration (S) of the stereocentre C6 remains unchanged during the synthetic procedure. An X-ray crystal structure determination of the molecular structure of compound (1) was carried out to determine its conformation.

The phenyl and dihydropyrrolone rings form a dihedral angle of 83.8 (1)°. O—H···O hydrogen-bonding interactions lead to the formation of a chain parallel to the a axis.

Experimental

The title compound was prepared by a method based on one described by Jiang et al. (2009). To a cooled (-78 °C) solution of (3S,7aR)-7a-hexyl-7-methoxy-3-phenyl-2,3-\ δihydropyrrolo[2,1-b]oxazol-5(7aH)-one (0.230 mmol) in dry dichloromethane (6 ml) was added dropwise a solution of TiCl₄ (0.245 mmol), followed by Et₃SiH (2.3 mmol) under nitrogen atmosphere. After being stirred at -78 °C for 2 h, the mixture was allowed to react at room temperature and stirred until the completion of the reaction. The mixture was quenched with saturated NaHCO₃ solution. The organic layer was separated and the aqueous phase was extracted with CH₂Cl₂ (3 × 5 ml). The combined organic layers were washed with brine, dried over Na₂SO₄, and concentrated under reduced pressure. The residue was purified by flash chromatography to give (S)-5-hexyl-1-((S)- 2-hydroxy-1-phenylethyl)-4-methoxy-1H-pyrrol-2(5H)-one as colorless crystals. Single crystals were obtained by slow evaporation of a petroleum ether/ethyl acetate solution.