(4R,5S)-5-Benzyl-4-isopropyl-1,3,4-oxadiazinan-2-one

Lacey D Addison; Delvis D Dore; Shawn R Hitchcock; Gregory M Ferrence

doi:10.1107/S1600536808013056

. 2008 May 10;64(Pt 6):o1040–o1041. doi: 10.1107/S1600536808013056

(4R,5S)-5-Benzyl-4-isopropyl-1,3,4-oxadiazinan-2-one

Lacey D Addison ^a, Delvis D Dore ^a, Shawn R Hitchcock ^a, Gregory M Ferrence ^a,^*

PMCID: PMC2961530 PMID: 21202562

Abstract

The title compound, C₁₃H₁₈N₂O₂, is an N₄-isopropyl-l-phenylalanine-based oxadiazinanone. Although the two molecules in the asymmetric unit are oriented appropriately for hydrogen bonding, the distance between the donor and acceptor atoms is large enough to support only weak, if any, hydrogen bonding. The absolute configuration is known based on the known starting compounds in the synthetic procedure.

Related literature

For related literature, see: Burgeson et al. (2004 ▶); Casper, Blackburn et al. (2002 ▶); Casper, Burgeson et al. (2002 ▶); Casper & Hitchcock (2003 ▶); Dore et al. (2006 ▶); Ferrence et al. (2003 ▶); Hitchcock et al. (2004 ▶); Hitchcock et al. (2001 ▶); Squire et al. (2005 ▶); Szczepura et al. (2004 ▶); Bruno et al. (2004 ▶).

Experimental

Crystal data

C₁₃H₁₈N₂O₂
M _r = 234.29
Orthorhombic,
a = 9.6423 (14) Å
b = 11.4974 (17) Å
c = 22.600 (3) Å
V = 2505.5 (6) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 100 (2) K
0.43 × 0.23 × 0.23 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan SADABS in SAINT-Plus (Bruker, 2003 ▶) T _min = 0.965, T _max = 0.981
25602 measured reflections
3499 independent reflections
3403 reflections with I > 2σ(I)
R _int = 0.041

Refinement

R[F ² > 2σ(F ²)] = 0.060
wR(F ²) = 0.133
S = 1.32
3499 reflections
307 parameters
H-atom parameters constrained
Δρ_max = 0.37 e Å⁻³
Δρ_min = −0.25 e Å⁻³

Data collection: SMART (Bruker, 2003 ▶); cell refinement: SAINT-Plus (Bruker, 2003 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶) and publCIF (Westrip, 2008 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808013056/sg2243sup1.cif

e-64-o1040-sup1.cif^{(23.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808013056/sg2243Isup2.hkl

e-64-o1040-Isup2.hkl^{(168.1KB, hkl)}

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

Enhanced figure: interactive version of Fig. 5

Acknowledgments

This material is based upon work supported by the US National Science Foundation (CHE-0348158 to GMF) and the American Chemical Society Petroleum Research Fund (to SRH & GMF). GMF thanks Adam Beitelman (ISU) and Matthias Zeller, Youngstown State University Structure & Chemical Instrumentation Facility, for the data collection and useful discussions. The diffractometer was funded by NSF grant 0087210, Ohio Board of Regents grant CAP-491, and YSU.

supplementary crystallographic information

Comment

The synthesis (Hitchcock et al., 2001), conformational analysis (Casper, Blackburn et al., 2002; Burgeson et al. 2004), and asymmetric applications (Casper & Hitchcock, 2003; Casper, Burgeson et al., 2002; Ferrence et al. 2003; Hitchcock et al. 2004; Hitchcock et al. 2001; Squire et al. 2005; Szczepura et al. 2004) of 3,4,5,6-tetrahydro-2H-1,3,4-oxadiazinan-2-ones have only thoroughly been studied in the last ten years. We have been interested in synthesizing new oxadiazinanones for use as chiral auxillaries in aldol addition reactions. We synthesized the title compound in order to study the conformation that the heterocycle adopts. Herein we report the single-crystal X-ray structure analysis of the N₄-isopropyl-L-phenylalanine based oxiadiazinanone.

Other oxadiazinanones have been reported and studied, but the title compound is one of few studied that is not substituted at the N3 position. Other oxadiazinanone structures (Burgeson et al., 2004; Casper, Blackburn et al., 2002; Casper, Burgeson et al., 2002; Ferrence et al., 2003; Hitchcock et al., 2001, 2004) are substituted with a carbonyl at the N3 position. These N3 substituted oxadiazinanones adopt a twist-boat conformation, as does the title compound. This is also consistent with related oxadiazinanones not substituted at the N3 position (Szczepura et al., 2004). The C7B—C5B—N4B—C14B torsion angle is 159.1 (2)°, and the C7A—C5A—N4A—C14A torsion angle is 155.5 (2)°. Previously reported oxadiazinanones with no substitution at the N3 position have torsion angles between 161.79–163.16°. A Mogul (Bruno et al. 2004) geometry check showed all non-H bond angles and distances to be normal. The molecular structure (Fig. 1.) of I includes two independent molecules in the asymmetric unit. The oxadiazinanone moieties are essentially isostructural. The primary difference between the two molecules is the orientation of the benzyl group attached to C5A/B (Figs. 2. and 3.). The respective -56.9 (3)° N4A—C5A—C7B—C8A and -175.5 (2)° N4A—C5A—C7B—C8A torsion angles quantify this difference.

Hydrogen-bonding interactions usually appear to play a key role in the crystal packing of oxadiazinanones (Szczepura et al., 2004). However, it may be that the optimal crystal packing simply happens to yield an arrangement of molecules which are suggestive of a hydrogen bonding motif. That is packing forces other than formation of the weak H-bonding fortuitously lead to the motif. In the title compound, the 2.83 Å N3A—O17B and 2.89 Å N3B—O17A donor to acceptor separations are large enough to support only weak, if any, hydrogen bonding (Fig 4.). This interaction is further illustrated in the Jmol enhanced figure (Fig. 5).

Experimental

The title compound was prepared as previously reported (Dore et al. (2006)).