1,3-Di-3-pyridyl-2,3-dihydro-1H-naphth[1,2-e][1,3]oxazine

Betül Şen; Zuhal Turgut; Emel Pelit; Muhittin Aygün

doi:10.1107/S1600536808003887

. 2008 Feb 13;64(Pt 3):o573. doi: 10.1107/S1600536808003887

1,3-Di-3-pyridyl-2,3-dihydro-1H-naphth[1,2-e][1,3]oxazine

Betül Şen ^a,^*, Zuhal Turgut ^b, Emel Pelit ^b, Muhittin Aygün ^a

PMCID: PMC2960797 PMID: 21201915

Abstract

In the crystal structure of the title compound, C₂₂H₁₇N₃O, the oxazine ring has a half-chair conformation. The dihedral angles between the best least-squares plane through the pyridine rings and the planar part (O–C–C–C–N) of the oxazine ring are 72.14 (6) and 35.44 (7)°, the smaller angle involving the pyridine ring adjacent to the oxazine O atom. The molecule has two stereogenic centers at the oxazine carbons, RS and SR. The crystal packing reveals that symmetry-related molecules are linked by intermolecular N—H⋯N hydrogen bonds to form chains parallel to the b axis.

Related literature

For related literature, see: Kurz et al. (2005 ▶); Turgut et al. (2007 ▶); Szatmari et al. (2003 ▶, 2004 ▶); Bernstein et al. (1995 ▶); Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₂₂H₁₇N₃O
M _r = 339.39
Monoclinic,
a = 12.1720 (8) Å
b = 8.0444 (6) Å
c = 18.7716 (15) Å
β = 112.615 (5)°
V = 1696.7 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 293 (2) K
0.28 × 0.22 × 0.12 mm

Data collection

Stoe IPDSII diffractometer
Absorption correction: none
15207 measured reflections
3703 independent reflections
1786 reflections with I > 2σ(I)
R _int = 0.124

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.092
S = 0.80
3703 reflections
304 parameters
All H-atom parameters refined
Δρ_max = 0.12 e Å⁻³
Δρ_min = −0.13 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2002 ▶); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶) and PLATON (Spek, 2003 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808003887/su2043sup1.cif

e-64-0o573-sup1.cif^{(20.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808003887/su2043Isup2.hkl

e-64-0o573-Isup2.hkl^{(221.2KB, 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
N1—H1⋯N3ⁱ	0.98 (2)	2.04 (2)	3.009 (2)	170.7 (17)

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors acknowledge the Faculty of Arts and Sciences, Ondokuz Mayıs University, Turkey, for the use of the Stoe IPDSII diffractometer (purchased under grant No. F.279 of the University Research Fund), and Dokuz Eylül University Research Funds (Project No. 04.KB.FEN.100).

supplementary crystallographic information

Comment

1,3-oxazine heterocycles are of interest because they constitute an important class of natural and non-natural products. Many of them exhibit biological activity such as analgesic, anticonvulsant, antitubercular, antibacterial and anticancer (Kurz et al., 2005; Turgut et al., 2007). In addition, they can be used as intermediates in the synthesis of N-substituted amino alcohols or in enantioselective synthesis of chiral amines. The tautomeric character of the 1,3-O,N-heterocycles offers a great number of synthetic possibilities (Szatmari et al., 2003; Szatmari et al., 2004).

Atoms (C11, C20, C21 and O1) of the oxazine six-membered ring are planar to within 0.014 Å. The oxazine ring adopts a half-chair conformation, with atom C22 and N1 deviating by -0.375 (3) Å and 0.308 (3) Å, respectively, from the mean plane formed by atoms (C11, C20, C21 and O1). The ring puckering parameters for the oxazine ring are Q = 0.451 (2) Å, θ = 126.2 (2)° and φ = 92.4 (3) ° (Cremer & Pople, 1975). The dihedral angles made by the best least-squares plane through all six atoms of the oxazine ring with the mean planes of the pyridine rings (N2/C1—C5) and (N3/C6—C10) are 79.62 (9)° and 36.40 (9)°, respectively. The sum of the angles at N1 of the oxazine ring is 334.1°, in accordance with sp³-hybridization. The H atoms bonded to atoms C22 and C21 of the oxazine ring are axial and trans to one another. The structure is centrosymmetric so the absolute configurations of the two stereogenic centres, C21 and C22, are RS and SR, respectively.

In the crystal structure, intermolecular N1—H1···N3ⁱ hydrogen bonds (Table 1) link the molecules to form an infinite one-dimensional polymeric chain. In this manner a C(6) chain (Bernstein et al., 1995) is formed and the axis of the polymeric chain runs co-linear with the crystallographic [010] direction of the monoclinic unit cell (Fig. 2).

Experimental

The title compound was prepared by cyclization reactions realised using 2-naphthol and pyridine-3-carbaldehyde in the presence of dry methanolic ammonia (Fig. 3). The structure of the title compound has been clarified by FTIR, MS and NMR techniques and confirmed by elemental analysis.

Pyridin-3-carbaldehyde (2 mmol; freshly distilled if liquid) and 25% methanolic ammonia solution (0.5 mL) were added to a solution of 2-naphthol (1 mmol) in absolute MeOH (0.5 ml). The mixture was left to stand at ambient temperature for 2 days, during which time a crystalline product separated out. The crude product was filtered off, washed with cold MeOH (2x2mL), then purified by column chromatography with ethyl acetate/n-hexane (3:1). Pale-yellow crystals of the title compound, suitable for X-ray analysis, were obtained by slow evaporation of this solution.

¹H NMR (CDCl₃, δ (p.p.m.)): 5.34 (s, 1H, CH); 5.89 (s, 1H, CH); 7.21–7.89 (m, 10H, ArH); 8.50–8.89 (m, 4H, pyridine)

¹³C NMR (CDCl₃, δ (p.p.m.)): 56.23, 81.75, 124.37, 133.67, 139.76, 148.27, 150.52, 154.3

FTIR(KBr, cm^-1, ν) 3335, 3056,3034, 1622,1596,1260,1233,1023,928