rac-4a,10b-cis,10b,5c-trans-5-(7-Methyl-2-oxo-2H-chromen-4-yl)-3,4,4a,5,6,10b-hexa­hydro-2H-pyrano[3,2-c]quinoline

M Kayalvizhi; G Vasuki; Shriniwas D Samant; Kailas K Sanap

doi:10.1107/S1600536813001876

. 2013 Jan 23;69(Pt 2):o280. doi: 10.1107/S1600536813001876

rac-4a,10b-cis,10b,5c-trans-5-(7-Methyl-2-oxo-2H-chromen-4-yl)-3,4,4a,5,6,10b-hexahydro-2H-pyrano[3,2-c]quinoline

M Kayalvizhi ^a, G Vasuki ^a,^*, Shriniwas D Samant ^b, Kailas K Sanap ^b

PMCID: PMC3569807 PMID: 23424553

Abstract

In the racemic title compound, C₂₂H₂₁NO₃, the nitrogen-containing ring of the pyranoquinoline moiety adopts a slightly distorted half-chair conformation and the oxygen-containing ring adopts a slightly distorted chair conformation. The benzene rings make a dihedral angle of 84.97 (8)°. In the crystal, weak C—H⋯O interactions link the molecules into chains extending along the a-axis direction.

Related literature

For general background and related coumarin compounds, see: Aazam et al. (2006 ▶); Chinnakali et al. (2009 ▶); Du et al. (2010 ▶); Pereira Silva et al. (2010 ▶). For ring conformational analysis, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₂₂H₂₁NO₃
M _r = 347.40
Triclinic,
a = 7.7529 (4) Å
b = 11.2790 (7) Å
c = 11.7563 (11) Å
α = 117.232 (3)°
β = 98.475 (3)°
γ = 101.301 (2)°
V = 862.60 (11) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 296 K
0.20 × 0.15 × 0.15 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker 1999 ▶) T _min = 0.984, T _max = 0.987
18945 measured reflections
5009 independent reflections
3544 reflections with I > 2σ(I)
R _int = 0.030

Refinement

R[F ² > 2σ(F ²)] = 0.055
wR(F ²) = 0.177
S = 1.03
5009 reflections
235 parameters
H-atom parameters constrained
Δρ_max = 0.41 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: APEX2 and SAINT (Bruker, 2004 ▶); data reduction: SAINT and XPREP (Bruker, 2004 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 2012 ▶); software used to prepare material for publication: PLATON (Spek, 2009 ▶).

Supplementary Material

Click here for additional data file.^{(21.7KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536813001876/zs2247sup1.cif

e-69-0o280-sup1.cif^{(21.7KB, cif)}

Click here for additional data file.^{(245.3KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813001876/zs2247Isup2.hkl

e-69-0o280-Isup2.hkl^{(245.3KB, 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
C12—H12A⋯O1ⁱ	0.97	2.59	3.307 (3)	131
C20—H20⋯O2ⁱⁱ	0.93	2.40	3.275 (2)	157

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors thank the Sophisticated Analytical Instrument Facility, IIT-Madras, Chennai, for the data collection.

supplementary crystallographic information

Comment

Coumarin is the simplest member of the group of oxygen heterocyclic compounds called benzo-2-pyrones. Coumarins are an important class of compound due to their presence in natural products as well as their medicinal applications, e.g. as anti-inflammatory, anti-viral, antioxidant, antibacterial, antifungal, anti-HIV and as anti-carcinogenic agents (Pereira Silva et al., 2010). Coumarin and its derivatives also have applications as fluorescent dyes for synthetic fibres and daylight fluorescent pigments (Aazam et al., 2006) and as cosmetics, optical brightening agents and laser dyes (Pereira Silva et al., 2010). The synthesis of pyranoquinoline derivatives has been the focus of great interest, because it was reported that these possess a broad spectrum of biological properties such as psychotropic activity and anti-allergenic activity and they are also used for the treatment of proliferative diseases, such as cancer (Du et al., 2010). Compounds containing pyranoquinolone motifs also exhibit antiproliferative and antitubulin activities and it includes antibacterial and antifungal activities. Some of the pyranoquinoline derivatives have been found to block acetylcholinesterase and cell calcium signals, and cause neuroprotection against calcium overload and free radicals (Chinnakali et al., 2009).

We report herein the crystal structure of the racemic title compound, a pyranoquinoline-substituted methyl coumarin derivative, C₂₂H₂₁NO₃ (Fig. 1). The dihedral angle between the phenyl rings of the coumarin molecule and the pyranoquinoline moiety is 84.97 (8)° . The C15 atom of the carbonyl group has a distorted trigonal geometry with O2—C15—O1 [117.36 (14)°] and O2—C15—C14 [125.26 (16)°], deviating significantly from the ideal sp² value of 120°, which is consistent with the values observed in a related structure (Pereira Silva et al., 2010). In the crystal, weak intermolecular C20—H···O2ⁱⁱ hydrogen bonds together with C12—H···O1ⁱ hydrogen bonds between inversion-related molecules (Table 1), give one-dimensional chain structures which extend along the a axis (Fig. 2). Present also in the crystal packing are C5—H···π ring interactions [minimum C···Cg separation, 3.910 (3) Å] (for symmetry codes, see Table 1). The substituent ring defined by (N1, C1, C6–C9) adopts a slightly distorted half-chair conformation with Q = 0.4852 (18) Å, θ = 48.0 (2)° and φ = 259.3 (3)° while the ring defined by (O3, C7–C12) adopts a slightly distorted chair conformation with Q = 0.548 (2) Å, θ = 2.8 (2)° and φ = 300 (5)° (Cremer & Pople, 1975).

Experimental

7-Methylcoumarin-4-azadiene (0.263 g, 1 mmol) and ZnCl₂ (0.136 g, 1 mmol) were stirred in dichloroethane (5 ml) for 15 minutes and dihydropyran (0.252 g, 3 mmol) was added slowly at room temperature. The solution was heated till complete consumption of the coumarin reagent. The solution was cooled to room temperature, quenched with water and the product was extracted with chloroform. The extract was dried over anhydrous Na₂SO₄ and the solvent evaporated to obtain a sticky mass which was purified by column chromatography on silica gel using chloroform.