2-(2,4,5-Trimeth­oxy­phen­yl)-2,3-dihydro­quinolin-4(1H)-one

Suchada Chantrapromma; Pumsak Ruanwas; Nawong Boonnak; Kan Chantrapromma; Hoong-Kun Fun

doi:10.1107/S1600536812002917

. 2012 Feb 10;68(Pt 3):o664–o665. doi: 10.1107/S1600536812002917

2-(2,4,5-Trimethoxyphenyl)-2,3-dihydroquinolin-4(1H)-one

Suchada Chantrapromma ^a,^*,^‡, Pumsak Ruanwas ^a, Nawong Boonnak ^a, Kan Chantrapromma ^b, Hoong-Kun Fun ^c,^§

PMCID: PMC3295454 PMID: 22412565

Abstract

In the title aza-flavanone, C₁₈H₁₉NO₄, an intramolecular cyclization product of chalcone, the central heterocyclic ring is in an envelope conformation and the dihedral angle between the benzene rings is 51.03 (10)°. The methoxy groups at the ortho and para positions are slightly twisted from the benzene ring to which they are bound [C—O—C—C = 21.9 (3) and −171.93 (18)°, respectively], whereas the methoxy group at the meta position is almost coplanar [C—O—C—C = 3.5 (3)°]. In the crystal, molecules are linked by N—H⋯O hydrogen bonds and weak C—H⋯O interactions into chains along the [001] direction. Weak C—H⋯π interactions also occur.

Related literature

For background to the syntheses and properties of aza-flavanones, see: Göker et al. (2005 ▶); Xia et al. (1998 ▶). For ring conformations, see Cremer & Pople (1975 ▶). For the stability of the temperature controller used in the data collection, see Cosier & Glazer, (1986 ▶).

Experimental

Crystal data

C₁₈H₁₉NO₄
M _r = 313.34
Monoclinic,
a = 10.7354 (11) Å
b = 17.1525 (16) Å
c = 8.6471 (8) Å
β = 102.981 (2)°
V = 1551.6 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 100 K
0.41 × 0.16 × 0.06 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.962, T _max = 0.994
13335 measured reflections
4511 independent reflections
2751 reflections with I > 2σ(I)
R _int = 0.062

Refinement

R[F ² > 2σ(F ²)] = 0.063
wR(F ²) = 0.156
S = 1.03
4511 reflections
215 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.38 e Å⁻³
Δρ_min = −0.30 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812002917/hb6602sup1.cif

e-68-0o664-sup1.cif^{(26.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812002917/hb6602Isup2.hkl

e-68-0o664-Isup2.hkl^{(221KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812002917/hb6602Isup3.cml

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

Table 1. Hydrogen-bond geometry (Å, °).

Cg1 and Cg2 are the centroids of the C1–C6 and C10–C15 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N1⋯O3ⁱ	0.90 (3)	2.32 (3)	3.156 (2)	155 (3)
C2—H2A⋯O4ⁱ	0.95	2.59	3.439 (3)	150
C16—H16B⋯O3ⁱⁱ	0.98	2.58	3.459 (3)	150
C8—H8B⋯Cg1ⁱⁱⁱ	0.99	2.74	3.698 (2)	164
C16—H16C⋯Cg1^iv	0.98	2.68	3.518 (3)	144
C17—H17C⋯Cg2ⁱⁱ	0.98	2.76	3.560 (3)	140
C18—H18C⋯Cg2ⁱ	0.98	2.75	3.574 (3)	142

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

Acknowledgments

The authors thank the Prince of Songkla University and the Universiti Sains Malaysia for Research University grant No. 1001/PFIZIK/811160. PR thanks the Crystal Materials Research Unit, Prince of Songkla University, for financial support. NW thanks the Prince of Songkla University for a postdoctoral fellowship. HKF thanks King Saud University, Riyadh, Saudi Arabia, for the award of a visiting professorship (23 December 2011 to 14 January 2012).

supplementary crystallographic information

Comment

Aza-flavanone or 2-aryl-2,3-dihydroquinolin-4(1H)-one, a synthesized analogue of flavanone, can be achieved by intramolecular cyclization of a chalcone derivative in basic medium (Xia et al., 1998). They are also found to exhibit antibacterial, antifungal (Göker et al., 2005) and anticancer activities (Xia et al., 1998). In the course of our research on medicinal chemistry, we have synthesized the title aza-flavanone (I) in order to study its biological activity.

The total molecule of (I) is twisted (Fig. 1). The dihedral angle between two benzene rings is 51.03 (10)°. The N-atom containing central ring is in an envelope conformation with the puckered C9 atom having the maximum deviation of 0.352 (2) Å, and the puckering parameter Q = 0.502 (2) Å, θ = 124.5 (2)° and φ = 110.8 (3)° (Cremer & Pople, 1975). The three methoxy groups of the 2,4,5-trimethoxyphenyl unit have two different orientations: the two methoxy groups at ortho (at atom C11) and para (at atom C13) positions are slightly twisted from the attached benzene ring with torsion angles C16—O2—C11—C12 = 21.9 (3)° and C17—O3—C13—C14 = -171.93 (18)°, whereas the third one at meta (at atom C14) position is co-planar with the torsion angle of C18—O4—C14—C15 = 3.5 (3)°. These angle values also indicated that the methyl group at para position points towards the ortho-methoxy but points away from the meta-methoxy due to the steric effect.

In the crystal (Fig. 2), the molecules are linked by N—H···O hydrogen bonds and weak C—H···O interactions (Table 1) into chains along the c axis. C—H···π interactions (Table 1) also occur.

Experimental

To a 50 ml round-bottom flask filled with 2,4,5-trimethoxybenzaldehyde (0.50 g, 2.55 mmol), EtOH (20 ml) and 2-aminoacetophenone (0.31 ml, 2.55 mmol) were sequentially added at room temperature. After stirring for a while, 5 ml of 30% NaOH (aq) was added slowly and was then further stirred for 2 h. A pale yellow precipitate was formed and collected by filtration yielding the title compound (I) (1.26 g, 75% yield), which was further recrystallized in EtOH to obtain yellow needles of (I) after several days, m.p. 419–420 K.