Crystal structure of 3-(4-methoxyphenyl)-1-(4-methylphenyl)prop-2-en-1-one, C₁₇H₁₆O₂

Source of material

Equimolar quanities of p-methylacetophenone (0.01 mol) and p-methoxybenzaldehyde (0.01 mol) were dissolved in ethanol (10 mL) under stirring and aq. NaOH (30%) was added dropwise. The reaction mixture was stirred at room temperature for a few hours. The reaction mixture was diluted with water & acidifed with HCl. The separated solid was filtered and recrystallised from ethanol [5].

IR (ATR) cm⁻¹: 2932 (aromatic—CH), 2837 (aliphatic—CH), 1651 (C = O), 1593–1416 (C = C); ¹H-NMR (δ): 8.00–6.94 (−CH), 2.41 (−CH₃), 3.91 (−OCH₃); ¹³C-NMR (δ): 21.54 (−CH₃), 55.51 (−OCH₃), 188 (C = O), 163 (HC = CH), 144–120 (aromatic—CH₃), 113.81–113.75 (aliphatic—CH). Anal. Calcd. for C₁₇H₁₆O₂: C, 80.95; H, 6.34; Found: C, 80.63; H, 6.07.

Experimental details

The structure was solved by direct methods and refined by full-matrix least-square techniques. All the H atoms in the molecular structure were found and located in difference Fourier map and refined freely. H bond lengths vary between 0.952(14) Å and 0.969(15) Å for aromatic rings.

Comment

Chalcones consist of two aromatic rings which are linked by three carbon atoms with a α,β-unsaturated carbonyl system. Chalcones and their derivatives are interesting materials for their biological activities such as anti-viral, anti-malarial, anti-cancer, antioxidant, anti-inflammatory, antifungal, antileishmanial, anti-tubercular, anti-hyperglycemic properties [6], [7], [8], [9], [10], [11]. They are also used in different applications such as agriculture [12], cosmetics and manufacture of pesticides [13].

The title compund, C₁₇H₁₆O₂, shows E conformation with respect to the C = C double bond (C7 = C8 = 1.318(2) Å). In the molecular structure, the methoxy substituted phenyl ring and the methyl substituted phenyl ring are inclined by 13.78(6)°. The maximum deviations within the ring systems are 0.0052(2) Å for C4 atom of the C1—C6 ring and 0.0033(2) Å for atom C12 of the C10—C15 ring. The attached methyl group is co-planar with the related aromatic ring system (C10—C15). The methoxy group is slightly twisted with the C4—C3—O1—C17 and C2—C3—O1—C17 torsion angles of −174.97(16)° and 5.0(2)°, respectively. In the molecular structure, the bond lengths and angles are consistent with the related structures [14, 15] . The crystal structure presents at least one very weak intermolecular hydrogen bond, namely C11—H11⋯O2′ (with symmetry code: −x, −y + 1, −z).