A second polymorph of (2E)-1-(4-fluorophenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one

Abstract

The crystal structure of the title compound, C18H17FO4, reported here is a polymorph of the structure first reported by Patil et al. [Mol. Cryst. Liq. Cryst. Sci. Technol. Sect. A (2007), 461, 123–130]. It is a chalcone analog and consists of substituted phenyl rings bonded at the opposite ends of a propenone group, the biologically active region. The dihedral angle between the mean planes of the aromatic rings within the 4-fluoro­phenyl and trimethoxy­phenyl groups is 28.7 (1)° compared to 20.8 (6)° in the published structure. The angles between the mean plane of the prop-2-ene-1-one group and the mean plane of aromatic rings within the 4-fluoro­phenyl and trimethoxy­phenyl groups are 30.3 (4) and 7.4 (7)°, respectively, in contast to 10.7 (3) and 12.36° for the polymorph. While the two 3-meth­oxy groups are in the plane of the trimeth­oxy-substituted ring, the 4-meth­oxy group is in a synclinical [−sc = −78.1 (2)°] or anti­clinical [+ac = 104.0 (4)°] position, compared to a +sc [53.0 (4)°] or −ac [−132.4 (7)°] position. While no classical hydrogen bonds are present, weak inter­molecular C—H⋯π-ring inter­actions are observed which contribute to the stability of the crystal packing. The two polymorphs crystallize in the same space group, P21/c, but have different cell parameters for the a, b and c axes and the β angle. A comparison of the mol­ecular geometries of both polymorphs to a geometry optimized density functional theory (DFT) calculation at the B3-LYP/6–311+G(d,p) level for each structure provides additional support to these observations.

(2E)-3-[4-(Dimethylamino)phenyl]-1-(4-fluorophenyl)prop-2-en-1-one

“…A review of antiinfective and anti-inflammatory chalcones (Nowakowska, 2007) and recent advances in therapeutic chalcones have been reported (Ni et al, 2004). The crystal structures of few related fluoro chalcones viz., 3-(3,4-dimethoxyphenyl)-1-(4fluorophenyl)prop-2-en-1-one (Butcher et al, 2006) (Jasinski, et al, 2009), (E)-3-(4fluorophenyl)-1-phenyl-2-propen-1-one (Jing, 2009), 1-(4-fluorophenyl)-3-(4-methoxyphenyl)prop-2-en-1-one (Harrison et al, 2006) and 3-(biphenyl-4-yl)-1-(4-fluorophenyl)prop-2-en-1-one (Sarojini et al, 2007) have been reported. In a continuation of our studies and in view of the importance of fluoro chalcones, we report the synthesis and crystal structure of a new chalcone, C 17 H 16 FNO, (I).…”

ss-NMR and single-crystal X-ray diffraction in the elucidation of a new polymorph of bischalcone (1E,4E)-1,5-bis(4-fluorophenyl)penta-1,4-dien-3-one

“…This structure was elucidated in 2007 and no polymorph has been reported until now. Indeed, this phenomenon is not very common in chalcones and bischalcones because of an apparent rigidity in the conformation of the open-chain backbone (Ramos et al, 2016;Jasinski et al, 2009). In this precedent structure, only the AS conformer was found.…”

(E)-3-(4-Chlorophenyl)-1-(5-hydroxy-2,2-dimethyl-2H-chromen-6-yl)prop-2-en-1-one

“…For the biological activity of chalcones, see: Tran et al (2009); Rao et al (2004); Opletalova & Sedivy (1999); Dimmock et al (1999). For related structures, see: Boeck et al (2006); Jasinski et al (2009); Wang & Yang (2011). For the synthesis of a related compound, see: Krohn et al (2002).…”

“…Chalcones can be easily obtained from the adol condensation of aromatic aldehydes and aromatic ketones. The crystal structure of related compounds:(E)-1-(5-Hydroxy-2,2-dimethl-2H-chromen-6-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (Wang et al, 2011) and (2E)-1-(2-Bromoppheny)-3-(3,4,5-trimethoxypheny)prop-2-en-1-one (Jasinski et al, 2009) have been reported recently. The crystal structure of the title compound (I) is reported in this paper.…”