Crystal structure of (2E,6E)-2,6-bis(2,4-dimethoxybenzylidene)- cyclohexanone, C24H26O5

Abstract

Source of materialThe title compound was prepared using the method as previously described [1]. An amount of 7.5 mmol cyclohexanone was added to asolution of 15 mmol 2,4-dimethoxybenzaldehyde in MeOH (10 ml). The solution was stirred at room temperature for 20 min, followed by dropwise addition of NaOMe/MeOH (1.5 ml, 7.5 mmol). The mixture was stirred at room temperature and monitored with TLC. When the reaction was finished, the residue was poured into saturated NH 4 Cl solution and filtered. The precipitate was washed with water and cold ethanol, and dried in vacuum. Single crystals were obtained by re-crystalliza-tion from amethanol/chloroform solution (1:2, v/v)at293 K. Experimental detailsThe hydrogen atoms bound to carbon atoms were positioned geometrically and allowed to ride on their parent atoms with d(Csp 2 -H) =0.93 Å and U iso =1.2 U eq (C), and d(Csp 3 -H) = 0.97 Å and U iso =1 .5 U eq (C). The relatively high temperature (293 K) in detection system may result in large displacement parameters. DiscussionCurcumin, awell-known food additive, has long been used in traditional medicine to treat various inflammatory diseases in China and India [2]. It has asurprisingly wide range of beneficial properties, including anti-inflammatory, antioxidant, chemopreventive and chemo-therapeutic activity and has been used to treat several different cancers [3][4][5]. However, although curcumin is non-toxic and has promising anti-cancer activities, preclinical and clinical studies indicate that its poor bioavailability and weak pharmacokinetic profiles derived from its structural instability under physiological conditions have seriously limited its application in anti-cancer therapies [6,7]. In the past two decades, alot of efforts has been put into the chemical modification of curcumin to identify potential analogues with better bioavailability and antitumor activities [5,[8][9][10]. The title compound, one of monocarbonyl curcumin analogues has demonstrated excellent cytotoxic properties against several human cancer cell lines in vitro (data not shown). The activity against tumor growth and stable structure renders it apotential candidate for therapeutic applications for cancers. The molecule C 24 H 26 O 5 contains two benzene rings. Their geometrical parameters are in normal range. The bond lengths within phenyl rings are between 1.367(3) Å and 1.397(3) Å,which highlights the aromatic character. The dihedral angle between the aromatic ring planes is 3.5(7)°.T he long and flat shape of the molecules favors their packing in the crystal structure. There are no hydrogen bonds and strong interactions between the molecules.