Crystal structure of (2E,6E)-2,6-bis[2-(trifluoromethyl)benzylidene]cyclohexanone, C22H16F6O

Abstract

Source of material (2E,6E)-2,6-bis[2-(trifluoromethyl)benzylidene]cyclohexanone was synthesized by an Aldol condesation between two molecules of 2-(trifluoromethyl)benzaldehyde and cyclohexanone, which was synthesized according our earlier published method [1,2]. An amount of 7.5 mmol cyclohexanone was added to a solution of 15 mmol 2-(tri-fluoromethyl)benzaldehyde 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 by 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. The solid was purified by chromatography over silica gel using CH 2 Cl 2 /CH 3 OH as the eluent to yield compound. All chemicals used for the synthesis were commercially available of AR grade, and were used as received. The yellow crystal of the title compound was obtained by slow evaporation of a CH 3 OH solution at room temperature. Experimental detailsPosition of the H atoms were calculated based on geometric criteria (C-H = 0.97 and 0.93 Å for methyl and aromatic atoms, respectively) then were placed in their calculated position and refined isotropically using a riding model with U iso (H) = 1.5 U eq (C) for methyl and U iso (H) = 1.2 U eq (C) for all others. DiscussionCurcumin has been demonstrated to possess a wide range of pharmaceutical activities, such as anti-tumor [3, 4], anti-inflammation [5], anti-oxidation [6], anti-bacterial [7], and cardiovascular protection [8,9]. However, its high metabolic instability and low bioavailability have dramatically limited its practical application [10]. Recently, our research group has synthesized a series of mono-carbonyl analogs of curcumin (MACs) by deleting b-diketone moiety [11][12][13]. The title compound, belongs to MACs and shown greater metabolic stability than that of curcumin. The crystal structure of the title compound is depicted in the figure. The asymmetric unit of this complex is constructed by two 2-(trifluoromethyl)benzylidene groups and a cyclohexanone linker. The C-C bond length of the cyclohexanone moiety ranging from 1.491 to 1.509 Å are quite normal single bonds. The C7-C8 and C12-C14 bond lengths of 1.328 and 1.324 Å conform to the value for a double bond. The C6-C7 and C14-C15 bond length of 1.466 Å are intermediate between the double and single bonds. The shortening of the C-C bonds showing the partial double-bond character of the C-C bonds, which are influenced by adjacent conjugated double bonds.

Efficacy of the monocarbonyl curcumin analog C66 in the reduction of diabetes-associated cardiovascular and kidney complications

“…The E , E stereochemistry of the exocyclic double bonds, the conformation of the cyclohexanone ring, and the dihedral angles of the aryl rings have been confirmed by spectroscopic and crystallographic data (Fig. 3 ) (Zhang et al 2015 ).…”

Structural Characterization, Theoretical Investigation and Hirshfeld Surface Analysis of 2,6-(E,E)-bis((thiophene-2-yl)methylene)cyclohexanone

“…In the molecular structure, the central cyclohexanone ring display a chair conformation with the C8 atom lying 0.385(4)Å above the plane C7-C9 atoms. The exocyclic alkenyl moieties defined by the C5=C6, C10=C12 vectors reveal bond distances of 1,345(5)Å and 1,346(5)Å, respectively consistent with their double bond character [29]. The C12-C13, C4-C5 bond lengths of 1.442(5)Å, 1.446(4)Å respectively, are intermediate between the double and single bonds.…”

Development of a spectrophotometric method for assessment of the relative reactivity of monocarbonyl analogs of curcumin with 2-(dimethylamino)ethanethiol

“…2E,6E)-2,6-bis[(2-trifluoromethyl)benzylidene]cyclohexanone (1, C66): recrystallized from methanol, yellow crystals, yield (79 %) mp 107-110 °C (lit 35,36. 108-110 °C); FT-IR (KBr): 1666 cm -1 (C = O); FT-IR-ATR (sapphire): 1665 cm -1 (C = O); FT-IR (CCl4 ): 1682 cm -1 (C = O); UV-Vis: λmax (80:20 CH3CN/H2O) = 302 nm (ε = 23675 l•mol -1 •cm -1 ); HPLC-DAD-MS, tR = 5.5 min; MS-APCI+ (m/z) = 411 (MH + ).…”