A new and economical synthesis of α, α′-bis(substituted-benzylidene)cycloalkanones has been achieved by the reaction of cycloalkanones with different aromatic aldehydes using nano-TiO2/acetic acid as a catalyst in ethanol under reflux conditions with excellent yields. Five new products and three new single crystal structures are reported.
Synthesis and Fluorescence Properties of α,α′-Bis(substituted-benzylidene)cycloalkanones Catalyzed by 1-Methyl-3(2-(sulfooxy)ethyl)-1<i>H</i>-imidazol-3-ium Chloride
α,α′-Bis(substituted-benzylidene)cycloalkanones were synthesized via a solvent-free cross-aldol condensation of aromatic aldehydes with cycloalkanones in the presence of a catalytic amount 1-methyl-3(2-(sulfooxy)ethyl)-1H-imidazol-3-ium chloride at room temperature with excellent yields. The screening for optical properties indicated that the size of cycloalkanone has an influence on the fluorescence
The phase-vanishing (PV) method using perfluorohexanes as the phase screen was applied to the aldol condensation using TiCl4 as the Lewis acid. A special test tube was used, in which an interface between the fluorous and organic layers was stirred, and cyclohexanone was treated with two equivalents of benzaldehyde derivatives under PV conditions to afford corresponding 2,6-dibenzylidencyclohexanone in good yields. The formyl-methylenation of ketones with triethylamine using TiCl4 was also demonstrated by the PV method. (C) 2017 Elsevier B.V. All rights reserved.
Cyclization of α,α′-bis(substituted-benzylidene)cyclohexanones and 4-hydroxycoumarin: synthesis of 11-benzylidene-8,9,10,11-tetrahydro-7-phenyl-6H,7H-chromeno[4,3-b]chromen-6-ones as new pyranochromene derivatives
A series of new 11-benzylidene-8,9,10,11-tetrahydro-7-phenyl-6H,7H-chromeno[4,3-b]chromen-6-ones has been synthesized through a new Michael addition domino cyclization between alpha,alpha'-bis(substituted-benzylidene)cyclohexanones and 4-hydroxycoumarin in acetic acid at reflux conditions. Very good to excellent yields of the products, operational simplicity, and simple workup are attractive features of this synthesis protocol.
Amoozadeh, Ali; Rahmani, Salman; Nemati, Firouzeh, South African Journal of Chemistry, 2010, vol. 63, p. 72 - 74