Search results
Results From The WOW.Com Content Network
Dibenzylideneacetone or dibenzalacetone, often abbreviated dba, is an organic compound with the formula C 17 H 14 O. It is a pale-yellow solid insoluble in water, but soluble in ethanol. It is a pale-yellow solid insoluble in water, but soluble in ethanol.
[1] [2] [3] An example is the synthesis of dibenzylideneacetone ((1E, 4E)-1,5-diphenylpenta-1,4-dien-3-one). [ 4 ] Quantitative yields in Claisen–Schmidt reactions have been reported in the absence of solvent using sodium hydroxide as the base and plus benzaldehydes . [ 5 ]
Dibenzyl ketone, or 1,3-diphenylacetone, is an organic compound composed of two benzyl groups attached to a central carbonyl group. This results in the central carbonyl carbon atom being electrophilic and the two adjacent carbon atoms slightly nucleophilic.
Benzylideneacetone can be efficiently prepared by the base-induced condensation of acetone and benzaldehyde: [3]. CH 3 C(O)CH 3 + C 6 H 5 CHO → C 6 H 5 CH=CHC(O)CH 3 + H 2 O. However, the benzylideneacetone formed via this reaction can undergo another Claisen-Schmidt condensation with another molecule of benzaldehyde to form dibenzylideneacetone.
Tris(dibenzylideneacetone)dipalladium(0) or [Pd 2 (dba) 3] is an organopalladium compound.The compound is a complex of palladium(0) with dibenzylideneacetone (dba). It is a dark-purple/brown solid, which is modestly soluble in organic solvents.
The mechanism for base-catalyzed aldol condensation can be seen in the image below. A mechanism for aldol condensation in basic conditions, which occurs via enolate intermediates and E1CB elimination. The process begins when a free hydroxide (strong base) strips the highly acidic proton at the alpha carbon of the aldehyde.
Condensation reactions likely played major roles in the synthesis of the first biotic molecules including early peptides and nucleic acids.In fact, condensation reactions would be required at multiple steps in RNA oligomerization: the condensation of nucleobases and sugars, nucleoside phosphorylation, and nucleotide polymerization.
The reaction mechanism is related to that for the Reimer–Tiemann reaction, which uses chloroform as the formylating agent. [1] Protonated hexamine ring-opens to expose an iminium group. Addition to the aromatic ring results in an intermediate at the oxidation state of a benzylamine.