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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.
For example, two molecules of acetone condense to a single compound mesityl oxide in the presence of an ion-exchange resin: [1] 2 CH 3 COCH 3 → (CH 3) 2 C=CH(CO)CH 3 + H 2 O. For synthetic uses, this is generally an undesirable, but spontaneous and favored side-reaction of mixed aldol condensation, and special precautions are needed to ...
The trans,trans isomer can be prepared in high yield and purity by condensation of benzaldehyde and acetone with sodium hydroxide in a water/ethanol medium followed by recrystallization. [ 2 ] This reaction, which proceeds via the intermediacy of benzylideneacetone , is often performed in organic chemistry classes, [ 6 ] and is called Claisen ...
The reaction product is a vicinal diol. The reaction is named after pinacol (also known as 2,3-dimethyl-2,3-butanediol or tetramethylethylene glycol), which is the product of this reaction when done with acetone as reagent. The reaction is usually a homocoupling but intramolecular cross-coupling reactions are also possible.
The Baeyer–Drewsen indigo synthesis (1882) is an organic reaction in which indigo is prepared from 2-nitrobenzaldehyde and acetone [1] [2] The reaction was developed by von Baeyer and Viggo Drewsen in 1880 to produce the first synthetic indigo at laboratory scale. This procedure is not used at industrial scale.
An aldol condensation is a condensation reaction in organic chemistry in which two carbonyl moieties (of aldehydes or ketones) react to form a β-hydroxyaldehyde or β-hydroxyketone (an aldol reaction), and this is then followed by dehydration to give a conjugated enone. The overall reaction equation is as follows (where the Rs can be H)
This reaction is named after two of its pioneering investigators Rainer Ludwig Claisen and J. Gustav Schmidt, who independently published on this topic in 1880 and 1881. [ 1 ] [ 2 ] [ 3 ] An example is the synthesis of dibenzylideneacetone ((1 E , 4 E )-1,5-diphenylpenta-1,4-dien-3-one).
This nucleophilic addition is a reversible reaction but with aliphatic carbonyl compounds equilibrium is in favor of the reaction products. The cyanide source can be potassium cyanide (KCN), sodium cyanide (NaCN) or trimethylsilyl cyanide ((CH 3) 3 SiCN). With aromatic aldehydes such as benzaldehyde, the benzoin condensation is a