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In organic synthesis, the complex diethylaniline·borane (DEANB) is used as a reducing agent. [4] Diethylaniline and dimethylaniline are both used as acid-absorbing bases. The advantage to the diethyl derivative is that [C 6 H 5 NEt 2 H]Cl is non-hygroscopic, in contrast to [C 6 H 5 NMe 2 H]Cl. [5]
Oxygen and the organic phase react under formation of the anthraquinone and hydrogen peroxide. Among other alkyl groups (R) ethyl-and tert-butyl-are used, e.g., 2-ethylanthraquinone. [2] [3] The hydrogen peroxide is then extracted with water and in a second step separated by fractional distillation from the water. The hydrogen peroxide ...
The reaction of quadricyclane with DEAD is a 2σ + 2σ + 2π cycloaddition that on water takes place within 10 minutes at room temperature with 82% yield. The same reaction in toluene takes 24 hours at 80 °C with 70% yield. An emulsion reaction in fluorinated cyclohexane takes 36 hours and the neat reaction takes even longer (48 hours).
The diazomethane is required in excess so as to react with the HCl formed previously. [2] Not taking diazomethane in excess results in HCl reacting with the diazoketone to form chloromethyl ketone and N 2. Mild conditions allow this reaction to take place while not affecting complex or reducible groups in the reactant-acid. [3]
Using a strong base in this reaction would induce self-condensation of the aldehyde or ketone. The Hantzsch pyridine synthesis, the Gewald reaction and the Feist–Benary furan synthesis all contain a Knoevenagel reaction step. The reaction also led to the discovery of CS gas.
Allylic shifts become the dominant reaction pathway when there is substantial resistance to a normal (non-allylic) substitution. For nucleophilic substitution, such resistance is known when there is substantial steric hindrance at or around the leaving group, or if there is a geminal substituent destabilizing an accumulation of positive charge.
In organic chemistry, the Mannich reaction is a three-component organic reaction that involves the amino alkylation of an acidic proton next to a carbonyl (C=O) functional group by formaldehyde (H−CHO) and a primary or secondary amine (−NH 2) or ammonia (NH 3). [1] The final product is a β-amino-carbonyl compound also known as a Mannich base.
Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH 3 CO) 2 O. Commonly abbreviated Ac 2 O, it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis. It is a colorless liquid that smells strongly of acetic acid, which is formed by its reaction with ...