Two general mechanisms are known for deacetylation. One mechanism involves zinc binding to the acetyl oxygen. Another family of deacetylases require NAD+, which transfers an ribosyl group to the acetyl oxygen.[1]
Organic synthesis
Acetate esters[5] and acetamides[6] are generally prepared by acetylations. Acetylations are often used in making C-acetyl bonds in Friedel-Crafts reactions.[7][8] Carbanions and their equivalents are susceptible to acetylations.[9]
Acetylation reagents
Many acetylations are achieved using these three reagents:
Acetic anhydride. This reagent is common in the laboratory; its use cogenerates acetic acid.[7]
Acetyl chloride. This reagent is also common in the laboratory, but its use cogenerates hydrogen chloride, which can be undesirable.[8]
Ketene. At one time acetic anhydride was prepared by the reaction of ketene with acetic acid:[10]
Шаблон:Chem2 <math>\Delta H = -63 \text{ kJ/mol}</math>
Acetylation of cellulose
Шаблон:See also
Cellulose is a polyol and thus susceptible to acetylation, which is achieved using acetic anhydride. Acetylation disrupts hydrogen bonding, which otherwise dominates the properties of cellulose. Consequently, the cellulose esters are soluble in organic solvents and can be cast into fibers and films.[11]
Transacetylation
Transacetylation uses vinyl acetate as an acetyl donor and lipase as a catalyst. This methodology allows the preparation of enantio-enriched alcohols and acetates.[12]
