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This Review contains major "Acylation"- related terms, short phrases and links grouped together in the form of Encyclopedia article.
- The acylation is conducted in a usual manner, for example, by adding a corresponding acid anhydride or acid chloride to an amino acid solution.
- Acylation is defined as the introduction of an acyl group (-COR) onto a molecule.
- Acylation is also used to form volatile derivatives of highly polar and involatile organic materials.
- Because acylation is such an important and widely used transformation, many novel techniques have been developed for this purpose.
- In chemistry, acylation (rarely, but more formally: alkanoylation) is the process of adding an acyl group to a compound.
- Friedel-Crafts Acylation The same aluminum chloride catalyst used in Friedel-Crafts alkylation is also used for Friedel-Crafts acylation.
- Friedel-Crafts Alkylation and Acylation and Nitration of Ferrocene and Acetylferrocene - Please see the attached file for the fully formatted problems.
- H 2 SO 4 or AlCl 3) such as nitration, sulfonation and Friedel-Crafts alkylation or acylation.
- Acylation, alkylation, sulfonation, nitration and halogenation reactions.
- G.10.1: Describe, using equations, the nitration, chlorination, alkylation, and acylation of benzene.
- G.10.2: Describe and explain the mechanism for the nitration, chlorination, alkylation, and acylation of benzene.
- Acyl halides can be used in Friedel-Crafts acylation to introduce the acyl moiety in an aromatic compound.
- Electrophilic aromatic substitution of benzene The Friedel-Crafts acylation is a specific example of electrophilic aromatic substitution.
- EXAMPLES Example 1 The Friedel-Crafts acylation of acetoanilide was conducted using a Ga Lewis acid catalyst according to the following reaction scheme.
- Typically, Friedel-Crafts reactions for alkylation or acylation of aromatic compounds are catalyzed by aluminum chloride or other Lewis acids.
- The Friedel-Crafts reaction exists as an acylation and an alkylation with acyl halides or alkyl halides as reactants.
- Reactions of amines as nucleophiles: alkylation, acylation, and condensation with aldehydes and ketones.
- High-purity silylation, alkylation and acylation reagents and labware for use in derivatization for drugs of abuse testing and other GC applications.
- Friedel developed the Friedel-Crafts alkylation and acylation reactions with James Crafts in 1877, and attempted to make synthetic diamond s.
- The alkylation reaction has many associated problems (see Friedel-Crafts), so it is less widely used than the acylation reaction.
- The present invention also represents the first acylation which has been achieved under supercritical conditions.
- Alkylation and Acylation of the <F128 a-Carbon via an Enamine Intermediate.
- With the much less active benzoyl chloride, acylation can still be performed by the use of excess aqeous alkali to facilitate the reaction.
- As indicated above, the Friedel-Crafts acylation reaction is controlled by the addition of an ionic controlling agent.
- For example, for a Friedel-Crafts acylation with AlCl 3, a kilogram of product yields up to 20 kg of (contaminated) waste salt.
- In acylation and alkylation reactions (Friedel-Crafts and related processes), aluminum halide is accepted as the preferred catalyst.
- Such protection is obviously achieved by acylation, for example, to yield compounds XIX wherein R.sup.8 is acyl.
- FIG. 10 shows a reaction for the acylation of hydrocortisone with chloroacetic anhydride.
- The mixtures are stirred and monitored by TLC until acylation is judged to be complete (typically from about two to about seven hours).
- The ring nitrogen of most pyridines undergoes reactions typical of weak, tertiary organic amines such as protonation, alkylation (qv), and acylation.
- Some examples of Friedel-Crafts acylation reactions are shown in the following diagram.
- Acylation temperatures from below 0.degree.
- First acylation of the substrate to form an acyl-enzyme intermediate and then deacylation in order to return the enzyme to its original state.
- A good method for the preparation of aromatic ketones is the Friedel-Crafts acylation of aromatic hydrocarbons with acyl chlorides or anhydrides.
- In particular, a method of performing Friedel-Crafts alkylation or acylation reactions is disclosed under those conditions.
- Acylation of 14 with a substituted amino acid N-hydroxysuccinimide ester provided derivative 15 in excellent yields.
- In acylation, though, virtually all the substitution happens in the 4- position.
- Friedel-Crafts acylation is also possible with acid anhydrides.
- The viability of the Friedel-Crafts acylation depends on the stability of the acyl chloride reagent.
- One advantage of using ionic liquids in acylation reactions is the enhanced reaction rates, conversion, and selectivity.
- If desired, the acylation of the benzoyl ring substituents may be avoided by the use of suitable protecting groups well-known in the art.
- Another method for resolving (.+-.)-calanolide A into its optically active forms involves enzyme-catalyzed acylation or hydrolysis.
- Surface hydroxyl groups, which may be esterified during the acylation step, may be converted back to hydroxyl form by hydrolysis.
- Those skilled in the art will readily recognize that when an addition complex is formed, it should not substantially deactivate the molecule to acylation.
- Desirably, such a route would also allow selective alkylation or acylation of aromatic substrates.
- Enantiomer selectivity of lipase catalyzed acylation of 2-acylated 1,2-diols was studied.
- The preferred enzyme for use in the enzyme-catalyzed acylation reaction is lipase.
- There are some reactions, such as acylation and phosphorylation, in which the reactions may be accelerated by both Lewis acidic and nucleophilic promoters.
- Patent applications in class Chemical aftertreatment, e.g., acylation, methylation, etc.
- Offer effective acylation of hydroxyl groups, primary and secondary amines.
- The Friedel-Crafts acylation is a specific example of electrophilic aromatic substitution.
- Succinic acid is also commonly used in a specific type of acylation called succination.
- The Friedel-Crafts acylation reagent is normally composed of an acyl halide or anhydride mixed with a Lewis acid catalyst such as AlCl3.
- By careful control of the reaction conditions the acylation may be the major reaction route and the esterification may be reduced to a minimum.
- Examples of acetylation reactions include acylation processes such as esterification (see below) and the Friedel-Crafts reaction.
- So for the acylation of an amine, it should nucleophilic character and also a H-atom on nitrogen is necessary.
- When the acylation of B29 lysine is complete, usually within 30 min, the reaction may be stopped by addition of an amine, such as ethanolamine, or ammonia.
- Acylation of the N-terminus; conversion of the C-terminus into an amide.
- The amide can be formed on a preformed polymer via an acylation reaction, well know in the art.
- The amide group is reprotected as BOC 6 and the azide group converted to the amide 7 by reductive acylation with thioacetic acid and 2,6-lutidine.
- Alkaline-earth, lanthanide and transition metal based catalysts for acylation and nitration reactions under solvent free conditions.
- Kobayashi et al, Synlett 1994, 545 have demonstrated that lanthanum and hafnium triflates are catalysts for Friedel-Crafts acylation reactions.
- Acylation under basic conditions is generally preferred in order to avoid undesired side reactions.
- In a preferred embodiment, the disulfide compounds contain reactive groups that can undergo acylation or alkylation reactions.
- In general, alkylation, acylation or other lipophilic modification of a heteroatom of the phenylindole will increase the stability of the compound.
- Compound 24 was converted to compound 27 via acylation of the amine with methyl oxalyl chloride (see for example, Sellstedt.
- Preferably the compound of formula I is treated with a demethylation step and an acylation step.
- Alkanes > Halogenation
- Nature > Chemistry > Acids > Acetic Anhydride
* Acetic Anhydride
* Acylating Agent
* Aromatic Compounds
* Lewis Bases
* Non-Limiting Examples
* Present Invention
* Room Temperature
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