Nucleophilic acyl substitution reactions derivatives

Amides are the least reactive carboxylic acid derivative, and the only nucleophilic acyl substitution reaction they undergo is hydrolysis. Amides are fairly stable in water, but the amide bond is cleaved on heating in the presence of strong acids or bases. Nominally, this cleavage produces an amine and a car boxylic acid. 

Nucleophilic Acyl Substitution Reactions of Carboxylic Acid Derivatives (Chapter21)... 

As a general rule, nucleophilic addition reactions are characteristic only of aldehydes and ketones, not of carboxylic acid derivatives. The reason for the difference is structural. As discussed previously in A Preview of Carbonyl Compounds and shown in Figure 19.14, the tetrahedral intermediate produced by addition of a nucleophile to a carboxylic acid derivative can eliminate a leaving group, leading to a net nucleophilic acyl substitution reaction. The tetrahedral intermediate... 

Carboxylic Acid Derivatives Nucleophilic Acyl Substitution Reactions... 

The chemistry of all acid derivatives is similar and is dominated by a single reaction—the nucleophilic acyl substitution reaction that we saw briefly in A Preview ofC ubonyl Compowuls. 

A nucleophilic acyl substitution reaction involves the substitution of a nucleophile for a leaving group in a carboxylic acid derivative. Identify the leaving group (Cl- in the case of an acid chloride) and the nucleophile (an alcohol in this case), and replace one by the other. The product is isopropyl benzoate. 

Amides, like esters, are abundant in all living organisms—proteins, nucleic acids, and many pharmaceuticals have amide functional groups. The reason for this abundance of amides, of course, is that they are stable to the conditions found in living organisms. Amides are the least reactive of the common acid derivatives and undergo relatively few nucleophilic acyl substitution reactions. 

The chemistry of carboxylic acid derivatives is dominated by the nucleophilic acyl substitution reaction. Mechanistically, these substitutions take place by... 

Amino groups are often protected as their tert-butoxycarbonvl amide, or Boc, derivatives. The Boc protecting group is introduced by reaction of the amino acid with di-fert-butyl dicarbonate in a nucleophilic acyl substitution reaction and is removed by brief treatment with a strong organic acid such as trifluoro-acetic acid, CF3C02H. 

The conversion of one type of derivative into another occurs via nucleophilic acyl substitution reactions. In these types of reactions, any factor that makes the carbonyl group more easily attacked by a nucleophile favors the reaction. The two most important factors are steric hindrance and electronic factors. 

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