Amides are organic chemical compounds that include the -amide functional group:

That is, amides are a class or category of organic chemical compounds that (usually*) include a part consisting of a carbon atom connected to both:

• a nitrogen atom connected to two hydrogen atoms by single covalent bonds between the nitogen and each of the hydrogen atoms (that is an -amine group).
  AND
• an oxygen atom (connected to the carbon atom by a double covalent bond).

Amide molecules can vary in size up to very long molecules most of which consist of carbon atoms attached to each other and also to hydrogen atoms.

*In some more complex cases one of the hydrogen atoms attached to the nitrogen may be replaced .e.g. by a methyl group, as in methylbutanamide. However, many introductory texts incl. A-Level course materials describe the amide group as simply -CONH₂.

The hydrolysis of amides What is hydrolysis? Technically, hydrolysis is a reaction with water. That is exactly what happens when amides are hydrolysed in the presence of dilute acids such as dilute hydrochloric acid. The acid acts as a catalyst for the reaction between the amide and water. The alkaline hydrolysis of amides actually involves reaction with hydroxide ions, but the result is similar enough that it is still classed as hydrolysis. Hydrolysis under acidic conditions Taking ethanamide as a typical amide: If ethanamide is heated with a dilute acid (such as dilute hydrochloric acid), ethanoic acid is formed together with ammonium ions. So, if you were using hydrochloric acid, the final solution would contain ammonium chloride and ethanoic acid.
	Note:  You might argue that because the hydrochloric acid is changed during the reaction, it isn't acting as a catalyst. In fact, it is doing two things. It is acting as a catalyst in a reaction between the amide and water which would produce ammonium ethanoate (containing ammonium ions and ethanoate ions). It is secondly reacting with those ethanoate ions to make ethanoic acid.
Hydrolysis under alkaline conditions Again, taking ethanamide as a typical amide: If ethanamide is heated with sodium hydroxide solution, ammonia gas is given off and you are left with a solution containing sodium ethanoate. Using alkaline hydrolysis to test for an amide If you add sodium hydroxide solution to an unknown organic compound, and it gives off ammonia on heating (but not immediately in the cold), then it is an amide. You can recognise the ammonia by smell and because it turns red litmus paper blue. The possible confusion using this test is with ammonium salts. Ammonium salts also produce ammonia with sodium hydroxide solution, but in this case there is always enough ammonia produced in the cold for the smell to be immediately obvious.
	Note:  This test is OK for UK A level purposes, but there are other things which also give off ammonia on heating with sodium hydroxide solution - for example, nitriles (but you won't come across them in a practical situation at this level) and imides (but they are beyond the scope of courses at this level).

Amide

          amide , organic compound formed by reaction of an acid chloride, acid anhydride, or ester with an amine. Under strong acidic conditions an amide can be hydrolyzed to yield an amine and a carboxylic acid. The reverse of this process results in the loss of water and is used in nature to link amino acids to form proteins

           In chemistry, the term amide has several meanings. It may refer to a particular inorganic anion, it may refer to a functional group found in organic compounds, or to compounds that contain this functional group.

           The amide anion is the conjugate base of ammonia, NH2-. It is an extremely strong base, due to the extreme weakness of ammonia as a Bronsted acid.

           Amides are the members of a group of chemical compounds containing nitrogen. Specifically, an amide is a derivative of a carboxylic acid in which the hydroxyl group has been replaced by an amine or ammonia.

Compounds in which a hydrogen atom on nitrogen from ammonia or an amine is replaced by a metal cation are also known as amides or azanides. The amide functional group is:

Synthesis and breakdown

Amides are commonly formed from the reaction of a carboxylic acids with an amine:

This is the reaction that forms peptide bonds between amino acids. These amides can participate in hydrogen bonding as hydrogen bond acceptors and donors, but do not ionize in aqueous solution, whereas their parent acids and amines are almost completely ionized in solution at neutral pH.

Amide formation plays a role in the synthesis of some condensation polymers, such as nylon. Their breakdown is possible via amide hydrolysis.

Amide linkages

An amide linkage is kinetically stable to hydrolysis. Amide linkages in a biochemical context are called peptide linkages. Amide linkages constitute a defining molecular feature of proteins, the secondary structure of which is due in part to the hydrogen bonding abilities of amides.

Derivatives

Sulfonamides are analogs of amides in which the atom double bonded to oxygen is sulfur rather than carbon.

Naming

• Example: CH3CONH2 is named acetamide or ethanamide
• Other examples: propan-1-amide, N,N-dimethylpropanamide

.


The most commonly discussed amide is ethanamide, CH₃CONH₂ (old name: acetamide).

The three simplest amides are:

HCONH2	methanamide
CH3CONH2	ethanamide
CH3CH2CONH2	propanamide

Notice that in each case, the name is derived from the acid by replacing the "oic acid" ending by "amide".
If the chain was branched, the carbon in the -CONH₂ group counts as the number 1 carbon atom. For example: