Amides are molecules that can form from a carboxylic acid and an amine group. In our body, when two amino acids come together to react, they form an amide bond, releasing "H"_2"O" in the process. This type of bond is also called a peptide bond.
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color(white)(aaaaaaaaaaaaaaaaaa) Mechanism
color(purple)(1.)
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To begin, we know that in the first step, a strong base is going to be used like "NaOH", where the color(blue)("OH"^(-) will act as the nucleophile and attack the electrophile, the partial positive carbon of the carbonyl group.
Now, when the bond forms between the "oxygen" of the "OH"^- group and the carbon, the pi "bond" of the carbonyl is broken and the electrons are pushed toward oxygen, leaving it with a negative -1 charge.
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color(purple)(2.)
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color(blue)("Oxygen will try to remove this negative charge by reforming") color(blue)("a double bond with the carbon"). But since we know that the "carbon" atom cannot form more than 4 bonds, the bond between it and the amine's "nitrogen" has to be broken. color(blue)("The electrons will be pushed onto the nitrogen of the amine and the") color(blue)("amine will act as the leaving group (a poor one at that)")
*The reason the amine is a poor leaving group is because the amine is a strong base, and strong bases are very unstable. Leaving groups are based off their stability in solution, like the halides, tosylate, "H"_2"O"
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color(purple)(3.)
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color(blue)("Here, the NH"_2^(-) "will act as a base and pluck off the H from the carboxylic") color(blue)("acid - type of acid-base reaction.") When this happens, a "carboxylate anion" forms and "NH"_3.
