Question

1) Draw the mechanism and product of: basic hydrolysis of propanenitrile.

2) Tylenol (acetaminophen) has a much longer shelf life than aspirin. Explain.

Answer 1

1) Alkaline hydrolysis of propanenitrile:

A) Alkaline hydrolysis (using NaOH of Propanenitrile to sodium salt of propionate.

1) Hydroxyl ion (HO^-) undergo nucleophilic attack at C≡N and the amide ion thus formed being very reactive base abstract proton from H-OH (water molecule) and get stabilized.

2) Then anathor mole of HO^‑ undergo nucleophilic attack and formation of gem diol and amine which is very unstable intermediate and break by C-N bond breaking which gives ammonia molecule with H-OH.

3)Under alkaline condition Propanoic acid formed undergo ionization and forms sodium salt of Propanoate.

4)Acidification of this salt gives Propanoic acid product.

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2)

Acetaminophene (Tylenole) has amide fuctionality and aspirine has ester fuctionall group which prone to hydrolysis if catches moisture.

Amided are harder than esters and less succeptible to the hydrolysis than esters.

Hence Acetaminophene on does not changes its structure even on prolonged moistur contact. But Aspirin containing ester functionality does show structural changes if catches moistur.

Hence Acetaminophene has much longer shelf life than aspirin.

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