Key Notes on Nitriles and Carboxylic Acid Derivatives

  • Nitriles:

    • Can be converted to aldehydes and ketones via alkyl lithiums and Grignard reagents.

    • Hydrolysis can yield carboxylic acids.

  • Acid Chlorides:

    • Named by replacing "ic acid" with "-yl chloride".

    • E.g., acetic acid → acetyl chloride.

    • Another example: Butanoic acid → butanoyl chloride.

  • Naming Examples:

    • 2-methylbutanoyl chloride has a methyl group on carbon 2.

    • Cyclic compounds: cyclohexane carboxylic acid becomes cyclohexanecarbonyl chloride.

  • Anhydrides:

    • Formed from two carboxylic acids losing water.

    • Symmetrical (identical R groups) or unsymmetrical (different R groups).

    • Named by replacing "acid" with "anhydride". E.g., acetic anhydride.

  • Spectroscopic Features:

    • Primary/secondary amides form hydrogen bonds; higher boiling points than carboxylic acids.

    • Carboxylic acid derivatives are characterized by their carbonyl (C=O) stretching frequencies.

    • Certain IR signals help identify different functional groups (e.g., amides vs. acid chlorides).

  • Reactivity Spectrum:

    • Acid chlorides > anhydrides > esters > amides (in terms of nucleophilic acyl substitution reactivity).

    • Better leaving groups increase reactivity.

  • Mechanism of Nucleophilic Acyl Substitution:

    • Nucleophile attacks carbonyl carbon → tetrahedral intermediate forms → revert back to carbonyl (expelling a leaving group).

    • Useful in synthesizing different carboxylic acid derivatives with various nucleophiles.

  • Important Nucleophiles:

    • Alcohols, amines, and carboxylate ions.

    • Acid chlorides can react with each to generate esters, amides, and more.

  • Conclusion:

    • Mastery of nomenclature and reactivity allows for effective manipulation and synthesis of organic compounds using carboxylic acid derivatives.