amides and amino acids

• amides functional group: - CONH2
• amino acid functional groups: - NH2 and - COOH
• amphoteric: acidic and basic properties
• why is an amino acid amphoteric?

  • COOH acts as acid
  • NH2 acts as base
• all amino acids, except glycine, are chiral molecules
• alkali reacts with amino acid:

  • forms conjugate base that reacts with cation to form a salt
  • RCH(NH2)COOH + NaOH = RCH(NH2) COO- Na+ + H2O
• acid reacts with amino acid:

  • forms conjugate acid
  • RCH(NH2)COOH + HCl = RCH (Cl- NH3+) COOH
• alcohol plus amino acid:

  • forms ester and water
  • requires strong acid catalyst (H2SO4)
  • RCH(NH2)COOH + CH3OH = RCH (NH2) COOCH3 + H2O