Amines Chemical / Biological / Neurological Activity. Measures of Basicity. The basicity of amines may be measured by: 1) K b 2) p K b 3) K a of conjugate acid 4) p K a of conjugate acid. +. –. ••. ••. R 3 N. H. OH. OH. R 3 N. H. • •. • •. ••. ••.
Ka Kb = 10-14
pKa + pKb = 14
The compound: cocaine, it is an organic base:Merck Index, #2450, 11th ed.: Caution: May be habit forming….
What structural feature makes cocaine a base? What simple compound can you relate it to?
What accounts for the differences in solubilities of the base and conjugate acid?
CH3CH2NH3+ is a weaker acid than NH4+;therefore, CH3CH2NH2 is a stronger base than NH3.
Notice that the difference separating a primary,secondary, and tertiary amine is only 0.3 pK units.
3.8 x 10-10
6 x 10-14
Cope Elimination Reaction
Histidine receptor antagonist (a precursor to histamine, a vasodilator)
Inhibits gastric secretions & pepsin output
Principal sympathomimetic adrenal hormone
& a controlled substance