Amines and Nitrogen Chemistry: every key term you need (+ practice quiz)
25 flashcard terms for Organic Chemistry II Topic 6, written to match the course framework. Study them here, then drill them as interactive flashcards, or test yourself with the 8-question quiz — free, no account needed.
Amines are named primary, secondary or tertiary by how many carbons sit on nitrogen, unlike alcohols which are classified by the carbon itself.
Amine basicity
The nitrogen lone pair accepts a proton. Alkyl groups increase basicity by donating electron density, while conjugation or nearby withdrawing groups reduce it.
Aromatic amine basicity
An amine attached to a ring is much weaker as a base because its lone pair is delocalized into the ring and is not fully available.
Amide non-basicity
An amide nitrogen donates its lone pair to the carbonyl, so it is effectively not basic and protonation occurs at oxygen instead.
Amine solubility and extraction
Converting an amine to its salt with acid makes it water-soluble, which is the standard way to separate amines from neutral organic compounds.
Gabriel synthesis
Makes a clean primary amine by alkylating a protected nitrogen source once and then releasing it, avoiding the repeat alkylation of direct methods.
Exhaustive alkylation problem
Direct alkylation of ammonia is hard to stop, because each new amine is at least as nucleophilic as the last, giving mixtures.
Azide reduction route
Substitution with azide followed by reduction gives a primary amine with no risk of repeat alkylation.
Nitrile reduction route
Reducing a nitrile gives a primary amine one carbon longer than the starting halide, which makes it a chain-extension method.
Nitro group reduction
Reducing an aromatic nitro group gives an aromatic amine, the standard sequence for installing nitrogen on a ring.
Hofmann rearrangement
Converts an amide to an amine with one fewer carbon by migrating a group from carbon to nitrogen and losing carbon dioxide.
Curtius rearrangement
Converts an acyl azide to an isocyanate with the same kind of migration, giving an amine after aqueous workup.
Hofmann elimination
Exhaustive methylation makes nitrogen a leaving group; elimination then gives the less substituted alkene because the bulky group dominates the transition state.
Cope elimination
An amine oxide eliminates through a cyclic transition state under mild heat, giving an alkene and a hydroxylamine with no external base.
Diazonium salt
Formed from a primary aromatic amine with nitrous acid at low temperature. Its nitrogen leaves as gas, so it acts as an exceptionally versatile leaving group.
Sandmeyer reaction
Replaces a diazonium group with a halide or cyanide using a copper salt, installing groups that cannot be added by direct substitution.
Diazonium coupling
A diazonium ion acts as a weak electrophile toward electron-rich rings, giving the extended conjugated systems used as dyes.
Amine as a nucleophilic catalyst
A small amine speeds acyl transfer by attacking first and passing the acyl group on faster than the direct route.
Sulfonamide formation
An amine reacts with a sulfonyl chloride to give a stable sulfonamide, historically the basis for distinguishing amine classes.
Chiral nitrogen inversion
A nitrogen with three different groups inverts rapidly through a planar transition state, so simple amines cannot be resolved.
Quaternary ammonium salt
A nitrogen carrying four groups and a permanent positive charge. It cannot invert and is used as a phase transfer catalyst.
Imine and iminium reactivity
Protonating an imine gives an iminium ion that is strongly electrophilic at carbon, which is why reductive amination works under mildly acidic conditions.
Alkaloid
A basic nitrogen-containing natural product, typically from a plant, whose basicity allows isolation by acid-base extraction.
Amino acid ionization behaviour
The amine and acid groups titrate at different pH values, so the molecule shifts between a cation, a neutral zwitterion and an anion as pH rises.
Hinsberg-type separation
Uses differing reactivity of amine classes toward a sulfonyl chloride and toward base to separate a mixture of amines.