Chemistry of Nitrogen-containing Organic Compounds FSF = Full Structural Formula
Key Areas • Functional group – name and structure • Characteristic chemical reactions - type - reactants - products - conditions - mechanism
Nitrogen-containing Functional Groups • NITRILES • AMINES • AMIDES • AMINO ACIDS • POLYAMIDES
NITRILES R C N • Not to be confused with cyanides (CN- ) • First member is ethanenitrile. Draw the full structural formula. • Name the fourth member of the family. • C N very polar • Will the C-atom be a nucleophile or electrophile?
Producing nitriles • Halagenoalkanes - heating under reflux with NaCN or KCNin ethanol - draw the FSF for 1-bromobutane and then for the nitrile produced on reaction with KCN - what type of reaction is this? - what is significant about the length of the carbon chain?
H - + CN C CH3 H H - I I C CH3 H - CN Reaction mechanism propanenitrile
Characteristic Reactions • Hydrolysis - under acid or alkaline conditions - occurs in two steps: Carboxylic acids O 1 C N H3C + H2O CH3C NH2 HYDRATION AMIDE O O + H2O 2 CH3C + NH4+ CH3C NH2 OH NUCLEOPHILIC SUBSTITUTION CARBOXYLIC ACID
Characteristic Reactions • Reduction - Lithium tetrahydridoaluminate(III) - in dry ether Amines C N H3C + 4[H] CH3-CH2-NH2 REDUCTION AMINE Draw the FSF for the compound produced when butanenitrile is reduced.
AMINES NH2 AMINO GROUP • Relatives of NH3, where H’s have been replaced by a hydrocarbon chain • Naming: CH3-NH2 METHYLAMINE or….. AMINOMETHANE METHYL AMINE
AMINES NH2 AMINO GROUP • Draw the full structural formula for 2-propylamine and give its alternative name. • What types of INTERMOLECULAR FORCES exist in amines?
SECONDARY PRIMARY TERTIARY AMINE STRUCTURE NH2 AMINO GROUP • Amines can be classed as primary, secondary or tertiary
Producing amines 1 • Halogenoalkanes - heat with ammoniain ethanol Overall, what type of reaction is this? 1 2
Producing amines 2 • Nitriles (What is a nitrile?) -C≡N - reduction - using LiAlH4(in dry ether + water) • Draw the simplified strucural formula for the amine produced by reducing butanenitrile.
Reactions of amines H • As bases N H H Primary amines, although weak bases, are stronger than ammonia Explained by the inductive effect
Inductive Effect H N CH3 H H+ Alkyl groups are electron donating (INDUCTIVE EFFECT) More Alkyl groups = GREATER INDUCTIVE EFFECT MORE BASIC
Reactions of amines 2 H • As nucleophiles - with acid chlorides (acyl chlorides) • Find out what an acyl chloride is and draw the general structure. • Draw a reaction mechanism for an acyl chloride with 3 carbon atoms reacting with ethylamine. • What is this type of reaction called? • What type of organic compound is the product? N H H
AMIDES O • Are white crystalline solids at room temperature (expect methanamide) • Are important in polymer chemistry • How can amides be made in the lab? R-C NH2
Reactions of amides • HYDROLYSIS Using acid or alkali This is the same as the second step as when nitriles are hydrolysed Using the notation as above, use FSF to draw the hydrolysis carried out under alkaline conditions O O + H3O+ CH3C + NH4+ CH3C NH2 OH NUCLEOPHILIC SUBSTITUTION CARBOXYLIC ACID
Reactions of amides 2 • DEHYDRATION Heating an amide with phosphorus(V) oxide dehydrates the compund. Using FSF, construct an equation for the dehydration of an amide with 4 carbon atoms. Name the amide. What type of organic compound is produced?
R C C H AMINO ACIDS O H • Are the building blocks of proteins • About 20 in total • Draw the FSF for a chiral amino acid • Draw the FSF of an amino acid when it is in: Water Acid Alkali N H OH Zwitterion
O H R N C R 1 amide An AMIDE group Reactions of amino acids • Amino acids join together to form peptides • This is a condensation reaction Draw the FSF of a peptide consisting of alanine, cysteine and serine
POLYAMIDES • Formed from a diamine and a diacid • Nylon is a polyamide • Kevlar is an aramid • Used to make bullet-proof vests H O O H N C N R C R H HO H OH