nitriles + amines + amides + amino acids Flashcards
amine definition
an organic compound derived from ammonia
3 types of amines
primary - :NH2R
secondary - :NHR2
tertiary - :NR3
outline how amines can act as a base
they are able to accept a proton due to lone pair on N
however they are weak bases
acid + amine»_space; ammonium salt
give the steps and reagents and conditions to produce aliphatic amines
reagents - haloalkane + excess NH3 - prevents further substitution of amine to form 2ndary/3iary amines
conditions - solvent is ethanol - this prevents substitution of haloalkane with water to form alcohols, also prevents formation of NH4+ which cannot act as a nucleophile
step 1 - ammonia + haloalkane»_space; ammonium salt (RNH3+Cl-)
- here ammonia acts as a nucleophile due to its lone pair
step 2 - ammonium salt + NaOH»_space; amine (RNH2) + salt + water
- to form a secondary amine with these steps, replace the NH3 with a primary amine
give the steps and reagents and conditions used to produce aromatic amines
reagents - nitrobenzene + conc HCl + Sn + NaOH
conditions - reflux
step 1 - reduce nitrobenzene with conc HCl and Sn
step 2 - add excess NaOH
- produces phenylamine
why is it difficult to produce a pure amine product
primary amines still contain a lone pair of electrons on the N so are able to produce secondary amines, this is again the case for secondary and tertiary amines so it is very difficult to make a pure amine product
nitrile definition
an organic compound with a C≡N group
give the reagents and conditions and mechanism to form a hydroxynitrile from a carbonyl - chain elongation
reagents - NaCN + H2SO4 to form HCN in situ - HCN can be used in equations
conditions - aqueous
why is HCN alone not used as a reagent
HCN is a colourless + poisonous liquid, and is also very volatile as it boils slightly above room temp, so it cannot be safely used in a lab
give the reagents and conditions to go from a haloalkane to a nitrile - chain elongation
reagents - NaCN + H2SO4 to form HCN in situ - HCN can be used in equations
conditions - aqueous
give the reagents and conditions to go from a nitrile to an amine - reduction
reagent - H2
conditions - Ni catalyst
- NaBH4 can also be used, but H2/Ni is better
give the steps and reagents and conditions to go from a nitrile to a carboxylic acid - acid hydrolysis
reagents - acid e.g. H2SO4
conditions - aqueous
step 1 - nitrile + water»_space; amide
R-CN + H2O»_space; R-CO-NH2
(forms C=O bond)
step 2 - R-CO-NH2 + H2O»_space; R-CO-ONH4
step 3 - R-CO-ONH4 + H+»_space; R-COOH + NH4
amino acid definition
an organic compound that contains both NH2 and COOH functional groups
how many common amino acids are found in the body + what type of amino acid are they
20
they are alpha amino acids
alpha amino acid definition
an amino acid where the amine and carboxyl group are attached to the same carbon
amphoteric definition
a compound which is able to react as both an acid and a base
what makes amino acids amphoteric
they have an NH2 group which can act as a base, and a COOH group which can act as an acid
what is formed when amino acids are reacted with acids
NH2 group reacts to form an ammonium salt
what is formed when amino acids are reacted with bases
COOH group reacts to form carboxylate salts
what is formed when amino acids are reacted with alcohols
the COOH group reacts to form an ester - if heated under reflux with conc H2SO4
the NH2 group would also be protonated to form NH3+
zwitterion definition
this is formed when the H on the COOH group of an amino acid dissociates and associates onto the NH2 group, forming both COO- and NH3+ ions
isoelectric point definition
the point at which a zwitterion is formed - unique for each amino acid
how to name amino acids e.g. glycine - simplest one, R group = H
the carboxyl group takes priority so NH2 group will always be at position 2 in alpha amino acids
e.g. glycine - NH2-CH2-COOH
2-amino ethanoic acid
why do many amino acids display optical isomerism + name 1 exception
on most amino acids, the alpha carbon is bonded to 4 different groups, being NH2, COOH, H and R group
this means there is a chiral carbon, therefore can display optical isomerism
one exception is glycine, as its R group is H, there aren’t 4 different groups bonded to the alpha carbon, so no chiral centre
state the general formula for an amino acid
H2NCH(R)COOH
chiral centre definition
an atom bonded to all different groups
amide definition
organic compounds with an amine group directly bonded with a carbonyl group
how are primary amides formed
acyl chloride/acid anhydride + ammonia/amine»_space; amide + salt/carboxylic acid
3 types of amide
primary - R-CO-NH2
secondary - R-CO-NHR
tertiary - R-CO-NR2
how are secondary amides formed
acyl chloride/acid anhydride + primary amide»_space; secondary amide + salt/carboxylic acid
by what mechanism are amides formed
nucleophilic addition elimination
optical isomerism definition
molecules that are nonsuperimposable mirror images of eachother
what must a compound contain to display optical isomerism
a chiral centre
racemic mixture definition
a mixture containing 50% of each optical isomer
- this means there is only 1 chiral centre
what are some properties of optical isomers
optical isomers are able to rotate plane-polarised light in different directions - each optical isomer rotates it in a different direction, either clockwise or anticlockwise
as racemic mixtures contain equal proportions of each optical isomer, this has no effect on plane-polarised light
