1.Amines ,Polymers and chirality Flashcards
What is an amine?
Replace 1+ H on a NH3 with an alkyl chain
Name of CH3CH2NH2
ethylamine
Name of (CH3)2NH
dimethylamine
or
N-methylmethylamine
name of (CH3CH2)2NCH3
diethylmethylamine
or
N,N-diethylmethylamine
What amine are soluble?
small ones as they can hydrogen bond.
What are alkylamins? and arylamines
alkyl is a straght chain
aryl is on a benzene ring
Synthisis of alkylamines
warm a halogenoalkane with EXCESS NH3 in ethanol
is a neucleophilic substitution
CH3CH2Cl+ 2NH3 —> CH3CH2NH2 + NH4CL
in excess so you dont produce tertiary/secondary
How is an amine a base?
a native covelant bond forms between the N and the H+ to accept a proton
AMin + acid —>
salt
eg methylamine sulphate
Synthisis of arylamine
- Nitrate benzene . conc HNO3 + H2SO4 below 50 deg
- Reduce nitrobenzene with tin+conc HCL under reflux
- Nitrobenzene + 6[H] –> phenylamine + 2water
What is an amino acid?
What is a peptide?
multiple amino acids joined together by peptide bonds
water is lost and the n is bonded to the c from the COOH part.
what is the isoelectric point?
The PH at which the amino acid exists as a the zeitterion (overall neutral)
what is a zwitterion?
a dipolar ionic form of an amino acid tht is formed by the donation of a hydrogen ion from the carboxyl group to the amino group. has no overall charge
At a ph above the iso electric point the amino acid is…
in the form COO-
At a ph below the iso electric point the amino acid is…
in the form NH3+
Define structural isomerism?
some molecular formula different structual formular
Types of structural isomerism?
- Chain isomers (branched chain)
- Positional isomers (position of functional groups)
- Functional group (different functional group , eg keytone/aldehyde. carbo acid/ester)
define sterioisomers
same structural formula but with a different arangement of atoms in space
types of sterioisomers
- geometric (E/Z, cis/trans)
- optical (non superimposable mirror images)
What is a chiral centre?
When a carbon has 4 different groups attached to it its known as a chiral centre
a molecule witn n chiral centers has….. optical isomers?
2n
what denotes a chiral centre?
* ont he chiral carbon
what is a racemate
a 50/50 mixture of both optical isomers
what is seperating the optical isomers in a racemate called?
resolving
its very difficult
how to identify optical isomers?
polarise light opposite ways.
three reasons its desirable to givbe asingle chiral drug?
- Dose is reduced
- Possible side effects are reduced
- Pharmacological activity is improved
How can a single optical isomer be created?
- Chiral pool synthisis- using a single isomer as the starting point.
- Chiral catalyst- enzyme/chiral metal complex.
Whats different about naturally occuring molecules that could have chiral centres
they are only mad eof one optical isomer, as its made by enzymes
How to form polyesters?
- Dicarboxillic acid and Diol
- Hydroxy acid (has a OH and a OOH end)
How to form polyamides?
- amino acids
- dicarboxilic acid and a diamine
Ester link?
Polyamide link?
what kind of polymer are polyesters and poly amides?
condensation
when formed water is lost
Alkaline hydrolysis of a polyamide?
aqeuous sodium hydroxide at 100 degrees
- Carboxilate salt and amine is formed
- reflux
acid hydrolysis of poly amide?
water is needed, acid
Carboxilic acid and amine salt
reflux
acid hydrolysis for polyester?
heat and aqeuous acid
reflux
heat
makes diol and dicarboxilic acid
alkali hydrolysis for polyesters
aqeuous NaOH
reflux
heat
makes diol and carboxolate salt.
number of water molcules mad ein condensation polymerisation
(2n-1)
Uses of polyesters
carpets, clothes, bedding
uses of polyamides
nylon, kevlar
what is a biodegradable polymer?
a polymer that breaks down completly into carbon dioxide and water
what is a degradable polymer?
a polymer that breaks down into smaller fragments when exposed to light, heat or moisure.
acid hydrolysis of a peptide?
water and acid and reflux
alkali hydrolysis of a peptide?
100 degrees , aquaus sodium hydroxide reflux
What is a condensation polymer?
when monomers join together to form a chain and another small molecule eg water is lost.
Alkene + water (steam)
acid catalyst
Oh on one side of db , H on the other forming 2 isomers.
How can a NH2 act as a base
lone pair on Nitrogen accepts PRoton/H+ to form dative bond
How can amino acids have different isoelectric points?
Extra NH2 groups mean the ph of the isoelectric point is higher
Extra COOH groups mean the ph of the isoelectric point is lower
