HL organic chemistry topic 20 More functional groups More functional groups Amines Amines NH 2 NH 2...
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Transcript of HL organic chemistry topic 20 More functional groups More functional groups Amines Amines NH 2 NH 2...
HL organic chemistry topic HL organic chemistry topic 2020
More functional groupsMore functional groups AminesAmines NHNH22
Draw 1-aminopropane (propanamine) Draw 1-aminopropane (propanamine) and give condensed formulaand give condensed formula
Methylamine (old) aminomethane Methylamine (old) aminomethane IUPACIUPAC
1,6-diaminohexane1,6-diaminohexane
1-butylamine, 1-butanamine, 1-butylamine, 1-butanamine, 1-aminobutane (all the same) 1-aminobutane (all the same)
Secondary aminesSecondary amines
N-methylpropanamine (name the N-methylpropanamine (name the longest chain)longest chain)
Tertiary aminesTertiary amines
CHCH33CHCH22N(CHN(CH33))22 name and draw name and draw N,N-dimethylpropanamineN,N-dimethylpropanamine
EstersEsters
Yeah, already doneYeah, already done
AmidesAmides
R-CO-NHR-CO-NH22
Name the longest carbon chain Name the longest carbon chain followed by amide (amides on the followed by amide (amides on the end)end)
propanamidepropanamide
2-methylpropanamide2-methylpropanamide
Secondary amidesSecondary amides
N-methylproanamideN-methylproanamide
N,N-dimethylpropanamideN,N-dimethylpropanamide
NitrilesNitriles
R-CNR-CN Used to be cyanides CUsed to be cyanides C22HH55CN ethyl CN ethyl
cyanidecyanide Now propanenitrileNow propanenitrile Draw itDraw it
Draw ethanenitrileDraw ethanenitrile
Pentanenitrile?Pentanenitrile?
Do question 1Do question 1
Nucleophilic substitution Nucleophilic substitution reactionsreactions
-ions or molecules with a nonbonding -ions or molecules with a nonbonding pair of electronspair of electrons
Act as Lewis basesAct as Lewis bases Use curly arrows to show movement Use curly arrows to show movement HH22O, OHO, OH--, CN, CN--, NH, NH33
SSNN2 mechanism2 mechanism
Ammonia and bromoethane forms Ammonia and bromoethane forms ethylamine and hydrogen bromideethylamine and hydrogen bromide
Need conc. NHNeed conc. NH33 and sealed tube for and sealed tube for pressurepressure
forms N-ethylethanamine then N,N-forms N-ethylethanamine then N,N-diethylethanaminediethylethanamine
Eventually tetraethylammonium Eventually tetraethylammonium bromidebromide
Make propan-2-amineMake propan-2-amine
Needed for halogenoalkane Needed for halogenoalkane reactionsreactions
Show bromoethane with potassium Show bromoethane with potassium cyanide(in ethanol and reflux) to cyanide(in ethanol and reflux) to form propanenitrileform propanenitrile
Show the SShow the SNN2 mechanism2 mechanism
Now reduce it to Now reduce it to propanaminepropanamine
Factors affecting the rate of Factors affecting the rate of nucleophilic reactionsnucleophilic reactions
electronegative can easily donate e- electronegative can easily donate e- pairpair
CNCN-- >OH>OH-- >NH >NH33 > H > H22OO Strength of carbon to halogen bond Strength of carbon to halogen bond
remember I >Br to Fremember I >Br to F
Type of mechanism SType of mechanism SNN1(tertiary) 1(tertiary) > > secondary (mixture) > Ssecondary (mixture) > SNN2 (primary)2 (primary)
Do question 2-5Do question 2-5 Lab activityLab activity Do questions 17-19 page 399 for HWDo questions 17-19 page 399 for HW
Elimination reactionsElimination reactions
Halogenoalkanes with hot NaOH in Halogenoalkanes with hot NaOH in alcohol to alkenealcohol to alkene
With water and BrWith water and Br- - also formedalso formed CC22HH55Br to CBr to C22HH44
OHOH- - in hot alcohol, refluxin hot alcohol, reflux
E2 (elimination bimolecular)mechanism to E2 (elimination bimolecular)mechanism to form alkeneform alkene
See pages 400 and 401See pages 400 and 401
Do questions 20-21 page 401 for HWDo questions 20-21 page 401 for HW
Condensation reactionsCondensation reactions
Acids and alcohols with HAcids and alcohols with H22SOSO44 as as catalystcatalyst
HH22O byproduct (makes a longer O byproduct (makes a longer chain)chain)
Pineapple is ethyl butanoatePineapple is ethyl butanoate
Esters have no H bonding, are more Esters have no H bonding, are more volatile, less soluble in watervolatile, less soluble in water
Naturally occurring fats and oilsNaturally occurring fats and oils
Acids with primary amines form Acids with primary amines form secondary amidessecondary amides
Ethanoic acid and metanamineEthanoic acid and metanamine
Secondary amines and acids form a Secondary amines and acids form a peptide bond (tertiary amide)peptide bond (tertiary amide)
Amino acids form peptide bondsAmino acids form peptide bonds
Alanine and glycine can form 2 Alanine and glycine can form 2 dipeptidesdipeptides
Many amino acids form proteinsMany amino acids form proteins
Do question 6-7Do question 6-7 AnimationAnimation
Condensation Condensation polymerizationpolymerization
To make polypeptides or proteinsTo make polypeptides or proteins Hexane-1,6-dioic acid with 1,6-Hexane-1,6-dioic acid with 1,6-
diaminohexane to form polyamide diaminohexane to form polyamide nylonnylon
Polyesters like dacronPolyesters like dacron Benzene-1,4-dicarboxylic acid and ethane-1,2-diol Benzene-1,4-dicarboxylic acid and ethane-1,2-diol
draw this monomer (polyester) draw this monomer (polyester) PET is polyethene-1,4-benzoate used for plastic PET is polyethene-1,4-benzoate used for plastic
bottlesbottles
Do question 8Do question 8 Do questions 22-24 page 406 for HWDo questions 22-24 page 406 for HW
Reaction pathwaysReaction pathways
Add nitrile, amine and amide to your Add nitrile, amine and amide to your algorithmsalgorithms
How can bromoethane be How can bromoethane be converted to propanamine?converted to propanamine?
Convert ethanol to N-Convert ethanol to N-methylethanamide using methylethanamide using
another organic compoundanother organic compound
Do questions 25-27 page 407 for HWDo questions 25-27 page 407 for HW Lab activityLab activity
StereoisomerismStereoisomerism
Same molecular and structural Same molecular and structural formula but atoms arranged formula but atoms arranged differently in spacedifferently in space
geometricalgeometrical
Multiple bonds cannot be rotatedMultiple bonds cannot be rotated Cis transCis trans But-2-eneBut-2-ene Build thisBuild this
Draw and name the geometric Draw and name the geometric isomers of but-2- enedioic acidisomers of but-2- enedioic acid
Similar properties but not the sameSimilar properties but not the same Depends on the functional group Depends on the functional group Polarity, shape and symmetry of the Polarity, shape and symmetry of the
moleculesmolecules
Cis and trans 1,2-Cis and trans 1,2-dichlorethenedichlorethene
Which has the higher boiling point, Which has the higher boiling point, melting pointmelting point
Can occur in cyclic compoundsCan occur in cyclic compounds 1,2-dimethylcyclopropane cis and 1,2-dimethylcyclopropane cis and
transtrans
5 isomers of dichlorocyclobutane5 isomers of dichlorocyclobutane 2 are cis 2 are trans2 are cis 2 are trans
Cis and trans-but-2-ene-1,4-dioic acidCis and trans-but-2-ene-1,4-dioic acid trans strong H bonding mp 286 trans strong H bonding mp 286 ooC C
and cannot form cyclic anhydrideand cannot form cyclic anhydride
H bonding in moleculeH bonding in molecule cis mp 131 cis mp 131 ooC with heat trans can C with heat trans can
form cis-but-2-ene-1,4-dioic form cis-but-2-ene-1,4-dioic anhydrideanhydride
lab activitylab activity
Optical isomerismOptical isomerism
Asymmetric carbon atom (chiral) 4 Asymmetric carbon atom (chiral) 4 different groupsdifferent groups
Make a model of a chiral carbon and Make a model of a chiral carbon and its stereoisomerits stereoisomer
Mirror images = enantiomersMirror images = enantiomers Do question 9Do question 9
Drawings of enantiomersDrawings of enantiomers Use an asterisk to designate the Use an asterisk to designate the
chiral carbonchiral carbon Butan-2-olButan-2-ol
2-bromobutane2-bromobutane
Draw the enantiomers of 2-Draw the enantiomers of 2-hydroxypropanoic acid (lactic hydroxypropanoic acid (lactic acid) Mark the chiral carbon acid) Mark the chiral carbon atom and show the plane of atom and show the plane of
the mirrorthe mirror
Demonstration of plane polarized lightDemonstration of plane polarized light Dextrorotatory d- rotated clockwise Dextrorotatory d- rotated clockwise
with a polarizor to get maximum with a polarizor to get maximum intensityintensity
Lavorotatory l- counter clockwiseLavorotatory l- counter clockwise Mixture of both is racemicMixture of both is racemic animationsanimations
Usually same chemical and physical Usually same chemical and physical propertiesproperties
Exception is when they interact with Exception is when they interact with other optically active substancesother optically active substances
2-amino acids must be l (-) form2-amino acids must be l (-) form Sugars d (+) formSugars d (+) form
Thalidomide in 1960’sThalidomide in 1960’s
For morning sicknessFor morning sickness One enantiomer causes One enantiomer causes
malformations in the fetusmalformations in the fetus
Do question 10-11Do question 10-11 Do questions 28-30 page 415 for HWDo questions 28-30 page 415 for HW Do questions 12-17 on page 74 of Do questions 12-17 on page 74 of
your study guideyour study guide Do questions 13-20 pages 416-418 in Do questions 13-20 pages 416-418 in
your textbookyour textbook