HL organic chemistry topic 20 More functional groups More functional groups Amines Amines NH 2 NH 2 Draw 1-aminopropane (propanamine) and give condensed formula Draw 1-aminopropane (propanamine) and give condensed formula

Methylamine (old) aminomethane IUPAC Methylamine (old) aminomethane IUPAC 1,6-diaminohexane 1,6-diaminohexane

1-butylamine, 1-butanamine, 1-aminobutane (all the same) 1-butylamine, 1-butanamine, 1-aminobutane (all the same)

Secondary amines N-methylpropanamine (name the longest chain) N-methylpropanamine (name the longest chain)

Tertiary amines CH 3 CH 2 N(CH 3 ) 2 name and draw CH 3 CH 2 N(CH 3 ) 2 name and draw N,N-dimethylpropanamine N,N-dimethylpropanamine

Esters Yeah, already done Yeah, already done

Amides R-CO-NH 2 R-CO-NH 2 Name the longest carbon chain followed by amide (amides on the end) Name the longest carbon chain followed by amide (amides on the end) propanamide propanamide

2-methylpropanamide 2-methylpropanamide

Secondary amides N-methylproanamide N-methylproanamide

N,N-dimethylpropanamide N,N-dimethylpropanamide

Nitriles R-CN R-CN Used to be cyanides C 2 H 5 CN ethyl cyanide Used to be cyanides C 2 H 5 CN ethyl cyanide Now propanenitrile Now propanenitrile Draw it Draw it

Draw ethanenitrile Draw ethanenitrile Pentanenitrile? Pentanenitrile? Do question 1 Do question 1

Nucleophilic substitution reactions -ions or molecules with a nonbonding pair of electrons -ions or molecules with a nonbonding pair of electrons Act as Lewis bases Act as Lewis bases Use curly arrows to show movement Use curly arrows to show movement H 2 O, OH -, CN -, NH 3 H 2 O, OH -, CN -, NH 3

S N 2 mechanism Ammonia and bromoethane forms ethylamine and hydrogen bromide Ammonia and bromoethane forms ethylamine and hydrogen bromide Need conc. NH 3 and sealed tube for pressure Need conc. NH 3 and sealed tube for pressure

forms N-ethylethanamine then N,N- diethylethanamine forms N-ethylethanamine then N,N- diethylethanamine Eventually tetraethylammonium bromide Eventually tetraethylammonium bromide

Make propan-2-amine Make propan-2-amine

Needed for halogenoalkane reactions Show bromoethane with potassium cyanide(in ethanol and reflux) to form propanenitrile Show bromoethane with potassium cyanide(in ethanol and reflux) to form propanenitrile Show the S N 2 mechanism Show the S N 2 mechanism

Now reduce it to propanamine

Factors affecting the rate of nucleophilic reactions electronegative can easily donate e- pair electronegative can easily donate e- pair CN - >OH - >NH 3 > H 2 O CN - >OH - >NH 3 > H 2 O Strength of carbon to halogen bond remember I >Br to F Strength of carbon to halogen bond remember I >Br to F

Type of mechanism S N 1(tertiary) > secondary (mixture) > S N 2 (primary) Type of mechanism S N 1(tertiary) > secondary (mixture) > S N 2 (primary) Do question 2-5 Do question 2-5 Lab activity Lab activity Do questions page 399 for HW Do questions page 399 for HW

Elimination reactions Halogenoalkanes with hot NaOH in alcohol to alkene Halogenoalkanes with hot NaOH in alcohol to alkene With water and Br - also formed With water and Br - also formed C 2 H 5 Br to C 2 H 4 C 2 H 5 Br to C 2 H 4 OH - in hot alcohol, reflux OH - in hot alcohol, reflux

E2 (elimination bimolecular)mechanism to form alkene E2 (elimination bimolecular)mechanism to form alkene See pages 400 and 401 See pages 400 and 401 Do questions page 401 for HW Do questions page 401 for HW

Condensation reactions Acids and alcohols with H 2 SO 4 as catalyst Acids and alcohols with H 2 SO 4 as catalyst H 2 O byproduct (makes a longer chain) H 2 O byproduct (makes a longer chain) Pineapple is ethyl butanoate Pineapple is ethyl butanoate

Esters have no H bonding, are more volatile, less soluble in water Esters have no H bonding, are more volatile, less soluble in water Naturally occurring fats and oils Naturally occurring fats and oils

Acids with primary amines form secondary amides Acids with primary amines form secondary amides Ethanoic acid and metanamine Ethanoic acid and metanamine

Secondary amines and acids form a peptide bond (tertiary amide) Secondary amines and acids form a peptide bond (tertiary amide) Amino acids form peptide bonds Amino acids form peptide bonds

Alanine and glycine can form 2 dipeptides Alanine and glycine can form 2 dipeptides Many amino acids form proteins Many amino acids form proteins

Do question 6-7 Do question 6-7 Animation Animation Animation

Condensation polymerization To make polypeptides or proteins To make polypeptides or proteins Hexane-1,6-dioic acid with 1,6- diaminohexane to form polyamide nylon Hexane-1,6-dioic acid with 1,6- diaminohexane to form polyamide nylon

Polyesters like dacron Polyesters like dacron Benzene-1,4-dicarboxylic acid and ethane-1,2-diol draw this monomer (polyester) Benzene-1,4-dicarboxylic acid and ethane-1,2-diol draw this monomer (polyester) PET is polyethene-1,4-benzoate used for plastic bottles PET is polyethene-1,4-benzoate used for plastic bottles Do question 8 Do question 8 Do questions page 406 for HW Do questions page 406 for HW

Reaction pathways Add nitrile, amine and amide to your algorithms Add nitrile, amine and amide to your algorithms

How can bromoethane be converted to propanamine?

Convert ethanol to N- methylethanamide using another organic compound Do questions page 407 for HW Do questions page 407 for HW Lab activity Lab activity

Stereoisomerism Same molecular and structural formula but atoms arranged differently in space Same molecular and structural formula but atoms arranged differently in space

geometrical Multiple bonds cannot be rotated Multiple bonds cannot be rotated Cis trans Cis trans But-2-ene But-2-ene Build this Build this

Draw and name the geometric isomers of but-2- enedioic acid

Similar properties but not the same Similar properties but not the same Depends on the functional group Depends on the functional group Polarity, shape and symmetry of the molecules Polarity, shape and symmetry of the molecules

Cis and trans 1,2-dichlorethene Which has the higher boiling point, melting point Which has the higher boiling point, melting point

Can occur in cyclic compounds Can occur in cyclic compounds 1,2-dimethylcyclopropane cis and trans 1,2-dimethylcyclopropane cis and trans

5 isomers of dichlorocyclobutane 5 isomers of dichlorocyclobutane 2 are cis 2 are trans 2 are cis 2 are trans

Cis and trans-but-2-ene-1,4-dioic acid Cis and trans-but-2-ene-1,4-dioic acid trans strong H bonding mp 286 o C and cannot form cyclic anhydride trans strong H bonding mp 286 o C and cannot form cyclic anhydride

H bonding in molecule H bonding in molecule cis mp 131 o C with heat trans can form cis-but-2-ene-1,4-dioic anhydride cis mp 131 o C with heat trans can form cis-but-2-ene-1,4-dioic anhydride lab activity lab activity

Optical isomerism Asymmetric carbon atom (chiral) 4 different groups Asymmetric carbon atom (chiral) 4 different groups Make a model of a chiral carbon and its stereoisomer Make a model of a chiral carbon and its stereoisomer Mirror images = enantiomers Mirror images = enantiomers Do question 9 Do question 9

Drawings of enantiomers Drawings of enantiomers Use an asterisk to designate the chiral carbon Use an asterisk to designate the chiral carbon Butan-2-ol Butan-2-ol

2-bromobutane 2-bromobutane

Draw the enantiomers of 2- hydroxypropanoic acid (lactic acid) Mark the chiral carbon atom and show the plane of the mirror

Demonstration of plane polarized light Demonstration of plane polarized light Dextrorotatory d- rotated clockwise with a polarizor to get maximum intensity Dextrorotatory d- rotated clockwise with a polarizor to get maximum intensity Lavorotatory l- counter clockwise Lavorotatory l- counter clockwise Mixture of both is racemic Mixture of both is racemic animations animations animations

Usually same chemical and physical properties Usually same chemical and physical properties Exception is when they interact with other optically active substances Exception is when they interact with other optically active substances 2-amino acids must be l (-) form 2-amino acids must be l (-) form Sugars d (+) form Sugars d (+) form

Thalidomide in 1960’s For morning sickness For morning sickness One enantiomer causes malformations in the fetus One enantiomer causes malformations in the fetus

Do question Do question Do questions page 415 for HW Do questions page 415 for HW Do questions on page 74 of your study guide Do questions on page 74 of your study guide Do questions pages in your textbook Do questions pages in your textbook