HW-2-Key - Cycloalkanes/strain PDF

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Cycloalkanes/strain...

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HW-2% Dr.%Shabbir%OChem-320M/328M% % % % % % % % % % Name________________________________________________% % % % Signature____________________________________________% % % % % UT%EID%_______________________________________________% % % % % % % Please%print%the%first%three%letters% of%your%last%name%in%the%three%box% % % % % % % Reminders:*** % In%order%to%get%a%grade%for%your%HW% % • You%must%have%ALL%your%answers%written%in%permanent*ink%% % • You%must%STAPLE%all%your%HW%pages%together% % • You%must%submit%your%HW%on-time%* % % % % % %

!

!

Due:%09-22-17%

!

HW-2% Dr.%Shabbir%OChem-320M/328M% Q1-Write%the%IUPAC%name%of%the%following%molecule%on%the%line%provided.%%

Due:%09-22-17%

% 1-ethyl-3-isopropyl-2-methylcyclohexane% ____________________________________________________________________________________% % %

% % % 3-ethyl-2,4-dimethylhexane% % %

% % 1-(tert-butyl)-5-ethyl-2-isobutylcycloheptane% % % % % CH 3

H

H

H

H CH(CH 3)2

% % 2-methylpentane% % !

2

HW-2% Dr.%Shabbir%OChem-320M/328M% Q2-%From%the%IUPAC%name%draw%the%appropriate%line%angle%drawing?% % 6-tert-butyl-3.4,5-trimethyl%dodecane%%

Due:%09-22-17%

% 4-ethyl-5-isopropyl-2-methyloctane%

% % Q4-% Rank% the% following% molecule% according% to% their% increasing% boiling% point.% Where% 1% is% the% lowest% boiling%point%and% 4%is%the%highest%boiling%point.%In%the%dotted%box%write%the%IUPAC%name%of%each%of%the% molecules%drawn%below.% octane

2-methylheptane

2,2,4-trimethylpentane

4

3

pentane

1

2

% % Q5-%Rank%the%following%molecule%according%to%their%increasing%stability.%Where%1%is%the%least%stable%and% 4% is%the%most%stable.%% %

2

4

3

1 %

* !

* 3

HW-2% Dr.%Shabbir%OChem-320M/328M% Due:%09-22-17% Q5-%For%each%of%the%following%molecule%circle%the%one%is%more%stable?%Justify%your%answer%by%marking%an% X%next%to%ALL%the%kind%of%strains%present%in%the%unstable%molecule?*

Angle Strain Torsional Strain Steric Strain H

HH

H

H

H

H

X

vs HH

HH

H

CH 3 (H 3C) 3C

X

vs CH 3

C(CH 3)3 Br

Br H

Br

H

H

H

H

X

vs H

H

Br

H

X

vs

X

Planar CH 3

CH 3

vs

X

H 3C

CH 3 CH 3

CH 3 H 3C

H 3C CH 3

vs CH 3

X

X

X

Convert(the(planar(molecules(into(a(chair( conformation(to(determine(their(relative(stability

vs

X %

* * !

* 4

HW-2% Dr.%Shabbir%OChem-320M/328M% Due:%09-22-17% Q6a)-%Draw%lowest%and%the%highest%energy%eclipse%conformations%for%pentane%looking%down%the%C2-C3% bond.% CH2 2

CH 3

H CH 3

CH 3

CH 2

CH 2 3

H 3CH 2C CH 3 CH 2CH 3 H

H H

H H

H H

Eclipse Highest Energy

Eclipse Lowest Energy

% Q6b)-*Draw%the%two-gauche%conformation%of%pentane%looking%down%the%C2-C3%bond.%Remember%they% are%related%by%reflection.% CH2 2

CH 3

CH 2 3

CH 2

CH 3

CH 3

CH 3 H

H 3CH 2C

CH 2CH 3

H

H

H

H

H H

H

* Q6c)-% In% the% space% provided,% draw% a% potential% energy% graph% of% all% the% different% conformations% of% bromopropane.% Looking% down% the% C2-C3% bond.% Draw% the% appropriate% Newman% Projection% of% the% molecule%at%each%peak%and%trough%on%the%graph.%Define%0°%dihedral%angle%as%your%highest%energy%point%in% the%diagram.%% H 3C Br HH

HH

Energy

Br HBr

!

H H Br H 3C

H

Br

H

Eclipse

H H 3C

HH

HH

CH 3

H

H 3C Br

H Br CH H 3

HH

Br H

CH2 CH 2 CH 3 2 3

H

H

H

H CH 3

H

H

H H

Anti

Eclipse

Gauche

180 O Dihedral Angle

240O

300O

Gauche

Eclipse

60O

120 O

Eclipse 360O

% 5

HW-2% Dr.%Shabbir%OChem-320M/328M% Due:%09-22-17% Q7-%Draw%the%alternative%chair%conformations%for%the%following%cyclohexane%derivatives.%Draw%the%alkyl% groups%in%their%proper%orientation%and%label%ax%for%axial%and%eq%for%equatorial%next%to%each%group%for% clarity.%When%there%is%a%difference%in%energy%between%the%two%conformers,%circle%the%more%stable% conformer?% A)

2

2 3

3

1

3

2

1

1

B) 2

2

1

3

1

3

2

3 1

C) 2 2 3

3

1

3

2

1

1

D) 2

3

2

4

3

4

1

1

5

3

2

1

4

5

5

E) 2

2 3

3

1 4

4 1

2

3 4

1

% !

6

HW-2% Dr.%Shabbir%OChem-320M/328M% Q8-%Circle%two%identical%structures%from%the%library%of%molecules%drawn%below.% Cl Cl CH 3

OH

Due:%09-22-17%

OH

CH 3

HO

OH

Cl

CH 3 Cl CH 3

Cl CH 3 OH HO Cl CH 3

%

% Q9-%Convert%the%following%condense%formula%into%a%line%structure.% A) CH3(CH2)3CHOHCH(CH3)2%

OH

%

B) CH3OCH2COCH3% O O % %

C) CH3CH2CONHCH3% O

N H

%

THE%END%J% !

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