Name: ________________________ TA:
Score:
/100
Section: _______________
à
Grade:
/20
Quiz 5 (Take home)
This Quiz is Open-(book, internet, friend), but closed-TA’s and Instructor
Scored out of 100, scaled to 20 points
1) (9 pts) Give systematic names for these three molecules
Cl
Br
F
6-ethyl-7,7,8-trimethylnon-1-yne
Let one of the
double-bond
carbons be carbon
#1
3-chloro-4-ethyl-1-fluoro-6isopropylcyclohex-1-ene
4-bromo-4,5-diethyl-5methylnonane
2) (6 pts) Draw bond-line structures for each of the following compound names.
Example: “propane” =
A. 4,5,6-triethyl-2,3-dimethyloctane
B. 5-fluoro-2,4-dimethylhex-1-ene
F
1
3) (16 pts) For the compound below, circle and name all functional groups (alkane
is not a functional group) If applicable, specify primary, secondary or tertiary.
Identify all chiral carbons with an asterisk (*). Please write neatly. You may
want to label groups with letters and make a legend in the space provided.
5
O
NH2
2
N
N
!
N
!
1
O 6
2
OH
!
8
!
!
7
9
O
3
O
NH
!
H
10
4
(1) aromatic amine (2) 3o amine (3) 2o amine (4) alkyne (5) amide (6) ether (7) ketone
(8) 2o alcohol (9) alkene (10) aldehyde
(*): chiral carbons
4) (15 pts) Draw the Lewis Dot Structure for each of the following molecules.
Indicate which contain optical isomers and identify any chiral carbon atoms with
H
an asterisk. Example: “CH3CH2CH3” or “propane” as
carbons)
H
H
H
C
C
C
H
H
H
H
( no chiral
A. CH3CHBrCH2Br
H
H
Br
C
C
H
H
Br
!
C2 is chiral
H
C
H
B. CH3CH2CHClCH2CH3
H
H
Br
H
H
H
H
H
H
H
H
No chiral carbons
H
2
C. 2-bromo-2-methylpropane
H
H
Br
H
C
C
C
H
CH3
H
H
No chiral carbons
D. 2,3-dimethylpentane
H
H
CH3
H
C
C
C
H
H
CH3
!
H
H
C
C
H
H
H
C3 is chiral
E. 5-fluoro-2,4-dimethylhex-1-ene
H
CH3
H
H
F
!
C
C
C
C
H
H
H
CH3
C
H
H
!
C4 and C5 are chiral
C
H
H
5) (15 pts) Which of the following complexes are chiral? Indicate if any are
enantiomeric pairs
B
B
C
D
D
B
mirror
plane
achiral; rotate mirror
image 90° clockwise to
make (a)
A
B
C
C
C
B
(a)
A
A
A
B
C
D
B
(b)
B
B
D
mirror
plane
C
B
chiral; mirror image is nonsuperimposable on (b)
3
A
A
C
A
B
C
B
(c)
B
A
C
C
B
B
mirror
plane
achiral; rotate mirror
image 90° clockwise to
make (c)
B
C
B
A
A
C
(d)
C
B
A
A
C
mirror
plane
chiral; mirror image is nonsuperimposable on (d)
6) (24 pts) Consider the reaction of hydrogen bromide with 5-methyl-1-hexene.
A. Draw all the structural isomers that may result as a product of this reaction,
and name them.
B. On the structures above, draw an asterisk (*) at all the chiral centers in the
products. Label each product as “chiral” or “achiral”.
See above, circled
C. If any of the products are chiral, draw the enantiomeric pair corresponding
to it (i.e. draw the product molecule, and its enantiomer).
4
There are a few possible ways of drawing this. The key thing is that you show
“stereochemistry” – which means drawing in the wedge/dashed lines. If you just
drew regular lines, that wouldn’t tell us anything about the 3D structure, and thus
we couldn’t tell if they’re enantiomers or the same molecule.
D. What is the general name for this type of reaction?
Addition
7) (15 pts)
A. Using resonance structures, explain why the nitration (adding a NO2 group)
of aniline (phenylamine, or C6H5NH2) gives exclusively the products orthonitroaniline (2-nitroaniline) and para-nitroaniline (4-nitroaniline) but not
meta-nitroaniline (3-nitroaniline).
See
section 18.8. The resonance
structures of aniline
place the negative charge at the ortho and para positions, exclusively. Since NO2
is an electrophile and a pi bond in the ring is the nucleophile, the NO2 will add to
the positions where there is a lot of electron density – para and ortho. (It’s sort of
analogous to an electrophilic addition reaction.)
B. Is the amine substituent an electron-donating or electron-withdrawing group?
Electron-donating. Substituents that have lone pairs at the atom right next to the
ring will tend to be donating, since the lone pair can jump into the ring through
resonance. (Substituents without lone pairs at that atom, but which can accept
electrons through resonance, like COOH, are electron-withdrawing.)
C. What is the general name for this type of reaction?
Electrophilic (aromatic) substitution
5