CHEM 224 Loyola pKa Difference Between P Nitrophenol and M Nitrophenol Lab Report

Chem 224 Practice exam 1Chapters 13-15, alcohols, ethers, aldehydes, ketones, carboxylic acids
1)
Compare the chemistry of oxygen and sulfur compounds. Why are they similar or different?
a)
S- is a strong nucleophile, so will do SN2 reactions on a secondary halide. O- is both a strong base and
nucleophile, so will do both SN2 and E2 reactions.
b)
Both alcohols and thiols can be deprotonated by a strong base to give strong nucleophiles which will do
an SN2 reaction to make an ether or sulfide, respectively
c)
CH3SH vs CH3OH reacting with a strong oxidizing agent
Alcohols oxidize to aldehydes and ketones (and potentially carboxylic acids). Thiols oxidize to disulfides.
2)
Give the major organic product(s) of the following reactions: (if there is no reaction, indicate
that). For reactions with 2 steps, give the product both after step 1 and step 2
a)
b)
c)
d)
e)
f)
g)
h)
i)
No reaction
No reaction
j)
k)
l)
m)
3)
Epoxides are ethers and alkoxides are normally bad leaving groups. Explain why epoxides react
with NaOH while normal ethers don’t.
While it’s true that RO- is a bad leaving group since alkoxides are relatively unstable, we can justify
forming an unstable ion if something even better happens. The ring strain for the epoxide is so large
that relieving the ring strain is more than enough to compensate for making an unstable ion.
4)
Propose multistep syntheses of the following targets. You can use any inorganic reagents you
want an other organic reagents with 6 or fewer carbon atoms.
a)
b)
Note that the direct reaction of cyclohexene and Br2 would give the trans dibromide
c)
d)
e)
5)
Draw an arrow pushing mechanism for the following alkyne reaction. (Hint –
what sort of intermediates form during the hydration of an alkene?)
7)
Rank the following compounds in order of increasing acidity. Explain your reasoning.
a)
Middle
Weakest
Strongest
Resonance puts negative
No resonance Resonance puts negative
Charge on carbons
charge on oxygens
b)
2nd weakest, close EWG atom, but low EN
Weakest, EWG is far away
nd
2 strongest, 1 nearby EWG
Strongest, 2 close EWG atoms
Chem 224 Summer 2021
Mini Exam 1
By taking this exam, I acknowledge and agree to the following:
1. I certify that work in this exam is solely my work. I did not receive input from another individual.
2. I accept the consequences of academic dishonesty.
3. This exam is open-book and open-note and you may use a molecular model kit, but no other resources are allowed.
Name ________________________________ Student #_______________________________
You have 60 minutes for this exam. You will take the exam using 1 of the 3 following options:
1. print the exam and complete it with a pen
2. write directly on the pdf file with your computer
3. write your answers on blank sheets of paper. These sheets MUST follow the EXACT same layout as the exam – 1 cover
sheet and then 7 pages of questions (you don’t need the periodic table).
You are NOT permitted to post this exam on any website.
Regardless of how you take the exam, you will then convert your exam into a pdf file and upload it to canvas by 2.35pm
without penalty, The canvas assignment link closes at 3pm. There is a late penalty (15%) if the exam is uploaded
between 2.35-3pm.
The Exam must be uploaded as one pdf file (not multiple pages).
Also, keep in mind the point value for each question when you allot time to each question. Work should be shown for all
questions, incorrect answers without any work will not be awarded any credit, Likewise, showing your work drastically
increases the odds of you receiving partial credit. If an explanation question gives a sentence limit, please keep to that.
Question
1
Points Possible
8
2
21
3
10
4
20
5
12
6
19
7
10
Total (100
For Q1-7)
100
1
Points Received
1. Draw the following compounds (8 pts, 2 pts each)
3-methylbutanoic acid
a.
b.
(3S)-3-hydroxypentanal
c.
octane-2,5-dione
d.
(2S, 3R)-3-chlorohexan-2-ol
2
2A. What are the MAJOR product(s) for the following reactions. Provide stereochemistry where relevant and if there
is no reaction state it in the box provided (18 pts, 3 pts per box).
OsO4
a
H2O
1. mCPBA
b
2. NaOCH3
3. H3O+
O
1. LiAlH4
c
2. H3O+
O
OH
O
Na2Cr2O7
d
O
1. DIBAH
e
O
2. H3O+
3
O
Cu(CH3)2Li
f
2B In which reactions in 2A (a-f) were the organic starting material Reduced in the reactions above (3 pts)
3. Design a multistep synthesis of the following alcohol. Must start with propene and any organic compound that
contains 1 carbon atom. (10 pts)
HO
4
4. Answer the following about carbonyls (20 pts total).
a) Draw the curved arrow mechanism for the following reaction (10 pts)
b) Circle and label the acetals and hemoacetals in lactose (your labelling should distinguish between acetals and
hemiacetals). (6 pts)
5
c) Explain (using resonance structures) why Nucleophiles can add to a conjugated system at the 2 and 4 carbons
but not the 3 carbon (4 pts).
1
O
R
4
2
R
3
5. Answer the following questions about oxidation and reduction (12 pts total)
a) Draw the curved arrows on the following reaction drawn and draw the structure of NAD+ that results (7 pts).
R
OH
N
A
H
O
O
O
H
O
H
NADH
b) What is the source of HA in the reaction shown above (2 pts)?
c) What is being oxidized in the reaction shown in part a (3 pts)?
6
O
+
NAD+
6. Answer the following questions about alcohols (19 pts total).
a) Draw the curved arrow mechanism for the formation of the diol shown below (8 pts).
b) Draw the curved arrow mechanism for the following hydration of an alkene (6 pts)
OH
H2SO4, H2O
7
c) Explain the pKa difference between p-nitrophenol and m-nitrophenol (5 pts).
O
OH
O
N
Note: the NO2 structure is
OH
NO2
pKa = 6
NO2
pKa = 10
7. Answer the following questions about carboxylic acids
a) Place the following in order of increasing pKa (4 pts)
O
O
O
OH
OH
OH
H2N
A
O
B
C
b) Explain your reasoning behind the order you placed the following acids in part a (in two sentences or less) (2
pts).
c) Show the synthesis of benzoic acid using a Grignard reagent (4 pts)
8
9