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*All of these reagents (not just NaBH4) reduce aldehydes to 1ºROH and ketones to 2ºROH. Transformations given here are some of the more common uses for these reagents.

Prelab: reduction of carvone

(Total 10 Points)

On my honor, in preparing this report, I know that I am free to use references and consult with others. However, I cannot copy from other students’work or misrepresent my own data.

…………………………………………………………….. (signature)

Print Name: _________________________________________

1. Which reagent (LiAlH4/NaBH4) would be useful for the following: (4 point)

(a) Reduction of a ketone to an alcohol in protic solvent?

(b) Reactivity depends on pH?

(c) Reduction of an ester group?

(d) Reduction of an aldehyde group in the presence of an amide group?

2. Write the major product from the following reactions. (6 points)

Grading

  • Isolation and analysis of the reduction product.
  • Analysis by Thin Layer Chromatography (TLC).
  • Write-up in your Lab Notebook.
  • Completion of Pre-Lab and Report Questions.
  • TA Points.

Materials required

Equipment Materials
5 mL conical vial (-)-Carvone
Stirring vane Sodium borohydride solution
Pasteur pipette 3 M HCl
Cotton 20% ethyl acetate in hexanes
Blue litmus paper Pure carveol
TLC plates Carveol diluted 10:1 in CH2Cl2
Capillary tubes Na­­2SO4
Methylene chloride

Safety

Wear gloves all the time, especially when you use sodium borohydride solution. Keep safety glasses on all the time to avoid some unwanted accident.

Experimental procedure

1) Place 0.5 mL of (-)-carvone in a 5 mL conical vial with a stirring vane.

2) Add 1.5 mL of the sodium borohydride solution drop wise. As the sodium borohydride begins to react with the carvone, the yellowish solution will evolve some heat and effervescence (bubbling) may be observed.

3) Place the mixture on a stirring plate and let it sit with gentle stirring for 15 minutes.

4) At the end of 15 minutes, very carefully add 3M HCl drop wise until the solution is acidic to litmus paper. There will be quite a bit of bubbling.

5) Once the reaction has subsided, add 1-2 mL of methylene chloride. Shake the vial gently, and then let it sit for a few minutes until two distinct layers form. Remember that methylene chloride is denser than water. Since the by-products are salts, they will be dissolved in the aqueous layer. (You can add more methylene chloride first, then water if the layers are not separating. Do not increase the total volume too much.)

6) Insert a small cotton plug into the tip of a Pasteur pipette. Then carefully add approximately 100 mg of Na2SO4 to the pipette. (If you add more than 100 mg, no harm - weigh it roughly) Use a Pasteur pipette to take up the methylene chloride layer from the 5 mL vial and transfer this liquid into the filter pipette. Hold the pipette over a clean, tared 3 mL conical vial with a boiling chip and let the methylene chloride drip into this vial through the filter pipette.

You may need to use a rubber bulb to force the methylene chloride solution through the Na2SO4 plug.

7) Use thin layer chromatography (TLC) to determine the purity of your product. Remember that you should see multiple spots resulting from the complex mixture of diastereomers and other products formed. Your teaching assistant will provide a sample of (-)-carveol to spot next to your sample as a control. Stain the resulting TLC plate with p-anisaldehyde. Although these TLC results may not be very clean, you should see three main spots between 0.4 and 0.6 Rf. Each of these spots represents one of the possible products described in the introduction to this lab. Note that the diastereomers produced by the reaction have different Rf values, unlike enantiomers. There will be other spots near the top and bottom of the plate, but the three spots in the center should be larger and darker. (Important Notes: 1. CH2Cl2 is denser than water. 2. MeOH is soluble in water. 3. Sometimes layers do not want to separate, force them as described.)

8) Remove the methylene chloride and methanol left in the solution by heating the mixture at 70C until it stops boiling. You may be able to identify carveol in the mixture by smelling it and comparing it to the pure carveol sample that your teaching assistant will provide. Describe the smell (odor) of your product.

9) Determine the boiling point of your product. Do you expect a sharp boiling point range?

CAUTION

1. NaBH4 is very reactive.

2. H2 (bubbles) tends to explode. So, do not cap the system.

Waste disposal

Dispose organic substances in the proper container.

Approximate lab time: 1.75-2.25 hours

Report QuestionsReduction of Carvone

(Total 30 Points)

On my honor, in preparing this report, I know that I am free to use references and consult with others. However, I cannot copy from other students’work or misrepresent my own data.

…………………………………………………………….. (signature)

Print Name: _________________________________________

1) What are the two products of the sodium borohydride reduction of 2-tertbutylcyclohexanone? Will one be favored and if so, why? (2+2 = 4 points)

2) Explain why the two diastereomers of carveol would have different Rf values. (2 points)

3) If instead of HCl, the reaction was quenched with DCl, where would the D be located? Draw the product. (2 points)

4) Give the structure of all the products of the following reactions. Indicate proper stereochemistry where appropriate. (18 points)

5) Explain the stereochemistry of the following product distributions observed. (4 points)

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
how can I make nanorobot?
Lily
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Chem 215 spring08. OpenStax CNX. Mar 21, 2008 Download for free at http://cnx.org/content/col10496/1.8
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