Name: carbonyl reduction with ir monitoring
Uploaded: 2023-04-30T06:55:51.000Z
Duration: 10 min 19 s
Channel: JoVE

1. Measuring Properties of Ethyl Acetoacetate
<ol>
	<li>Take an IR of the starting material (ethyl acetoacetate).</li>
	<li>Take a TLC using 40% ethyl acetate in 60% hexanes.</li>
</ol>
2. Reduction of Ethyl Acetoacetate with Sodium Borohydride
<ol>
	<li>Add 1 mmol of ethyl acetoacetate to a round-bottom flask.</li>
	<li>Add 5 mL of ethanol and swirl to mix completely.</li>
	<li>Lower the beaker into an ice-water bath.</li>
	<li>Weigh 1 mmol of sodium borohydride and slowly add to the stirred solution of ethyl acetoacetate.
	<ol>
		<li>Add in small portions. The reaction is exothermic and bubbles vigorously.</li>
	</ol>
	</li>
	<li>Immediately after, monitor the reaction by TLC every few minutes until the reaction is complete.</li>
	<li>Once complete, add 10 mL of water to the reaction mixture.</li>
	<li>Transfer into a separatory funnel and extract with ethyl acetate (2x 30 mL).</li>
	<li>Dry with DI water (1x 30 mL) and with brine (1x 30 mL).</li>
	<li>Dry over sodium sulfate and filter into a round-bottom flask.</li>
	<li>Evaporate the solvent on a rotary evaporator.</li>
	<li>Take a TLC and IR of the reduction product.</li>
</ol>
3. Reduction of Ethyl Acetoacetate with Lithium Aluminum Hydride
<ol>
	<li>Add 1 mmol of lithium aluminum hydride into a dry round-bottom flask and cap it with a septum.</li>
	<li>Purge the flask with nitrogen gas using a nitrogen inlet line. Make sure to have an exit valve.</li>
	<li>Add 10 mL of dry THF.</li>
	<li>Place the round-bottom flask into an ice bath.</li>
	<li>Make a solution of 1 mmol of ethyl acetoacetate into 3 mL of dry THF and slowly add dropwise into the reaction flask.</li>
	<li>The reaction will vigorously bubble until all of the reagent is added.</li>
	<li>Immediately after, monitor the reaction by TLC every few minutes until the reaction is complete.</li>
	<li>Once complete, add 1 M HCl dropwise. The reaction will bubble vigorously until all of the LiAlH4 is consumed.</li>
	<li>Once consumed (no more bubbling), the septum can be removed and diluted with ethyl acetate (40 mL) and 1 M HCl (20 mL).</li>
	<li>Transfer to a separatory funnel.</li>
	<li>Extract with ethyl acetate (3x 50 mL).</li>
	<li>Dry with brine (1x 50 mL).</li>
	<li>Dry over sodium sulfate and filter into a round-bottom flask.</li>
	<li>Evaporate the solvent on a rotary evaporator.</li>
	<li>Take a TLC and IR of the reduction product.</li>
</ol>

The trends of carbonyl reactivity and hydride donor ability have been reviewed and demonstrated. The visual reactiveness of the two commonly used reagents is apparent and can be appreciated.
The understanding of the reactivity of reagents and functional groups is of high importance when developing new methods for reductions or any other kind of reaction. Controlling the selectivity and reactivity of any reaction is an important factor to consider when deciding on the reagents used for a chemic...

reducing agents

Reducing Agents

Source: Vy M. Dong and Daniel Kim, Department of Chemistry, University of California, Irvine, CA
Controlling the reactivity and selectivity during the synthesis of a molecule is very important criteria for chemists. This has led to the development of many reagents that allow chemists to pick and choose reagents suitable for a given task. Quite often, a balance between reactivity and selectivity needs to be achieved. This experiment will use IR spectroscopy to monitor the reaction and to understand the reactivity of carbonyl compounds as well as the reactivity of hydride-reducing reagents.

<img alt="Infrared spectroscopy graph of ethyl 3-hydroxybutyrate with chemical structure diagram." class="xfigimg" src="/files/ftp_upload/10354/10354fig1.jpg" data-altupdatedat="1761830439000" data-alt="Figure 1"> 
Figure 1. Representative IR results for ethyl 3-hydroxybutyrate.

Source: Vy M. Dong and Daniel Kim, Department of Chemistry, University of California, Irvine, CA
Controlling the reactivity and selectivity during the ...

The reduction of carbonyls is a common task in organic chemistry. Chemists use different reducing agents to carefully control the outcome of the procedure.Carbonyls are functional groups with a carbon atom double-bonded to an oxygen. Carbonyl groups appear in many types of compounds. When carbonyls are reduced, the product will depend in part on the exact chemical composition of the compound. Additionally, a particular reactant may have different reduction products. By using different reducing agents, chemists can control these products, or whether the reaction takes place at all.This video will illustrate the reaction of a carbonyl compound with two different reducing agents, and the different products that result.Carbon is less electronegative than oxygen, so when they share a bond, as in a carbonyl, the carbon will have a partial positive charge, making it electrophilic. This in turn makes it susceptible to nucleophilic attack, like the hydride transfer that starts most carbonyl reductions. Increasing this positive charge increases the electrophilicity, increasing the reactivity of the carbon. Decreasing the charge will make the carbon less reactiveAcyl halides have another stro

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Organic Chemistry II

carbonyl reduction with ir monitoring

Carbonyl reduction with IR monitoring shows how chemists track a reaction while choosing the right reducing reagent. The focus is on controlling reactivity and selectivity during molecule synthesis. That balance helps chemists pick reagents for a specific task.

The experiment uses carbonyl compounds to study their reactivity. It also examines hydride-reducing reagents, which donate hydride ions during reduction. IR spectroscopy is used to follow the reaction as it happens. This lets students connect bond changes with the progress of the reaction.

Carbonyl Reduction with IR Monitoring

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Carbonyl reduction with IR monitoring shows how chemists track a reaction while choosing the right reducing reagent. The focus is on controlling reactivity and selectivity during molecule synthesis. That balance helps chemists pick reagents for a specific task. The experiment uses carbonyl compounds to study their reactivity. It also examines hydride-reducing reagents, which donate hydride ions during reduction. IR spectroscopy is used to follow the reaction as it happens. This lets students...

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This collection covers the theory and reactions necessary to carry out syntheses on a more advanced level. In addition, a few videos introduce methods commonly used to analyze the reaction products such as infrared spectroscopy and polarimetry.

Study carbonyl reduction and hydride-reducing reagents while using IR spectroscopy to monitor reaction progress and compare reactivity and selectivity.

Carbonyl Reduction with IR Monitoring

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