We've got a really interesting reaction today, and a little experimentation.

In the presence of a strong base, ortho-nitro-toluene can be deprotonated on its methyl group.

It can then react with bioethyloxylate and eliminate a molecule of ethanol to form the compound you see here.

To get this to work the literature says that you need to use potassium ethoxide and that sodium is just not basic enough.

But we've tried using a little trick and we've got an interesting result.

Here's a 200.

A 50 ml flask with a condenser on the top.

Strong magnetic stirrin is also important.

Let's get some cool water going.

And we've fitted a calcium chloride drying tube to the top of the condenser to keep moisture out.

We washed all the glassware with acetone and then dried it carefully.

Keeping water out is important.

Okay, first our solvent.

Here's a mixture of 40 ml of absolute ethanol and 10 ml of mecanol.

We'll explain this mixture later.

Let's get this into the flask.

And closed back up again.

Okay now for our strong base.

To make this we're going to use sodium metal which will dissolve and form sodium ethoxide.

We're using 4.5 grams which will be a 50% excess over what we theoretically need.

Wipe off the mineral oil and then let's get this into the flask to react.

Close back up and then wait for the sodium to react and dissolve.

This will take a little while.

When we performed the pyridine reduction experiment, we found that sodium ethoxide was not enough.

In the experiment a few videos ago, we noticed that a small amount of methanol added to the ethanol stops the ethoxide formed from crystallizing and keeps the mixture much more liquid.

So by doing this, we seem to be able to get a more concentrated solution.

So while this is reacting, let's have a look at the chemistry involved in the reaction we're going to do.

You don't normally think of nitrotoluene as being acidic.

But in the presence of a strong base, it does.

One of the hydrogen's on the methyl group can be removed.

This sounds far-fetched but it's possible because the resulting ion is stabilized by

the presence of the adjacent nitro group, and you can write resonance forms like this

which sort of explain this.

When we add diethyl oxalate, the deprotonated nitrotoluene can then act as a nucleophile,

attacking one of the carbonyl groups in the oxalate, and forming the intermediate shown.

This can then eliminate and reform the carbonyl group to form the product.

What is interesting though is that this product in the strongly basic conditions can then

be deprotonated and it forms a potassium salt.

This is a phenylgluic acid derivative, and is what we'll actually get as a product

of sodium.

Okay that's the mechanism.

Let's prepare our other reactants while the sodium is dissolving.

Here's 19.2 grams of dried diethyl oxalate.

We prepared this in the previous video by reacting ethanol and anhydroxalic acid, so

check it out for details of how to make this yourself.

It's important that it's dry, so it's worth distilling it properly and getting a

pure product.

And here's 18 grams of ortho nitro toluene.

Again, we prepared this back in our first ever completer video by nitrating toluene and

slowly freezing out the pyronitrile isomer.

Before we use this in the reaction we're going to make up a solution of the nitro toluene

in diethyl ether.

Here's 30 mils of diethyl ether.

The ants like this stuff.

And here's 18 grams of ortho nitro toluene.

Let's add the nitro toluene to this.

And we'll keep this ready for later.

Our sodium is nearly all dissolved.

It helps to switch on the heat a bit towards the end.

You can also add a little more ethanol if you want.

Okay now it's all dissolved.

We're first going to add the diethyl oxalate.

There's a bit of an exotherm as it goes in.

And the mixture boils slightly.

Okay we've got an orange colored mixture now.

What we need to do before we add the nitro toluene in the ether is chill the mixture

down.

So we place the flask in an ice bath for a couple of minutes until the temperature is

back down to about 30 degrees C below the ether boiling point.

Once it's there, get ready with the nitro toluene solution.

Get the mixture stirring very vigorously.

And add the nitro toluene solution ether.

An intense deep blue color is first formed.

On complete addition, make sure the stirring is at full throttle.

You'll slowly see the mixture begin to become thick as a solid is formed.

Leave this stirring as best you can.

And start to heat the mixture again.

Just gently, until you see the ether start to reflux in the flask.

And then keep it here for an hour, gently refluxing.

Then allow to cool.

The mixture at this point should appear to be a very deep brown color.

And almost completely solid with precipitate.

Now prepare another 30 mils of diethyl ether.

And add this to the reaction flask through the condenser.

This should loosen things up enough to be able to get the mixture out easily.

Give the mixture a thorough stir using a metal rod.

Then, once completely cooled, dismantle the apparatus and stopper the flask securely.

We're now going to leave this overnight in the fridge to make sure that crystallization

has completed.

And here we are 12 hours later.

It's hard to see through the flask, but there's a slurry in here containing lots of solid.

So we need to filter this.

We started off with a glass center.

But filtration was really, really slow.

And the center seemed to clog up.

So we switched to a glass filter.

And in about two and a half hours we got to where we wanted to be.

Here we go.

It's a semi-solid thick paste with a very dark brown color weighing about 45 grams in total.

Getting this dry just through filtration is virtually impossible.

So we did some experiments with a few solvents.

What we found was that by mixing some of this paste with diethyl ether and mixing it very thoroughly,

the solubility was reduced enough in the residual ethanol that a dry powder could be obtained and easily filtered.

We found that the substance was soluble in DCM so booze didn't work.

But it was insoluble in petroleum ether.

So this might also be an option to use.

Using the diethyl ether method you can get a perfectly dry and clean product like this.

So we mixed the semi-solid paste we obtained with about 150 ml of diethyl ether.

Mixed very well for 15 minutes and then filtered the product.

And here's the result after drying.

A fine paste.

Dark brown almost crimson red colored powder weighing 26.5 grams.

This is the sodium salt of ethyl ortho nitro phenyl pyruvate.

And this represents a yield on starting nitrotoluene of 78%.

Not bad.

Especially when the literature claimed that using sodium ethoxide led to a terrible yield.

We'll be testing this out soon though because this is quite an interesting intermediate compound to another product.

If you check out the structure, you can see that the nitro group on the aromatic ring is just waiting to be reduced to an amine.

And when it's reduced it's going to be able to react pretty quickly with the carbonyl group to form a brand new heterocyclic ring.

An indole.

In fact, the compound produced is indole 2 carboxylic acid.

And this can in theory be decarboxylated to indole itself by heating.

So we'll be hoping to come back to this compound soon and see if we can use it to synthesize indole.

So stay tuned for more reactions.