In this video we'll be synthesizing the compound called ethyl acetopyruvate.

It looks complex but we'll use a strong base to deprotonate acetone, and the resulting anion will attack a molecule of ethyl oxalate, displacing ethanol and thus forming our product.

If you don't have ethyl oxalate available you can make it yourself.

Click on the link shown here for our video which demonstrates this.

First we need to make up a solution of our strong base.

Measure out 60 ml of ethyl oxalate.

For absolute ethanol, it's important that this contains no water.

Pour this into a dry 250 ml flask containing a magnetic stir bar.

And now set up the apparatus for reflux using a lead big condenser and cold water circulating.

Get everything ready and have the liquid stirring gently.

Now weigh out a small amount of ethyl oxalate.

Take a small piece of sodium metal weighing 3.5 grams.

Use a popper towel to remove mineral oil and then cut into three or four small pieces.

Temporarily remove the condenser and add the sodium metal to the flask.

The sodium will immediately start to react, bubbling and producing hydrogen gas and the mixture will become hot.

Replace the condenser and lead.

Leave this reacting for the next 30 to 40 minutes.

As the sodium dissolves it forms a solution of sodium ethoxide, a powerful base.

The heat from the reaction will cause a small amount of reflux to occur, but not too much.

While this is reacting weigh out 20 grams of diethyl oxalate.

Dry this before you weigh it by leaving for a few hours over anhydrous calcium chloride.

Mix the sodium and the diethyl oxalate together in a small beaker or flask.

Cover this to avoid evaporation of the acetone and prepare a small dropper.

Once the sodium has all dissolved, start adding the mixture through the top of the condenser slowly.

As you add the first bit of the mixture the contents of the flask will turn a milky color.

As you add more you will notice some heat being produced in the flask and the color will change and become more yellow.

Keep adding the mixture slowly and over a period of about 30 minutes.

The mixture will reflux slightly and they will become yellow.

The yellow color will become stronger.

You'll notice the mixture become thicker as a precipitate forms.

At the end of addition the mixture is still stirable and the color is almost orange.

Now leave the flask stirring.

The reaction will be complete when stirring is no longer possible.

This may take up to 20 minutes.

Here we go.

At this point switch off the stirrer and leave for an hour to cool completely.

As you can see the contents are now pretty solid.

You'll need to use a spatula to break this up and extract it out of the flask for the next step.

Transfer the solid into a filter attached to a vacuum pump.

This takes a little work.

Wash the flask and the solid in the filter with 40 ml of dry acetone.

The result is a slurry of yellow solid like this in the filter.

The bad news is that this takes a long time to filter until it's relatively dry.

Set aside a good 2 to 3 hours.

You will eventually have a pasty semi-dry yellow solid a bit like this.

Transfer into a 200 ml beaker.

It's not completely dry and still contains some ethanol and acetone.

Measure out 12 ml of 50% by volume sulfuric acid in water.

This should be sufficient to convert the sodium salt of our product which is the yellow precipitate into the acid ketone form.

Add this to the solid in the beaker and stir to start to mix this up.

The yellow solid will dissolve and soon you'll have a mixture that is able to be stirred magnetically.

So drop in the magnetic stirrer and stir.

Stirring slowly becomes easier as the solid dissolves.

Now add water in 10 ml portions over about 20 minutes until virtually all of the solid has gone into solution.

Not quite there yet.

Once nearly everything is in solution, measure out 50 ml of dichloromethane.

Add this to the stirred solution.

And allow to mix thoroughly to form a suspension.

Then, after a few minutes, allow to separate.

Pour the mixture into a separating funnel and allow the layers to separate completely.

The bottom layer is our dichloromethane layer containing our product.

So separate this off into a beaker.

And then add a further 25 ml of dichloromethane to the separating funnel to extract any residual product.

Shake and then allow to separate.

And once again, separate the bottom dichloromethane layer and combine it with the previous dichloromethane extract.

Now we'll dry the solution using some anhydrous magnesium sulfate.

The cloudiness should disappear leaving a nice transparent dichloromethane solution.

You could evaporate the solvent to give a crude product.

But we're going to attempt to distill off the dichloromethane and then vacuum distill our product.

There's a risk here because our vacuum quality is average and the product is almost certainly quite heat sensitive.

But we'll give it a go.

Dichloromethane comes off very rapidly at first.

And with cool enough water is largely recoverable.

The temperature then rises and we start collecting some remaining ethanol and acetone.

Then above about 100 degrees we see no more solvent coming off and so we insulated the distillation head using some aluminium foil.

The temperature of the distillate then rises rapidly and we can also see some charring taking place in the boiling flask.

A pale yellow colored distillate begins to come over.

This begins at a temperature of around 155 degrees C.

Unfortunately we don't know exactly how strong our vacuum is.

This distills fairly quickly but at this point we can see the carbonization in the flask.

The flask getting worse so it's possible that this also contains some decomposition product impurities as well.

Here's our product.

14 grams of a pale yellow distillate collected between 155 and 175 degrees C under vacuum.

If pure this represents a 65% yield based on starting ethyl oxalate.

Not bad.

But we think this probably has a small amount of impurity in it due to decomposition.

Hopefully this is pure enough for our planned pyridine synthesis.

Stay tuned to find out.