phenylethylidenehydrazine conversion

[markosheehan]

Do they make and sell phenylethylidenehydrazine or can one react phenelzine with something to covert it?
I think I could get the liver enzymes to convert but they are too expensive.

I would need to add something so it reacts with the H bonded to the nitrogen and hopefully then the N would just form the double bond.

The N going from a secondary to tertiary amine so i guess It should not be not that hard. I only have a very basic organic chemistry knowledge.

Also does PEH have maoi properties or is it just phenelzine with that?

 

[Pomzazed]

Selective oxidation of alkylhydrazine (maybe use this keyword)
Sorry but synthesis details are against the rule, whether the cmpd is legal or not

Edit:
Btw, that changes N is not a tertiary amine, the C=NR compounds are called “imine”
while when R is an amino group like in your case, the overall functional group is called “hydrazone”
You can search alot about making it using the functional group name.

While I’m not going into synthesis detail, i can sum it up like
- most common way to make a hydrazone is reacting corresponding carbonyl compound (aldehyde or ketone) with a hydrazine or substitued hydrazine if choices; under acid catalyst and mild heating.
- another uncommon way (hard to control; may get alot of side product and need purification; bad case, fire, worst case, explosion) is carefully oxidation of hydrazines of choice.
-

 

[markosheehan]

thanks for your reply.

what is the corresponding ketone or aldehyde that should be used? and how are you supposed to tell?

is this a reversible reaction and if so how did you know?

 

[Pomzazed]

thanks for your reply.

what is the corresponding ketone or aldehyde that should be used? and how are you supposed to tell?

is this a reversible reaction and if so how did you know?

- It’s the one that the carbonyl will get replaced with hydrazone;
Separation of product depends, if the solubility is different then can just precipitate or using antisolvent to precipitate them out.
If not, may still need chromatographic separation. I am not so sure about your case, have not handled that particular hydrazone myself.

- The reaction is reversible (hydrolysis) back to starting carbonyl compound and hydrazine.

- For basic understanding about hydrazone formation reaction, i suggest you to read one of the standard test for a carbonyl group.
It is the reaction of carbonyl cmpd with 2,4-dinitrophenylhydrazine (2,4-DNP) forming a hydrazone.
This test is sensitive to aldehyde and some unhindered ketones, so if the fn group exists, it change from orange solution to red or deep red precipitate (hydrazone from 24DNP in this case isnt soluble, except when your carbonyl is formaldehyde)

The same principle applies to other hydrazone formation from aldehyde/ketone and hydrazines(or substituted hydrazines)
Just the separation tech may be diff.

See more on wiki

https://en.m.wikipedia.org/wiki/2,4-Dinitrophenylhydrazine
https://en.m.wikipedia.org/wiki/Hydrazone

So, in your case, the aldehyde is this one: (notice the func gr)
https://en.m.wikipedia.org/wiki/Phenylacetaldehyde

And hydrazine is unsubstituted hydrazine (just H2N-NH2)

At “appropriate condition” it forms tour target compound, and reducing it under hydrogen/metal gives phenelzine. So your cmpd is actually an intermediate in (one of the possible) phenelzine production routes, and not the other way round. However in commercial scale i think phenelzine is made from SN2 reaction between phenethyl halides and hydrazine. The reason being phenylacetaldehyde suffers from (H+ catalysed) isomerization and also (aldol) self-condensation in acidic media required for this reaction, giving lower yield)

 

[markosheehan]

I still can not see which ketone would be suitable.

It will not work out like other hydrazone formation reactions because the HN on the phenelzine is not at the end of the chain so it can not be replaced on the c=0 .

Maybe reacting acetophenone with hydrazine might work but the is one carbon sticking out past the c=o on acetophenone so it wont work.

 

[Pomzazed]

I already mentioned it is phenylacetaldehyde and unsubstitued hydrazine...

 

[sekio]

Somehow I do not see phenylethylidenehydrazine being stable for very long, especially in aqueous state.

The jar of phenylacetaldehyde I had the "pleasure" or storing at r.t. turned into clear resinous gel after about a month...

 

[Pomzazed]

Yup... base catalysed aldol is so real, and that hydrazone still have a basic N

 

[Limpet_Chicken]

Also, as a general principle, be damn careful with hydrazines, in this case, I should imagine it is HIGHLY toxic. Its pretty close to N-ethylidine-N-methyl-N-formylhydrazone, otherwise known and somewhat infamous as a mycotoxin, it occurs in the fungi of the genus Gyromitra, called gyromitrin, and aside from being hepatotoxic, nephrotoxic, causing haemolysis, and subsequent further kidney damage, myoglobinuria, and severe gastrointestinal symptoms. The false morels used to be a highly regarded species, as long as they were prepared correctly, in finland primarily, they were (and by some idiots still are) eaten after boiling them after cutting into small pieces, throwing away the water the pieces were boiled in, before boiling again, throwing away the water, and ideally boiling again, again tossing out the boiling water before finally cooking them as they were meant to be served in a dish.

Sensitivity varies greatly between people, with often, some people at a meal using the same harvest of false morels poisoned, some unharmed, at least not visibly, whilst some might die or be hospitalized.It gets metabolized to monomethylhydrazine, its also volatile, and some people might find no diners were affected, but that a cook, who consumed not a single bite, were poisoned, or worse, by the monomethylhydrazine metabolit as it was driven off in gaseous form during cooking;.Its generally toxic and nasty, specifically also reacting with pyridoxal phosphate, the active vitamer of vitamin B6, which throws a spanner in the works of B6 dependent processes, one of which includes GABA biosynthesis, rendering it a convulsant and one difficult to adequately treat. Huge doses of pyridoxal-5-phosphate help reduce or stop the seizures, but it doesn't do anything about hepatotoxicity, nephrotoxicity, peripheral neurotoxicity, or its general obnoxious, toxic nature.

Rather energetic stuff too, at least monomethylhydrazineis, they use MMH for rocket fuel.

 

[markosheehan]

The synthesis seems too difficult

A lot of the positives from phenelzine come from this metabolite. Does anyone know anything one could do to just get the benefits of the metabolite but not the maoi properties from the phenelzine?