Sciencemadness Discussion Board

N methylation of 4-pyperidone

noufalmc - 27-5-2018 at 19:39

I wanted to convert 4-piperidone into N-methyl 4-piperidone. Could any one help me.
thank you

Chemi Pharma - 28-5-2018 at 00:31

You can methylate the active nitrogen of piperidone, and also any kind of primary, secondary amines and aminoacids following one of the methods below:

1 - With aquous formaldehyde and zinc with phosphate buffer;
2 - with methyl halide, usually methyl iodide, because the low volatility of bromide and chloride, with K2CO3, in acetonitrile media, at reflux, for 5 hours;
3 - with dimethyl sulfate (very nasty stuff) in basic aquous media, using K2CO3 as Ph+ source;
4 - with paraformaldehyde and oxalic acid, refluxing at 100ºC.

All of this methods are well covered here in SM.

Outer - 28-5-2018 at 12:31

https://en.wikipedia.org/wiki/Eschweiler%E2%80%93Clarke_reac...

Chemi Pharma - 28-5-2018 at 12:48

Classical Eschweiler–Clarke reaction favours the dimethylation and trimethylation of the nitrogen atom, instead stop on mono-methylation.

@noufalmc wants to mono-methylate 4-piperidone. The methods I have given favours the mono-methylation of amines.

See, paraformaldehyde and oxalic acid at 100º will produce formic acid and formaldehyde too but, unlike classical Eschweiler–Clarke, it's easier to control the methylation to stop at stage I, just adjusting the rate of reagents.

Look at the paper I attached below.

Attachment: Methylation of Amines-paraformaldehyde and oxalic acid.pdf (137kB)
This file has been downloaded 425 times


Outer - 28-5-2018 at 20:18

Quote: Originally posted by Chemi Pharma  
Classical Eschweiler–Clarke reaction favours the dimethylation and trimethylation of the nitrogen atom, instead stop on mono-methylation.

It is so for ammonia and primary amines (RNH2).

4-Pyperidone is a secondary amine (R2NH), and can be only mono-methylated under these conditions.

[Edited on 29-5-2018 by Outer]

oblivionbubble - 2-9-2019 at 15:52

May I ask what is this compound used for?

From experience, replacing n-Me-4-piperidone for NPP and treatment with propionyl Cl produces an inactive analogue?

Or am i missing something?

draculic acid69 - 3-9-2019 at 04:56

Npp is what causes Parkinson isn't it? That's basically the reason that there's analogue laws.if that is the intended application I'd recommend replacing with any other substituted piperidone but the n, methyl version.and methyl iodide will cause di&Tri methylation won't it.

oblivionbubble - 3-9-2019 at 07:03

NPP as in N-Phenetyl-piperidone. Starting material for fentanyl and analogues.

But since i couldnt find a single mention of N-Me-piperidone in fentanyl synth texts, Im wondering why are there several threads, where people are interested in preparing this compound?

draculic acid69 - 4-9-2019 at 00:14

It wasn't a fentanyl analogue it was a pethidine analogue that was synthesized poorly resulting in a byproduct that is an impurity in the n, methyl piperidone analogue that causes Parkinson's.it is a really good way to fuck someone permanently.

oblivionbubble - 21-9-2019 at 16:21

Do you perhaps know why this compound would be of interest?