ISSUE:

Hello everyone,
I am looking at a topic on amine synthesis and they ask me to show the mechanism of the synthesis of ethylamine from acetylene, 1) without any contamination with another amine and also 2) approximate the conditions in which they are carried out just.
About the first thing, I know that the reaction is not recommended with between alkyl halide and ammonia because a mixture of primary and secondary amines, etc. would be produced. which is precisely what I want to avoid. So what would the reaction be like? I thank you, who can help me...

Hello Cav.

I propose three alternatives, to prepare the ethylamine.

Alternative A is known as the Gabriel synthesis, which I'm sure you know, only that the necessary halide is prepared from acetylene.

Alternative B, starts from the same acetylene, until reaching a proponamide, which is subjected to the HOfmann rearrangement reaction, to eliminate CO and reach ethylamine.

Alternative C, starts from acetylene, to form an aldehyde with disiamilborane, which then forms an imine with NH3, which will be reduced to arrive at ethylamine.

I beg you to complete the diagrams, analyze it and at your own discretion make an option;) .

Greetings:

wilbert

Hello, another way occurs to me, starting from acetylene we can make a hydration in which an enol is formed and tautomerized to an aldehyde, then the aldehyde can be oxidized to form a carboxylic acid, and then it can be treated with thionyl chloride and transform it into an acyl chloride to make it react with ammonia, forming in this case Ethanamide or Ethylamide, which is reduced with lithium aluminum hydride in the appropriate solvent to form the desired amine, Ethylamine:)

You can also do the reduction of a nitrile, with a Chloride or METHYL bromide and you make it react with Sodium Cyanide, and you obtain the acetonitrile and reduce it with lithium aluminum hydride !

Hello Metal.

I would like you to analyze whether it is correct to propose the transformation of an aldehyde into a carboxylic acid with PCC/CCl4.

Well, PCC is one of the specific oxidants, which oxidizes primary alcohols only to aldehydes and prevents the passage to the respective acid. PCC also participates in other oxidations of active allylic alcohols or with methylene, these oxidations are accompanied by rearrangements in the molecules. Greetings.

wilbert

Thank you very much, I will choose the mechanism that is most viable.
Now I have another question and it is the following: Ammonia and amines can be reacted with nucleophiles or electrophiles to form amines. Is it better to use nucleophiles or electrophiles for that purpose?
Because? Thank you for helping me, because according to what I know, amines are mucleophiles, so they would only react with electrophiles... or am I wrong?